"But seeing they could not See; hearing they could not Hear"
“The views expressed herein are those of the author and do not necessarily represent those of the National Weather Service or affiliate/related organizations. Please consult .gov sites for official information”

"From its chamber comes the whirlwind, and cold from the scattering winds." - Job 37:9.

"The wind blows to the south and turns to the north; round and round it goes, ever returning on its course".

Wednesday, September 29, 2010

Tropical Storm Warning Issued For the Treasure Coast - More Threats Possible Elsewhere

(Image: 7-8" rain producing storm over Port St. John. Note the mirror glass water. Wind at this time was light from the east. This is looking Northwest)
TROPICAL UPDATE: As of 5AM the tropical storm watch for Indian River, St. Lucie, and Martin Counties has been upgraded to a warning. A warning means that sustained tropical storm force winds are likely within the warned area. Further north, although Brevard County is not in the warned area, storm force gusts are possible in the heaviest of storms that could occur, mainly east of I-95. North of Brevard the concern quickly wanes due to the forecast track of TD16. More on this newly developed scenario is briefly discussed below under "TODAY".
NOW/LAST NIGHT: The storm system that generated a rainfall total of over 7" in Cocoa with possibly higher amounts toward Port St. John and lower amounts such as 3.52" in Cape Canaveral with slightly lesser amounts into South Brevard moved offshore and thinned out, with the last gasp dissipating near Cocoa Beach late last night. From that point on, a discernible baroclinic zone was established stretching from Cape Canaveral toward Port Charlotte on the SW Coast. One normally would not find such conditions this far south, as this is usually a mid-Atlantic to New England type synoptic set up. But given the depth to which the mid-upper level trough has dug over the past two days into the Deep South, we almost went "Summer Turned Winter" over night (did you see that Marianna, Florida yesterday morning was down to 52F degrees while the east coast was nearly 80 at sunrise?).
This zone sank south over night to a Naples to Vero Beach line. As such, all precipitation over night has been along and south of this zone. Meanwhile, TD 16 is located about 360 miles south of Cape Canaveral or 300 miles SSW of Ft. Pierce and is moving NNE at 14mph. The system appears to be becoming better organized. The strong convection that has been pounding Jamaica well to the east of the storm center has increased more toward the west or closer to the center of circulation. The system will cross Cuba during the morning and early afternoon and approach south Florida shortly thereafter.
TODAY: There is much hype locally for East Central Florida as events unfold (I'm hearing it on TV as I type), but there is a fly in the ointment. As noted, there is a baroclinic zone oriented South of Brevard County which is situated SSW from just south of Sebastian toward Ft. Myers. All precipitation over night and early this morning has been occurring south of this zone. So that's where we stand as of 6AM. Believe there is likely a coastal trough established just offshore as well, which as the sun rises and some heating ensues (and not much will be required)  will begin to retrograde toward the coast as early as 9AM. This seems more assured by early afternoon as the depression crosses Cuba and approaches S. Florida and surface winds gain a solid SE-SSE trajectory along the coast from the Cape and points south. The result would be something similar to what occurred yesterday, but probably not nearly as dynamic as that event as far as rainfall totals are concerned. (please refer to "*Important Note" below for disclaimer).
Rain has moved into the entire warned area as of this writing, and has just begun to penetrate extreme SE Brevard County near sunrise. I'm inclined to believe that given a few hours of daylight and backing of the surface winds, these rains will either translate onshore further north and/or simply fill in along a zone from Titusville SSW to Port Charlotte (or between Orlando and Melbourne south to Lake Okeechobee). Any storm activity could acquire rotation from noon on), particularly along the immediate coast from Cape Canaveral south where convergence is maximized along the coastal trough/baroclinic zone. This means that we might have some more tornado warnings again today. There were only a few warnings yesterday, and that will probably be the case again today. However, even if no tornado warning is issued, these cells could translate downward momentum to the surface and produce stronger/tropical storm force wind gusts along or near the coast outside the Tropical Storm Warning area, primarily east of I-95. The threat for rotating cell formation will wane quickly during the time this system, which at this point will likely, but not necessarily be named Nicole, exits the Florida East Coast.  Outside of this minimal threat, the greater threat will be heavy rainfall totals where cells train repeatedly or stack up over the same area.
As TD16 crosses the Florida Straits during the early afternoon it may be named Nicole. This is not really too important for landlubber though, since a majority of these winds will be east of the center of circulation (off shore). Given the fast motion the system will acquire as it starts to be united with the deep latitudinal trough digging down the U.S. East Coast, the system could pass across the land area of SE Florida with little affect on storm strength. It may in fact, be at its strongest as it passes east of Brevard County early this evening on its approach to the Carolinas before it become extra-tropical. Just because the system will become extra-tropical is neither here nor there though, as the storm systems interaction with the frontal boundary further north from the eastern Carolinas to New England will generate a much greater wind/rain hazard than Florida will ever know.
In any case, there is the possibility that what we'll call Nicole (give or take 5 mph of winds to make the difference between depression or storm), could make a few wobbles on a more northerly track during its crossing of SE Florida which would mean the system would exit off the east coast somewhere between Ft. Pierce and Vero Beach. Hence, the watch was upgraded to a warning.
(*IMPORTANT NOTES: (1) It would be irresponsible not to mention that the weather over the majority of Brevard/Orange/Seminole Counties might not be nearly as unaccommodating as the official forecast would lead one to believe. Namely, if the coastal trough / baroclinic zone does not retreat from its current location or only does so to a small degree, these areas could remain not rain free entirely, but would have significantly less hostile weather conditions than what we are being led to believe. Given the current synoptic scale set up is very rare for this time of year over Florida (where near winter meets the tropics), tremendous uncertainty on my part is admitted on how to deal with this situation). I'm picturing a Christmas card with Santa wearing a Speedo relaxing in a hammock stretched between two swaying palm trees).
(2) To take the level of uncertainty to up another notch, it is possible that should nasty weather develop, north of the warned area, it might be restricted to solely the intracoastal or even just the region from Cape Canaveral north to the Pads A and B. Should this be the case, activity of intensity worth noting would be limited to occur between 2-8pm today.)
TONIGHT: Conditions will rapidly be on the improving side as the storm makes its closest pass off the Space Coast. It may also be beginning to develop it's greatest strengthening phase as it passes the Cape over the Gulf Stream before making a second landfall in Central South Carolina by early Thursday.
THURSDAY-FRIDAY-SATURDAY: After  a slight chance of showers early Thursday, the remaining period will be quite pleasant with drier atmospheric levels (lower PWATS) and early fall conditions.
SUNDAY: The system will be out of everyone ones hair, but what evil lurks in the minds of the breeding season. High pressure to the north will combine with the continued simmering area of low pressure in the Caribbean to produce very breezy conditions along the coast from Ft. Pierce to Jacksonville. As these winds shift from NNE-NE-ENE that could usher in a shallow layer of moisture to the coastal communities. This moisture, combined with passage across the warm Gulf stream with steady winds could manifest as low topped ocean showers anywhere along the coast with breezy conditions for a number of days. Some minor beach erosion could become a concern, mainly north of Daytona Beach.
Meanwhile, the Caribbean won't be on its own. It's looking more like the forces from the Tropical Pacific as well as the Tropical Atlantic could be meeting up for generation of not 1, not 2, but perhaps three more systems during the first three weeks of October. At this time, the Bahamas appear to be most likely to be first affected by anything that would form. However, as we head later in time some transitions over the eastern portion of the continental U.S. will abet to generate a synoptic scale weather pattern that would result a tropical threat to somewhere in the NW Gulf, most likely Florida.

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Tuesday, September 28, 2010

POST 2: Tropical Depression 16 and Local Weather (East Florida)

(Image: NAM FCST for 2pm Wednesday)
SYNOPSIS: Frontal boundary has pushed south to roughly a Daytona Beach to Brooksville line and come to an abrupt halt. In deed, rain echoes shown on radar are not penetrating north of North Brevard County along the east coast and remain in place the past hour. During the past 3 hours atmospheric moisture throughout has increased markedly in the upper levels over Central Florida. Meanwhile, TD 16 has been proclaimed and is located 560 NM SSW of Cape Canaveral, FL.  The system is moving NNE. A tropical storm watch/warning has been issued for the counties south of Sebastian Inlet to Miami. The official forecast track takes the system offshore very close to Boynton Beach tomorrow.
Meanwhile, the mid-upper level trough continues in place to the NNW into the Florida Panhandle with a speed max  and associated vorticity plummeting south along the backside of this trough toward Southern Alabama. East Central Florida remains in a somewhat volatile environment in a battle between becoming fully tropical and maintaining a more continental weather regime in place. Per the increase in moisture, it appears the tropics are beginning to win out as the dominant player in this battle of wits, but it'll take the rest of the daylight hours and into this evening to complete the transition (if it ever actually does).
TODAY: In the interim, an outflow boundary from convection well off the Central Florida Coast has moved onshore. As such, the surface winds over East Brevard, at a minimum, have switched from light from the south to gusty from the East.... These winds are being accompanied by increased cloud coverage and radar returns and radar has really filled in, with a well defined line of convection stretching across the entire state from Port Charlotte on the SW Coast to Cape Canaveral.  Additional storms are filling in south of this line with heating of the day. Thunder booms now.
Jumping to tonight and tomorrow:
NOTES: The latest GFS and NAM forecast models are not in sync with the official forecast track of this system. They insist on this system remaining mostly as a hybrid type entity, and as such the results are much different as far as Central Florida is concerned. I've included an image for the system location at 18z (2pm) tomorrow as forecast by the North American Model. Note that the center of lowest pressure is located near the Cape. What is hard to decipher from this image is that there might be another center further south toward Indian River County.  What occurs is that the system, being that it wouldn't be fully tropical in nature, begins to interact with the trough to the north and west of Brevard and begins to become absorbed within the "mean trough' feature. As such, the current NNE track continues..with perhaps a slight turn even more toward the north during the 'absorption process'.
If indeed this system follows the track followed by these models, weather conditions north of the official forecast to Jacksonville will be significantly different from what is currently officially being announced. This is just a heads up...and not an argument. Thus, remain abreast to your most favored media outlet for details.
In either case, at this time the winds won't be too much an issue, although they could be noticeably gusty, especially in rainstorms beginning over night tonight. More so further south of Sebastian Inlet to Miami in the watched and warned areas. Close scrutiny as to what will occur once the system comes fully ashore over extreme South Florida tomorrow morning might be necessary. Again, refer to the latest statements from the NWS or the Hurricane Center for the official forecast.
And in continuity with today's earlier post. I believe there is a very remote chance of rotating storms, from near Palm Beach to Daytona (and potentially further north) along the immediate coast well prior to the more direct impacts from this system. This threat will lower as we work toward mid morning tomorrow.
AFTER THE SYSTEM PASSES: Not so fast, another bag of tricks at hand. Once this system impacts the U.S. East Coast from North Carolina to New England in rapid fashion, high pressure builds across the Mid-Atlantic Region in its wake while the Caribbean continues to simmer with rejuvenated vigor. The GFS I believe is suffering for an overdose of steroids, with multiple low pressure systems being generated down there, all of which train across the Bahamas for some time to come in the future. But tossing this aside, of more immediate interest to East Coast Floridians may be an increasing pressure gradient between this high pressure area to the north and the low down south. With those two mechanisms at work, ENE-NE winds could become steadily moderate to strong (breezy) for a prolonged period of time. The availability of moisture at this time remains in question...but the two combined could make for a windy and wet weather regime for the immediate east coast from Jacksonville to Ft. Pierce beginning Sunday near JAX and encompassing the rest of the coast by late Monday. The GFS picked up on this two days ago and has been consistent with both the winds and potential for rain showers of stratiform nature. Perhaps just flat out cloudy conditions...perhaps not. Point being, erosion could become an issue if this regime lasts for too long. Again, another heads up.
ANOTHER TOSS IN THE POT: Forgot to mention, the GFS is showing a strong tropical system to cross South or Central Florida in about two weeks, after it meanders around the Caribbean for several days moving this way and that. Accuracy for any such occurrence that far out is pretty close to negligible. Point is though, that the tropics won't be done quite yet. Not thru the first two weeks of October at least.

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POST 1: Tropical Storm Develop Much More Likely - Rotating Storm Structures for East Central Florida?

(Image: Total Rainfall forecast for 2am - 8am Wednesday shows max over Brevard County and SE Florida)
OBSERVATION ONLY: Breaking down the details very early this Tuesday and monitoring trends in RUC Model updates.
The current observation is noted. Surface front extends from Jacksonville to Tampa. Mid-upper level support for this feature has moved NNE from Alabama yesterday to West Virginia and continues north toward NW Pennsylvania. Likewise, vorticity maxima are plunging south down the backside of the trough through Wisconsin prior to sunrise with expectation this energy will penetrate as far south as Southern Alabama by early Wednesday morning. The result will be to reinforce the the mid-level trough in its current position and thus prevent further eastward progression of the surface front as its southern tip skims close to North Brevard and then becomes cut off as cyclonic circulation from the south takes the leading role. Meanwhile, Central Florida will be influenced by negative vorticity advection early on this Tuesday morning during the following transition:
1) Area of low pressure with a 60 percent chance of becoming a closed surface circulation over the Western Caribbean and its  peripheral circulation begins to drift north toward Cuba. ***UPDATE: This has just changed to 80 percent***. We could have a Nicole on our hands by the next update from the Hurricane Center. But I digress,
South Florida was never affected by the trough and front, and thus have been in continuous ESE-SE flow all along, unlike folks from Central Florida and points north. Current water vapor loops and surface observations indicate that South Central and Central Florida will be encompassed with the low level circulatory pattern between 11am-1pm today directly related to the developing system to the south. Meaning, surface winds will shift from SSW-S to a more SE-ESE component. Meanwhile,  the mid-upper level features described above reinforce the wind aloft at those levels maintaining the current SW direction overhead.
2) Transition of these two wind field parameters occurs primarily between 11am -4pm during the time of maximum surface heating, although cloud cover could be a big factor in damping out the overall convective nature of shower activity from what could otherwise be a more potent situation. During this time frame, as the outer parameter of the cyclonic circulation from the south enters Central Florida, positive vorticity advection is ushered in from the south.
The combination of low and upper level vorticity, low level directional wind shear, and influx of even greater moisture from what currently exists could harbor resultant rapidly developing small, but rotating storm cells. The affect will be maximized along the East Coast from Sebastian Inlet to Ormond Beach.
Believe the main affect of this, should it occur, would be strong, gusty winds associated with fast moving, small thunderstorms...but circulations reaching the ground can't be ruled out. This covers Tuesday afternoon, now what about over night tonight?
AFTER MIDNIGHT: The NAM and GFS continue to support the first vorticity maximum directly related to the Tropical System (by this time Nicole?) to impact Indian River, Brevard, and Volusia County between the hours of 1am - 9am Wednesday morning as further development continues. As noted, by this time we might have a named system which would add fuel to the fire. The HPC has forecast a precipitation bulls eye for mostly Brevard County during this time frame of over 1" of rain, so they must be seeing something. Believe this rainfall will come in the form of convective storms containing brief periods of heavy rain rather than a solid, steady state rain. Conditions do not look as ideal as yesterday morning for rotating storm cell structures, but should the system approaching from the south indeed wrap up as much or more than anticipated the weather radios might be blaring with Special Weather Statements or warnings while most folks are in bed.
SPECIAL NOTE: Should Invest 96L develop into a named system, the timing on the over night situation tonight might still occur, but could be a full 12 hours later, at least, than current thinking. Thus, this could take place  during the afternoon on Wednesday. Additionally, note that this is not information from official resources. Namely, I'm thinking out loud. Just providing a heads up.
P.S.: Should the system to the south develop into a named system and strengthen toward hurricane intensity, all forecasts for the state will be blown out of the water as far as wind speeds and precipitation coverage are concerned. Based on track forecasts from multiple models I've flipped thru this morning, should a system develop, the tracks are most clustered from South of Naples toward West Palm Beach, with 2 or 3 others going as far north as New Smyrna Beach on the East Coast. (opting out the other tracks taking the system toward Texas for now...but that possibility has been indicated).

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Monday, September 27, 2010

Florida to Hatteras May Need To Brace For Big Rains, Possibly Much More

SYNOPSIS: Surface low at noon positioned over extreme N. Georgia with attendant surface trough (cold front) extending south into the Gulf across the Florida Panhandle. This low is located within a much larger area of generalized low pressure extending from the eastern Great Lakes south to all of the Western Caribbean Sea. Upper level cut off low is located a bit to the west of the surface low over northern Alabama. Another area of low pressure in the Caribbean appears to be trying to organize per the deep convection occurring down there. Surface low will move NNE during the course of the day as the upper level supporting system begins to open up and toggle NNE as well. The surface front will be pressed slowly east as this action occurs. Latest KSC sounding indicates an increase in precipitable water values over East Central Florida in the atmosphere aloft since early morning, and now reads 1.81", with a convective temperature of only 83 degrees. Early morning shower activity that formed off shore moved off quickly to the NNE, and new generation of showers has begun over the immediate coast near Indian River and St. Lucie Counties. Motion in general is to the north. Thus, parts of Brevard County might be seeing some rainfall between 2-4pm (for starters), with possible thunder and strong gusty winds. These storms are moving fairly steadily, so impacts for any one shower should be relatively short-lived. In the short term, look out Brevard County as I now write!
TODAY: The front will try to move further east into tonight but have a hard time making much additional eastward progression as the parent low pressure system moves NNE and the surface feature loses its support. Ongoing convergence along and ahead of the front has warranted an alert for severe weather from North Florida to the Carolinas. For the most part, East Florida will be sunny today, save for the fact that there are some showers further south at this time, which I'd expect to increase in coverage and intensity as we work into the late afternoon hour. Shower motion will be from the S to SSW.
TONIGHT: Convergence ahead of the front should continue over North Florida with some of this activity expanding into Central portions after sunset toward after midnight. Thunder is quite possible in these showers/storms as would some gusty winds be expected both within and near the vicinity of this activity.
TOMORROW: Much of tomorrow will be similar to today but with more clouds and showers / thunderstorms likely to develop ahead of the surface front which will have gone stationary very close to a St. Augustine to Brooksville line. In the meantime, the Caribbean will be a witches brew of TNT just waiting for someone to light a match. By late tomorrow, under the premise that thunderstorm activity will be much more likely that today due to the proximity of the trough combined with a booster shot of moisture from the Caribbean, all eyes will most assuredly be Western or Central Cuba as the first of what may be several; storm systems makes head way into or very close to Florida. These systems will be on the approach from the South so naturally it will be the Keys and 'southern tip peninsula' to experience the first affects, particularly by mid-late afternoon.
WEDNESDAY: Over night into Wednesday is the big question mark in the darkening skies. We could end up waking up Wednesday morning with a rapidly strengthening tropical storm on our hands. Or maybe not. Point is, "A word of the wises, be prepared for surprises". There is one model that actually indicates a storm or perhaps hurricane could form a take a similar track to that of Charley 2004, from near Ft-Meyers-Napes on the SW coast to near Melbourne to Daytona on the East Coast during the course of the day. On the other hand, the other models agree that the energy from the Caribbean won't be so nearly focused on any on point, but rather widely spread out in the form of piece meal 850mb lobes of vorticity, producing periods of heavy rain fall. Should the latter be the case, there has been a trend over the past 12 hours to shift the impacted region in Florida east with each consecutive run. With the final run this morning indicating that it would be the Naples-Ormond Beach zone, east of the surface front that would be most impacts. Brevard would fall right on the cusp of either drought or drown! Take your pick.
Another item of note is the potential for severe weather activity ahead of either one of the aforementioned scenarios. The system as a whole, whether it be a concentrated bundle named Nicole, or an un-named cyclonic blob, will be preceded for a 3-6 hour period of time by a mid-level speed max over head East Central Florida as the Caribbean system gains dominance over the entire synoptic scenario. As such, and this is very iffy considering the number of uncertainties already on the plate (which hopefully you have been able to realize), the possibilities of land falling, rotating cells could become an increasing possibility sometime in the wee hours of Wednesday toward mid-morning this day. Rotating cells equates to the possibility of severe weather in the form of a brief tornado or land falling waterspout. This is a worst cast scenario, but given the level of uncertainty this bears watching. The main reason I wanted to at least mention this is because the timing at which this appears most likely this would occur...that being while everyone is asleep. So take that and do with it what you will; hoping one has an on-alert weather radio.
Should the Nicole situation develop, well then, we have a hurricane passing over South and Central Florida. Wouldn't that just be too much?! This really doesn't seem very likely though. On the other hand, per the second scenario...heavy rains seem a given for Southeast Florida with increasing doubt as to rainfall amounts once one gets north of the Cape. But to end this portion of the post with some sense of finality, best bet now is to expect a lot of rain from St. Augustine- Daytona-just west of Orlando-Charlotte on the west coast. Other portions of the state north and west of this line might remain close to dry.
BEYOND WEDNESDAY: Whatever happens Wednesday, things should change significantly by noon Thursday as 'the system' impacts the Outer Banks on its way to New England. It appears now that there will be another system of possibly much larger impacts going into next week to come out of the Caribbean. Keep attuned!

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Sunday, September 26, 2010

Could ECFL Drought End in a BIG Way?!!

(Could the end to the extreme drought in Brevard County be coming to and end? This anticipated rainfall depiction is from the HPC forecast for this upcoming week)
SYNOPSIS: Things so far pretty much on schedule in the short term. 6AM KSC Sounding depicts the retreating ridge axis overhead at roughly 850mb level (6000 ft) with light SW flow developing above there. In essence, things continue to change since yesterday with more in store. PWAT at 1.65" (down from this time yesterday) with the driest of air in the column located within a somewhat broad, critical mid-lower level range for rain shower development. Hence the lack of precipitation this hour across Central Florida. Meanwhile, mid-upper level troughing down the Mississippi River Valley and attendant surface trough (cold front) reside to the north and just west of the state. The mid-level low will sink further south and a bit east during the course of the day and begin to cut off tonight.  At the surface, the ridge extends across the Florida - Georgia border this morning, but will be cut eroded as upper level support for this feature shifts further east and the aforementioned trough progresses further south during the day. As such, by day's end we will be under an entirely new bag of tricks from what we've endured for several weeks now and are still experiencing at sunrise this Sunday morning. Elsewhere, tremendously huge area of low pressure encompasses the Western Caribbean and across Central America, Honduras, and the Bay of Campeche. Locally, of surprise is the thunderstorms over the Florida Keys this morning. Coverage appears much stronger and extensive than was being considered by the local office down there; however, activity was anticipated. Good show guys.
TODAY: Very nice day in store for the start. The sky was SO BLUE this morning. Like none I've seen for quite some time. Winds were light and variable with cloud motions aloft from West to East and anomalous  rain echoes of unknown origin (not real) moving from SW to NE. The atmosphere over Central Florida, for the most part, requires continued modification for any rain to co-exist under current conditions. As such, most of the day will be quite pleasant. At least until early afternoon. For now, will run with a 'worst case scenario', which is not at all consistent with current official resource proclamation. In keeping with yesterday's schedule, the best chance of rainfall today some of which will be in the form of thunder, will occur toward very late afternoon through late evening from the Cape and points north as the ridge is finally cut off to the north and deeper SW flows ensues ahead of the low pressure over the Deep South. Central area activity should be pretty isolated though (even in this worst case scenario). Some of the storms north of I-4 could be strong, although I am a bit leery concerning coverage over this region. It might be much lower than current 'official' thinking (and as indicated by overnight NAM/GFS runs). South Florida continues for one more full day of what has been status quo for quite some fact, extreme SE Florida might never feel the impacts from the trough at all (ever), at least not south of the South Shores of Lake O. SW Interior and coastal areas could see afternoon and evening storms though, but under entirely different circumstances.
TOMORROW: Monday might actually appear to the innocent by-stander to be like a normal summer day; one in which there are afternoon and evening thunderstorms which would favor the east side of the state north of West Palm - Port Charlotte line, but anyone/anywhere in the state will have a shot. However, in reality, the synoptical set up will be nothing like those of summer for the most least not mid-summer. Thunderstorms/rain showers possible by mid-afternoon to late evening once again. Likelihood of such will be greater on Monday than today though from Vero Beach north beginning mid afternoon (earlier than today).
TUESDAY-BEYOND: This looks like the 'make or break' day, with a 'wet pattern ramification' should things pan out as advertised by the NAM and GFS. First to look at what is being implied. It is suggested that although the vorticity ('energy') with the Deep South low lifts off to the northeast which would otherwise put a damper on rain chances, the area of low pressure to our south becomes joined at the hip with the continental low pressure area in (to my mind) a very questionable fashion. That is why this time frame remains highly uncertain. The result is that deep tropical moisture surges northward across the peninsula. Will this occur? If so, current forecasts being advertised could very well be, well, "blown out of the water". I think what we are hearing now over the media is the underlying need to stick with persistence until certainty in the forecast can be made clearer. So heads up!
Perhaps no big changes are in store at all, which totally justifies not crying wolf. On the other hand, should this second transformation occur the flood gates will be wide open to the peninsula for several low pressure disturbances to cross South and Central Florida from Wednesday on (for up to a week). Thus, "Could the Drought End in a BIG Way?!!".
Upon perusing through the official Hydrological Prediction Center's website, they seem to be favoring the GFS forecast, as described above (and from which the attached image was obtained). That forecast opens the gates. We could be talking a weekly rainfall total in the several inch amounts from the period of this coming Wednesday through next Wednesday. OR...well, you know what "OR" means. (OR-not). But our waiting period concerning when we'll finally get some respectable rainfall over extreme East Central Florida might soon be over...all this leads to the TROPICS.
TROPICS: What forecast mayhem lurks in the minds of models. Models are the forecasters friend as well their worst bitter sweet.
I'm disregarding what Matthew was and is now (a remnant low for the most part). However, it's that area combined with much of the Western Caribbean that continues to be on high alert in the forecasting world. Upon viewing all the models at hand this morning, there appears to be developing a consensus that there will not be a major hurricane affecting the state. A lot is contingent upon what happens this week. If the flood gates do indeed open, all the energy down there will arrive over the state 'piece meal' in the form of perhaps a depression...or several un-named low pressures areas of which would contain gobs of atmospheric moisture. On the other hand, that area down there could slowly organize over several days and drift slowly north as a single entity to encompass the entire state for quite some time...which would take a bit longer to arrive but with similar results. Then again, maybe it will never get here until the current trough now developing over the Deep South completely pulls out of the picture...which at this time is essentially undeterminable. I'm not even wasting my breathe with what all the models are depicting. But will go so far as to narrow it down to two scenarios.
The first one being what has been just been described (and questioned a bit while doing so) in the preceding paragraphs. The other scenario is that the energy associated with Matthew maintains, morphs, and drifts back offshore...moving around a common center and going nowhere fast. But just to illustrate an increasingly common scenario, at least from over night model runs, whatever goes on down there ends on most models with a large 850mb low near western Cuba by mid-week which has progressed toward the NNE (and South or SE Florida).  Will it ever arrive at all?
Now I know why main has hair; it's for pulling.
This is liking reading "Gone With the Wind". Will the nonsense ever end, and when it does..will Florida be "GWTW"? Probably not.

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Saturday, September 25, 2010

All Eyes on the Tropics

SYNOPSIS: Western fringe of high pressure over the southeast states lingers one more day as developing mid-upper level trough encompasses the Mississippi River Valley to the Great Lakes. Meanwhile, broad area of low pressure over the Caribbean into the extreme SW Gulf of Mexico, highlighted by Tropical Storm Matthew near La Ceiba Honduras. The storm is 'forecast' to eventually weaken over the weekend and become absorbed in a monsoonal low pressure area expected to form over Central America. We'll see. (do you detect a hint of uncertainty here? See more).
TODAY: Latest short term model (RUC) matched with the XMR (KSC) sounding shows the ridge remains over South/Central Florida, with the axis at roughly 15,000 Ft located overhead where winds are calm. Radar is showing very light rain returns moving from SW to NE. Believe these may not be reaching the ground for the most part, since their motion is SW to NE and would be a manifest of denser cloud patches associated at or just above the ridge axis aloft. The RUC indicates during the course of the day that these winds could lower to approximately 8,000 ft entering the mean steering current for late afternoon thunderstorm range; however, winds below that level (to the surface) remain solidly steady from the east for the most part. Atmosphere not as moist this morning as late yesterday with a PWAT at 1.80". Skies are mostly cloudy with a few patches of partly cloudy skies across the peninsula. Cloud motion is weak from SW-NE, namely with the mid-upper level clouds. Once low level cumulus clouds start to form they will move steadily from east to west.
Clouds may keep afternoon high temperatures down a few degrees today and preclude ample heating for thunderstorm generation until late when a boost will be provided by sea breeze convergence on the west side with a few pockets of Lake/Sea Breeze interactions thrown in. Wouldn't expect coverage to be very high at all though (i.e., would be isolated) and well west of I-95. However, with the winds aloft gradually becoming SW with time by late at lower levels, some of this activity may propagate back toward the coast from the Cape and points north in the early-late evening in the form of light or perhaps moderate rain fall.
SUNDAY: The ridge begins to break down even more, and might complete the transition after sunset. As such, similar conditions as today with a chance of thunder reaching the coast primarily from near Melbourne and points north by late afternoon. It should be noted that South Florida will be under going a completely different set of circumstances, most notably that the more westerly steering component does not become established down there. Moisture will be plentiful though, so what they will incur is a somewhat modified version of what has been occurring in the past few days...but perhaps less of it.
MONDAY-WEDNESDAY: Somewhat of a summer like pattern to prevail as a cold front associated with the deepening trough (and eventual cut-off low) over the Deep South becomes the playing factor for North and Central Florida early next week. This would be a summer pattern favoring the east side of the state for late afternoon thunderstorms and rain showers from West Palm Beach north to Jax. Cloud cover during the early portions of these days will be a factor in timing of what/when/where activity will occur, thus these days will require closer scrutiny on a daily basis.  At this time, there are hints that a well organized area of thunderstorms, and nearly a squall line of sorts for North Florida, could push into the panhandle which would push east and south to as far south as Daytona Beach or even extreme N. Brevard by Monday night. After which it should wash out with remnants lifted off to the northeast. Thus, we could see an up tick on thunderstorm potential/strength and/or coverage late Monday.
BEYOND: As we head toward the later portions of the week into next weekend much of the weather over South and Central Florida will be contingent upon what occurs over the western Caribbean which is a tremendously huge unknown, thus it would behoove the forecaster to go into details concerning the whys and where rain is most likely to occur, or for that matter, not to occur. If indeed, the organized line of convection does manifest and maintains itself into Central Florida, any remnant surface boundary left further complicates matters. Thus, we'll leave it at there 'should' be a continued chances of showers or at least cloud periods, with thunder quite possible.
TROPICS: Not going to go too deep into the tropical Caribbean at this time, but will illustrate why. Tropical Storm Matthew to drift toward the S. Yucatan region over the weekend and meander over this region. Models continue to indicate that it will either retrograde back east into the waters, or at least one, if not two, more low pressure areas could form any where from south of the Dominican Republic to South/Central Cuba. Models from this yet to occur event provide eventual solutions of a named storm Nicole moving north and either up the far eastern Gulf off the Florida West coast to further east just off the Florida SE Coast, contingent upon both the origination point and the timing coincident with the passing of a upper level trough to the north. Further down the road, the GFS latest solution actually takes a Nicole around the entire periphery of the Gulf with it ending back where it starts in the Bay of Honduras while another system which would be Otto, develops and moves quickly toward the NE over the Bahamas. This would leave Florida in between both systems with little impacts. But that's just one model describing what is already apparently becoming a very complex, yet to develop, situation. Other models indicate one solid storm approaching the Tampa Area...and another takes just one system near the SE tip of the state. Point is, this scenario could be a never ending story for the next two weeks as alluded to in the previous post. And to add fuel to the fire, the timing off the overall broad-brush picture might be delayed to even further out in time, as often occurs at this time of year. For you see, we not only have to monitor not only what is already an ambiguous situation in the Caribbean (as just described), but also what sort of developments occur closer to home over the continental United States during this time frame. How they eventually interact, whatever 'they' may be, will determine the outcome...which could be anywhere from late next week to late the week after that (or even beyond).

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Thursday, September 23, 2010

First Full Fall Day Ushers In Somewhat Frenetic Florida Forecasts

Image: A Harvest Moon occurred nearly coincident with the start of fall at 11:09pm last night. The next time these two events will be so closely tied together will be in 2029.
SYNOPSIS: Broad expanse of high pressure extends across the Atlantic Ocean into the S.E. U.S. Low pressure across the Caribbean, Yucatan Peninsula, and into the SW Gulf is flayed out south of the high pressure creating a deep, easterly flow component to the wind field.
Invest 95L  within this area of low pressure in the South-Central Caribbean, well south of the Dominican Republic, is becoming organized as it moves generally west. This area is part of a tropical wave that was generated from an African off shoot, the other part of which became Julia; that storm remains loitering well off in the Eastern Atlantic. Atmospheric moisture over Central and South Florida on the increase producing sporadic rain showers, most concentrated over the Keys at time of writing. Other widely dispersed showers making it to land from Daytona to Miami. This moisture field is working north today. Elsewhere, a trough is passing across Minnesota this morning generating a flood/severe storm threat over the upper Mid-West region this morning and this afternoon. This area will move east and be replaced by a second one as we head into late Friday. Believe it or not, it is the second one that will be the indicative harbinger of things to come way down here in Florida as we head into the beginning of next week! So watch the weather in Minnesota, because what hits there will eventually be affecting this state indirectly in the days to come. Also, I haven't heard mention of this anywhere, but there is a weak upper level low over the central  Gulf of Mexico that I first noted late yesterday which is evident on satellite imagery. The NAM model did not pick up on this feature very well, but the GFS nailed it on the 300-200mb analyses. This is a seemingly insignificant feature in the short term, but in the long term could contribute to the long term eventualities of what will occur as the second Minnesota short wave digs southward through the weekend. Just thought I'd throw that out there for good measure.
TODAY-TONIGHT: Nothing new as far as temperatures or winds at the surface and aloft. They are all generally from the east. The only change is the gradual increase of PWAT (precipitable water) values. As such, the chance of rain showers passing overhead today over Central Florida will increase just a bit, but more so from Vero Beach and points south, especially by later this afternoon. The depth of moisture isn't overly tremendous, but low level availability of what is there is enough to generate showers as far north as Ormond Beach, just more so the further south one goes as amount and depth within the atmosphere increases. As such, best chances of rain today south of Vero Beach at almost anytime...with detectable chances further north with time, especially late. Probably not much in the thunder category due to warm air aloft, although some could occur over the far interior and western portions of South-South Central Florida late in the afternoon.
FRIDAY: By sunrise, PWAT values over Central Florida will have climbed to levels we have not seen for quite some time now from near New Smyrna Beach south. The moisture will have already been in place from Jupiter Inlet and south for a good 12 hour previous. Moisture levels will sustain themselves throughout the day, with perhaps a greater depth to the moisture field from Jupiter Inlet - Ormond Beach and west across the state by late in the day and into Saturday. As such, rain chances tomorrow will be higher for Central Florida than for today, but thunder not anticipated. Not an all day rain event by any means. Just more clouds in the low and mid levels, with more showers coming in off the Atlantic. Easterly flow will prevail, but begin to weaken over night Friday into Saturday. Showers on Friday could occur any time day or night. Just look toward the east from whilst they will arrive.
SATURDAY-SUNDAY: Already stepping into 'dangerous forecast territory' from Saturday and beyond, so will go with the broad brush for South and Central Florida. It looks as though the deepest moisture will be over Central Florida rather than further south over the weekend. Both the GFS and NAM are highlighting the highest concentration or likelihood of showers, some heavy, from Sebastian Inlet to Daytona Beach along the immediate east coast (very generally east of I-4). The GFS kicks it up a notch with a vorticity max riding up the Florida East Coast over night Friday and lingering just offshore through all of Saturday and into Sunday. Would expect considerable cloudiness on Saturday as a result with continued east winds, but less in strength than what we've been seeing the past week. The potential for some of this activity to active lightning will increase as we work into the latter portion of the weekend, but can't discount 'ocean thunder' on Saturday.  Rain chances should be highest on Saturday as will rainfall totals as storm motion should slow considerably. Mid-Upper level winds to wane as a break in the overall synoptic scale pattern which has been in place for a few weeks finally breaks down. That second system alluded to near Minnesota begins to drop south along the Mississippi River Valley toward the Deep South and ridge axis makes the break, placing all of Florida in weak pressure fields, nearly a COL in fact. And one that is filled with moisture at that.
MONDAY-BEYOND: Chance of having thunderstorms over South and Central Florida increases as moisture laden steering changes from what was easterly becomes nearly calm to now S-SW. Temperatures remain status quo with lows in the mid 70s inland to nearly 80 east of US1. Perhaps a few degrees cooler than days of recent due to weakening of the easterly gradient flow, hence less advection of warm ocean water temperatures during the over night. Highs in the upper 80s to very low 90s. As such, the coast could see upper 70s for a change across the boards which would be a pleasant change. Now, the BEYOND portion will be briefly discussed in the TROPICS portion, since that is what the 'future' will be all about for the entire state next week.
TROPICS: As noted, we have Invest 95L in the South Central Caribbean. A lot of emphasis has been placed (from what I've heard and read) on this system becoming the next depression or storm. Upon review of the forecast tropical model plots, as well as the GFDL, GFS, ECMWF, HWRF, and NOGAPS models, there is a very close consensus as to what will occur in the near term period. That being, the system heads toward the Yucatan. It's what happens from there that things diverge. I'm intrigued by implications made by the GFS, namely because it takes the what will by that time be '95L turned depression or Storm Matthew into the Yucatan while yet another Invest develops near Jamaica in its wake. It is this second area the model eventually develops into what could be of immediate interest as far as Floridians are concerned as it is the second one that would be either Matthew or maybe even Nicole (if 95L/Depression gets named).
On the other hand, the majority of the other models leave what would be solely Matthew just east of the Yucatan or partially over it and begin to deviate it northward with time. As you can see, we are well into Science Fiction at this point in time. So point is, we'll be reading/hearing/seeing lots of fiction on the press until things become a reality.
As long as we are talking fiction, and since I mentioned the GFS evolution of things to come already, we can take it a step further. The GFS way out out there takes this 'second yet to be system' across Florida as what appears would be a depression accompanied by copious rainfall, into roughly Eastern Georgia and merges it with what would be that what would be the system out of Minnesota. Talk about irony. But it doesn't end there. It's the NEXT system after that, as we end the first week of October...that could be the big player for somewhere in the Gulf Coast.
Point being in mentioning this, is  illustration that although as one would expect at this time of year, this is all completely ambiguous, the trend is indicative that a somewhat prolonged period of unsettled tropically associated weather over the state of Florida to varying degrees, could be well at hand September 25th - October 9th (more tropical at times than others). The good thing for east coasters though, as things look now none of these yet to develop systems would pose a Storm Surge threat to the east coast.

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Tuesday, September 21, 2010

Pattern Change In Store Very Soon

(Image: Sunrise beams filtered by vertically challenged cumulus as Igor passes well to the east)
SYNOPSIS AND FORECAST SYNOPSIS: High pressure encompasses the entire eastern U.S. seaboard in the wake of IGOR. This system has been a thorn in the side as far as drought conditions are concerned for portions of East Central Florida (namely Brevard County now in a moderate drought). Subsidence behind the system combined with continental high pressure over the southeast states played hardball against towering cloud formation...if there was any clouds to be found at times. But IGOR is now getting out of the equation (and our hair). Bermuda didn't fare bad at all considering the storm was a Cat 4 before it's near central passage to the island at Cat 1 strength. Seems erosion and inconveniences was the gist of the system there.
In any case, as IGOR moves away high pressure over the SE states will merge with the high pressure out over the Atlantic (in Igor's wake) to produce a massive swath of easterly flow stretching far out into the Atlantic and across the state, which will weaken during the course of a week. In the meantime, perhaps the first trough of the fall season (right on time for official fall by the way), will be moving into the intermountain region. Initially, our weather locally in Florida will be dictated by deep, broad easterly flow with periods of enhanced low to mid-level atmospheric moisture availability. As such, with time, showers and eventually thunderstorms will become prevalent for many days ahead.
The rest of today's post will speak mostly in generalities given that the predominantly dry weather of recent days will persist through most of today.
But a change appears to be in order as has been indicated by models would occur for several days now, as described in the previous paragraph.  The problem has been a broad disparity between the models as to when this change from our recent dry days to a more climatically normal regime would resume. Model consensus is finally becoming apparent enough to warrant a post. As such, daily posts will likely be required in coming days as each day will have it's own bag of tricks to deal with...especially as we approach this time one week from today.
TODAY: Same old same old, until late this afternoon. For the most part, today will be the same story as what we saw all weekend and yesterday. Albeit, there was a few very light showers here and there over the weekend, but they were so far and few between and so light that they aren't worth mention. Yesterday was the driest of all. The clouds in Central Florida had no breadth and were profoundly vertically challenged. The first hints of a change trying to get together were over South Florida after sunset where a few showers came ashore at Palm Beach County.
One shot of low level moisture eked by shortly after sunrise, with some better looking clouds than anything to occur yesterday. They are since gone, but the fact that these moved over the coastal area was just a harbinger of things to come. By later this afternoon it's safe to introduce onshore moving rain showers across South Central Florida, and maybe as far north as Canaveral to Sarasota by sunset. Just showers, no thunder.
TOMORROW: Shower chances (and aptly, coverage) increases as moisture in the lowest levels of the atmosphere works in from the Atlantic and up from South Florida. South Florida might hear thunder, but not central.
THURSDAY-FRIDAY: More moisture, hence more chances of showers. Don't get me wrong, it's not going to be a 'rainy day' or anything, just better chances of receiving a shower pretty much anywhere south of Daytona Beach - Crystal River (on the west coast of Florida). We might be able to introduce the chance of thunderstorms as well, especially by later Thursday afternoon for inland portions, but more so on Friday.
THE WEEKEND/TROPICS: This period will be interesting to see what occurs in the Caribbean, especially off the NE coast of Nicaragua. The GFS and European model have come to a mutual agreement of storm development down there, which translates north ahead of the aforementioned upper level trough developing over the intermountain region mentioned earlier. By Sunday into the beginning of next week a plethora of weather variabilities and possibilities exists incumbent upon what occurs as the mid-upper level trough translates toward the Mississippi River Valley and attempts to ambiguously 'coalesce' with the disturbance near Nicaragua which will have been drifting north into the open Caribbean in the meantime.
As whatever is trying to go on down there, the point is that at least Florida won't be dry any more. We will need to look more into increasing chances of flat out thunderstorms pretty much anywhere over South/Central Florida as we head toward the weekend and into next week in the meantime.
Perhaps nothing much will happen way down near the Caribbean, but it's becoming more and more apparent per models and climatologically that these changes are not out of order. We may be hearing more and more by the weekend of a tropical threat becoming apparent to the Gulf Coast states (including Florida) the first of October. Remember though, these developments of which we speak have yet to even develop. We're still at the hypothetical stage.

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Wednesday, September 15, 2010

Brief Sprinkles Possible Through Friday

(Image: Photograph of IGOR from space late yesterday before it got dark)
SYNOPSIS: High pressure are the words of the next 12 days, coupled with tropical systems of no weather impact of only satellite imagery interest.
High pressure prevails all along the U.S. Eastern Seaboard this morning and the SE States, across Florida, and into the Bahamas. Strong Hurricane Igor well out in the Atlantic almost achieved CAT 5 status last night and may do so again anytime between later today through early Saturday. Tropical Storm Karl just made landfall on the Yucatan to emerge in the Bay of Campeche by tomorrow and likely achieve hurricane status before making a second landfall in Mexico.
TODAY-FRIDAY: Very dry air aloft with a prevailing easterly flow prevails across all of North, Central, and South Central Florida. Only persistent low level moisture remains from Ft. Lauderdale and south over the SE portion of the state. Very shallow layer of higher dew points (moisture) has developed over night along the immediate eastern shores from Jacksonville to Ft. Pierce. There's just enough moisture to generate some nice, rain threatening clouds, although none has yet to be detected on radar other than well off shore of Central Florida and making landfall near Miami and the keys.
With this said, and these conditions expected to prevail through Friday, across all of Eastern North, Central, and South Central Florida expect periods of enhanced low level, pretty clouds with a small chance of a few drops coming down under the larger clouds. We do have a chance that from Brevard Vero to Jacksonville (particularly Brevard) that the moisture level may increase between 1-4pm for cloud enhancement enough to generate a measurable amount of rain along the immediate coast east of I-95, but that would be the worst case scenario. This will be the case for the next two days as well...most likely in the morning hours though the next two days. Otherwise, persistent easterly winds across the state will prevails which will wane a bit after 9pm each evening.
SATURDAY-MONDAY: Hurricane Igor will be making its pass east of the state overnight Friday into Saturday. Seas and rip currents will be on the increase with waves well offshore reaching near 10 ft with onshore winds. Rip currents will be the story for all of the U.S. Seaboard, particularly north of Jupiter Inlet to Hatteras then further north with time. The weather will be almost entirely dry for the whole state as perhaps weak subsidence around the periphery of Igor reaches the offshore waters precluding formation of showers over they area ...thus precluding the possibility of onshore moving showers since none will be generated. Skies could be almost down right totally clear at times on Saturday and Sunday.
MONDAY-BEYOND: Moisture to a moderate degree will be on the increase as we work toward Tuesday, but nothing significantly so. Easterly flow will prevail as high pressure remains intact from Texas to offshore Florida. Chances of onshore moving showers picks up, but no thunderstorms expected the entire time frame through at least Wednesday.
TROPICS: Outside of Karl and Igor (which will be quite the sight to see on satellite imagery the next 4 days) there is little of interest. Igor could strengthen once again and just MAYBE reach CAT 5 status anytime until Saturday, after which point it will enter waters still stirred up by Earl east of Hatteras and weaken significantly from that point on. No land impact to the U.S.
Of greater interest at this point is the Caribbean beginning early next week, and particularly from September 22 and points on. Indications, although in varying degree...are pointing to more development across this entire region especially off the NE tip of South America. The GFS has been showing a U.S. landfall of some sort of named storm anywhere from Texas to Florida with more activity to follow. October could be quite active in the Caribbean and the Gulf as we enter the last week of September and head into October. Trick or Treat?

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Monday, September 13, 2010

Few Showers Early Afternoon to Early Evening...Few Storms Inland/South

(Image: Cat 4 Igor imagery from last night)
SYNOPSIS: Frontal boundary at surface meanders over N. Florida this morning and dissipating as mid-level boundary works south into Central Florida this morning. Sharp drop in upper level moisture observed on vapor loops with low level drying lagging back toward north of Daytona.
TODAY: Things occurred yesterday as expected, with the NAM coming closer to reality when we worked into the after sunset hours with heavy activity moving down the east coast. No other model showed this event to unfold, so kudos to the NAM which I haven't been giving much credence too. The main slug of activity died as it crossed the Brevard County line to the north as it tried to cross the mid-level ridge axis which was located just north of the Cape. In staying with yesterday's line of thinking, believe the mid-level / low level drying will be a little slow in fully manifesting today south of Daytona. Sea breeze to generate before noon but remain light until very late this afternoon. Showers could develop just west of I-95 during development of the sea breeze along it's leading edge as it pushes inland, but those will be few and far between. Before that time no showers anywhere except well off shore. Oddly, I think if the immediate coast is to see showers today it will be behind the sea breeze from Vero Beach north to the Cape between 2-8pm as the mid-level ENE wind kicks in across the offshore region where greater moisture will reside and be advected onshore until maybe an hour after sunset. All activity today will primarily run south of a line running diagonally from the Cape to Central Osceola County toward Sarasota, with the strongest/most activity limited to near Okeechobee County,  Southern Polk, and further SW toward Ft. Myers to Port Charlotte.
TUESDAY-NEXT TUESDAY: Little chance of rain throughout the period, with maybe some occasional nocturnal shower activity affecting solely the immediate coast in isolated and light fashion anywhere from Daytona to Miami east of I-95 in the over night and early morning hours.
Seas will be on the increase as IGOR makes its pass well to the east of the state, with rip currents being a big hazard next weekend beginning around Thursday.
In wrap up: Watch for showers moving on shore along the coast from Vero Beach to the Cape later this afternoon, with storms well inland and south later this afternoon into the early evening. After today, everywhere in the state much  more quiet.

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Sunday, September 12, 2010

Isolated Strong Storms Possible Near Orlando This Evening

(Image: Dark cloud bases off the Coast near Cape Canaveral last summer)
SYNOPSIS: Surface front/boundary near I-10 in North Florida early this afternoon will press south and weaken over land during the course of the next 18 hours as it tries to move into Central Florida. For the most part, the meat of the boundary will remain well offshore. As the boundary sinks south later this afternoon it will be stretched thin with a respectable ribbon of middle level moisture remain through noon tomorrow over Central Florida. Meanwhile, high pressure is building east and south behind this boundary and getting ready to pounce on the north half of the peninsula by Tuesday Morning.
TODAY: Will it be a repeat of the past two evenings over Central Florida? A house was struck and damaged last night, and the night before two football players were injured...both over the immediate Central Florida peninsula near Orlando. It looks like  now as of 1pm that this will be the case once again.  This mornings KSC sounding came in relatively dry compared to days past, but this could change after 6pm this evening as the boundary sinks south. The west coast sea breeze is getting the head start north of Tampa and south of West Palm on the east side of the state. The east coast boundary will work inland and likely make it as far as the Orlando Area (the Turnpike this evening) south of Orlando...then slant more along the I-4 corridor toward Daytona. Enhanced Cu field and a shower already forming near northern Lake County...much earlier than yesterday...whereas the Cu field is pretty meager south of I-4. More enhanced Cu area in Western Volusia and passing offshore near Daytona.
Expect most thunder to begin to occur north of I-4 before sunset, but about that time through 10pm could fill in toward I-95 as far south as far West Cocoa closer to the Brevard County Border...elsewhere...most activity should be close to the turnpike over Osceola County toward Lake Okeechobee...but lessen in coverage the further south one gets.  Rain and possibly thunder could occur near Titusville and Cocoa, perhaps reaching the coast after 10pm this evening. There is lots of lightning being detected with the activity currently near Tallahassee, and expect the meat of such to possibly occur over Lake-Orange-West Seminole-Western Volusia Counties shortly before dark to two hours after dark. It is noted that the NAM model is being most aggressive with all features as has been the case for over a week, and in fact brings the core of storm to drought parched region of Brevard County from 10pm-midnight, but this is for the most part being discounted. The GFS shows maybe some light rain the same area..which could manifest as cloud cover in actuality. The RUC, although doesn't go out that far in time, isn't even leaning at hinting at the possibility of anything remotely close to either of these solutions, which sounds probably most appropriate based on persistence and the current air mass over Brevard which will probably slow to adjust to a showery environment, if in fact it ever does.
Further south, they're not playing with frontal boundaries to any degree whatsoever yet. Pattern south of West Palm being dictated by the same pattern as the past many already with a moist environment in place and light west to east shower motion in place, albeit very very weak. Showers and perhaps thunder could occur between the coast and the East Side of Lake O almost anytime now and generally propagate south or north along the sea breeze boundary. Other showers could back build across I-95 near SE Palm Beach County to Miami. This activity will be at it's strongest just east of Ft. Myers - Naples, mainly over Big Cypress National Preserve and Everglade National Park between the hours of 4pm -7pm as this activity peaks then dies over swamp lands. Further north, activity could push offshore toward Port Charlotte to Sarasota.
TOMORROW: Ridging building in across N/C Florida..with the last of whatever moisture is left of the boundary to remain over east central Florida until early afternoon. Thus, a few isolated showers possible late morning near the coast but quickly transitioning south and inland during the day.
South Florida will continue with a day similar to today.
AFTER TUESDAY: No much rain if any through next weekend. Slight chance of nocturnal showers along the coast from Miami to Melbourne Beach, but these will be very light and isolated...if even.
TROPICS: Not much change locally until after IGOR makes its most threatening blow to Bermuda. IGOR already is a Cat 2 Hurricane, and could make it to CAT 4. This storm already is, and will continue to be more so through at least the first half of next week, a very impressive looking storm on satellite imagery. Looks like the U.S. will not be impacted though. However, by next weekend swells from the system should be impacting the Florida East Coast, and with such pleasant weather in-store for that area next weekend as it looks now, rip current threat will probably go up not unlike with those associated with Danielle. Swimmer beware.
System in the Caribbean still appears to be heading toward the Yucatan, and may never become a depression...but still poses a rain/flood threat to Cuba and the Dominican Republic through the first half of the week. The next system behind IGOR might become our next named system, but as it stands now appears to be to close to IGOR and will pull off something like a Fiona..playing tag along with the Igor. If it can maintain its distance, it will get pulled north and east behind IGOR and be of no threat to any one.

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Friday, September 10, 2010

Isolated Storms Central to Scattered South Today - Very Warm

RECAP: Some thunder yesterday over East Central Florida, namely right over the Melbourne NWS around noon time then near downtown Orlando in the early evening with linger light rains in that area as well as near Kissimmee in Osceola County. The greater coverage and stronger storms were over SW Florida.
SYNOPSIS: Ridge of high pressure extends roughly from Cape Canaveral diagonally toward Central Alabama. Aloft high pressure extended across the North Gulf. Surface trough/weak front across south Georgia and Alabama.
TODAY:  Pre-model availability post being made this morning other than 5am local WRF runs. As was expected for the early portion of today, a very light land breeze developed along the coast at sunrise. KSC sounding from 6am now available showing ridge axis over the Cape at 800mb where winds are dead 0. Below that very light west component wind and above it more substantially measurable NW wind from 650mb to the jet stream level at 15-20 kts. PWAT is up from over night hours and yesterday at 2.01" which is somewhat higher than expected and temperatures aloft are relatively warm once again.
As expected, expect today's pattern to generally be much like yesterday, with most (and more) activity along the east coast from West Palm to Miami...Once again, the area south of the ridge axis running across Central Florida will be considerably different from that along and north of this axis.
The ridge axis will sink only slightly during the course of the day. Before that time expect isolated rain showers to form near the intracoastal due to the high PWAT shown at the Cape before noon time...but mainly along and west of I-95 from Port St. John and points south toward 1pm right as the sea breeze is showing hints of moving in a daytime heating has fully ensued; closer to US1-A1A over Martin County to Miami. Additional showers to form near the coast from South of Naples north to around the geography of Tampa Bay.
Sea breeze to form by 2pm with strong subsidence behind the sea breeze front squelching rain potential everywhere east of I-95 entirely with greater chances of showers or a thunderstorm from extreme SW Brevard then south to Miami along US1-I95 corridor. The region generally from West Palm to just south of Bradenton will be in deeper moisture and begin their day with weaker sea breeze boundary storms evolving into thunderstorms which will move generally W-WNW during the course of the day over far South and Southwest Florida. Only isolated showers are expected north of this line over all of Central Florida..and those will be well inland from either coast. Temperatures will work into the low 90s along the coast before the sea breeze develops with far inland locales seeing little deviation throughout the day with widespread low-mid 90s prevailing. Any collision of sea breezes in the early evening will result in an isolated storm or two far inland over the interior.
As usual, outflows from collapse of earlier larger showers or lightning storms will put a crimp in the broad brush forecast as to determination of where the stronger activity will eventually be located. Also, any storms that go up near the East Coast from Brevard to St. Lucie county near noon time will collapse and accelerate the sea breeze inland more efficiently that in those areas that do not have storms.
Overall though, only isolated showers and storms for Central Florida, scattered up to a brief period of numerous coverage from roughly St.Lucie County on the east coast to Charlotte County on the west coast.
TOMORROW-SUNDAY: Much the same scenario evolves, with some minor variations anticipated. At time anticipating lower rain possibilities over west side of Brevard to St. Lucie county from today and all points west with the crux of rains ending up in the SW corner of the state, more so on Sunday.
Essentially, a nice weekend for the Beach for all of East Central Florida after today's meager rain chances early, not so much so necessarily from southern Palm Beach County to Miami and all points west of there.
MONDAY ON: No fronts to make it through Central Florida as high pressure at all levels becomes prevalent over North and most of Central Florida. Looks like a stationary boundary could sink and simultaneously wane as far south as near Jacksonville and across all the immediate panhandle but that's about it. The only affect being lower dew point temperatures and thus cooler morning temperatures, but afternoons will still be quite warm up that way. A drier easterly flow will be the gist for most if not all of next week with rain chances highest over any portion of far South Florida and lowest over the east half of North and Central Florida.
TROPICS: No concerns at this time. Still looks possible that some development may occur in the Caribbean which would be pushed toward the Yucatan. Otherwise, Depression EyeSore could redevelop as conditions will become more favorable during the weekend. Expect we could be seeing an IGOR once again as soon as tonight or before the weekend is develop into a big hurricane.

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Thursday, September 9, 2010

Generally Very Warm Day In Store With Isolated To Scattered Showers

(Image: Circumscribed Arc photo'd this morning with bird on perch. These form when the sun is approximately 29 degrees above the horizon with columnar ice crystals present and all oriented in the same way.)
SYNOPSIS: Ridge of high pressure extends generally from East Texas and across the Northern the mid levels it is located directly over the Space Center where 11am sounding showed winds at 850mb to be 0, that's ZERO as in dead calm. Winds at all other levels are around 5 kts or less up to almost 20,000ft. Moisture wise, PWAT has risen a bit since 6am to 1.81". There is a bit of an inversion near 2500ft...with no moisture consolidation noted other than right at this level. Just enough to form showers which as they grow in height encounter drier air. A little more moisture resides south of Lake Okeechobee across South Florida where winds are more defined by shower motion from East to West. Further north from Vero north through Central Florida shower motion is essentially non-existent as one would expect with the winds described above. Temperatures aloft have warmed to those reminiscent of most of the second 1/2 of the summer, with 700mb at 10C and 500 at -4C.
PENINSULA WIDE: In satellite animation and radar trends, appears an axis of greater mid level moisture as noted by a greater cumulus field extending roughly from Ormond Beach on the east coast to must north of Brooksville toward the West Coast about 40 miles wide either side of this axis. This axis seems to be moving little. Showers are going up along I-95 near MLB (where they reported a shower last hour as can be seen from my porch), . Probably of greater meteorological interest is an east coast sea breeze boundary from near Ft Lauderdale to just south to west of Miami. It made a good forward surge toward the NW initially but seems to have slowed down over the Everglades. The heaviest showers, one of which is producing lightning, is located NW of Miami over the Everglades in no-man's land. Aloft, cirrus clouds are streaming over the the Gulf Coast Ridge and washing across North and Central Florida but have thinned significantly since earlier this morning. These clouds helped in forming the circumscribed arc shown in this post which last over an hour.
TODAY: Warmer temperatures aloft, moist air, and light winds aloft and at the surface with no triggers make for a generic forecast on my part which will lean on the dry side on the broad brush. Almost all shower and storm development will rely initially on sea and lake breeze boundaries, after which other showers can initiate as a result of outflow from collapsing ones. With such widely scattered shower amounts anticipated due to warmer air aloft it might be hard for boundary interactions between adjacent showers to develop. East and West coast sea breezes will begin (other than the one over SE Florida) by 2pm but move very little from either coast. Thus, we might not even see a sea breeze collision today over the interior. If there is one, it would most likely be around Lake Okeechobee on the west side. Toward Central Florida is would occur around sunset after heating begins to be lost.  Expect greatest shower coverage overall to be during the 6-8pm hours, with the strongest of which to be along the W-SW Florida Coast between that and Lake Okeechobee. Another hot spot could be over Polk County and perhaps western Osceola County as expecting the West Coast sea breeze to be a bit more active over the South Half of the state. If this proves to be so, this area would be wet for quite a while as activity lingers.
TOMORROW: Very similar to today. Not expecting cirrus over head tomorrow morning, so day time heating might get things started roughly an hour earlier. Winds aloft should become somewhat more determined by the ridge axis consolidating into more of a well defined circulation near N. Louisiana, as such winds aloft would become measurable from the NW. Trough moving off the mid-Atlantic today with a surface boundary across Central Georgia -Alabama will get no further south due to the ridge across the N. Gulf which will hold fast. However, as the trough exits the U.S. East Coast and gets further from the continental ridge it could make a little bit of a dig to allow a light land breeze to form by was mentioned in yesterday's post from near West Palm to Jax. Mid level winds may also become W-NW around the ridge across Central Florida..but all these winds will be only 10mph aloft or less and have little overall affect on storm motions other than to keep activity more focused to the east side of the state but west of the sea breeze boundary which will develop around 1-2pm. Perhaps a better chance of activity over N. Brevard tomorrow over the Cape toward Titusville and Port St John early afternoon, but also development possible along the intracoastal for a brief time before and during the initial phases of the sea breeze. Speaking of which, it should make less inland progress tomorrow than today and not expecting a collision of west meets east once again.
Further south. An entirely different ball of wax. Generally the region from Ft Lauderdale to Sarasota is under a different flow regime entirely with activity focused more toward the West side of the state during the afternoon and evenings...and on the east side early morning to early afternoon.
SATURDAY: Little change in the overall pattern with a greater influence of mid-level winds to mount moisture up in  the late afternoon through mid-evening hours along the SW FL Coast from Bradenton to Naples and west of Lake Okeechobee. Other areas will receive a wide scattering of showers and perhaps an isolated thunder, more likely over South Florida but not discounting Central Florida.
TROPICS: Igor the EyeSore. Won't do much for a while as it is currently being sheered by upper level winds. But don't be fooled. This system could still end up as a large and strong Hurricane, but as mentioned yesterday is most likely going to remain a thrill for only the satellite imagery lover. Point blank though, despite what models currently depict, it's way too early to now with any degree of confidence whatsoever at this point that it will definitely be a fish storm. If it circumvents the next trough coming off the U.S. East Coast next week it would mean shear panic for somewhere on the U.S. East Coast. Eyes might do better to focus toward the Caribbean where development of an area of disturbed weather appears to have the upper development hand. This area should track toward the Yucatan and into the Bay of Campeche...but bears watching. Where ever this thing goes, somebody is going to be affected. Can't say that about Eyesore as it stands now until next week...but first it needs to get organized...for now, it's just that.

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Wednesday, September 8, 2010

Stagnant Yet Periodically Eventful Pattern In Place Next 36 Hours

(Image: Wall of rain moves in on Cocoa Beach late this morning)
SYNOPSIS: High pressure at the surface over the Western Atlantic is sinking south and simultaneously retreating further East as a trough enters the Mid-Atlantic region this afternoon. Central Florida is positioned on the extreme western extent of its direct influence, where as South Central and more so South Florida remains under its influence more directly. With weak winds aloft, afternoon sea breezes are acting as a the primary influential factor for where it will rain this afternoon. It was noted this morning that a weak southwest flow aloft was developing at the mid level over NE Florida ahead of the trough approaching the mid-Atlantic region, and apparently this entity is working south into Central Florida. Although winds right on the coast are quite discernibly from generally the east to southeast, showers over Brevard County are clinging to the western county border east of Orlando while others fill in further west. The coast from Volusia, south, is totally scoured out by the sea breeze. Further north to Jacksonville, those SW winds aloft are having a greater influence and the sea breeze is almost non-existent up that way. Hence, showers and storms are occurring nearer the coast north of Daytona, but nothing of much interest as far as intensity goes. Looks like the sea breeze might be winning out on whatever has managed to form up that way as well...barely.
TONIGHT-THURSDAY: Winds aloft remain quite light but begin to assume a westerly component at 10 mph or less after midnight over Central and South Central Florida. Winds along the coast of most of Eastern Florida should wane by daybreak to allow a light land breeze to develop by daybreak Thursday with light westerlies aloft, mainly north of Fort Pierce. Further south, the winds aloft remain very light from the east. Models are depicting SW-W surface winds tomorrow over Central Florida, but these will be offset by a sea breeze that will develop by noon and progress toward I-95 by afternoon. Due to light and gradually shifting surface winds near noon time...early shower/thundershower activity could develop anywhere from near Jupiter to St. Augustine, with the intracoastal land strips of Brevard the preferred location due solely to its unique geography, especially north of Cape Canaveral over North Merritt Island and the Cape. With daytime heating, a light sea breeze will develop against the light/perpendicular mid level west flow. Thus, storms should be on the upswing in the US-1 to I-95 corridor after 2:00pm-3:00pm along this boundary. Meanwhile, expect the west coast sea breeze to make better east ward penetration than recent days with an eventual collision up and down the Central Peninsula, more likely between I-95 and the Florida Turnpike. As is the case with such weak steering flows, storm motions will be essentially based on propagation with pre-established Lake/Sea breezes and Outflow Boundaries basically north of Vero and south of Ormond Beach on the east coast and North of Bradenton on the west coast. Further south toward West Palm expect more of a diurnal pattern of late evening to mid-morning activity to begin along the immediate east coast to progress toward the west and strengthen as the day wears on. Due to slow storm motions, some big rain fall accumulations could be anticipated well west of I-95 tomorrow, but due to a return to upper level temperatures where they've been all summer of 2010 overall coverage will be just at or below normal.
FRIDAY: Expect the pattern to continue into the first half of Friday with a land breeze more likely to develop from Daytona Beach south to Ft. Lauderdale or maybe even Miami. Once again, showers could form over and near the intracoastal around noon time from the Cape to Sebastian Inlet. Motion will be close to non-existent, with both coastal sea breezes coming into play but slow to work inland...with an eventual collision over the spine of state after 6pm. Same story as far as coverage is concerned.
ALSO LATE FRIDAY: By this time, a high pressure center will be building somewhere near the Georgia/Alabama border with a light NW mid-upper level flow developing with the trough by this time moving further off the Mid-Atlantic Coast. Circulation around the ridge will come off the Carolina Coast and will be composed of drier air. Eventually, this high pressure will retrograde further North and west toward Arkansas and merge with the Atlantic High trying to push back over Florida in the wake of the trough that will have moved well into the Atlantic. The result will initially be a drier NW flow aloft with an east then northeast surface wind developing Saturday into Sunday. During this transition East Central Florida will have one last gasp of receiving a thunderstorm, from somewhere around Sanford to Central Brevard before sunset.  This scenario will most likely not unfold...with the aforementioned NE-E winds at the surface and aloft being the sole event to occur sometime near sunset to after dark along the coast. This could manifest as a very weak backdoor boundary through NE Florida but that's about as far as it gets.
THROUGH THE WEEKEND: NE surface winds prevail over most of the peninsula with moisture being mostly likely squeeze out from roughly Sarasota to Naples late in the afternoons against the west coast sea breeze. Temperatures inland remain in the low 90s and upper 80s along the immediate coast with little in the way of showers anticipated on the eastern 1/3 of the state, and even that might be generous.
TROPICS: Storm Igor looks as though it will be quite the sight to see on satellite imagery for a number of days. It currently looks like this could end up being a large hurricane by the beginning of next week, but it seems at this point it will be picked up by a second front that will be moving off the U.S. East Coast sometime in the Monday-Tuesday time frame...which wouldn't even begin to occur until about this time next week..or later.
If Igor does not get picked up by this second trough...all bets are off and some serious eye-balling for the folks from Florida to the Carolinas will have to begin. That's a long time from now, so not dropping any loose ends. Leave it to say for now, the models indicate the coast will be clear of Igor...but as we all know by this point the tropical season (lest some haven't already learned from previous seasons)...the models are what they are...I'll believe it when we are talking no more that 48 hours best.

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