WEATHER MADE CLEAR FOR ALL TO HEAR

"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, October 20, 2010

"C'mon Man, Shuffle The Cards!"

(Image: Mid-level moisture abetted by a mid-level lifting mechanism <stronger wind aloft> makes for pleasant, sunrise sky gazing shortly after sunrise)
 
SYNOPSIS: Mid-level moisture introduced in yesterday's discussion continues at noon time, this Wednesday, from the Gulf of Mexico and across the Southern and Central Peninsula. A cold front extends SSW from the Eastern Carolinas, through SE Georgia and into S. Alabama where it then tails off to nothingness.  Further west, high pressure is shifting east across the Northern and Central Gulf. Sounding data shows precipitable water value (PWAT) at 1.32" which is better than some recent days, but a far cry from our 1.90"+ that is present during almost the entire summer.
 
To add insult to injury from a thirsty man's perspective, the canteen remains empty since the majority of this moisture is locked in the mid-levels or roughly between 6-12,000 feet. Above this narrowly sliced level of moisture the winds increase from uniform direction from about 22kts to 80kts much higher up. Essentially, the higher winds speeds just above the moisture layer air were acting as an escape, or lifting mechanism, for the air below them to rise just a bit before reaching drier air and evaporating at their first opportunity. As such, no rain anywhere in the state as of this writing. In fact, now that the sun is out mixing with the drier air both above and below the moisture layer is acting like the top half of a broiled Monte Cristo Melt..in other words, it's "toasted'. Nice little cumulus forming though with what moisture remains boiling out under otherwise  full daytime sunshine. This makes for something to at least look at if one happens to look up to see a UFO passing overhead.
 
Elsewhere , "Go West Young Man!". The cut off low now near the Northern Baja will move E-ENE during the next  36-48 and impact SE New Mexico, much of the Texas/Oklahoma Panhandles, and eventually almost all of Oklahoma by Friday into Saturday with severe weather. Could be seeing a severe thunderstorm or tornado watch box going out for SE New Mexico into extreme SE Texas near Midland/Odessa later today, which will be the first of many in this outlined area through Friday-Saturday. Figured they'd get more than what was originally out-looked for in that area in yesterday's post.
 
HERE TODAY: Not much change, if any, from yesterday's gaze into the future. As expected, the circulation coming off the N. Yucatan is completely gone, although the general circulation from which it developed is providing the moisture necessary for clouds. Further south off the SW Florida coast, there's actually a decent little line of heavy showers which can't seem to penetrate, which I'm philosophizing as being, the drying low level air mass over the near by landmass (otherwise known as the Florida Peninsula). Also, much to my amazement, there's a teeny-tiny, two-pixel'd shower near Ft. Pierce. Otherwise, nice temperatures and partly cloudy (to maybe mostly cloudy for a brief time near sunset in a few isolated locations) conditions will prevail. Note though, The Weather Channel is calling for a 30% Chances of thunderstorms here in Brevard...I imagine it is, or was, the same case for folks further south). I think they were looking at a 12 hour old run of the North American Mesoscale (NAM) Model when that forecast was generated some time over night. Hey guys, wake up there in Atlanta! Who knows, then again, the Rapid Update Cycle (RUC) indicated defiantly with a 'no colored precipitation panel' earlier today that we would remain without rain, but the latest one now shows the possibility of a trace any where south of a Cocoa Beach - Tampa line by 8pm. Wouldn't expect we'll see anything more than a quarter inch anywhere today...since anything that can form will be isolated, small, and moving at a 20-25mph clip from WSW to ENE. And t'were that to occur, it will most likely be south of a Ft. Pierce, Sarasota line.
 
TOMORROW-WEEKEND: The Carolina cold front will ooze south and lay flat close to a Brevard to Brooksville line before pulling off to the east and losing identity at the southern flank over Central Florida as it does. High pressure will be moving in from the west across the Gulf and over the state by late Friday and through the upcoming weekend. No significant change in temperatures in days ahead. Here we go again, getting dealt the "Joker". Not funny. Go fish!...and speaking of fish....:
 
THE TROPICS: System Invest 99L (under investigation) continues to become better organized just to the WSW of Jamaica this afternoon. Visible satellite imagery clearly shows there is a low level circulation in place, and I suspect that we will be addressing a TD (yeah, 6 points for the gipper)...by tonight or overnight. Where it goes from there, in all reality, is not any one's guess...it's everyone's. Some models do little with the system for at least 72 hours as it's "sheared, not steered" by conflicting mid-level winds. In fact, all the rain action with the circulation is well to the N-ENE of the circulation center and over Jamaica close to the surface. 
 
But by 72 hours, if not sooner, these winds should die for a bit before reinforcements come in associated with the high pressure that will shift across Florida. The models seem to have a handle on all this to occur (except the GFDL and HRWF), but what it does in the mean time can be part 1 of many other significant and required chains-of-events necessary for future development and resultant storm track taking. To make a "paint by numbers" portrait based on the latest GFDL run, we have a moderately paced, but steadily developing no holds barred Hurricane in 54 hours and within 6 days we're staring up the barrel at a Cat 5 bullet passing through the Yucatan Channel with an evil eye on Florida. Man your battle stations!! We're playing "WAR!". Interestingly, the HRWF takes a similarly chaotic tracing around/near Jamaica before taking "Richard" to nearly the same location as a Category 2 by Sunday. (spell check tries to correct 'GFDL' to "GODLY'...does it know something we don't?)
 
Meanwhile, Typhoon Megi is just hours (several) away from SE China.  Looks like it could make a landfall just North of Hong Kong, but this region is very highly populated and even after landfall flooding could pose a problem for days afterward. I bet we'll hear a lot about this system on the nightly news by the weekend if not sooner. This storm is responsible for the loss of approximately 10 lives in the Philippines. But you know, Megi can be one of the reasons that the models are having problems with what happens in the SW Gulf. It's a "Domino Affect"...air currents flowing around the system are disrupted down stream from it, and this has a rippling affect as far east the Caribbean...so the next 72 hours..and/or until Megi landfalls we still might see future model chaos.
 
Now, let's reshuffle the cards. I see a lamb, a cloud, and an image of Christopher Columbus...oh wait, these are Tarot cards. Doesn't matter. The other models show essentially nothing but weak low pressure for the next 72 hours. I believe the make or break point will be known for sure by late Friday, but in the meantime I'm running with gut feeling...which says that high pressure will win out...especially over the weekend as a healthy dose of "happy pills" spills across the Gulf and Florida...forcing the system southward in a state of dismay..."Go Fish". But never say never until all is said and done. It would be nice to get some rain...but I think our first real statewide rain event is going to end up arriving in the form of a tail end Charlie of what will be a squall line passing across the Dixie Region within the next 10 days....hopefully, we too can proclaim, "Gin!"
 
 

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Tuesday, October 19, 2010

L.ocal S.torm D.eprivation (LSD) Symptoms

RECAP: Local Central Florida L.acks S.erious D.evelopment of any storm or even rain shower development. I think the weather God's are on 'happy pills', which is great for celebrating outside in early, fall-type weather. Such has been the case since the departure of the pre-mature birth of Tropical Storm Paula, and so the trend continues.
 
SYNOPSIS: Mid-upper level low pressure circulation referred to in the previous post was off the California coast yesterday just SW of San Francisco. This system continues to wind up and has dropped southward just offshore and down the coast, but now appears poised to shift toward land over the Northern Baja. Cut-offs are notorious for being difficult to forecast as far as how long the will persist within any one general region...so we approach the forecast for that the Desert SW region and Southern Plains with a swift, broad brush of relative uncertainty. The low appears that it will finally, but slowly, be caught up in the southern branch jet (which is weak) and shift across extreme Southern Arizona, Central New Mexico, and gradually lift and fill as it moves across the Southern Plains and finally skedaddles off to the ENE as the remnant circulation and energy (vorticity) gets wrapped around low pressure east of James Bay by the weekend. This system will leave widespread impacts in its wake, first across Southern (SE) California, much of Arizona, New Mexico, Southern (especially SW) Colorado, and then the Panhandle region of Texas/Oklahoma. We'll probably be hearing about severe thunderstorms and maybe a few tornadoes as a result anywhere in this zone through Friday before it begins to loose identity. It will be interesting to see what other types of weather erupts in the areas currently not forecast to receive any...especially over Oklahoma and Northern Texas.
 
Meanwhile, high pressure prevails over the Southeast States, the Gulf of Mexico, and Western Atlantic. The only noteworthy Item of Interest has been a weak, mid-level circulation off the Northern Tip of Yucatan which was forecast and finally analyzed late Sunday per model consensus. There is no active weather associated with this feature; however, it is now caught up in the weak southern branch jet/upper level flow and getting reading to pass over South and Central Florida as a remnant non-entity. It has managed to draw some moisture with it from the Caribbean, but in passing overhead it is essentially riding over high pressure at the surface (in other words, there's no depth to the system (and in calling it a 'system' anymore is a big stretch)). I've read no references to this item in forecast discussions from weather service offices, but I've been watching it for a number of days now in hopes that it would at least be a 'siggy' rainmaker for the every increasingly drought parched portions of Florida and/or other southeast states.
 
TODAY: Moisture at the mid-levels is being advected across Florida ahead of what remains of the aforementioned, dwindling circulation aloft and it's presence is clearly visible outside this morning (see included image). The moisture is just now arriving and will continue to flow overhead like a gentle stream through the day and tomorrow...particularly south of a Tampa Bay - Sebastian Inlet line. What remains of an elongated surface boundary well to the north will press south during the next 36 hours in a significantly dwindled state and interact with what remains of the moisture plume before it exits east of the state or full out dehydrates in place. As such, expect partly cloudy to cloudy skies early today...with maybe a light spinkle anywhere from near a Melbourne to South Tampa Bay line and points south. Per latest satellite trends (visible loops are only just not becoming viewable due to the early time of day), the clouds should break up by late morning to near noon time over portions of Central Florida, at least for a short time. However, daytime heating may work on the incoming moisture in such fashion that we would see an up-tick in cloud coverage once again by late afternoon, if not sooner. Temperatures will run a little cooler today by a couple of degrees due to the clouds, especially inland where the moderating affect of the sea-breeze is never as pronounced as it is along the coast. Come to think of it, the sea-breeze might altogether be hard pressed to form in earnest. As such, either way, the winds will be quite light with comfortable temperatures.
 
TONIGHT-WEDNESDAY: Continued periods of partly cloudy to occasionally cloudy, especially over South East Florida south of Ft. Pierce. Best rain chances currently appear to be east of Lake Okeechobee. The clincher though in all reality, that light surface winds combined with abundant cloud coverage will offset sea breeze/lake breeze formation and/or strength and thus low-level convergence boundary interactions...that precipitation will be of stratiform/light nature for the most part where it does fall due to the deepest moisture being aloft. It looks like the best chance of anything truly measurable though will be ENE-SE of Lake Okeechobee and extreme South Florida from Naples-South Beach and points south. Temperatures running around normal or perhaps just below where clouds persist in depth and coverage the most.
 
THURSDAY-FRIDAY: What's left of the mid-level moisture dissipates in form and function as high pressure approaches from the West (which will be south of the pesky low mentioned earlier). High pressure to move over head, thus precluding any frontal passages and/or moisture influxes. Thus, temperatures running around normal, or maybe even above that under sunny skies, especially by late Friday all regions of the state.
 
WEEKEND: LSD continues brewing. What the "high" (pressure) does is to continue the drought over East Central Florida. Note: South Florida is not in drought. Perhaps a 'trip' with a spiral design on the blot for the storm Gods is in order.
 
TROPICS: Just a few brief statements. The SW Caribbean is not yet to be forgotten, at least not in the world of models. Just to provide you with an idea of what is being depicted, the models show anything down there from nothing more than what is there now (unsettled weather) to development of a Cat 4 Hurricane within a week near Jamaica. I think both scenarios are unlikely. Hate to do it, but I'm riding down the bottom end of the curve and going with development of a least a depression with 2 days per observation of satellite loops and climatology (which of course, considers the time of year for this location where the weather is now occurring). This is in deviation from the assumption that the activity would simply be lost over Central America as written earlier, so anyone near the East Side of the Yucatan should keep at least one eye open to any future wild cards that might be dealt.
 
As far as the United States is concerned there does not appear there would ever be a threat no matter what happens down there, but I digress. Remember that cut off low approaching Southern California/Northern Baja? Need to keep watching what becomes of that. Should it slow down as often does with these systems we could all be thrown for another Hula Hoop. Those cut offs, especially in early spring (though) can be quite the thorn in the side of even the best forecasters. In the meantime though, at least for the next 72 hours..."round and round they (both go)...where they stop..nobody knows".
 
Elsewhere, Typhoon Megi is a very large storm and posing an entirely different forecast problem for anyone within a few hundred miles of Hong Kong. They have a good 2 days to narrow down the storm's eventual track and to prepare accordingly. Just how strong it will be and where it eventually makes a second landfall remains unknown.

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Sunday, October 17, 2010

Taking the Brrrr out of Octoberrrr

(Image: Sunrise flame)
SYNOPSIS:  High pressure encompasses the entire SE U.S., the North/Central Gulf, and the Western Atlantic. Low pressure is developing near Southern California. Stratocumulus clouds along the immediate east and southeast Florida coast overnight kept overnight minimum temperatures warmer than days past, with a 5AM temperature at PAFB of 74F, whereas Crestview, FL was a frigid 39F. Prior to sunrise the clouds broke up allowing the temperature to drop to 73F at PAFB and Crestview had dropped to 37F! It's likely they had frost there with a dew point also at 37F. Tallahassee was the second coldest at 45F.
 
TODAY: High pressure will continue to prevail over all of Florida today. The wind this afternoon to gain a more ENE-E component of light nature under nearly clear skies with some inland diurnal, scattered low topped cumulus clouds. Late afternoon and evening hours may introduce some nocturnal stratocumulus clouds along the east side of the state with an easterly, light breeze. Otherwise, it looks to remain dry in the rain gauge.
 
UP COMING WEEK: Low pressure near California will move inland and cutoff at the mid-upper levels. As a result, the main jet stream will ride up and over the low into SW Canada and take a dip across the mid portions of the country and into the northeast states (New England) where it remains a bit on the chilly side for morning lows. A secondary southern jet will round the base of the cut off and flow across the Desert SW-Texas-Northern Gulf and Florida. The low will gradually fill and move ENE with an accompanying cold front to enter the Deep South Tuesday and Wednesday but never really make it through Central or South Florida. The only affect from it will be to shift winds a bit to SE-SW for a brief time as high pressure to our east repositions. The winds will shift back to the NE as the front lays flat to the north and another bubble of high pressure approaches from the Northern Gulf and then to our north, re-enforcing the dry air mass overhead. Temperatures along the immediate coast will remain in the low to mid-60s with highs in the low-mid 80s. Inland temperatures will be both cooler in the morning and warmer in the afternoon, with highs in the upper 80s range by Tuesday and Wednesday. Other than a happen chance trace of rain late Tuesday or Wednesday (and that is being generous), things look to remain dry. Looks like we are headed for a record dry October over portions of Central Florida as it stands now. Most locales have received not even a trace, and where measurable amounts fell it was less than 0.10".
 
The first low will be absorbed by much larger low pressure circulations encompassing the Canadian Maritimes to the Hudson Bay area, as yet another one follows in its heels by next weekend. Meanwhile, the southern branch jet will continue in a modified form across Florida for the most part and the North and Central Gulf as we head toward next weekend and Halloween.
 
TROPICS: Continuing to watch the extreme SW Caribbean, but as things stand now given the current outlook for the continental United States and the Gulf, anything that does form down there now appears that it will remain out of the picture.  Still need to watch what comes after the first aforementioned low yet to form near S. California though as well as the one to follow. Models have really shifted gears the past 24-36 hours and now take future development in this region westward across Central America north of Panama. The big story of the day is Super Typhoon Megi/Juan approaching the mountainous terrain of Northern Luzon of high end Category 5 Hurricane strength. Quite an awesome satellite presentation on this storm this morning. 

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Thursday, October 14, 2010

Pleasant Weekend State Wide

(This weekend won't require updates for local weather)
SYNOPSIS: A weak cool frontal boundary is currently located just offshore the Florida East Coast from near Vero Beach northward. Further south this boundary becomes difficult to locate, but appears to meet to a weak area of low pressure just off the coast of Ft. Lauderdale. Only a wind shift accompanies this boundary. Cloudiness across Central and South Florida is associated with moisture from the region encompassing diminutive Hurricane Paula (located just off the NW coast of the western tip of Cuba) combined with what appears to be an approaching mid-level wind speed max rounding the base of a mid-upper level trough approaching from the WNW. A more significant cold front associated with this feature is a bit difficult to locate at the surface, but inspection at 5000 ft definitively draws out the front extending from a low over Pennsylvania extending southward through the Carolinas and nearly bisecting the Florida panhandle. The low pressure over Pennsylvania will swing toward the W-WNW during the next 48 hours producing wet-n-windy weather for Northern New England for at least the first half of the weekend.
 
TODAY: Locally, cloudiness at sunrise this morning exists over Central Florida on a line from roughly extreme N. Brevard County toward southern portions of Tampa Bay, more extensively the further south one goes.  There are some rain showers associated with the cloudiness mainly south of a Vero Beach to Ft. Myers line, and for the most part this will continue to be where the showers will remain today. There's a fine line between where the clouds persist and suddenly cut off. North-Central Brevard on the east coast is on the cusp. South Brevard to Sarasota and everywhere south are well within the clouds and will probably remain there today. Winds should remain from the NW to W this afternoon, although a light NE component could develop close to the coast this afternoon, either way, wind speed will be insignificant. Any rain chances, it appears, will remain south of Brevard in the region outlined by the denser cloud shield from roughly Vero Beach to Sarasota and south through all of the Keys; however, there is a remote chance of a sprinkle along the coast during the mid afternoon as far north as The Cape as the cold front approaches from the west.  Best rain chances overall appear to be down the east coast from Vero to Miami this afternoon. It appears the the main weather change later today associated with the actual front will be clearing sky conditions as drier air aloft penetrates southward from the north accompanied by a more definitive NW wind. Frontal passage will occur first along the Florida West Coast, Jacksonville, to Orlando- the eventually the coast north of Vero by sometime between 4:30pm to sunset.
 
TOMORROW: Dawn should crack at the face of nearly clear skies across North and Central Florida, with the front still pressing south and east across the southern peninsula. Very pleasant day in store with a NW-NNW breeze and drying air at all atmospheric levels.  It has been quite dry this month, in fact, ever since Tropical Storm Nicole was in the neighborhood. As such, the dry air combined with the northerly breeze will set the stage for possible Fire Watch criteria during the afternoon hours over the inland counties. The coolest air will not arrive until overnight Friday night into Saturday morning, so we could still reach high end low 80s tomorrow under such dry conditions and full sun shine.
 
WEEKEND: Great weekend for the fair in Cocoa Beach with a north wind and nearly clear sky. High pressure behind the front will pass overhead and eventually into the Western Atlantic by some time Monday. Lows where the fair will be (Cocoa Beach) in the low-mid 60s and a high near 80 both days. Much cooler mornings inland. Looks like Sunday will overall be the coolest of days. Winds should veer to NNE-NE (off the Atlantic) by Sunday afternoon tempering temperatures.
 
NEXT WEEK: Carte Blanche check signed, "give me more benign weather". Winds will veer more toward the east through Wednesday with modifying temperatures and a gradually moistening air mass approach from the south as high pressure pushes further east and north as yet another dehydrated frontal boundary approaches. Periods of clouds during the afternoons due to day time heating, and perhaps some nocturnal/early morning stratocumuli along the coast with more moisture present. Maybe even a sprinkle along the coast in the day preceding and 'early morning of' the next front which right now has an ETA of very early Wednesday morning. This front, although as equally benign as the one today will be, could be the 'make or break' determinant concerning the weather over Central, and more so, South Florida next week. See TROPICS:
 
TROPICS: At 7AM bare minimalistic Hurricane Paula was located 45 miles west of Puerto Esperanto, Cuba (just off the NW tip of Cuba), moving NE at 5mph with seemingly 75mph over the water. The storm is encountering shear from all directions via opposing forces, both from high pressure in the Atlantic which is blocking eastward motion and the approaching trough in the NW Gulf of Mexico tearing at the system aloft from the west (these same winds are generating the clouds over Central/South Florida at this time). These winds, combined with the storm's close proximity to the Cuba landmass and its dismally small size will put a demise to the storm in the next few hours. I'd bet the next advisory is no longer indicates a storm of hurricane status...and in 24 hours it will be all but gone. A piece of upper level energy will likely breaking off during passage of the mid-upper level trough to the north which will cross the Florida Straits and the Bahamas, whereas the low level energy and remnant surface circulation could eventually move ESE to SE and dwindle, dousing western Cuba in the process.  The Keys will continue to have a period or two of heavy rainfall, and perhaps some thunder as the moisture from the storm interacts with the approaching frontal boundary in that area through much of Friday.
 
Elsewhere in the tropics. An area of vorticity remains in the far SW Caribbean and over Central America with a broad area of cyclonic circulation. Another, an more importantly, is another vorticity area approaching the Leeward Islands. At this time, there's only a few showers associated with the second feature. The vorticity will continue to move west and become imbedded within the first area in the SW Caribbean by Monday, and in all probability instigate the initiation of the next named tropical system, "Richard" in the Tuesday time-frame NNW of Panama. This a quite some time from now, and seeing as how this chain of events is only apparently beginning to unfold quite a bit could change.
 
So, in speaking from persistence of the GFS model: This particular forecast model has been indicating that this transformation in the SW Caribbean would occur for over 48 hours now, and has been fairly consistent on the timing of a Hurricane crossing Cuba sometime late next week. Just exactly when or where will be critical for South, and perhaps Central Florida, when considering the next front to affect the state referred to several paragraphs previously. Since the time of forecast inception, what would be named Richard has taken directly from as far west as across Florida from near Naples to Ft. Pierce to as far west as off the Florida East Coast and across the Central  Bahamas. The latest available run was the furthest east with this system never directly affecting any part of Florida.
 
In summary, the meteorological community will be approaching Wednesday with furrowed brow of inquisitive interest. No matter how one looks at it so far, somewhere in the Bahamas is most likely to be dealt the Ace of Spaces in a game of Russian Roulette.

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Wednesday, October 6, 2010

A Strange case of Dr. Jekyll and Mr. Hyde

(Images: There are 2 images included today; Facebook viewers will need to open this post to view in entirety).
 
Shown: Bi-polar Jekyll and Hyde twin conditions shown in today's mid-level(700mb) presentation of the U.S. The polar opposite is shown in roughly 4 days in the second image when by this time each stormy low level pressure system is replaced with high pressure, leading to the U.S. Synopsis.
 
As can be seen in the first image, an "Omega Block" pattern is at perfect peak performance this morning. "Jekyll" is over the Northeast U.S. and being his sedate self: mostly cool, cloudy, and somewhat wet. A sop. On the other hand, Mr. Hyde is up to devilish no goodness over the Desert Southwest region.  In between these two characters is high pressure over the mid-section of the U.S. Note this as this area will be discussed again later.
 
The dynamic duo began the adventure over the weekend with some severe warnings in S.E. California and wet, cold slop over the Great Lakes into Pennsylvania (of many locales), and since that time Hyde has continued to be nothing less than the Devil's Advocate in Arizona, especially since near noon time yesterday up to the time of this writing. Numerous severe level hail and wind reports have been driving the teletype in full gear, with a plethora of sub-severe level yet exciting weather conditions jamming the lines. Two confirmed tornadoes already, with warnings going out as I type. The weather services in Phoenix and Flagstaff are quite busy. Might add, there has been some tornado reports with significant damage as well. As Flagstaff puts it: "IT CONTINUED TO BE A VERY ACTIVE MORNING WITH NUMEROUS SEVERE/TORNADO PRODUCING THUNDERSTORMS. A CONTINUATION OF THIS ACTIVITY IS EXPECTED THROUGH THE DAY AS A STRONG LOW SPINS OVER CALIFORNIA." North/Central portions of Arizona and portion South/Central Utah are in a Tornado Watch until 8PM EDT.
 
Second Image: But there is a good side to everything as well as a bad one. Jekyll will run out of potion. By the end of the weekend instead of Jekyll and Hyde (the old toy "Clackers" comes to mind if your old enough to know they even existed, but were banned due to their propensity to apply personal injury to the 7-8 year old users)...we will be looking at Pom-Poms in the NE and SW U.S. High. Sort of like going from hard to soft porn...a pleasant break from the rough and tumble. Meanwhile, right where we have the High Pressure over the mid-section mentioned above, we will find a trough cutting through the mid-section of the U.S. At time, doesn't look like there will be much impact directly associated with this, but honestly have not delved deeply into this fairly fast moving system. It will head toward the N.E. states in Jekyll's wake, while the Desert S.W. remains sedated, living up to its good old self once again -- dry.
 
LOCALLY/TODAY: Wow, cold this morning in Crestview at 41F and Tallahassee at 45F! But that's long gone, in fact those temperatures rose almost 15 degrees in the first 3 hours of day light. Locally, breezy N-NNE winds and a few clouds. Cool with a high in the low 80s. Tonight, like last night. Much the same through the end of the work week with winds letting up noticeably by later in the day Thursday and a little warmer, but not by much. SE Florida could have the winds until Friday though.
 
WEEKEND: Little change, but even nicer. Winds die down significantly, and what wind there be will exist will be NE-E. Slight chance of a very light rain shower, but really and for the most part, negligible. Will watch to see if more moisture advects toward the coast to generate showers, but it appears the low/mid level winds won't be strong enough to do the trick.
 
LATER TUESDAY-WEDNESDAY: A front approaches as winds become more southerly to perhaps southwesterly for a brief time, but of light strength. The front might go through dry though (no rain)...but it's still too soon to say for sure. Gonna have to monitor the trends as we go through the weekend.
 
TROPICS: I think we'll be seeing Tropical Storm Otto if not by early evening then by tomorrow morning. The low pressure system is located just north of Puerto Rico and is currently tangled up in a meteorological mess with an upper level low near by, as well as with the low pressure trough off the U.S. East Coast. As such, it's categorized as a sub-tropical depression. Whatever. But everything is pointing toward this low probably going from a 'subtropical low' to a flat out Tropical Storm at whatever point the Hurricane Center opts to flip the switch. Exactly how long the system remains a tropical entity varies per model runs, but it won't be too long. Perhaps only 2 days, maybe 4. Regardless, it'll be history. Although the eventual impacts to Great Britain are intriguing.
 
Elsewhere, Otto (I'll call it that for simplistic sake and since it doesn't matter either way) might have a little sister Paula. Are you seeing the trend that I am? Things are happening in pairs. Named or not named, it appears likely another 'system of sorts' will form within the same broad, scheme of things, trough that 'yet to be named Otto' forms in. Only at the extreme tail end which is somewhat intermingled with the area of low pressure that's been over the Caribbean for quite some time now. This system is up for grabs for now, considering that other than model hints, there's nothing to prove its eventual birth...but the Caribbean still looks a little pregnant.
 
To paint an entertaining picture though and to emphasize how nuts things get when foreseeing something beyond the horizon, last night's 00Z GFS run turned this area into a full blown hurricane and took it north across West Cuba...heading straight for Florida. But fear not, the 06z run came out and simply took this area on a free tour through the Western Caribbean across the Yucatan and back to it's origins...and at perhaps Depression status it is picked up by a trough off the U.S. East Coast to follow a path similar to "Otto". The 12Z shows similar, but lets the system die in place, never being named. Almost likes the tropics has an abortion (all seriousness aside,pulleez). We'll see.

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Tuesday, October 5, 2010

Chance of a Sprinkle East/Central Brevard , Otherwise Pleasant/Breezy

(Casting the sunrise fishing line in hopes of a catch -- he succeeded)
SYNOPSIS/LARGE SCALE OUTLOOK: Not much has changed since yesterday mornings post. And as such, pleasant weather prevails across all but extreme SE Florida this morning where low clouds linger. Low pressure prevails over the Bahamas and the East/Central Caribbean, across the Leeward Islands, Puerto Rico, and further east. Trough extends from the far NE states down the offshore Eastern Seaboard to meet the area of low pressure just outlined. Low clouds along the extreme SE Florida coast are associated with the western fringes of the lower pressures. Meanwhile, high pressure bridges the gap over the entire Central U.S. where pleasant, but somewhat cold conditions, prevail (especially cool toward the upper Ohio Valley region). In the mid-levels in fact, gradient flow between the low pressure trough and this high pressure are gradually developing a northerly component flow that streams the whole way from NW Minnesota, across Florida, then south to near Panama (Central America)! This general pattern will persist for the next several days with no storm systems to impact any of Florida. Elsewhere, the Omega Block pattern will be at its peak perfect performance later today into tonight before the low over the upper/inland mid-Atlantic States lifts to the ENE then NE, while the low over the Desert southwest lifts north, weakens, and gets caught up in the upper level westerlies and like wise moves east in a much weakened state. The most exciting weather today will be over Arizona, Southern Nevada, and Southern and perhaps Central Utah before this low slowly moves out in a weakened state today. This region has been outlined by the Storm Prediction Center to be in a Slight Risk for severe storm today.
 
LOCALLY: As high pressure builds south and east this afternoon over the Plains and eventually the Deep South states, the pressure gradient between the trough aloft (and somewhat at the surface over the Gulf Stream waters) will tighten, producing some breezy conditions mainly from the Cape south to Miami (more so the further south one goes).  As noted yesterday, there are some patches of moisture developing within this squeeze play which are producing sporadic patches of stratocumulus clouds (one of which passed over East Central Florida around 9AM). More of this benign activity can be expected in unpredictable intervals this afternoon and this evening. Winds will back a little more to the NE by early afternoon along with tightening of the isobars to a mild degree, as such we could see breezy conditions along the coast by early afternoon and through the evening hours. Models have backed off on rain chances since last night, but consistently produce fluke shower chances over extreme East Brevard County as well as extreme East Dade County. Latest visible satellite animation does show some concentrated streams of stratocumulus heading toward the Cape at this hour, with perhaps some barely detectable raindrops within, but of no significance whatsoever.
 
TODAY: Becoming breezy along the coast with a few moments of stratocumulus clouds possibly giving some character to otherwise mostly clear skies. Very tempted to discard any chance of even a raindrop to fall given the shallow depth of atmospheric moisture aloft, as well as the lower dew points at the surface in which any rain that could fall from a denser, small cloud patch would evaporate before reaching soil. Melbourne radar is currently in "clear air mode" if that's any indication as to their concerns about rain falling. It appears the best chance of detectable rainfall would be within a narrow window between late afternoon to shortly after sunrise Wednesday, worst case. High temperatures in the low 80s. Otherwise, the gut says even that might be a stretch. No worries, but boating on the Atlantic today wouldn't be advised for other than the experienced due to rough, offshore waters and heightened winds and seas.
 
TOMORROW: Continued a bit breezy but no chance of rain. Perhaps a few clouds, but again, we'll probably have to look hard to find them.
 
THURSDAY: The only change for this period is an abatement of the wind under mostly clear skies.
 
FRIDAY-WEEKEND: Continued much the same with a teeny-tiny warm up of undescript nature. Will watch to see another, stronger influx of cool/dry air infiltrating down the peninsula during this time frame, with little affect other than to reinforce the current conditions of the past two days. But really, this period remains up for grabs in my mind as far as how much more easterly the wind will get, but rain wise...close to nada.
 
TROPICS: Their making sort of a big deal about the area designated 97L on The Weather Channel this morning, I think mainly because it's just something to talk about. Development of this system to depression or Otto Status remains sketchy, although the Hurricane Center has upped the chance of tropical development for this area to 40%. Regardless, it poses no threat to any landmass other than some rainy conditions over the Leeward Islands and eventually Puerto Rico late today. As noted yesterday, a piece of energy appears consistently now to break off this area and form another system south of Jamaica in days ahead. Models are coming close to agreement to this eventuality, with a system forming in the far SW Caribbean near Nicaragua. The GFS model is the sole model to have this system actually get picked up by the trough running down the U.S. east coast, and as such taking this potentially named system across Eastern Cuba and the Western Bahamas way beyond one week from now. Otherwise, the system just meanders way down there and either dissipates or moves in to Central America as hinted at in other models.

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Monday, October 4, 2010

No End In Sight To Early Fall Weather for the East

Image: "Omega Block" pattern indicated by nearly cut-off low pressures aloft over the Ohio Valley and SW U.S.  for Tuesday evening as forecast by the NAM model
 
MORNING RECAP: Weak frontal boundary passed through Florida yesterday afternoon and now resides near the Keys and into the Bahamas this morning. Graphical depictions and surface observations indicate a fairly classic drainage flow scenario in place for all but extreme S. Florida (over the Keys and the Southern Tip) where cloud conditions prevail over the Keys and extreme SW Florida. A narrow band of low/mid-level clouds is sweeping down the east coast just offshore, with some partly cloudy observations being observed along the landmass as the deepest extent of the clouds remains offshore now approaching Daytona Beach.
 
TEMPERATURES: Further south, the keys are socked in this morning where the front seems to have come to a halt, or at least slowed down quite a bit. Rain showers fall over the Florida Straits either along or south of this boundary, hard to say for sure. Meanwhile, coldest temperatures as one would expect are over the Extreme North/Western Florida Panhandle with, if you can believe, there's a Wind Chill Index (WCI) temperature of 43F (!) and ambient air temperature of 46F at Mary Esther at 7AM. Elsewhere, the extent of the coolest air (but not nearly as cool as that at Mary Esther) gives credence to drainage flow with temperatures as far south and west as Tampa to Punta Gorda; Tampa Exec. this morning just prior to sunrise is 57F and Punta Gorda and Okeechobee are 63F. In retrospect, despite the cloudy conditions over the Keys they are still the warmest with sunrise mercury readings just under 80F!
 
For comparisons sake, and to emphasize the affect of having close proximity to the near shore Atlantic Waters, Patrick AFB is 72F (my porch is 69F) where as Melbourne is 63F. That's nearly a ten degree difference just by crossing the Intracoastal. Sky at sunrise at my place is a cobalt blue clear with a light northwest wind right as the first hints of the rising sun become evident to the east. As was written about last winter, we will see the affect of the near shore waters at times having a distinct affect on A1A corridor temperatures almost every morning; 10 degree temperature differences between the I-95 Corridor and A1A are not unusual. Also, as is noted this morning, coldest morning temperatures over Central and South Florida are found in those same locations noted in the previous paragraph.
 
SYNOPSIS: As can be seen in the included image, an "Omega Blocking" pattern has been becoming established now for the past 48 hours and will continue through at least Wednesday. It is called an "Omega Block" because the pattern shown in the image of the two low pressure areas and the high pressure in-between resembles the Greek letter "Omega". These can last for several days or even a couple of weeks. Elsewhere, broad area of low pressure continues over the Caribbean and SW Atlantic over Puerto Rico and east of there. Invest 97L is located over Puerto Rico and ESE of there with a 20% chance of development. Another area of 10% interest is located even further east and south of 97L.
 
SYNOPSIS FORECAST: In this case, it appears the Omega Blocking pattern will last under a week, but needs to be watched.  Models are known for trying to kick these patterns out too quickly, but from all appearances they seem to have a respectable reason for kicking out the low now over the Ohio Valley; after all, that low has been up there for nearly 48 hours already. This low will fill and be shifted to the E and ENE then eventually NE toward Eastern Nova Scotia as we head into late week as the low over the Desert SW Region begins to weaken and drifts only slowly east with time. Meanwhile in the short term, the Desert SW is enjoying a rather late season monsoonal rain event for them, with a slight risk of severe thunderstorms being issued for West Central Arizona tomorrow by the Storm Prediction Center. They are expecting some isolated strong storms today as well, mainly over extreme SE California, southern Nevada near Las Vegas and south into Arizona. A funnel cloud was sighted and filmed over S. Cal Saturday with flash flooding concurrent. This storm had slight rotation with it.
 
LOCALLY: As the low over the Ohio Valley kicks out winds aloft will become more westerly whereas surface winds will become progressively from a more northerly component and eventually NE component by later today and seemingly for eternity. Thickness values change little (the thickness between the 'standard' 500mb -1000mb levels). This thickness is determined by the average temperature between the two standard levels. Since thickness values change little, so will be the surface temperatures. Although, at the very lowest levels, that which we feel and read on the thermometer, temperatures will be begin a small warming trend most notable by morning low temperatures warming a bit beginning Tuesday along the coast and most all locations by Wednesday, with the result being temperatures around normal or perhaps a few degrees below 'normal', but no big deal.
 
MOISTURE/RAIN: The short term and extended period as far as clouds and rain are concerned are predominantly dry. Any influx of atmospheric moisture to the peninsula (other than the Keys) will be shallow and short-lived, and mostly limited to the east coast from Daytona to Miami. Things get a bit stickier from Ft. Lauderdale and points south, but will omit discussion for that region this morning. Either way one slices the pie, as noted, moisture will be limited to and below the 5000ft level, and its appearance will come in the form of periods of stratocumulus clouds and perhaps a light sprinkle detectable on the car windshield with nothing even measurable. It does not look like these periods would produce any more than partly cloudy to maybe mostly cloudy conditions when they do occur, but their presence should be relatively short lived (6 hours at most).
 
TROPICS: Invest 97L persists just east of Puerto Rico and shows an ever decreasing threat to anyone, including Bermuda. To exemplify a scenario painted by the latest GFS run, this system is expected to get booted post haste to the NE but some energy remains which continues to drift west toward Jamaica with time. As such, we might be seeing a new Invest area somewhere South of Jamaica over the weekend. But even still, if this system develops to the degree implied, the winds aloft over Florida and across the Gulf are easily from the west which would either sheer the system out or quickly give it a swift kick to its tropical butt way out there in time to the NE. Pure speculation. In essence, no tropical threats as things appear now through mid-October. On the other hand, some models show a threat to the Bahamas of  a named system. Either way, no U.S. threats are indicated.
 

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Saturday, October 2, 2010

Summer ("OFF) - Fall ("ON")

(Image: low pressure center near or over the Cape mid-morning this Satur-day)
 
SYNOPSIS: Who flicked the switch on October 1st!? Just stick your toes outside and feel the difference in the air mass out there which began yesterday. Low and mid level low pressure contained within a large, deep upper level trough which extends along the entire U.S. East Coast is located very close to the Space Center mid-morning. Image included in this post shows the moisture trying to wrap around this low with some enhanced cumulus showing up on recent visible satellite imagery to the north of the Space Center which is visible with the naked eye from Canaveral. Meanwhile, a short-wave trough/upper level vorticity max is rotating around the more prevalent upper level trough and is bottoming out near the NW Keys (where some isolated showers have popped over the waters NW-N of Key West). This vort max will translate NEward in the upper level trough and pass across south and central Florida this afternoon and evening. A few rain showers exist off the N. Brevard Coast and points north to meeting land near Jacksonville.
 
TODAY: Beautiful morning to start the day, with a 7AM surface observation at the Port Entrance reading 70F degrees and a dew point of 70 degrees as well with light/variable winds. This would reflect this area being near the center of the low shown in the included image. With light winds and drier air in surrounding areas, temperatures will quickly rise thru late morning into the afternoon, especially away from the coast toward Orlando.  As noted above, an area of upper level energy is passing near the Keys this morning. This area is about to reach the base of the upper level trough and from this point on will translate NEward during the day across South Florida and across South Central Florida this afternoon. As it crosses the depicted low the resultant coalition will (1): strengthen the low to a small degree, and (2) Begin to lift the low off to the NNE and away from the state. As it lifts north and pulls away from the state drier air will be advected down the state, mainly across North and Central Florida in the form of a 'dry front'. But as far as the weather goes today...
 
Current analysis shows highest dew points and mid-level moisture, enough to support rain showers, are playing a gambling game with the immediate east coast from near Patrick AFB - Jacksonville, more so once one gets south of the North Brevard County border where it's very touch-n-go. Light winds this morning should eventually become NNE by noon time as the low shifts slowly away from the coast. In doing so, some richer atmospheric mid-level moisture will be advected around the backside of the low into North and perhaps Central Brevard County and all points north to near St. Augustine. At the same time, the pocket of upper level energy will begin to pass over head, with its first heralding been made around the 1-2pm time frame in the form of increased near shore showers mainly north of the Cape. As we work into mid-late afternoon some of these showers will advect south along the coast and possibly reach as far south as Patrick AFB, at the most, in the more prevalent NNE flow which would affect the areas mainly along and east of I-95 before passing offshore near South Brevard. The Weather Channel and the SPC (Storm Prediction Center) are showing a slight chance of thundershowers this morning for the east coast this afternoon and evening, but I do not believe this will occur, but if it does it will be over Volusia / Flagler County. Meanwhile, across South Florida from near West Palm Beach and south other isolated rain showers could form by early afternoon with heating of the day in widely scattered fashion which will move off to the east or ENE and off the east coast as the upper level energy passes overhead that area. Just in noting though, should the area of low pressure depart the coast earlier in the day the chance of rain will go to pretty much zero this afternoon for East Central Florida.
 
TONIGHT: Chance of an isolated shower continues from near Cape Canaveral and points north after dark with South Florida clearing out due to departing upper level energy and loss of daytime heating, combined with drier air impinging on this area first. Again, these showers will be very widely scattered if they do exist at all over the land mass, so most everyone will be dry. If it does rain anywhere today or tonight, it will be brief.
 
MONDAY-TUESDAY: "Dry Front" passes through. Temperatures inland will be cooler mainly because of the drier air in place and not so much due to cold air advection as one would expect in a  true FROPA (frontal passage). Drier air and northerly winds will permit high temperatures inland to reach the mid-80s with lower 80s along the immediate coastal communities. On the synoptic scale, upper level trough will remain over or just to the east of Florida with the mid-level low cutting off near Tennessee. This low will move ENEward during late weekend into early next week and impact the NE states with more rain and wind, somewhere around Pennsylvania-Virginia-New York look to be the most impacted at this time. As this low moves out and weakens high pressure bridges east across the Mid-Atlantic States from the Central Plains while low pressure persists over the Caribbean eastward toward Puerto Rico.
 
Meanwhile, another reinforcing front will be passing across the Central States and enter the Deep South. This front will be the clincher as far as temperatures go for Central Florida by midweek, since it currently appears it might become stationary over Central Florida as it meets the boundary delineated by the lower pressures over the Caribbean. As such, the forecast for Wednesday and beyond becomes a little sketchy, although the impacts for Central and South Central Florida temperature wise appear to be pretty minor either way.
 
WEDNESDAY-FRIDAY: What will become northwest-north winds tomorrow will veer more toward the NNE-NE by late Monday and eventually NE-ENE along the coast on Wednesday. This will be a long fetch surface flow, and as such rip currents will become an issue as seas offshore become somewhat rough and winds become breezy at times due to the low pressure to the south and high pressure to the north across the entire state. As this flow persists shallow moisture will be advected across the state with an ever increasing chance of low topped showers to develop well offshore which would traverse across much of the state, mainly south of a St. Augustine-Cedar Key line. With such persistent NE-ENE flow in place, temperatures will vary little and begin to modify toward a norm 'central point' especially along the coast, where lows will be in the low 70s with highs near 80 (plus or minus two degrees). In other words, little variability between over night lows and daytime highs, most notable at the coast.
 
Exactly how long this pattern will persist is almost beyond the scope of reason, so in other words...not expecting much change locally for quite sometime beyond late Wednesday. However, further south toward Homestead and the Florida Keys moisture associated with the broad area of low pressure over the Caribbean might be able to creep northward beginning late Monday or Tuesday, and thus increase the chance of showers or perhaps even some thunder down there by mid-late week.
 
TROPICS: Invest 97L has been designated by the NHC (National Hurricane Center) and is located over a relatively broad west-east oriented region east of Puerto Rico. Elsewhere, and as one would expect per the discussion above, the Caribbean is being ogled with little affection toward tropical development. Actually, the chance of development there is pretty much zero during the next 48 hours. It appears that invest 97L has two options, either (1) strengthen into a tropical system, perhaps an Otto, which could play games with the forecast for the Southeast Bahamas but pose no threat to the U.S. East Coast; or (2) continue moving west or westnorthwest and never strengthen. Either way, Puerto Rico, the Dominican Republic, and the southeast Bahamas will see an increase in rains and gusty winds associated with them from time to time at a bare minimum.
 
So are we done with Tropical Concerns for the 2010 Season? Not necessarily so. A shift in the current pattern, which at this time is actually increasing in its complacency this morning will eventually come to an end, but this could take a good 2 weeks to do so. Expect the activity in the Caribbean to persist for quite sometime, and perhaps shift a bet west toward the Yucatan. Development down there could still impact the SE U.S. states later down the line. Hurricane season officially ends November 30th. Climatology shows that in late October storms have formed mostly from the Dominican Republic northwestward to off the Florida East Coast as well as in the SW Caribbean near the Yucatan peninsula, although storms have formed in all areas in between these zones as well.

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Friday, October 1, 2010

Early Fall Like Weather For Florida To Persist

(Image: Memories of Stormy Wednesday. Might not see something like this again until 2011)
RECAP: Happy October!  Ex-Storm Nicole is ex-no-more with mid-upper level energy currently impacting New England south to Coastal Virginia as it meets a cold frontal boundary up that way. Further south, and I'm sure some would quickly disagree, it appears there remains a surface reflection  of what was originally Nicole situated between the Western Bahamas and Jupiter Inlet. This area has moved little since late yesterday and from latest forecast models will continue to remain off the Florida East Coast during the upcoming first half of the weekend. Meanwhile, a cold front has pushed through the entire state as of early this morning, with a reinforcing boundary pushing through the state as I write, most notable by a drop in dew point temperatures behind this second boundary.  Higher aloft, broad low pressure trough extends down the Eastern seaboard with embedded bubbles of lower pressure within the trough up and down the the Southeast U.S. Coast just offshore. Further NW, high pressure tries to dominate but the trough can't get further east due to another area of high pressure to the east of it.
 
TODAY: Nice weather prevails. Lowest surface pressure at this time over the state noted at Canaveral, indicating the presence of the surface low well off to the SE..with a reading of 29.76" (compare this to surface pressures well above 30.20" when under the influence of high pressure at the surface and aloft under other circumstances (mainly in the winter). However, with the drier air mass moving in to re-enforce the already drier air than what has been in place all summer, expect skies to remain nearly clear. With drier air in place tonight, morning low temperatures everywhere will be even cooler than this morning. It was 69F on my Canaveral Porch this morning, with PAFB reporting 70F the hour prior (at the same time the porch also showed 70F). Just a little verification check on the accuracy of this Wal-Mart wonder. Winds will be NW-NNW to start the day and gradually veer to N -NNE by or shortly after sunset. High temperatures today in the mid-upper 80s, but with drier air in place it will feel almost like fall especially after 5pm.
 
TOMORROW: As noted above, cooler tomorrow morning most locales, although temperatures along the barrier islands might be the same as this morning if not warmer due to a slightly onshore wind component becoming established blowing across the warm Atlantic waters, mainly north of Jupiter Inlet. Otherwise, another nice day in-store until at least mid afternoon. This is in total negation to what is showing on The Weather Channel here this morning which is stating a 50% chance of rain tomorrow with thunder possible (I'm seeing that now as I type). So, just sayin'...perhaps it won't be so nice?
 
LATE SATURDAY AND BEYOND: Clustering this period together with a note of what the models have been trending toward. As mentioned in two earlier posts, it appeared that a strong NNE-NE wind regime would develop placing the coastal communities in a windy and possibly wet regime. This no longer appears will be the case. Each consecutive run of the NAM and GFS show a brief period of concentrated rain somewhere from JAX to Melbourne working toward Miami with time, but have shifted this event to occur from Early Saturday now to early Sunday. Additionally, strong surface winds are now no longer reflected to occur, ever. If this trend continues, we might not see any rain at all, anywhere...except perhaps extreme S. Florida with time in association with tropical activity in the Caribbean interacting with a surface boundary. But that would be many days away should that manifest, well beyond the scope of believability. Still awaiting completion of model runs as of this time, but for now will go with what the 'trends' have been as well as what the ECMWF has been indicating since last night.
 
As such, believe the chance of rain will wane even more with time in later model runs. If it's going to rain at all it will be late Saturday (mostly after dark/early Sunday). And this would be spotty and light at worst anywhere from Jax southwest to Naples. Beyond Sunday, another front could enter the picture as we head into later next week reinforcing the dry air already in place with no sign of rain on the horizon for quite some time. Any modification of the air mass along the east coast due to an onshore wind component appears will be too shallow for generation of showers, although can't throw out quite yet the chance of a cloud deck which would only put a damper on one's outlook on life, but not on outdoor activities.  A lot depends on what occurs with the generalized area of low pressure residing off the SE U.S. Coast and over the Bahamas. Should this area somehow shift to the west, the picture changes entirely for Florida...and this will be reflected in upcoming posts. The NAM does indicate it could come closer to the coast in the mid-levels by Sunday, but with little affect other than clouds before it lifts off to the NNE.
 
TROPICS: Latest NHC discussions and graphics indicate two areas of concern located in the western Caribbean and Western Atlantic. Any development in either area should be of no concern to the continental United States, as either one or both of these areas weakens with time, or any development worthy of intensification should be extracted toward the N and eventually NE and out of the picture. Still need to watch the Caribbean though as we head out in time. Eventually, the pattern over the continent will shift with yet another front working through which would open the gates for a system to move north toward the state. One could speculate one way or the other as to whether anything will occur, but for now it's purely speculation either way and thus will not elaborate further until something becomes even close to speculate upon realistically.

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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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