Questions Abound Today Concerning Where, When, and If

Storm Approaching Merritt Island toward Port St John on Saturday viewed near the South Gate Entrance of the Kennedy Space Center near Port Canaveral. It is evident from this image that this storm was 'feeding' on the mid-level boundary across Central Florida by the long line of clouds on the right portion of the image . Although not frequent, this storm ejected powerful lightning bolts and dropped very heavy rain. Another storm was further north, and outflow from that storm fed into this storm, further magnifying its very small but dutiful strength.

Zoomed in a bit. Lightning was coming out well to the left and right of the rain core noticeable in the center

TODAY: Very difficult forecast for today. And no surprise. Recall the model forecasts for today were 'dumped', and it was stated we'd figure it out today?...It is still hard to figure out even at this hour.  After looking through overnight guidance, that which came out so far this morning, as well as monitoring actual information using 3 hour animations of the changes since sunrise...today's post is again in lieu of any model. They all agree to disagree concerning where and when it will rain today...if anywhere.  Thus, here's the line of thought and how it transpired.


Initially, it looked like good rain coverage over most of the state along and south of I-4 with the most south of Lake Okeechobee oozing into toward East Central and perhaps toward Jacksonville. But....

IN looking at water vapor loops, it appeared that a weak circulation off of SE Florida which contains drier air might prevent the tropical wave forecast to move in from the East to have the effect thought in regard to increased rain chances over South Florida (which was to be high end coverage). In fact, it is now noon and there is not hint of rain to occur anytime soon. In fact, after reviewing time sequenced loops of the past several hours, this area is becoming more stable. There is moisture, but it is at the wrong levels to generate storms.  The other area is the old boundary across North Central Florida. It seems to have moved little, and actually a storm went up along it off shore earlier this morning that showed rotation and quite a bit of lightning. This boundary remains in place today, but not nearly as clearly.

Rotating Thunderstorm Off Shore Along the Boundary Across Central Florida

See the colored text for important  finer details. With all factors considered and after some internal 'negotiating a reason for rain', the case for best rain chances was  created. Storms were thought to form west of the coast of SE Florida and move toward the West Coast as well as over the Keys. Across Central in the white lines is south of that boundary that has been in place for 4-5 days. Out in the Northern Gulf though appears to be a disturbance moving east to move over the state..or approach after 5pm. This could add lift but add nothing for an atmosphere too dry over NW Florida but toward JAX is a different story.  The SPC analysis page also shows a circulation over NE Florida and it now shows up on the satellite image last hour (below). I was also watching for an outflow boundary to move west from the Atlantic to maybe start off some showers around 1pm ..but that seems to be fizzling well off to the east...although one model managed to pick up on it, to generate rain by 1pm. Not going to happen though

The circulation near JAX is evident, and another along the East Central Coast which was on analysis is not evident but drawn in with a question mark. Note how at noon nothing is happening  anywhere. 

Finally, the last factor that just became evident is that unlike any model forecast has shown and which explains why nothing is happening, most of the state has become capped in the mid-levels with convective inhibition. Thus, it looks to be another late day to evening rain chance, if any. One model showed close to no rain most anywhere today which might have ended up being right on...


The other 'finally' is that the next trough approaching from the WNW-NW forecast to up the rain chances on Monday might be moving in faster than thought. This could mean less rainfall coverage tomorrow due to the bad timing of its arrival for late day storms (except toward the South Half of the State). Thus, the forecast for Monday is in limbo. 


And one more thing while on a roll, so too may be the forecast for Tuesday out to lunch (per TV). Much depends on how strong, big, and in which direction Maria takes in the next 48 hours.


 If it stays further to the east than thought, the state might not get into the sinking air surrounding the storm..so there could be some rain chances as shown by the very conservative and unreliable NAM model.  The next boundary moving in tomorrow could get hung up across South Central Florida on Monday (in that case) and be a rain player for 'somewhere' for Tuesday, of isolated fashion.  Beyond Tuesday, the rain chances dwindle either way with an up tick on the weekend coming up.

FINAL CONCLUSION: This might be way over generous on the rain fall today but watching these areas when push comes to shove. The red is most concentrated rainstorms, and the areas near those red L's need
to be monitored. South Central is where the most unstable air is evolving as of noon time with the greatest moisture in the mid levels right along that old boundary shown in purple. With stronger upper level winds pushing in from the WNW late today and increasing mid level winds late as well, storms appear to be late in coming (after 5pm) once again north of Okeechobee County/St Lucie County. If a storm forms along that boundary and rolls off to the southeast (or even northeast toward Volusia), it could become quite potent toward Seminole County and into NE Orange and North to North Central Brevard County or into Volusia as it meets the east coast sea breeze from the SE - SSE which will form later in the day to any degree of 'strength'.  If it can rain...unlike some models show nearly none, we'll find out later today. But , if so, it could linger over interior South Central toward the east coast of Brevard/Indian River/St. Lucie County until mid-evening.

Summer's Last Gasps Through Monday, Cape Verde Season Shut Down (?)

Launch of a Delta II Rocket this morning from Cape Canaveral as captured by this blogger

“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”

TODAY'S SYNOPSIS (ANALYSIS): Not sure if there is a lot to talk about today or if there is very little. In general, the surface boundary has moved very little since yesterday and has become much less defined. Today seems to be a sort of 'transition' day with the mid-level trough having shifted much further north. Although moisture is now much further north nicely aligned with the best wind fields, instability further north is very insufficient for surface based storms, but sufficient to carry a storm based in the mid-levels. Exactly how the transition will have evolved further prior to sunset is unknown. None of the models have seemed to once again captured reality. In review of radar/satellite animations and trends, it is apparent that a weak disturbance is again crossing the state, but of much weaker origin than that of yesterday. It also appears to be based in the mid-levels but does have lightning associated with it regardless. This area of interest is  to cross just north of  Dead Central along the Beach Line and south of I-4, but favoring more toward the North.


Further South, dry air in the mid-levels is attempting to impinge across Southwest Florida but might make little more progress. This could actually enhance thunderstorms along the Southern  portions toward the Everglades/Lake Okeechobee/ and near the coast from Ft. Lauderdale north to  Ft. Pierce, especially along the east coast sea breeze.


Further North toward Central. Very light east coast sea breeze circulation close to the decaying surface boundary should prevail. Skies are quite sunny and heating is strong, but there is a very persistent area of sinking air over Brevard County in the wake of yesterday's system. Another disturbance (weak) is approaching, but will take until nearly 3-4pm to reach beyond the Orlando area, during which time the far east might be able to fully 'recover' and uncap. Thus, Brevard in particular is highly uncertain.

In this image from the Storm Prediction Center's webpage it can be seen that precipitable water is lower over the SE Gulf and trying to move into SW Florida. This is attributed solely to lower moisture in the mid-levels and could eventually enhance storm strength across South Florida especially along the East Coast sea breeze and around Lake Okeechobee breezes as far north as Ft. Pierce. The area near Brevard is circled mainly because nothing could happen in this area today. BUT, on the other-hand, conditions could change quite rapidly between 5-6pm as the area of weak rain-showers with some lighting approaches from the West, especially along and east of the east coast sea breeze .  

 The area in red is noted as being a bit capped this afternoon which currently completely precludes the area from receiving rain today. However, if it suddenly becomes uncapped late today, it would be right as the weak disturbance approaches from the west. To add, spiraling low level currents associated with the east coast seabreeze could build up around Canaveral Bight toward Port St. John and south toward Sebastian/Vero.  Southern Brevard/Indian River/St. Lucie Counties might contend as well with outflows from storms around the Big Lake to add to the mix. Under the assumption of course that anything can get going. Might be a late rain or storm show far east coast again tonight with rains lingering toward 10pm...and storms could get feisty if they can manifest along coastal Brevard and Indian River Counties.


Final note that again models are useless today. For example, according to the GFS it should be raining over much of East Central as I type, yet the sky is blue. Perhaps it is just fast. If it is correct but wrong on the timing, then east central could get a prolonged rain (light) in places through 10pm tonight. Looking out there now though, nothing suggests it will even rain at all.

**NOTE Best bet is keep an eye to the sky for those in this purple area heading toward 5pm and beyond in Brevard.. The surface boundary is still around there regardless and you never know when someone will slide one under the table to the waiter.

SUNDAY: Another random day of either very low rain chances or good ones. Thus, we'll play it by ear . I can see what guidance states but I again do not trust it mainly because it looks like something might be waiting in the wings well out in the Gulf which could head toward the state. The only thing that does not change is that the areas for rain look best roughly as in the same spots it has already occurred during the past 3 days.


MONDAY: Perhaps the last gasp of summer in the rain department. Not that we won't have more rain chances coming down the pipe. Simply, it looks like the end of the diurnal cycle, which actually ended with the passage of Irene. After Monday rain chances go to near zero through Friday when a small chance will be introduced somewhere, probably over South Florida. There where be some small chances somewhere, but it would be fleeting and small.


TROPICS: The Climate Prediction Center formally announced that as of August we are in a La Nina pattern. Much more will be posted in that regard in a follow up post in a day or so concerning what impact that has on Florida weather later in the year and into the winter. In regard to the tropics, it often means a continued late Tropical Season. Already, and as noted the other day, the Caribbean 's Pot Has yet to really be stirred...and is prime and ready for activity. It is that time of year that the Cape Verdes Season ends..and  it is definitely looking like there is little more to come down the pipe from there from off of Africa. Thus, we shift toward the Caribbean/ Eastern Gulf and western Atlantic closer to Florida and the Bahamas.  


Indeed, the morning GFS has a very large cyclonic circulation developing over the entire Caribbean all of next week including the Bahamas, all of the Great Antilles..and portions of the Lesser Antilles after Maria has made its final goodbyes (more on that storm tomorrow).


In closing, it was during the La Nina of 1999 that two storms came out of the Caribbean..one of them being..ironically...IRENE, in October.

Harvey and Irene , September and October 1999, La Nina 

Potential Exists For More Active Rain/Thunder Central/South

Image shows a departing disturbance east of Florida and a much larger and organized disturbance (up to this point in time at least) approaching the West Coast of Florida  from the WSW-W. Nate is shown in the Bay of Campeche (BOC)

  Rather interesting and a bit complex day in store. As has been the case, a stationary frontal boundary remains across Dead Central. This boundary has oscillated a bit off and on, sometimes acting more like a warm front as it moves north a bit (Wednesday) and then south a bit as a cold front (Thursday). It looks as if today the boundary will act again as a warm front...which means better chances for thunder as opposed to predominant rain with only isolated thunder that stays more toward South Florida.  Today's post, being what it is, almost completely disregards the model forecasts for today since none of them seemed to have picked up on this system. The main fall back or 'concern' is how well put together this area will remain during the course of the afternoon. Since  early this morning it has not faltered, and lightning activity associated with it has increased. It is even showing up on a Tropical Web site , appearing almost more impressive than Nate to the untrained eye. (see the figure further below). The clincher today will be whether this 'complex of storms' holds together or simply fizzles before reach Florida. This post trusts it will hold together, but either way there is still a rain chance over the South half of Florida.


Timing of the actual disturbance shown in the image west of Tampa Bay puts it toward the East Side around 9-11pm tonight, but it is the lifting in the atmosphere ahead of it that might actually generate (and potentially enhance) rainfall coverage and strength of thunderstorms particularly south of the surface boundary. The air so far today, like the past three days, is most unstable over South Florida or roughly from Ft. Pierce and South. However, it is possible a good part of that instability will be lifted north later today closer to the stationary boundary into Central Florida as this disturbance presses closer to the west coast.

This is the latest radar as of 1:30pm out of Tampa's NWS WSR-88D radar. Drawn in is the stationary front's approximate location. The two red lines indicated the area within them to be effected by this disturbance through midnight tonight either by rain, thunder, or simply enhanced cloud coverage. South Florida will likely see rains well in advance of this system since that location is already most unstable and had no early morning clouds in place. It may be that South Florida will not be nearly as effected by this system as will Central Florida and Portions of North Central if not North Florida from near Gainesville - St. Augustine....that would be tonight.

This Gulf Disturbance does not have any vorticity analyzed with it, but it does have Low Level Convergence and Upper Level Divergence with it..which means that perhaps the vorticity is not being picked up and/or showing on analysis, which after all is extrapolated from a model (which I've tossed for today).

This images looks rather messy. I didn't think so until i look at it now.  Florida is in the upper right. Note the disturbance to the west of Tampa. The white arrows are the DLM, or Deep Layer Mean flow. The blue and yellow circles near it are convergence and divergence. Thus, it looks like this 'whatever'...or disturbance should make it across the state.  Otherwise, Nate can be seen in the BOC spiraling in place. The cloud coverage is not as 'impressive' with Nate it is west of Tampa  when not in animation. DRY AIR is noted north of both systems..which is located North of the Boundary lying  across Central Florida,. The driest air is restricted to the Panhandle currently.. 

TODAY:Having not seen any official forecast discussions regarding what is in the Gulf   remains an allusive mystery this hour of the day. Timing clearly showing it moving toward the East or ENE and approaching Tampa Bay..per their radar. Based on this timing, it will cross central Florida from late afternoon through and past midnight...in some form or another. Thus, it could cross as merely cloud cover, under the assumption it even makes it as far as the state. Models for two days showed something coming to Florida today, but for some reason as of this morning it was no longer portrayed. This sure looks like one to me though.


The best thunder/rain should occur system or not this afternoon over South Florida working north with time. Again, guidance has been a bit all over the place with where the best or strongest thunder will occur today, but the consensus would be from near Boynton Beach north to Vero Beach. Yet further north ...North Brevard to the Volusia Line could be a contender for thunder or heavy rain (or perhaps long lasting light to moderate rain) due to outflows from the south meeting up with the surface boundary combined with  increasing mid-level  lift ahead of the system to the west. Although in the image below is a caption reading 6pm and beyond for the northern areas, 5pm might be a better time frame for starters just to play it safe. Some stronger storms appear to be  most likely to occur, if any where, over Palm Beach, Martin, St Lucie, and Indian River Counties.

Storms could be enhanced near and north of Ft Pierce due to the lake shadow as well as toward West Palm. Further south, the east coast sea breeze combined with a SW steering flow that is weaker than further north could generate stronger almost summer like storms toward the Broward/Palm Beach County line.  To the north toward Brevard county a light sea breeze combined with lift ahead of the approaching system and its location closer to the main frontal boundary..as well as the outlying possibility of outflow from storms created earlier to the south could enhance a storm toward Ports Canaveral/St. John/Rockeldge/Cocoa Beach area. If So, that would be between 5pm -7pm. Elsewhere, rain is possible further north and just maybe thunder as far north as Daytona...from elevated type storms with what would probably be in - cloud lightning as opposed to cloud to ground lightning. This area has never stood out in guidance (yet) to be a thunder contender, but since I'm not using much guidance anyway we'll give further north the benefit of the doubt. Again, just for starters. rains could linger until midnight on the east side of Central Florida tonight.

  
TROPICS: As of now, Nate is not expected to get beyond his little Watering Hole in the Bay, as opposed to the sudden shift in models that occurred yesterday. This bears with the initial line of thinking and forecast reasoning, as well as with what history has told us over the past 120 years..so why change now?  Likewise, Maria's fate is uncertain if there is to be one. The official forecast has the storm heading right through the Lee ward Islands and toward the Bahamas which at that point uncertainty becomes quite large. In fact, the storm's short term course toward the WNW for days ahead seems a bit flaky. 


If per chance the storm were to follow a path noted earlier of low level convergence it  would again  be steered a bit more toward the west..in which case then any projections further out in time are already out of sync/agreement with reality. Even the most southern track in the forecasts though have the system curving before reaching Florida. That seems quite realistic as of today ...namely because the Blocking Pattern Referred to the other day remains...and thus so does the surface boundary over Florida. 


*** Future Forecast no matter What I'm hearing on "TV" are being disregarded by this listener. The future of the forecasts is completely contingent upon when the blocking pattern breaks down..which can be anywhere from 4 -10 days (at least)...we are on Day 3-4 now..and the pattern so far looks to hold until AFTER Maria presses north of Florida to the east.  Models keep breaking it down (which is normal to have happend)..but the truth of the matter remains uncertain. It's a day by day deal. ..therefore, until the blocking pattern has clearly broke which could be as soon as Sunday or as late as  Wednesday...the best forecast rule to follow is "Run With Persistence"...and keep an eye on Maria.


For pre planning purposes though, late Sunday through Monday look to have much better chances for rain.

Nate's Fate (or Lack Thereof) Grows Uncertain By The Hour - And Maria?

Analysis From www.spc.noaa . gov   , The Storm Prediction Center. This nformation is extrapolated from trends, observations, and the RUC Model (without going into the finer details). This Image shows a 'disturbance' or vorticity maximum (max) crossing Central Florida. After which, things will be quite calm for a majority of the day, East Central. Another disturbance is shown to cross Central Florida During the afternoon (lower left). South Florida will remain the most unstable throughout the day, while north of the Purple area some recovery from passage of the first disturbance will take all of the afternoon to accomplish. In short, rain chances end up occurring in the same places and at the same time as yesterday for the day with some minor differences.

TODAY/FLORIDA: A disturbance is crossing Central Florida now but you'd never know it from looking outside. In its wake will be some minor drying in one atmospheric level and NVA (negative vorticity) and subsidence over Central Florida. South Florida will not contend with this settling of the atmosphere and will grow increasingly unstable during the afternoon, although the level of instability attained yesterday so far does not look to be as great as yesterday to start with.


Meanwhile, further north the passage of the boundary shown in orange above continues to impact North Florida. In fact, Tallahassee last hour was 56F degrees and Crestview was 59F. Many other readings hovered close to 60F this morning with much drier air. This influx of lower dewpoints (drier air) reaches to Flagler County  toward Brooksville if not closer toward North Tampa Bay. Temperatures this morning actually got into the low 70Fs in many locations, and last I looked Okeechobee was at 68F with light fog. It has been a LONG time since temperatures have gone this low..since late Spring.


Thus, it will take a while for the atmosphere to be in working order for storm generation today (Central)since the sun rises a bit later and is at a lower angle in the sky. Regardless, with enough destabilization at work   under sunny skies (clouds not a problem like earlier yesterday) and another disturbance approaching..thunderstorms are again a good bet across South Florida and portions of South Central Florida mainly along the east side from Vero Beach south to Ft. Lauderdale or just north of Miami beginning just away from the coast sometime after 2:30pm -3:oopm time frame. Not sure a sea breeze will come into play today, but I suspect a light one can sneak in there.Some of these storms could be rather strong with gusty winds and inherent lightning strikes.


There is a chance that if activity gets started earlier(South) than expected that outflow from these storms will work back away from the coast and generate another round well west of I-95. That same outflow could press north to St. Lucie/Indian River/and Southern Brevard Counties for activity after 4-5pm.


Further north the thunder chance looks a little less certain, but a storm might be able to get going near the Surface boundary in Northern Brevard due to outflow moving north from earlier storms to the SW and South and ramming into the prevalent synoptic scale frontal boundary.  Once again, rains could linger until around 8pm in light fashion along to just off the coast of Central Brevard south to St. Lucie Counties.


Even further north, do not believe that much beyond the Volusia county line the atmosphere will recover enough with ample moisture in depth coincident with the vort max passage to generate anything other than rain showers...but changes are in the works and this could change during the course of the late morning to early afternoon. So far though, not seeing through any guidance for storms to transpire beyond what has already been written above.


FRIDAY: Models again are showing a series of disturbances to cross the central peninsula..even more pronounced than today. Almost makes one wonder if they aren't 24 hours slow. Regardless, tomorrow looks again similar to today..however, as noted yesterday, moisture and the boundary will lift further north as Katia moves away and further North as well. That factor combined with the agreement that high pressure will press in from the east across South Florida in the wake of Maria. Dynamics should then also cross further north but not be as strong, so the fate of Friday is a bit uncertain, especially over South Florida where there will be near zero dynamics other than daytime heating, (which should be sufficient for thunder west of Miami Metro in the Glades).


BEYOND: Saturday and 'Beyond' depends on the pressure  and moisture pattern more closely related to tropical activity, which has been changing rapidly this morning now that overnight model data has become available and will still be filtering in through 3 pm this afternoon. Speaking of the Tropics:


TROPICS: In summary and to cut to the chase, models are trending to agree to disagree this morning. Last night almost all guidance was in near complete and total agreement that Tropical Storm Nate would be doomed for shelling pesos in Mexico; however, the 2AM GFS (which has been quite good all summer)...just shifted gears into reverse. It was first to show that NATE would now lift out of the BOC (Bay of Campeche) once Katia pulls further away...and other more frequently processed data is starting to follow suit.


 Although there is very dry air over the Northern Gulf behind the boundary that is over Central Florida..as noted previously, that boundary is to lift north as Katia moves further north and the ridge builds in across South Florida (Friday). This in turn lifts moisture north as well as merges it with some that has oozed south around the backside of the broad expanse of territory covered by old Lee which is now all in the mid-levels of the atmosphere. Until this can be fully ascertained to be of truth, the future forecast for Florida remains uncertain. We will know with much greater certainty though by 3pm this afternoon. But note that even the shorter term track models are trending the turn northward as opposed to only 3 hours ago prior to this writing.

Most recent 8AM EDT information. Earlier, only 2 tracks took NATE northward. I have also drawn in YELLOW the latest forecast 2AM track of the GFS Model. The official forecast track is shown in WHITE.
Note that the GFS takes NATE as a tropical Storm/Depression into a loop around North and Central Florida as the system begins  to bump heads with high pressure building across the Mid-Atlantic Region. 

NATE is shown in the little white circle , center of image. In lavender is the error of margin in the official forecast track. Two things to notice is that there is abundant heat energy to the north of the system, partially under that dry air by those reds and oranges over the Northern Gulf Coast region. There is energy under that dry air though, as well as in the Caribbean. The CARIBBEAN has not been touched this hurricane season and could easily remain a hot bed for future activity. That area has been shown to get active from time to time now...but guidance has yet to figure how, when, or why.

Elsewhere, there is Maria. This storm is just ekeing out  tropical storm strength and is moving rapidly to the west around 23 mph. I've noted in this image the forecast margin cone of error the Hurricane Center has generated (yellow arrows). Included as well are notes that the greatest shear currently is toward the north side of that cone and the best heat energy is located to the south side of the cone. Forecast tracks of consensus models are very close to the official forecast track, but several other models are taking Maria further south toward the Central Leeward and maybe even northern portions of the Windward Islands. That is what the NAM model has been showing, but then again, the NAM has not been remotely reliable in months. 

Here we see the steering in the white arrowed lines. If Maria remains weak (which looks likely at this time)..the storm could continue west and into the greatest heat energy levels in the water. This heat energy extends into the Caribbean. Thus, this storm ALSO needs to be watched, although all models at this point are taking Maria well north of the windward islands, and then to curve out to sea even further east of the U.S. than Katia has. 

  
Lastly, some model guidance had indicated that a tropical wave would be pushed out ahead of Maria toward the Caribbean and South Florida during the next 72 hours. Whether or not this will even come to fruition is too soon to set in concrete, but if so, would affect the weather outlook for Florida going into latter parts of the weekend.  Also to note, the GFS has been showing every other run or so for another storm, perhaps Ophelia, to form or move into the Caribbean heading toward the last week of September. The last run no longer shows this. Perhaps it was actually picking up on Maria though but has yet to resolve the information as it filters in (?).  


To further complicate matters is that fall is trying very hard to take hold of Florida. Typically, the first cold frontal passage into Central Florida occurs during the mid-last portions of the month, although last year this did not happen in full until September 31st. It was with that event that summer ended immediately overnight with a flick of a switch as a tropical system cut past far South Florida.  That event ended summer for all but SW Florida for another 7 days as easterly flow took over. The GFS of 8pm showed that to occur as soon as next week, but as of 2AM that all abruptly changed. We will need another 2 runs to confirm  Which will it be..End of Summer or Beginning of Fall? 

Faith in Future Forecasts Fruitless - Synechdoche Required

RUC FORECAST FOR EARLY AFTERNOON: At the surface a stationary frontal boundary is aligned near Tampa Bay toward North Brevard County. Aloft, a mid and upper level trough is located in general where the lavender boundary is drawn. The deepest atmospheric moisture is focused along the surface boundary, but ample moisture resides in both directions for showers or thunderstorms today.   Note the large red circle. This is shown as such for a reason which is later discussed.

TODAY: Another day of sketchy forecasting at hand so synecdoche is the word of the day, but a few rules of thumb can likely be applied, so I'll try not to palliate.  As expected could occur, a vorticity max passed across Central Florida overnight producing thunderstorms on the west side into the interior which weakened the further east it progressed. It is possible at least one or two more will follow suite during the course of the next 36-48 hours, but timing is nearly impossible to determine. The latest RUC does forecast a fairly significant impulse to cross Central Florida after noon time through dark though today, so rain chances could elevate during this time frame, hence the good chance of rains in the official forecast per official outlets (I'm assuming). On the otherhand, that energy might go into manifesting as simply cloud cover, especially north of the Beach Line. 


Otherwise, the best instability and chances for thunderstorms will occur along and south of the stationary frontal boundary (wherever it happens to be this afternoon) and where skies are cleared enough for instability to build up. Those storms will move briskly toward the ENE so even locations upstream of their formation could get in on the act, even if mostly cloudy. Skies over South Florida are much more sunny this morning than they are closer to the frontal boundary, but bigger breaks are anticipated central by noon time..not so sure about that either if more energy moves in to early. The best instability is forecast to mount South of the surface front for storm initiation, but steering could transport this activity into the prevalent cloud covered skies just to the north of their initiation.  The surface front will waiver north/south by 50 miles today and tomorrow, but should lift north as Katia progresses north as well. 


In the image above is the mid-level depiction of Hurricane Katia to the east of Florida. As the storm lifts north of the latitude of Central Florida, this should also lift the surface boundary north a bit as well, especially because high pressure is expected to build in from the east across South Florida in Katia's wake. By Friday the boundary should be as far north as I-10.


In consideration of all the factors above, it appears showers or considerably cloudiness could be in store for  North Florida, with showers and a very small thunder chance from near the Flagler/Volusia County line south to North Brevard. Further South toward Central Brevard to Palm Beach County (especially if a sea breeze can form), thunderstorms are more likely. Indian River/St. Lucie/Martin/Palm Beach County toward the coast seem the most likely candidates for this activity after 3pm and beyond until dark at some point. The west coast also has a chance of thunderstorms.     


THURSDAY/SATURDAY: There is great uncertainty in the forecast for the follow up days, but given the expectation (and likelihood) that high pressure will build across South Florida from the Atlantic, this will place South Florida in very weak steering currents with an east coast sea breeze as far north as at least Sebastian Inlet. But, this high pressure will have drier air associated with. Hence, the greatest moisture reside across Central and North Central Florida..at least for a day or two. What happens in the Bay of Campeche in regard to a potentially strengthening tropical system is also a big player. If a storm can get wrapped up in this location, then the moisture source for Florida will be reduced and as such, the rain chances everywhere. So far, it looks like it will be a long time coming before that will occur though. Thus, thunder storm and rain shower chances prevail during this time frame..with that chance working northward toward JAX with time.

LATEST enhanced infrared satellite image and precipitation locations today with notes included on the right margin in orange. Note the cleared skies over South Florida south of the boundary across Central Florida. The blue dot on the east coast is what is left of thunderstorms that formed along a vort max (vorticity maximum, aka - 'disturbance') early this morning and moved across the state. Thunder 'seems' most likely today in the orange areas, but naturally can't possibly be all inclusive. Thunder will not occur in those entire areas either. NOTE the area in the Bay of Campeche and toward the SOUTHEAST SIDE of the Yucatan. This is referred to below in the "Tropical" headlines.    

  
TROPICS: "Much ado about nothing or reason for greater attention in the SW Gulf ?" is the question of the day. Models are split 50/50 on whether this area will become well organized and then threaten the northern Gulf toward the Pensacola/SE Louisiana area...or...never progress into the Gulf at all. Big Difference. So word of the wises, be prepared for surprises...but not anytime soon. This system has a long way to go before becoming 'well organized'..at least as of this morning. Once the area is investigated by the Hurricane Hunters more will be revealed.


For instance, the ECMWF model implies that as Katia moves north, that storm literally drags all of the dynamics and pressure systems associated with remnant Lee along with it. That includes a profound blocking pattern the United States has entered. Blocking patterns tend to hold fast for 4 to 10 days, thus, it is more then questionable that a hurricane in passing would have such an effect on a Northern Hemisphere blocking pattern. But, that is not to say that some variant of that model's hypothesis can't be reached. Either way, all models show that Katia will become one MONSTER of a extratropical storm heading into the North Atlantic ocean in the next 3-7 days. Extratropical Katia could be a major player in many locations in the Northern Hemisphere two weeks down the line.


In regard to the  ECMWF, haven drawn the blocking pattern out, the next assumption is that this willl open the gates for the system in the SW Gulf to emerge and work north and east toward the NE Gulf as a hurricane.


HISTORY OF THE BOC: Historically, the majority of storms that form in this location are pulled northward , but not all of them. In going back and looking at this history, I found that the storms that did so nearly ALL occurred early in the season and not later. This would be because cold frontal boundaries, such as what is now in place...penetrate further into the Deep South the later in the season one progresses with time preventing from working north. That is...all of them but 3 since 1900..and two of them occurred onlly 2 years apart around 1903. The only other one that was actually a hurricane at this time of year was Hurricane Opal...which incidentally followed a Gulf storm just a time prior to another one. Think Lee. The problem with such a due course of action in 2011 is the current location of the frontal boundary and the VERY dry air behind it. This will have to be greatly displaced..and for that to occur, so would the high pressure over Texas have to be displaced, which has been in place since Spring. 


Another observation made this morning is that the models might be giving this system more 'pre-organization' than is realistic. This determination was realized when looking at lightning data and satellite imagery. The most lightning is occurring on the Southeast side of the Yucatan and not in the Bay of Campeche. Thus, the area of low pressure might be much broader than the tight knit depiction of the models.


Below is a two fold image..the lightning as noted above..placed side by side with the track of Opal. Note that Opal FORMED SE of the Yucatan, then crossed it..then took its course toward the Southeast U.S. Other storms that were tracked from the BOC (Bay of Campeche)  toward the U.S.  did not originate there..but rather further east in the Caribbean.

To the left is lightning imagery. To the right is the track of Opal. Note where Opal Formed.

Opal crossed the Yucatán Peninsula while still a tropical depression from September 27 then strengthened northward in the Gulf, becoming the most powerful Category 4 Atlantic hurricane before making a second landfall, October 4, in the Florida Panhandle near Pensacola as a 115-mph (185-km/h) hurricane. Opal devastated the Pensacola/Panhandle area with a 15-ft (5-m) storm surge and travelled up the entire state of Alabama, becoming a tropical storm in Tennessee. Opal also caused heavy damage in the mid-Atlantic states before dissipating. This is the track implied by the ECMWF, except it is not generating in the BOC..and it has the storm taking this course of action in fairly rapid fashion. That means, Katia needs to pull out the blocking pattern in place in the next 96 hours. The ECMWF is not the only model to show this trend as a side note. So this is not to imply the ECMWF solution is not plausible.


The other side note to consider is that 'even if' this system develops in the BOC and lifts northward, it still must contend with upwelling created by Tropical Storm Lee as well as cooler rain waters that drained into the coastal areas off the Mississippi and other tributaries. Thus, to palliate the storm's future course (in this example) perhaps a 'big storm' would be greatly weakened before a true landfall.


The final note on this system...is that other than hurricanes..there was a   Tropical Storm that crossed the Big Bend area of Florida at this time of year ..this seems more likely if anything were to move north.


Outside of the BOC, there is yet another developing system approaching the Leeward Islands. This looks to be our next named storm system. Again, guidance is leading the reader in two directions. Will that system follow the course of Katia..or continue toward the Caribbean?  Again, we are back to square one with what Katia does or with..or what results from..the storms interaction with the remnant blocking pattern of "Lee".


Thus, Future Forecasts are Fruitless not only in regard with Florida's Local Weather, but with regard to the tropics as well.


In closing, the more interesting system if none of these systems impacts the Deep South will be the NEXT one toward the last week of September. By that time, and under the assumption the blocking pattern does not break down early (in which case none of these shorter term systems will directly strike the U.S)..the pattern will or should be in the process of breaking down, but not before the next Atlantic system will already be in the Caribbean. As always, all thoughts are of the writer's own..images provided are actual guidance or real-time information...and future projections, especially beyond 1-2 days are as good as a blind man relying on a blind seeing eye-dog.

Strong/Marginally Severe Wind Gusts in Storms Today

(1)Image shows mid and upper level support for storms . Divergence (purple)well overhead sustains storms, whereas mid-and lower level convergence (red) creates and holds them intact. Note the lack of rains and cloud cover toward Southern Volusia and South. Also to watch for lightning prone storms near the Lake Okeechobee Shadow in Martin/Palm Beach Counties..and Indian River toward Southern Brevard Counties

Images 2 through 4 (below) (1 is above) and  1 above reflects the upper levels. Not too often we see those purple and red lines overlapped in Florida this time of year...now the lower levels, Surface:

(2) Original image shows 0-3km helicity, looks to be caused by wind speed shear (vs. directional shear).
The greatest thermal instability will mount where skies stay clearer longest which is more into Brevard (Central/South)..and Indian River. But synoptic scale wind shear is not quite fully in the southern most area..but could work in after 4-5pm.  Additional highlights: Storms could regenerate further north in Flagler County later as well despite early day cloud cover and nearby showers. Purple Boxes are for the synoptic scale winds (North) and Lake Shadow (South, particularly the one for near MLB to Vero Beach/Sebastian Inlet) .

The above image is mainly showing the best wind profiles will be over Central Florida, but greatest instability will likely mount a bit further south of the best winds ...rather..best for manifesting strong/severe storms. Thus, storms could be active out of those winds as well, along the northern side of the Lake Okeechobee shadow'...assuming there is one. If skies stay clearer long enough, a near neutral sea breeze/vs gradient wind could develop at the coast south of MLB Beach. Either way, that should not make a difference.  Also to watch, is toward Coastal Palm Beach County. 

(3)Latest visible satellite image shows extent of clear sky vs. cloudy.
The leading edge is progressing at a rate it should reach the area around KSC by noon
 ..by which time heating will have begun to increase instability. It is also unsure if the leading edge  will slow down as heating commences. It looks like pure 'outflow' right now..with the true leading edge running back toward Flagler County. Other showers to develop along the SW Coast and work ENE-NE during the late morning hours.

In summary, the same boundary that absorbed Tropical Storm Lee is moving into North Florida. In fact, the temperature across the panhandle was only 60F last hour or two up there. Meanwhile, the boundary extends well into the Mid-Atlantic states and south toward the Bay of Campeche..but might not get much further east in the next few days. The reason being the approach of Hurricane Katia. High pressure surrounding that system could work as a 'blocking mechanism' preventing further east ward progress of the trough. For Florida (other than the panhandle), it could get as Far South as North or Central Brevard. The NoGAPS, latest GFS, and SREF models agree on this scenario through Thursday.  


The Storm Prediction Center has placed Central Florida in a Slight Risk for Severe Thunderstorms today due to winds gusting to in excess of 58mph. There will likely be more fast moving rain showers than thunderstorms...but even heavy rain-showers could generate some gusty winds in the area noted ..which matches closely to the area highlighted in the above images:

(4) SPC FORECAST from www.spc.noaa.gov 

BEYOND TODAY: Expect that the boundary will work toward Central Florida and struggle against approaching Katia and high pressure beginning to build westward across South Florida in the mid-levels. This in turn would create a 'deformation zone' across Central Florida of closely opposing winds at the same level side by side.  Additionally, low pressure development along the far south end of the boundary will generate an area of low pressure in the bay of Campache area which would also slow further eastward progression. Between that area, the deformation zone..and then the remnants of Lee (which is expected to retrograde..or rather, be forced back toward the WNW rather than advancing on to the NE) toward the Ohio Vally.. these three low pressure areas will generate:

A Menage A Trois' of Low Pressure areas:

IMAGE FORECAST FOR THURSDAY: Strength of low in Bay of Campeche highly uncertain but is not likely to impact Florida directly in the next 5 days, if ever. Note that Former Lee, Katia, and this low are loosely 'connected'.  

 THURSDAY: Wednesday might be more of a 'rainy' or showery day..but we'll cross theat bridge tomorrow. On Thursday, the initial surface boundary will begin to wash out. It is possible a low pressure area will form along it either in the Gulf WSW of  Naples or over Central . Either way, it would cross the Central to South Central Peninsula and again create a potential severe weather threat...mainly Southern Volusia toward Ft Pierce on the east coast with general thunder south to Key Largo.


FRIDAY:  Another Sea Breeze day with SW Steering. Thunder again possible South of Titusville to Miami/ Key Largo Area

Un-Named "Lee" Now a Bigger Threat -"The 'Tropical Connection" Remains, Floridaekend"

Area in Blue Should have an Enhanced Tornado Threat as Old Storm Lee Opens Up a Bit..taking a course as shown in Black. The Official Track from the NHS is shown in White just to the left. Either way, makes little Difference. The area in Green will be prone to Heavy Rain and a Tornado Threat Throughout Today. The chance of Tornadoes today looks higher than yesterday as Lee begins to interact with approaching frontal boundary. Note the DRY AIR behind that front. Also note there is a Lagging Trough into the Gulf with active thunderstorms associated with it. This area could approach Florida beginning Wednesday and Be In Place (at play) over Central Florida by Wednesday/Thursday. The heavy rain area shown could shift around and is not meant to be exclusive of areas 50-100 miles to the east or west of that shown

TROPICS/SUB TROPICAL BLEND CAST: Lee was downgraded, but even so, the system now Un-named as a former storm likely poses MORE of a threat than it did while it was named. Reason being two fold: (1) Entering a more mountainous area with deep moisture and interacting with a frontal boundary/plenty of wind/energy dynamics ..the combination makes for a lethal rain making machine.  (2) The system , now having opened up a bit, will continue to do so through the day, and with that, wind fields will become less unidirectional with height. The area in Blue is the best area for a tornado chance today, but even along the Gulf Coast of Alabama, The Florida Panhandle, and Mississippi, the smaller threat will continue.  I would not be surprised to see the risk area extended further to the east and south a bit later today toward the Jax/St. Augustine area..more likely toward Gainesville...very late...but...


FLORIDA ELSEWHERE: Skies have cleared today as opposed to yesterday. As such, very warm today with highs in the 90Fs everywhere. Thunderstorms most likely almost anywhere Central Florida after mid afternoon through mid-evening. There seems to be a potential for 'enhanced' activity from Brevard County and North along and east of I-95 as instability has been building up offshore Brevard since yesterday. In deed, last night an area of thunderstorms developed well off shore the county and persisted for nearly 5-6 hours. This CAPE (instability) has increased even over night.  Thermal profiles for lapse rates (changes in temperature with height in certain levels between two altitudes) aren't all so great. but moisture is high...and sufficient. Do not expect wide spread activity at any one time..but they could line up and move on through inland areas any time after 2-3pm, perhaps a bit earlier further south. The only area that does not look all so great for storms is far South Florida (Dade/Southern Monroe). Most of this activity might only be showers...it is too early in the day to say for sure, but that currently appears to be the more prevalent mode except for near the east coast and interior. 


BEYOND: Tuesday looks similar as the remnant low moves slowly toward the ENE-NE toward the Southern Appalachians and weakens. Moisture and some dynamics might remain for part of the day..but the rains will continue for quite some time as it by then will be interacting fully with the approaching cold frontal boundary.  This moisture/front combination will stretch further north and east toward the NE states. Thus, more rains for the Appalachians of the Deep South and Mid-Atlantic, with run off of creeks, rivers, streams running into the lower land areas. Downstream communities should be on high alert for Flash Flooding.


For Florida, Tuesday looks like a variant of today, with perhaps a tornado threat emerging toward the NW Coast as the lagging boundary approaches the west coast. A tornado watch MIGHT be needed for an area around Brooskville/Cedar Key/Gainesville/ and maybe toward Ocala and west to far NW Volusia and western Flagler County late.  Areas further south might actually dry out just a bit, with a dry slot of air possibly remaining just ahead of that trough..this will have to be re-evaluated on this day. The trend has been for that dry slot to fill in with moisture a bit with time.


WEDNESDAY/THURSDAY: Potentially interesting day for Central Florida. The latest model forecasts are showing CAPE/CIN fields VERY similar to that which appeared when Squall Lines went through Florida in the late winter and early spring. With perhaps a very shallow sea breeze along the east coast of South Central to Central, these storms if this scenario unfolds could be very 'active' in some form. TBD on Wednesday/Thursday.  


BEYOND: The tropical connection continues as of Lee's Demise across the state. The trough so far is not forecast to get beyond Brevard as far as Southern Passage...not for a long time. Recent trends have shown it not to get quite as far south...never barely clearing Volusia before retrograding and weakening by  Friday and through the weekend.  


It is interesting that in the meantime that same boundary will extend the entire way to the Bay of Campeche.


Tropical Development is again anticipated along that boundary anywhere between that location toward the north side of the Yucatan. This activity will likely interact with the decaying boundary for a time..and if it becomes more organized and closes off, then rain chances would go down for a time. However, the trend has been for this 'low' to cross Florida going into the weekend later on down the line, but never getting very far beyond the state. This in turn sets the stage for further development. Bear in mind, that while this is all going on over and near the state and the Gulf, another tropical entity will be on the approach from the western Atlantic and/or the central Caribbean.  Thus, for the rest of the month (or at least the next 3 weeks), watching the Caribbean/Southern and Eastern Gulf/and SW Atlantic for future storm formation.


Katia is now the best looking storm of the season, but it appears will hold very little U.S. threat. Even the outliers like the Navy NOGAPS has trended the system just far enough off the coast than to be nothing more than a marine and near shore/rip-current interest.

"Lee the Loopy Chimney" Lingers - Lingering Effects Could be Long Lasting

General Area of Lightning Indicated By Dots. Circles Show
in General  The Lopsided Configuration of Lee as it entrains (extracts)
dry air from the WNW. Locally today, showers and some thunder most likely as shown over Florida..some sprinkles are possible into sunset further north near the east coast, St John River Valley basin, brief and no impact. Note that the lightning is well out in the Gulf..not near Lee's core. This shows that 1) There is plenty more energy out there to be utilized and 2) There is more to Lee than just the central lowest pressure and immediate wind fields are located, as opposed to well organized, tight-knit tropical system.  Now, see the next image.

See the captions. Lee is Shown by the Red "L". Heat energy in the Gulf in Orange and strongest stacked winds in Black.

Other colored areas show upper level divergence and low level convergence which extend well to the south and east of Lee. That is where the lightning is most located. 

TODAY: Going to try to leave it brief today for the locals. Latest on Lee is that the storm was drifting north at 5 mph or so...and latest radar animations show that Lee is doing that as well as perhaps taken a dogleg to the west. Rain has moved into far Eastern Texas as a result. Although dry air has been getting entrained (pulled in toward) into Lee from Texas, the storm is creating a bit of its own moisture field as it has gained a bit in organization. The very broad wind field over the Gulf is taking in the highest heat energy residing to the south and east of the central area of Lee shown in orange above, of which there might be actually two if one goes up a few thousand feet. Lee seems to be feeding off the heat energy and, like a chimney, is spewing its ashes and soot over the far reaches of the Gulf (divergence aloft), and most of the Northern Gulf Coast communities as fuel keeps being supplied from the Gulf (convergence). The storm can not move at this time far from the source due to high pressure now located to the NE through North of the storm...there is very little shear to inhibit or rather tear down the chimney..so the Chimney Sweeps are in high demand to keep the embers burning. Looks like they are doing a good job too.


Per the latest NHC forecast and model consensus, Lee could linger well into Monday before making a painfully slow move toward the North then eventually NNE-NE as a frontal boundary of unseasonably strong proportions swoops into the Central and Southern Plains states.  All of the models have Lee eventually succumbing to this trough and finally breaking down and being stretched out toward the NE with time. All of them that is, except the NAM...which insists Lee will maintain itself..likely do a loop, then head back toward the breeding grounds.

The North American Model (NAM) has this course of action indicated. Note Katia in the right side of the image. but this time around Thursday or Friday. Again, this is by far an outlier, but nonetheless, indicative
of not only the uncertainties in where Lee will make its even larger impact in days to come, but also those that have been indicated in the long-range through the 3rd week of September. In other words, although this model perhaps can be disregarded it could be used as a tool to read between the lines of what other models are showing as being more definitive. Eventually, something in between all  of them will be the reality.

ANOTHER way of Looking at Lee. The red L near the LA coast is the storms location (very roughly). The heat energy is SOUTH of the low...and divergent upper level wind flow is shown right over the storm's core area. This is helping the storm to spread out..and maintain and even lower its central pressure. In black, I drew in the NAM model track as shown above in the previous image. Disguarding the model in full, but not in part. Overall, it could mean that Lee will be around longer than was originally thought by a good 24 hours at least. Also note the heat energy over the SE Gulf and the western Caribbean. A lingering trough(s) from Lee in this area and/or small tropical waves toward the SE Coast Of Florida are  future contenders for a least some sort of partial tropical development in the next two weeks. Lee will leave a legacy behind in more ways than one. 

In closing with Lee, the main point to realize is that it will likely never be a classic looking tropical system, but regardless, the effects from the storm could be significant from Coastal Lousiana to the Florida Panhandle..extending north to Mississippi, SE Arkanas, East half of Tennessee, W-NW Georgia mountains, and the Appalachians of North Carolina , Virginia, and West Virgina. It still as a frontal boundary to interact with assuming it does head toward the NNE-NE.  That being...remember all of the wind and heat energy shown in the first image over the Gulf which could at least be partially escorted with the system once it lifts north (under the huge and popular assumption that it will). But how much will be left behind? Looks like a lot will be. 


The water further south remains untainted by up-welling of cooler waters underneath.


IN SUMMARY: If there was a lesson to be learned from Irene, NOW is the time to consider the future plans Lee might have in store for the mountainous areas and those downstream of rivers/ogrges in the interior/mountainous/hilly areas of the SE and mid-Atlantic.


LONGER RANGE FOR FLORIDA: Going into this week the forecasts are calling for increasing rain chances as soon as Sunday. So far, that appears to be feasible. Beyond Sunday or Monday (when they might decrease a bit)...it becomes increasingly uncertain since much will be contingent upon the future path of Lee. 


 The GFS has been very consistent though with regard to total rainfall over the next 6 days, with highest totals being near SE Florida in Dade, Broward, and Southern Palm Beach Counties, with another area along the Barrier Islands of Brevard. (Nothing like the rainfall totals that will continue to occur along the Northern Gulf Coast and along the future track of by then Post-Lee ,which will likely be addressed as "Tropical Depression Lee" for quite a while...so might as well get used to it now). 


It is not completely certain if even half of that rainfall over Florida will even be from thunderstorms. Reason being, very warm mid-level air is forecast to wrap around the system..decreasing low level lapse rates...it'll probably be fifty fifty..with most of the rainfall in those locations due to near east coast sea breeze convergence in the noon-sunset time frames. Moisture is never forecast to be far removed from Central Florida and never over far South Florida.  Only the North Half of the state might have a few days of respite from rain chances as we head toward Thursday..but even that might be relatively short lived in the scheme of things once Lee is fully out of the picture and a new page can be turned on the day by day calendar for September.  

For today, not going to say much about Katia. As if Lee weren't enough, the future of this storm is a bit uncertain when it comes to intensity and track. The storm will be moving into a less shearing environment, but also by that time once it gets north of the latitude it will be moving into less favorable ocean energy. This might not have any bearing of the strength of the storm. For now, it is best to focus closer to home, because whatever happens with the Lee-scapades will indirectly have an effect on the future course of Katia in 3-5 days and beyond,