It's "10-4 Good Buddy" As Phase 2 of 3 Begins This Afternoon

IMAGE from the Local Data Integration System (LDIS) around the time of sunrise this morning, taken from the Melbourne, Florida National Weather Service (NWS) provider web links. This image shows, in general, the surface temperature at 7:15AM. The coldest temperatures are noted from the interior north along I-10 south to Gainesville and nearing Ocala toward The Villages. Although not as cool this morning (40Fs are still present), this is the same areas where it has been coolest the past 3 mornings as was thought would be in the post 3 days ago . Note it is the A1A corridor to far south Florida that is the warmest, as was the case all mornings.

TODAY: Continuing on track today with the gradual evolution of events leading up to the first bonafide chance of measurable rainfall sometime toward sunrise toward noon Thursday along the east coast. Most likely, any measurable rainfall will occur between St. Augustine to Vero Beach, with trace amounts possible just about anywhere. 


For today, similar weather to that which was experienced yesterday wherever one was. Another chance of skies becoming mostly cloudy at times south of Lake Okeechobee, initially near the coasts and working into the interior and west side later in the day. It appears the only chance of rain will be along the Keys, with a chance of thunder along the middle and lower Keys.


PHASE 2: Yesterday, very light NNE winds north of far SE Florida occurred as the winds at 2000 ft became NNE. Today, the low pressure area in the NE states is very close to the coast just south of Boston Harbor resulting in moderate to heavy rainfall across that area into the Southern 1/4 of New Hampshire and up along Coastal Maine. This low will move off to the ENE during the day very slowly. Meanwhile further south, the 850mb trough extending from this low (at 5000 ft) <associated with the large low pressure system> is working down the east coast. With its passage down the Florida east coast this afternoon, winds at that level will become NNE-NE as well, remaining very light. All in all, this means nothing to the observer, although surface winds this afternoon might become a tad stronger today making for a more notable light wind from the NNE-NE late in the day with a slightly better chance of stratocumulus clouds of greater vertical height, but still remaining widely dispersed/apart from each other. Toward South Florida overall moisture depth and extent is greater due to the circumstances surrounding the old frontal boundary over the Florida Straits.


As the mid-level trough works down the coast toward this evening associated with high pressure building toward the mid-Atlantic states, this boundary should be pushed south of the Keys even further and ending the chance of rain by nightfall.

Weak low pressure west of the Keys is shown in this graphic from the Storm Prediction Center (SPC) website. High pressure is seen in the Deep South. This high pressure extends well to the north , building into SE Canada. The strength and depth of it will be increased as the low near the NE U.S. Coast moves further offshore through Thursday., eventually ending any chance of rain for the keys.  

On the flip side, the more the chances of rainfall decreases for the keys, the better the chances of clouds and eventually rainfall along the Florida East Coast increases going into overnight Wednesday night/Thursday.


Below is an image from the RUC (Rapid Update Cycle) model for 7am this morning. Also noted on this image is what is to evolve going into late Thursday/Friday out West.

This image is for the 850mb standard level, or near 5000 feet Above Ground Level (AGL): Near Florida, we see by the dashed red line indicating the trough at 5000 ft (850 millibars MB) in this plot for that level. The old frontal boundary is in solid red along the Straits. High pressure building northward into Southern Canada at that level. The high pressure will strengthen and build east toward the Mid-Atlantic and Northeast states behind the departing low shown near Boston.  Out WEST, the developing low pressure trough is pushing across the Western States with a low center near the SE Bay of Alaska moving into British Columbia. Annotations are for the late Thursday time frame. Very cool/cold area within the large trough will make for cold temperatures over the mountains/higher elevations of the Rockies along the Wasatch and Rockies, with a cold pocket in the sinkhole of SW Colorado...due to drainage near Cortex.  Meanwhile, Southerly flow ahead of that trough and on the backside of the high pressure further east will up rain chances, with severe weather possible in the Texas Panhandle northward into Western Kansas. 

WEDNESDAY- PHASE 3: As the low pressure off the NE states moves further away, phase 3 - The 700mb trough will swing down and pass across Florida. High pressure behind that boundary during the day will shift winds at that level to ENE-NE eventually as well (as opposed to the WNW direction they are today). Surface winds will remain NNE-NE round the clock at this point at 10-15mph and moisture depth will gradually increase as well, as such will the chance of more cloud cover but remaining mostly partly cloudy state wide as South Florida conditions improve. The old frontal boundary will now be down across Cuba.


THURSDAY/FRIDAY: Low pressure all across the Caribbean and SW Gulf toward the SW Atlantic, combined with high pressure building into the Mid-Atlantic States through a deep layer will increase moisture further with time across Florida. The pressure gradient will eventually increase with steady state 15 -20mph winds by early Friday. The first chance of measurable rainfall somewhere along the Florida east coast appears to come with and just ahead of the first wind surge early Thursday. During the day this chance spreads up and down the entire coast, but remains fairly light, but measurable EAST of I-95.


FRIDAY/SATURDAY: Additional wind surges in the 2-5000 ft levels increases low level speed shear and lift. With these winds comes vorticity streamers embedded in a bit of a baroclinic zone , with thermal winds aided in lower level wind speed strength, with pressure gradient winds at ground level. Rain showers increase in frequency and number and become heavier as moisture levels in the atmosphere above increase. Some thunder could occur by late Friday into Saturday. The GFS run of 2AM has an affinity for Indian River County north to Central Volusia counties on Saturday for bigger rainfall totals with potentially thunderstorms. At this time, there might be a slight chance of waterspouts mainly offshore, with perhaps a land-falling waterspout, although that chance will be very low and remote.


Throughout the duration of higher rain chances along the east coast much of the state beyond the spine of the state will likely remain rain free. In fact, most areas beyond 20-30 miles from the coast will be rain free through Friday. 


The typical drive from further west, say for example from Orlando on Saturday, could consist of seeing increasing and lowering clouds as one approaches the coast, eventually running into some rain near I95 getting heavier crossing US1 and the rivers. Just an example, but the same general scenario about anywhere except perhaps South of Lake Okeechobee where there could be an 'Everglades Affect" along Alligator Alley heading toward Sunday. It will not be raining anywhere all the time, but an umbrella could become mandatory equipment when heading out; either that or simply wearing a bathing suit.


Late Saturday-Monday: The same old same old. Temperatures along the coast could possibly not vary more than 8 degrees if not less in areas of more consistent shower activity , remaining in the mid-upper 70Fs. Eventually almost every where along US1 and east will receive measurable rainfall by Friday Evening into Saturday.  So far as of 2AM, the GFS is honing in on Saturday being particularly 'active' along the east coast from Brevard toward Martin Counties with stronger winds and possibly storms with thunder (but that could easily change with the next model run which will become early this afternoon).


It does not look like any stronger activity will move faster than 6-10mph since steering currents will remain around that speed. The strongest winds will be found 'just above the deck' around 2-8000ft, which is below the steering level, but fast moving low clouds are likely to be observed. Thus, the bigger rainfall totals of possibly over 4" by Tuesday over a 96 hour period will occur where the slower moving and heavier rain/thunderstorms occur.


The GFS still indicates totals of 9", namely just off shore from Port Canaveral to Central Palm Beach County, with actual land based estimates up to 4.5". 


As suspected, the latest GFS is now extending the length of the REX blocking pattern to evolve as noted yesterday might be the case, from Monday to Wednesday, however surface winds will decrease in that case.  And talking about winds, it looks like the strongest winds will remain just offshore, with coastal winds perhaps quite noticeably breezy to near windy on Saturday. Otherwise, it does not look like they will be anything unusual. The shallower shelf waters will aid in lift, and local geography could end up in higher rainfall totals though on land if all of the above evolves, but I will point out that none of the official resources (those being the Weather offices of the NWS) are talking big rainfall totals. In fact, only Miami mentioned them, and they as of early morning played them DOWN (might have been a mistake on their part though in regard to Palm Beach County).


BEYOND the TUESDAY/WEDNESDAY TIME FRAME: Models are in excellent agreement (of the 6 different ones I looked at including the Canadian, the European ECMWF, and the Navy NOGAPs...that we will have high pressure to the north and low pressure to the south in a modified REX block (modified in that the low is not completely closed in the mid-levels). The latest GFS (Global Forecast System) Model however eventually closes the low near Cuba to South Florida by Wednesday...and works it down to the surface just off the SE Coast of Florida. A Subtropical or a hybrid type low pressure system could form almost anywhere from off the Florida East Coast to off the West Coast into the SE Gulf, through the Yucatan Channel over into the Caribbean toward the Bahamas anytime and anywhere by early next week. 


Models all seem to agree on such, but not on where or how.  For example, the 2AM GFS shows a low to form off of SE Florida that gets wrapped NW ward , strengthening into a sort of hybrid tropical storm (of name) that cross NE and North Florida, then wrapping around the parent upper low over the Caribbean and moving the named system into the East Central Gulf of Mexico.  I'm not buying it though. In any case though, the point is that although the prolonged wind/rain conditions of onshore winds developing Thursday will have by then been long gone, rain chances continue for a different reason. 


Models seem to agree as well that heading toward Monday/Tuesday, low pressure over the Southern Gulf to the SW Atlantic will build northward across Florida as the high pressure to the north relaxes/realigns. This will end the stronger onshore flow as well as rain chances along the coast, but would also induce more of a modified afternoon thunderstorm regime.


It should be clear to realize from all that has been written above, that there is great uncertainty throughout all time frames beginning Friday (considering that is 3 days away already). But some heavy rainfall totals, if only just offshore, seems to be in the cards. The devil's in the details.    
  

Text Book Pleasant Except South - Weekend Beach Plans a NoGo

TODAY: Image taken from the Storm Prediction Center's (SPC) Mesoscale Analysis Page
at spc.noaa.gov. Note the high pressure over the Deep South and Low Pressure Associated with the old cold front over  or near the Florida Straits. Both are KEY players heading toward the Weekend and early next week as is noted further down in this post.

TODAY: Near picture perfect weather today for all but the area near and south of Lake Okeechobee with highs in the low-mid 80Fs and only a few clouds during the afternoon, if even that. The chance of more clouds increases toward Lake Okeechobee and along the east coast near Ft Pierce and south with some rain showers possible coastal Southern Dade County and through the Keys as well as coastal Monroe County toward Flamingo.  


Like yesterday , the best chance of rain is for the middle keys area where Key West reported radar estimates of up to nearly 5" of rain overnight at one spot, with other areas in the middle Keys reporting 2-4", believe it or not. The chance of rain continues in these same locations through Late Afternoon Wednesday as the high pressure in the Deep South shown in the above image builds toward the mid-Atlantic and joins with even stronger high pressure the will work south from Canada behind the stubborn low pressures over the NE/New England area. More big rainfall totals could amass over the Keys during this time frame. Interesting that on the mesopage referred to in the image caption, indications exist for the possibility of a stronger storm or two over the Keys, which seems just a bit questionable today, but maybe not so debatable later on Monday.


TUESDAY/WEDNESDAY: Little change expected for South Florida with afternoon breezes, whereas further north a very gradual change is in store. Very light onshore flow is expected to develop over night tonight with slightly warmer overnight lows, especially east of I-95. Only a slight increase in clouds on Tuesday, and more so on Wednesday as deeper easterly flow develops, with the more breezy conditions coastal SE Florida. The GFS does show that some sprinkles are possible almost anywhere along the immediate east coast, but it seems more likely this will be some mostly cloudy periods along and east of I-95 at the most, and not constantly.

THURSDAY - SUNDAY NIGHT: Little change in forecast thinking from yesterday morning's post. High pressure stacks up along the Mid-Atlantic States both contributed  by the Deep South as well as from the Great Lakes states once the low pressure area (The Cut off Low Pattern of MANY days now), finally is forced eastward behind departing Ophelia. This sets the stage for deeper (higher up through the atmosphere), stronger (from the surface to 10,000 ft), and more atmospherically moist ENE-E flow.


As the high pressure builds in, the rain chances end for the Keys, likely sometime late Wednesday as the frontal boundary is forced to Cuba and into a region of already lower pressures (the Caribbean). The high pressure to the north of Florida, and low pressure to the south sets up (or so it appears for several runs) yet another Blocking Pattern, the Tyrannosaurus "REX Block", named after the scientist who dubbed the pattern. But it can be a beast. This blocking pattern is most often found off the SW Coast of California in the winter months, but can occur anywhere. If so, as blocking patterns are by nature, the deep and moist onshore flow would persist across Florida and as far north as Coastal South Carolina.


With the blocking pattern in place, the next 'big trough' to enter the Pacific West Coast will be forced to Dig South rather than move from west to east as would occur in a progressive pattern. In turn, Arizona and all of the region along and west of the Rockies cools off significantly while the region east of the Rockies warms up, especially across the Northern Plains (Dakotas) and into Wisconsin and Minnesota as well as into the NE states, while Florida toward South Carolina has a good chance of rain from time to time.


Snow looks likely for parts of the Wasatch front in Eastern Utah as well as the Southern Rockies...with very  cool to cold temperatures round the clock, especially toward SW Colorado due to the geography in this location at the base of the higher Rocky Mountains. Cortez, Colorado comes to mind.


This can all be seen , or envisioned, with the image below. This image was taken off the 2AM of the GFS (Global Forecast System) model. The color codes in this image are precipitation totals for the 96 hour period from Thursday night through Monday night.

  

  ABOVE: Note the low pressure circulation centered over the Caribbean with high pressure to the north where it is rain free and warm.  When this type of pattern develops and remains stuck in place, it is dubbed a REX Block. Block because it moves very little, only realigns in the same areas day after day.  The trough to the west gets backed up over the Rockies, and in between the two rains add up from Texas to Nebraska. Wait, did we say rains in Drought Parched Texas??! 


The colors are 96 hour rainfall totals, with the total fallen over 96 hours keyed up in the upper left hand corner where the black arrow points. As noted yesterday, the model continues to show totals up to 9" during this time frame (Thursday night - Monday evening) just off the Florida to SE Georgia Coasts. Still believe the area around West Palm to Ft Pierce will need to be watched. Again, realize this is getting far out in time, so in terms of this post, all info should be regarded as a 'heads up, you've been warned' precursory first best guess. We will have a better idea of what will actually occur heading into Tuesday evening.


As long as we're on a roll, also note the sharp drop off of the forecast rainfall once one moves toward the interior of Florida toward locations such as the west side of Orlando, other than the spurious red area shown toward Crystal River/Inverness/Cedar Key.  Also note how the biggest totals are aligned in streaks associated with vorticity streamers that develop in the baroclinic zone created by the Rex Block . This was described in greater detail in yesterday's blog post. The other area of heavier rain fall in the Gulf seems to be associated with the Loop Current. And note the big totals over the Caribbean along the old frontal boundary in the zone of low pressure. This area needs to be watched for tropical development (s) well down the line into the second and third week of October.


So when does the chance of all these coastal wind convergence showers and possible thunder storms with gusty winds (in either) end? The GFS is consistent with Monday afternoon. However, as noted in the past, blocking patterns are difficult not only to determine when they will form (thus, all of the above could be incorrect if it never forms)..but also, once they do form, when they will eventually break down. Once they form, models can be easily 24-48 hours too fast (and almost always are). Thus, should it form, we could be in for the rain chances and windy conditions (which will start very late Friday) through Tuesday.


BEYOND REX: The GFS is consistent with a trough of low pressure forming across Central Florida as the block breaks,  with a subtropical low or two (and who knows, maybe more) moving across the state from the SE Gulf. Additionally, another low forms near the Central to Southwest Caribbean in which either case Jamaica is impacted initially. During that time, Florida could still be impacted by showers and thunderstorms of more diurnal nature. 


One thing is certain, when the pattern breaks we'll know it in a heart beat because the easterlies will quickly wane to zero and become SW and light, with the rains ending (for good in this pattern) simultaneously. 

Record Lows Set This Morning: Potential For Late Week Coastal Rain Event

'Rainbow Friday' Near Sunset Looking ESE. Note the colors emanating from the breakers only 75 yards  away from the viewing perspective. This was a good time to prove that chasing rainbows is as much a fruitless endeavor as chasing your shadow. One is better off buying Skittles.

TODAY- TUESDAY: Little change through this period. Onshore flow has evolved from near Ft. Pierce and South to the Upper Keys and more extensive stratocumulus cloud cover has evolved with skies becoming almost cloudy at times. Further north, some startocumulus clouds have formed as well, but to a much lesser extent. The surface front now lies along the Florida Straits, but sufficient moisture and some unstable air remains along the Middle Keys toward Southern Dade County; thus, a rainshower or maybe even some thunder is not entirely out of the question especially near Southern Key Biscayne area toward Key Largo/Flamingo, although thunder looks very remote so far at this time today.

WEDNESDAY-SATURDAY:
Evolution of Events that could eventually unfold  -


Light onshore flow will continue over Southeast Florida during the day time, possibly becoming a bit stronger Monday and Tueday, decreasing over night. During this time frame the low pressure areas at the surface and aloft over the NE U.S. will finally wrap up and move out through Tuesday. 


During this time frame the key factors at work for Florida weather next week will happen in stages starting from the bottom (surface)..and up (to 15,000 ft). That main factor will be the depth of easterly flow which will come in stages. Stage 1 is shallow easterly flow working up the east coast beginning Monday afternoon when stratocumulus cloud chances will become more likely further north. The chance of showers remains mainly for Dade county and the middle Keys.


Stage 2 will begin Monday night into Tuesday when the depth of easterlies up and down the coast builds to 2000ft above ground level further increasing the chance of clouds with showers/and thunder chances remaining over South Florida but beginning to decrease.


The trend is for continuous surges of high pressure to move south for Southern Canada early in the week, each deeper and stronger than the previous.  Eventually on Wednesday, the 850mb high pressure builds in with easterlies increasing to a depth over head of 5000 ft at which point coastal sprinkles and additional cloudiness ensues. By this time the low pressure area off the NE U.S. Coast will be displaced as the high pressure continues to build south to greater atmospheric depths reaching the 10 to 15,000 foot level by Thursday morning and increasing in strength. 


Initially, this will be a cold core high pressure ALOFT, with colder air passing over the much warmer air above the ocean, near shore the Florida East Coast. It does not look like surface winds will be any stronger than 15-20mph, but eventually as the high pressure builds south and remains centered over the Mid Atlantic states (composed of cold air in the mid levels), this will generate a thermal wind just above the ground from 2,000 - 10,000 ft, blowing at a speed in the 30-35kt range, with winds right at the coast and perhaps along the west coast near 20mph (maybe stronger toward the west side of the state). 


During the final stage which is to begin Friday thunderstorms are possible, and even heavier rain storms could generate wind gusts to 45mph if the forecast of deep 35 kts winds just above the ground comes to fruition. It is interesting the GFS is also showing temperatures around 4C at 700mb and temperatures as low as -11.5C at 500mb. 


These are a good 5-10 degrees colder aloft than what was seen most of the summer, while surface temperatures will remain in the lower/mid  80Fs or upper 70Fs. Such cold air aloft, combined with 35 kts winds  would result in strong surface wind gusts as down drafts in even only heavy rainshowers work to the surface. Wouldn't be surprised to hear a few tornado warnings for landfalling waterspouts, but lets first find out if even ANY OF THIS will evolve. 


 (The GFS during latter portions of the summer over estimated the temperatures aloft in regard to how cold they would be beyond 48 hours almost continuously, so such extreme temperatures aloft are highly questionable, and thus so is the expectation of high rainfall totals and stronger wind gusts).


Strictly based on the GFS at this point since I do not have access to the ECMWF model in detail:


The ingredients at time appear will all come together during the course of late Friday lasting through Sunday. By Friday evening or late afternoon, thunder could accompany onshore moving showers and fast moving low level clouds. Rain fall totals over a 6 hour period could add up to 2-3 inches if not more as hypothesized by the GFS runs which first showed this to unfold beginning nearly 36 hours ago. Actually, the GFS has shown rainfall totals just offshore if not onshore up to 10" over a 72-96 hour period between Thursday sunrise through Sunday night. ..with the first real rainfall commencing along coastal Brevard associated with this scenario occurring toward late morning to early afternoon on Thursday. If so, that would be just a precursor for what is to come later Friday through Sunday. The baroclinic zone is then forecast to gradually sink south toward Palm Beach County heading toward Sunday.


Rain could fall anywhere from Southeast Georgia to Key Largo, with some 'hot zones' for highest totals so far being indicated for JAX to SE Georgia,  Central Volusia to Vero Beach, and Ft. Pierce to Southern Palm Beach County. The latter of which could end up being Ft Pierce and West Palm Beach toward Boynton Beach as the supposed event unfolds, with the Canaveral area being another 'hot spot' indicator. These last three spots would be due to geography for the Cape and proximity of the Bahamas further south where vorticity streamers are more likely to be induced upstream of them toward Palm Beach County.


Recall, it was two days ago that before the GFS showed this to occur it was mentioned in a post that a major rain event for the east coast could set up 'somewhere' along the East Coast, especially toward Ft. Pierce to West Palm Beach area. This model has now continued to show such an evolution since that time consistently for three full runs of the model so that chance of said event seems more likely.


The causes of the rains would be steep mid level lapse rates, low level speed shear, and vorticity streamers in the mid levels which form along what is referred to as a baroclinic zone, which as mentioned above.


The baroclinic zone is a region in which a temperature gradient exists on a constant pressure surface. That would be contained in the deep , unidirectional flow from the surface to 12,000 due to stacked high pressure over the mid-Atlantic states in which the temperature gradient aligns vertically along a long-fetch easterly flow at the surface. 


As defined, baroclinic zones are favored areas for strengthening and weakening systems; Wind shear is characteristic of a baroclinic zone.  The term "baroclinic" refers to the mechanism by which vorticity is generated. Vorticity is the curl of the wind velocity field. In general, the evolution of vorticity can be broken into rain contributions from advection (as vortex tubes move with the flow), stretching and twisting (as vortex tubes are pulled or twisted by the flow) and baroclinic vorticity generates.

In other words, key ingredients for generation of rain. During this time frame the surface front along the Florida Staits will sink into the Southern Caribbean toward the Yucatan and Central America. And as chances would have it, so will to the Southern Branch subtropical Jet stream. This leaves the area from the SE Gulf, Florida to the Bahamas, Cuba, and Jamaica in a more favorable environment for subtropical  cyclone development either over or very close to Florida as the baroclinic zone components wane (Monday/Tuesday) or over the South Central/South West Caribbean along the old frontal boundary which will also be another but much weaker   zone for tropical development.

MONDAY AND BEYOND: The pattern so far has been shown to break down toward Monday or Tuesday, at which point we are beyond one week from today. During this time frame much of the Plains States and the Ohio Valley into the Northern Plains in areas like Minnesota and the Dakotas could be experiencing an early Indian Summer.      

Lastly, although not shown, we will have to watch for a blocking (Omega Block) to form. If so, changes from the pre-established pattern could be much longer lasting..but first, it has to happen. 

Fall Has Trickled in On Cue , More Through Monday A.M.

'Last of the Great Mohicans' ( of Summer Storms) - Severe Thunderstorm Warned For Sharpes to Port Canaveral - Approaches Port Canaveral late yesterday afternoon. From here on out, most thunderstorms until next spring will be driven by synoptic scale features other than sea breeze/lake breeze mergers. Actually, the true purely summer like storms ended in late August (those driven by solely lake/sea breezes). But for even the non-purist,  Fall has arrived. The other stronger storm occurred in Dade County toward sunset.

TODAY: The primary frontal boundary passed through my location at 5:12AM this morning noted by a slight uptick in the NNW wind and a whopping temperature drop of 2-3F degrees over the first hour. The morning low at my location was nearly a bone chilling 72F, the coldest since early May. A secondary boundary looks to drop down the state during this afternoon, crossing the Beach Line to Tampa around 4-5pm. This could be accompanied by a secondary wind surge lasting for an hour or so after dark. It is with this boundary the drier air (lower dewpoints) will move in, but for the most part coastal East Central and South Florida will never reach the itchy skin and brittle hair stage of dryness like that of winter. Not so bad.  This 'surge' is expected to continue to south Florida through the mid-evening hours. There might be a small line of clouds with this feature, but nothing more other than perhaps a shower along the Palm Beach County coast toward sunset, but even that chance looks very low. 


TONIGHT THROUGH MONDAY MORNING: The weather pattern over Florida will be influenced by the monster low pressure duo that has been near the Great Lakes all week which is finally pushing out in two phases. The first low is now in NE Canada, with its replacement nearing West Virginia. It will take through Tuesday for the entire system to fully pull out and be replaced by high pressure pressing in the from the west as well as from Canada. Until that time, and during the transition , we can expect two more wind surges. The first and less noticeable one (after today) associated with the first high pressure building in toward the Mid-Atlantic states later on Monday afternoon, and the second and deeper push with the second reinforcing high pressure Wednesday afternoon. Until that time it will remain dry, with some stratocumulus clouds (stratocu) beginning to be seen, mostly along the coast later Monday or Tuesday, and then some low topped showers possible remaining offshore, very isolate, with more stratocumulus clouds of greater vertical depth later Wednesday.


Here is the current pattern, with the low near West Virginia and the subtropical jet across South Florida. This area (South) is most likely to see some jet stream cirrus, if any is to be found the next few days). Wet conditions continue off and on in the Northeast states as lobes of energy rotate around the low pressure area.

Another way of looking at the above infrared satellite image, is to use visible imagery. This is included to emphasize the amount of low and mid level cloudiness associated with the low pressure area in the NE States and New England areas not otherwise so apparent in infrared imagery. Also note Major Hurricane Ophelia on the right side of the images. This has been the most 'classic' looking storm of the Hurricane Season, after having been nearly downgraded  to a non-existent state just the other day:

TEMPERATURES: To simplify matters, I created a sketchy sketch  in general noting where the coolest and warmest mornings will be Sunday/Tuesday mornings. The least cool areas will be the outer barrier islands of Brevard (east of the Banana River) and coastal SE Florida south of West Palm Beach east of US1 and through the Keys and all of southern   Collier County. The warmest days from today through Monday will be near the Beach line to South Tampa Bay and south where highs could reach  80F toward the mid 80Fs toward Lake Okeechobee and south. North of that line temperatures might never reach 80F degrees for the next two days. The warmer overnight areas will see lows around 63-69F and cooler elsewhere varying from the mid 50s to even the lower 40Fs toward Tallahassee/Crestview. I'm still shooting for 67F tonight in Canaveral, although Monday morning might be the cooler of the two mornings. During the afternoons, winds will become more northerly or NNE, but will die and become more NNW-NW overnight and early morning. By Monday afternoon before the first of the two wind surges winds might go to near calm for a period through early afternoon.

White: warmest overnight lows, dark blue - coldest

 


WEDNESDAY NIGHT - FRIDAY: It now appears it is with the second wind 'surge' from the ENE (which will be more noticeable with breezy 15 -20mph winds along the coast), that the chance of rain increases mainly heading toward sunrise Thursday. The vertical depth of this wind will extend upwards of 10,000ft uniformly with the surface wind as opposed to a shallower 2-6000ft wind on Monday/early Wednesday, and thus, cloud tops will be high enough to be rain producers. The strongest winds will remain just offshore but will be  extended  faar out into the Atlantic for hazardous boating conditions. Rains initially, assuming they do develop which looks like a good bet, will impact only areas east of I95, but with continuation of the winds they could extend toward the west coast by later on Thursday.  It should be needless to say that with the deep onshore flow passing over ocean temperatures in the low-mid 80Fs that temperature (air mass) modification will be in full gear ending the relatively 'crisp' autumn feel to the air. Overnight lows and daytime highs along the coast will hardly vary diurnally by 10 degrees with lows in the upper 70Fs at the beach with highs in the low-mid 80Fs depending on how much and where rain falls. Away from the coast, temperature variations will be much greater.


Southeast Florida might remain dry through Thursday, with the main impacts in the rain buckets being from Indian River county and north to JAX, but after the second surge, winds will become progressively more easterly which puts all of Southeast Florida in the picture, with the potential for Bahamian induced 'streams' impacting the Palm Beach area if the wind can veer enough from due east to ESE.


Special Note: If you don't like prolonged east winds, get used to it now, because it looks like they will be in the picture through the entire first half of October (at least), and probably even longer.


EXTENDED HEADING TOWARD OCTOBER 15: The pattern can't last forever, and as such, the long range GFS model has been portending tropical development in the Caribbean if not toward the SE Bahamas. Then again, the GFS has been showing the same type scenario to occur in the long range for 10 days now. Believe it just might be for real this go around, or rather, if were ever to happen it should happen then. Reason? The frontal boundary, what is left it, will end up draped into this area for quite some time to come. This is the time of year for tropical systems to form along these decaying boundaries.


Oddly, though, another scenario has unfolded as well the past 36 hours. That being for a severe weather event in the SE states heading toward the 19th...as well as a tropical system. In any case, it looks like the last half of October could get interesting in some form or another. 

Pot-O-Gold Storm Friday. Note the rainbow is visible in the breakers. This rainbow heralds the end of summer and the beginning of fall. Some see gold for such a time, but others, it's a pot of coal ...the end of summer storms.

Fall Arrives On Cue After Midnight - With a Severe Storm Possible

A Severe Thunderstorm Was Reported near Mims Yesterday with 1" Diameter Hail
Other Lightning Storms Were Subsequently Generated in part due to outflow from this storm in Osceola County toward SE Polk County well after dark  

TODAY: Confessing first off that I've delayed posting today to see how parameters would materialize with some day time heating. For the most part, not many  surprises from earlier. Today's post is based on model trends (although they do not agree at all), SPC mesoscale analysis which updates every 15 minutes (but based in the upper levels on the RUC model), radar and satellite trends, and bit of gut feeling. In short, the final straw drawn was from the Magic Eight Ball app...which read, "A word of the wises, be prepared for surprises". Although, not sure if that meant "Surprise, no rain anywhere except in one spot... or, Go for the Big Rains over South Florida". I chose neither, but sided a bit to the unreliable NAM of summer and latest trends.

NOW: The first cold front of the fall season is moving through the panhandle as we speak, and seems to be draped from near St. Augustine to Gainesville to north of Cedar Key. Elsewhere, a mid-level trough is pulling off the Central East Coast which was responsible for the activity yesterday with a bubble high having filled in behind it and responsible for the nearly cloud free skies central early today with southern branch high clouds and some developing cumulus over South Florida. The vorticity max with the upper level trough is strengthening since sunrise and the upper level trough is aligning with mid-level features as well as surface features which was thought might occur in yesterday's post. 


Heating of the day should slow the boundary down just a bit as the coolest temperature plunge is still a full 24 hours away. Despite unfavorable moisture levels over South Central Florida , we still might be able to squeeze out a storm or two as the vort max crosses Central Florida by mid-afternoon through sunset into South Central Portions.  Vorticity advection is also increasing as the vort lobe is now much less linear than earlier this morning.  Moisture is being drawn up the immediate east coast toward Canaveral and Titusville and might be enough to pull off a shower today if not a storm near or just off shore. It is tempting to say there will be very few showers if any today, and all will hinge on one or two storms over South Central Florida. If so, any such storm could be severe due to 1" or larger hail or strong wind gusts around 58mph. On the otherhand, will there be a storm at all?!! 


Sea breezes today should be quite light and remain close to US1, but I am watching for the west coast sea breeze to start to move eastward toward North Central behind the front itself during the mid-late afternoon, that could be a key and final ingredient if so. Winds aloft are averaging up through the steering level around 15 kts from the WSW. Thus, storm motion will be zero until one that forms can latch on to the upper level winds at which point deviant motion, more likely toward the South or SSW-SSE is possible.
Bulk shear is increasing to 35kts over Central Florida, and upper level temperatures are cold enough to support hail.

This image shows the Vorticity Max and frontal boundary with it across north Florida moving ESE. The blue circle shows where it is advecting toward. No storms are occurring now because it is over much drier air, but as it enters the area of better moisture a storm could suddenly pop up unexpectedly south of the Beachline after 3-4pm. Red shows  preliminary areas thought for a very strong or severe storm. Bear in mind, any storm will be very isolated, so most people will not see rain today, if any one does for that matter.   

     The final ingredient for a severe storm today is the mid-level moisture gradient along eastern portions of South Central Florida ...although I must say that during the past hour some of that moisture seems to be mixing out with daytime heating, thus the very low confidence in storm formation there. All in all, if I had to narrow down the red area even smaller it would be for one lone storm over  Okeechobee or Southern Osceola County advecting toward or forming another in Southern Brevard toward Palm Bay.


Further south, a problem down in this region is the high level clouds. Those didn't seem to stop one lone storm from forming yesterday though in Palm Beach County near the lake/sea breeze boundary. The parameters over South Florida for severe are not as good other than here lies much more  low level instability, thus more showers could form in this area, but again, moisture here is waning with peak heating approaching. Temperatures aloft here were cool this morning per the MIA sounding, but guidance also shows those were from the overnight boundary in place which is pulling out, so those temperatures might be warmer than the sounding indicated here bu later this afternoon  . 


Thus, isolated showers despite the better moisture and with lack of better upper level support such as bulk shear and vorticity which is over Central until late, as well as less dynamic sea breeze/lake breeze interactions. Not sure sea breezes will be as effective today as much either as much as mid-upper level dynamics, and with light Lake Breezes those too might only play a small role in storm or shower formation. If I had to pick 'somewhere' over South Florida it would be near the East Coast from Central Palm Beach County through Southern Dade toward interior Dade/Broward, with a possible storm or two as well in Martin County or St. Lucie. 


For the most part, most people will not receive rain today, but those that get more than 1/4" will likely to so in the form of a very strong or severe storm.


TONIGHT AFTER 10PM: Storms could still form, or a storm could still be in progress, through 9pm in any of the highlight areas in the image above. The cold front proper will arrive like  'fall clockwork', after midnight on October 1st per last year, with frontal passage in East Central between 1AM and 5AM, and southward to South Florida from daybreak through mid-morning. It should progress toward Central Cuba where it could eventually retrograde back north to the northern portion of the Florida Straits by Monday.


Morning lows will be the coolest north and central than in quite some time, with the magic 67F possible along A1A in Brevard but cooler west of the Banana River. Afternoon highs on Saturday over South Florida should reach the mid-80Fs, but even 80F might be a stretch along and north of the Beach Line with increasing NNW-NW winds during the afternoon. The driest and coolest air will arrive Sunday morning and remain in place until day break Monday when morning lows everywhere will be at their coolest.


The only areas that will escape the very driest of air is far eastern South central and South East Florida and around the tip toward south of Naples. This will allow daytime highs to heat up toward 80-85F South Central and South on Sunday after a very cool start, but also will allow a fairly rapid temperature drop shortly near and during sunset. Overnight lows along the east coast should occur in the middle of the night, although one more very cool morning could occur Monday west of US1 before NNE winds set up.


The next chance of showers near the east coast appears to be on Thursday, with some stratocumulus clouds advecting on shore on Wednesday. The only other thing to watch for during this cool down will be high cirrus clouds over South Florida streaming across from the Southern Gulf. If so, daytime high temperatures will not be as warm as the current line of thinking advertises south of Lake Okeechobee.

This second storm, part of a cluster, was observed near St. Cloud yesterday toward sunset. cloud to ground lightning was intense, but not too frequent. There also appeared to be a funnel cloud (upper left) induced by  wind shear outside of the rain foot  visible on the right side of the image. 

  

Very Isolated, Briefly Strong/Late Thunder Central Interior Late

Low that was over the Upper Midwest has opened up as a stronger modified  polar like trough drives ESE kicks it off toward the ENE. The main frontal feature this afternoon will be diving through the mid-sections of the country, while the weak boundary over North Florida washes out over Central During the afternoon/evening

TODAY: The upper level low over / near the Great Lakes is finally opening up to an open wave and being booted ENE-ward as a stronger low pressure trough drives in behind it from the WNW-NW. The two will gradually merge over the weekend and be out of everyone's hair up north by Late Monday (at the latest).


Further south toward Florida, the south half of the state appears to be under the 'general ridgy-ness' at the surface and mid levels that Central Florida was under yesterday as the main frontal feature starts to develop well away to the NW and deepens with time today.   The actual front itself is quite dry (inactive) other than over the more northern tier of states.  Meanwhile, the north half of the state is under general but weak  "troughiness" increasing with time, but it is a slow process. 


Morning  KSC profiles are all showing a developing westerly flow above 5000 ft, although very very light and not of any significance until above 15,000 ft or higher. Thus, steering is close to negligible once again. Further south, an equally light steering from the east is apparent. Southern branch jet stream cirrus are moving in across the south half of the state, mostly south Florida. There is a big break coming for them earlier today, but that might fill in heading toward early afternoon. So , despite the big rain chances reflected by the RUC model especially along their west coast, believe that this moisture might or should be attributed to moisture at non-precipitable levels; thus, South Florida might end up with high level partly to mostly cloudy skies by mid-afternoon, inhibiting further rain shower development beyond what could form toward the east coast with the sea breeze as far north as Martin County.


Further north toward Central/South Central, cirrus will come and go throughout the day, but not be the prevalent mode. Ultimately, storms / showers will form along the east coast sea breeze (very isolated) with a delayed seabreeze north of Sebastian Inlet, namely Brevard County. A heavier shower or thunderstorm is also possible after the 3-4pm time-frame, apparently toward Palm Bay, but that chance is remote.


The heavier activity should occur after 5-6pm toward one hour before sunset west of I-95 along the final sea breeze mergers over Central Orange south Osceola County, and possibly far northern Okeechobee County.  Like yesterday, one storm could form closer to I95 earliest, with a subsequent outflow from it inducing yet another storm further from the coast late. I've noted that the RUC has been insistent that much of the north half of the state remains under convective inhibition until after 2-3pm, although the NAM breaks this down after 2pm, at which point the sea breeze should have penetrated to at least I-95 as the west coast sea breeze will be in full gear toward the east north of Sarasota.

NOTE SHOWN; Showers toward the west coast, but see all the cirrus? Not so sure about that. Also note shown is the remote chance of a shower/storm toward Volusia County or Flagler County.

Further north yet still, believe the northern most extent of any thunder today will be Central Volusia County closer to the coast , but it is still too early to determine if any last minute moisture squeeze with the sea breeze convergence could dish out a shower or thunder that far north. This can only be determined by watching hourly advances as the situation develops, but for now I did not sketch that area in. The latest LDIS plots from KSC/MLB show more moisture in the mid-levels associated with the old boundary than any model guidance does to the north, so it's hard to know exactly which one to believe.

FRIDAY: Very tricky day. It could be either near rain free, or we could once again have a strong storm or two toward the Central/East Side mid-late afternoon. The frontal boundary is forecast by the NAM to become stacked or nearly so at the surface with upper level features during the course of the day. It must be pointed out at this stage that the GFS showed no such chain of events in the last two runs, and actually has the front through..or rather..a preliminary front through..after tonight..with the second one indicated by merely a dry wind-shift...if even that.  The reason for this is because it quickly builds high pressure over the Gulf across the state after sunset tonight, never to again be replaced by the secondary trough on Friday associated with the primary front.  


This is a big shift in 'model reasoning', so will run with persistence of its previous runs as well as that of the morning NAM. (but will say, the GFS has done quite well this summer as a hint to what my gut is thinking).   In which case, moisture convergence ahead of the boundary which will be aligned NNE-SSW across NW Florida toward JAX late in the day should result in a similar set up as today, but with slightly cold air well aloft. It may be that Friday will be completely rain free, but as noted, will ride with previous persistence for now.  Any rain tomorrow with the front will be over Central or South Central Florida, and South Florida could be close to rain free other than showers like today  .

BEYOND: FALL ARRIVES DURING OCTOBER 1 , JUST LIKE LAST YEAR:

Timing is still tricky as usual in regard to exactly WHEN the front will cross the peninsula in full. A mix of the previous GFS and latest NAM dictates the front to go through overnight Friday night and clearing the entire state by mid-morning Saturday if not sooner. It could be accompanied by a stray shower near the coast of Brevard, but otherwise frontal passage itself elsewhere will be uneventful due to the timing of its passage with overall low moisture accompanying it.


The driest air associated with the front, as well as the coolest air, will be limited to west of I95/US1 zone from the Beach Line toward Sarasota (typical). As such, the coldest mornings Saturday through Tuesday will be in those areas, with the coolest afternoons Saturday/Monday. South Florida will never really get into the driest of air nor will the far east coast of Brevard and South. Winds on Saturday should be NNW-NW under sunny skies making for a very pleasant day with highs in the low 80Fs for a brief time, with near 79F being the prevalent temperature.  During the night heading toward Sunday, if the front does go through as it now appears it will, winds could become North to NNE by daybreak Sunday, which for Port Canaveral and South is slightly onshore...and again, will prevent this area from cooling down over night.  This is not for all certain though, so maybe East Central (COASTAL) Brevard will reach the magic 67F Degrees Sunday morning, as is often the case time and time again with the first front of the year from my experience. 


Interior areas as far south as Okeechobee and closer toward the SW coast could also be quite cool, with the areas near Ft. Myers all in all being cooler that much further north and east toward Coastal Brevard. The coldest of all will be the Panhandle and east to Gainesville and south to Ocala, where overnight lows could reach the mid-40Fs over the west half of the panhandle and near 50F toward Ocala.

MODIFICATION BEGINS SLOWLY ON TUESDAY with a small chance of coastal low topped showers, east of I95 from Brevard and north to Jax by overnight Wednesday into Thursday with continuing, never-ending ENE-NE winds gradually becoming more easterly by next weekend. It will be a slow process as the high pressure area behind this front will get locked in place over the eastern Mid-Atlantic states all of next week and beyond. In other words...CURSE OF THE FALL EASTERLIES WHICH SEEM TO GO ON FOR A LIFETIME ensues for the entire state well into mid-October.  
 

Better Chance For Very Isolated Showers/Thunder Today

TODAY: There is much less over all atmospheric moisture availability today state wide as opposed to yesterday, on the other-hand, high cirrus clouds which moved in yesterday that likely capped off the rain chances to very low do not appear will be a problem today across Central Florida; however, they do appear to  be encroaching into SW toward all of South Florida as of 1pm. Already, developing cumulus cloud fields over SW Florida have dissipated (for the time being) in that area, whereas showers have formed along the east coast sea breeze.


This post today is a blend of the RUC and latest 8AM GFS. The RUC has been ADAMANT at nearly scattered thunderstorms this afternoon across all of Central Florida into South Florida, this is due to vorticity at the low through upper levels that it presents. However, no such feature (s) is apparent, so will downplay to isolated activity due to low atmospheric moisture with not boundaries. A ridge axis from the North Central Gulf extend across Central Florida, whereas another ridge axis does the same from the Atlantic. Storm/shower motion should be toward the SSW/SW but be quite slow to negligible since activity should not move far from where it forms.  Showers/storms should wane quickly with the setting sun, although there could be a few showers or small storms over the interior until just after sunset. The more dominant feature will be a stationary boundary along the northern Gulf Coast from Louisiana through the Florida Panhandle extending toward JAX, where a more prominent storm could from West of the St. Johns in northeast Florida, with more activity along the western Panhandle.


THURSDAY: The upper low over the Great Lakes will be on the move late today very slowly toward the East as a more powerfully progressive trough tracks across Southern Canada. As the large low moves east the boundary over North Florida will wash out into Central Florida on Thursday, with a slightly better chance of showers/thunder over the NE quadrant of the state, namely from Brevard County toward Ocala/Gainesville/Jax triad. South Florida will have a day similar to today with mainly showers along the sea breezes, and maybe an isolated thunder chance.


FRIDAY: The upper low over the Great Lakes will move east and relax into an open wave/ trough while the secondary, more powerfully progressive trough drives ESE-SE into the Great Lakes to replace where the former one had been stationary. As the two systems merge a more organized cold front will form Thursday night which will drive into the Mississippi River Valley and  the Deep South Thursday night into Friday. Like on Thursday, this boundary will be located across Central Florida on Friday during peak heating, with the better chance of storms associated with it over Dead Central, favoring the east side from early afternoon through sunset. Moisture still isn't all the greatest, but colder air aloft in the mid-upper levels should help negate the lack of overall moisture, which should converge along and ahead of the boundary under the cold air aloft and continued high temperatures near 90F at the surface. Some of this activity could be quite active into Sunset Friday night mainly along central Florida from Daytona Beach toward Vero, with other showers further south along the east coast...but again, it will be isolated in nature. 


SATURDAY: So far, timing has the actual frontal boundary driving through the state after sunset Friday night through mid-day Saturday, perhaps even faster after dark. Northerly winds should be in place for all of the state Saturday afternoon accompanied by near clear skies and temperatures Saturday afternoon in the low 80Fs to upper 70Fs far north Florida.  Overnight Saturday night high pressure builds in quickly across the southern tier of states and winds become more NE-ENE during the day Sunday, strongest across far South Florida and the keys.  


SUNDAY/TUESDAY: The only favorable location for rain showers/thunder will be across the Far Southern tip of the state from Southern Dade County and through the Keys, including Key Largo.


During the course of this first frontal passage, which coincidentally is forecast to occur on the exact same date as last year, October 1st, morning lows along the east coast will be close to 70F and highs will be in the low to mid 80Fs, with some upper 40s to mid-50Fs mostly around the Big Bend and all of the panhandle. By Tuesday east coast temperatures will essentially be equal to the ocean temperature near shore, or just a bit below that by noon time, with only about a 10F degree variation in the temperature fields between morning lows and afternoon high temperatures. So far, it does not look as likely that a major rain event, or any event, will be in the works as opposed to earlier model runs, but this will need to be watched for as the time approaches (by Wednesday), when such a set up would be more likely as winds become more due easterly.

Recycling Day As Deepest Moisture Moves Out and New Troughs Move InBi

Low Rotates Back toward It's origin - Lake Michigan - toward Wednesday as occluded (purple) front wraps around it. Another stationary front runs out ahead of it, and the old mid level boundary that was over North Florida sinks and stretches out more NNE- SSW down Florida. The pressure pattern over the Atlantic is breaking down 

SYNOPSIS: The large upper low over Illinois is slowly moving toward the east to ENE today but will make little progress. Meanwhile, there appears to be a mid-level trough axis running down the east side of the State this morning, and latest RUC forecast shows very little displacement of it during heating of the day, likely due to a thermal low level trough being established across the interior with heating of the day down the spine of the state. The deepest moisture is along the east coast from Brevard and south. South Florida had the most moisture this morning, but it appears as though since the time of their sounding at 8AM it could have lowered further. In all, the deep moisture of days past is moving out along with yesterday's cloud cover. 

The large low over the upper MidWest will move east to ENE through Thursday as a series of vort lobes and surface boundaries continue to dig deeper into the eastern and SE states through Friday. Another low pressure trough moving across Southern Canada is expected to push the first low out of the picture, at last, but re-establishment another deep upper level trough near the same location by Friday as the first one which finally also press east through the weekend. 


 During this course of events, Florida has lost its deep tropical moisture connection (air mass), so most moisture for storms will rely on the ever critical location of surface/mid level boundaries where winds converge to enhance localized deeper moisture such as along Lake/Sea Breezes and mid-level troughs. This could be an ongoing theme through Friday, with the rain chances diminishing to near zero for north Florida (mainly the panhandle region) on Thursday.

TODAY:  As usual, transitional periods are tricky at best, especially now that we have lost the deep tropical connection and an apparent mid-level trough axis is elongated down the state;  in short, we have an entirely new 'ball game' to play. 


SW Flow seems to be the consensus along the east side of the state, albeit quite light. However, as of 12:30pm the ECSB has yet to set up, so the RUC/GFS might just have something there with their propositions of a delayed or at least east coast sea breeze until mid-afternoon . The hamartia for forecast busting today will be just exactly where deeper moisture can re-establishment as a result of moisture convergence as opposed to the free flowing moisture of the past few days.


Showers have already formed near Lake Okeechobee, as residual pockets of fog and low clouds continue to burn off elsewhere.  The most unstable atmosphere is along the west coast near TPA and north, and this should move inland during the day across most of the north 1/2 of the state. However, this area is also most dry atmospherically speaking.  Sea breeze circulations might not set up in full until mid-afternoon, if not later north of Lake Okeechobee. Meanwhile, a jet stream speed max is apparent coming across the Gulf in model guidance and satellite imagery.

MAIN FACTORS TODAY: Deepest moisture along the east side and convergence along mid-level boundary (blue)..as highest instability advects  eastward toward the east from the Gulf, combining with divergence well aloft associated with a jet stream speed max at 30-35,000 ft of 60-70kts. Stronger storms near the Lake and interior North Central to NE Florida.
There could end up being highest coverage due to outflows from north and south over Osceola County by tonight. 

  
THUS, for today more thunder as opposed to rain showers, but all in all should remain fairly isolated, although there could become a time of better rain coverage by early evening over the interior spreading toward the east coast and offshore, especially along and south of SR 46. Thus, today, like all the others could end up cloudy in many locations along the east side by sunset.  South Florida as always should kick off soonest, but the strongest storms will wait for possible sea breeze convergence underneath the mid level trough axis where the deepest moisture resides, which would be further north. The coldest air aloft is near I-4 and north, but only by a very small margin. The strongest storms , although more isolated should be near NE Lake County, Seminole, West Volusia, Flagler, and western St. Johns counties..with another stronger storm or two in St Lucie/Marian Counties and maybe Southern Brevard/Vero area. The strongest storms will result from where two or more boundaries meet late in the day..somewhere along the east side of the state or the interior. Greatest coverage of rainfall does not equate to where the strongest storms will be.

Not meant to be 'all inclusive' because thunder could occur near the east coast anywhere over South Florida to DAB, but the greater concentration should be a little away from the coasts. Although not shown, Osceola County through Orange counties and north could end up with bigger rainfall totals due to training or slow motion of heavier rains after 5pm. There could be a 'cluster' of moderate rain to move offshore tonight somewhere along the east coast almost anywhere, most likely north of Lake Okeechobee.

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WEDNESDAY/FRIDAY: Late Friday or  Saturday could be fall's climacteric, if for only a day or two..more so for the northern 1/3 of the state. Expecting that local forecasts will go up and down on rain chances up until that time due to the uncertainty of where boundaries will be found until the final blow, or front, can press south. As of the 2AM GFS, that would occur Friday night, with the front over or near the Florida Straits by Saturday afternoon. Before that time, thunder is possible..and if timed just right per the GFS early today, would be across Central Florida during peak heating on Friday. Thus, some stronger storms (isolated) could occur this day in that location. The front has yet to be forecast to cleanly clear the Florida Keys, so rain chances might actually pick up in that location over the weekend. 

With the frontal passage, whenever that might be, the east coast could expect a 'fall like' morning in the temperature department, but with the progressive southern tier of states pattern in place abetted by the southern branch jet stream, it will be short lived as onshore flow ensues within 24 hours after fropa if not sooner (frontal passage).

NEXT WEEK: We could be setting up for an east coast rain event, most likely south of SR 50 and north of Ft Lauderdale by the middle of next week. The most likely area would be Palm Beach County upstream of the onshore flow off the Bahamas, with the Ft. Pierce area coming in a close second as a contender. Other areas south of I-4 might get in on the act in-part. ..put rain chances do pick up again over South Florida at least  due to the lagging   mid-level frontal boundary. 


 In the longer term, a much deeper full latitudinal trough of threatening proportions is forecast to develop in the country's mid section toward next weekend as we progress through the first week of October. Not shown yet, but there is a chance that too will cut off neat the Great Lakes, or could be a severe weather maker at various stages of its frontal life cycle stage from the Central Plains toward the Ohio River Valley and portions of the SE states in the great beyond.