WEATHER MADE CLEAR FOR ALL TO HEAR

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

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

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

Saturday, January 15, 2011

Going from "Benign" to "Beastly" By Monday? 'Bears' Watching






Images: 1) Forecast for Sunday night; 2) Forecast for tonight 3) Current Cape temperatures; 4) graphic depiction of 7:45AM Saturday morning temperature. Note the warmest air from Daytona Beach Shores along A1A to Miami and across the Keys

TODAY: Benign weather pattern will remain in place through the weekend with very mild temperatures along the east coast tomorrow morning once again with comfortable afternoon temperatures in the low and maybe some mid- 70s. Inverted trough from the Cape and off to the NE was evident yesterday and remains in place today through Sunday. Note the warmest temperature at sunrise in the image above is at the eastern most tip of the Cape. Local LDIS picks up on the trough in the wind and moisture fields nicely (with greatest low level moisture along it , penetrating Brevard Country), and model guidance has as well. This trough may play a bit of 'forecast havoc' in regards to afternoon high temperatures, namely they may be warmer then thought. Should it manifest as a bit more 'defined' surface winds may remain ever so light backed from the NW today allowing the mercury to rise minus an onshore, cooling component.

NOTE: This trough, benign as it may be now, will be a big player into Monday as we will read below.

The KSC sounding shows a strong inversion at 5000 ft (roughly 850mb) with moisture trapped just below the inversion. Very weak wind fields are in place under the inversion level while westerlies prevail above it and strengthen with height. Cape temperatures yesterday morning were 10F degrees warmer from those of Thursday, and nearly 10F degrees warmer again this morning from Friday morning. Once again, temperatures fell very little after 8 or 9pm as was the case the night before. In short, temperatures are moderating and the cold snap is gone for all but North Florida.

Might add, the low in Tallahassee yesterday was 18F (Crestview was 15F!!), and the low there this morning was 20F. Additionally, Tallahassee finally broke 50F degrees for the first time in 5 days yesterday. Just a side note if we thought it was cold over Central and South Florida.

Otherwise, low level ridging continues from near the Texas Big Bend and across the Deep South as a subtropical jet streams from Southern Texas eastward to nearly across the Florida Straits while the main polar jet stream remains to the north of Florida within an upper level trough along the eastern U.S. seaboard through mid-week. Main storm impulses at this time continue across the Great Lakes and the Northeast States.

SYNOPSIS FORECAST: Most importantly for late in the weekend, a mid-level impulse passing over Mexico crosses Southern Texas on Sunday, providing for thunderstorm chances there tomorrow and continues along the subtropical jet, crossing the Central Gulf of Mexico during the overnight hours into Monday morning.

Meanwhile, the inverted trough closely snugging the Cape since yesterday remains in place during that time and becomes better organized as mid-level impulses crossing the NE and mid-Atlantic States within the upper level trough enhance it. The trough remains in place though due to high pressure to its east. This trough, benign as it may currently be now, becomes a major player (as previously noted above) during the day Monday afternoon into Tuesday morning.

SUNDAY: Mid-Level, subtropical impulse crosses Southern Texas during the day and enters the Gulf of Mexico overnight into Monday morning and begins to strengthen, possibly manifesting as a weak surface low Monday morning in the Central Gulf. Locally, very little change from today with temperatures in the upper 60s and low 70s along and south of a line running from the tip of the near shore inverted trough and across the state to Tampa Bay. Periods of stratocumulus clouds possible at any time but rain free. Morning lows once again warmest along the east coast, with inland temperatures moderating tonight as moisture levels increase slowly. In short, tomorrow's high temperature will be close to today but with a broader expanse 70s northward.

MONDAY MORNING: Very mild morning once again with lows along the coast probably in the low 60s and cooler inland. Expecting rapid transition in the sky this day as the Gulf disturbance/impulse/short wave/low (?) moves ENE and begins to integrate with the tail end of that inverted trough still remaining near the Cape over the weekend. This is why I noted earlier that the feature could become important. Somewhat of a pseudo warm front will form in advance of the approaching system, which by the way I fully expect to be exhibiting lightning strikes in the Central Gulf at sunrise, Monday. High clouds well in advance of this system will likely begin streaming overhead well in advance of its approach system which will aid in keeping overnight temperatures warmer, but also hamper temperatures rises during the day.

LATE MONDAY MORNING BEYOND: Big question mark! It is appearing more assured that Central Florida, close to the pseudo warm front will initially experience overrunning cloud coverage and eventually rain fall by around noon time which could evolve into thunderstorms by afternoon and early evening as the wind profiles and veering wind profiles associated with the trough approach the west coast and cross what appears will be the Central or South Central Peninsula during the day. Just exactly where it will cross and its intensity remains yet to be unknown, so there is great uncertainty in how events will unfold during this time frame. It is possible we could be seeing strong/severe thunderstorms embedded within the rain zone anywhere from south of a line from Cape Canaveral to North Tampa Bay area, in other words...all of the South half of the state. The area of greatest threat will be narrowed in on more later tomorrow, and likely be watched intently by official outlets (the National Weather Service) come Monday morning. Be sure to tune in to your most favored weather resource before bed time Sunday night and especially upon awakening Monday morning!! We may see issuance of a severe thunderstorm watch, although believe at this time that the limited coverage of severe parameters amassing may preclude such.

TUESDAY-THURSDAY: The impulse crosses Florida overnight Monday with a more assured surface low formation ongoing just east of the Cape as it runs along the trough that will have been in place there since Friday (yesterday). A cold front of sorts will following the front but with almost no changes in the temperature department. As noted yesterday, the next cold period would not come once again as one piece meal system. In stead, we may see a lull in rain chances after Tuesday morning and through out the day with the true cold front still on the approach for Wednesday. As was the case last time, most of the moisture will be swept out with the first system, but enough will remain for some light rainfall accompanying the front proper which is timed to pass early Thursday.

THURSDAY: With the second front crossing Thursday the atmosphere will yet to fully dry out, but it will be cooler Thursday with the driest of air to arrive sometime Friday, January 21st. I normally think of January 21st as being Florida's "cold core" time, or about the time that it's most assured to be cold here if one were to draw a date out of the hat. Maybe not so oddly, this is exactly one month after the time the sun is at its lowest angle (the first day of winter, December 21st) which jives perfectly with the time lag between the lowest sun angle and the coldest temperatures (1 month). Looks like this year will be no different.

FRIDAY-SATURDAY: Another cold event similar to this last one. Same temperature regime as well with one or two very cold mornings everywhere but the A1A strip from the Cape To Miami again escapes the worst with a prevalent NW-NNW wind regime under advection freeze (windy) conditions. Naturally, this is well beyond any scope of reality (in case this all reads as sounding like absolute 'truth'). This is simply what information is showing early this morning. I have not waited for morning weather model runs to make this post, namely because when I saw the overnight runs this morning there was no big surprises. In short, should this forecast come to fruition, then yesterday's comment about there being no cold air on the horizon was a bust. We'll see what eventually transpires.

IN THE MEANTIME: Watch for updates from all offices as we approach late Sunday. Monday will remain sketchy and become possibly briefly somewhat traumatic contingent upon how parameters evolve. Consider this a heads up on there being a true 'heads up' "Bears" watching...Grrrr!

No comments:

Friday, January 14, 2011

"The Weather Critic Within" - Weather or Not


Images: 7pm temperatures tonight and 7am NEXT Friday morning at a glance. Not much change in this department as a gradual warming trend begins today through Tuesday from Florida to California.







SYNOPSIS: High pressure from the SE Texas Coast toward Louisiana is building ENE'ward across all of the Deep South today and this trend will continue through the weekend as it expands in areal coverage into the mid-Atlantic by next week. Warmest locales in days to come will be Central and South Florida, the northern Gulf of Mexico's southern border state regions (near I-10), much of Texas west to Southern California and up the California coastline to Oregon/Washington coasts.

RECAP: In a snap the cold air event ended overnight from Daytona south to Miami east of I-95 with the coldest air over North Florida south to Okeechobee (the interior) and over toward Punta Gorda. Remember this thermal regime, as it may very well hold fast in varying degrees for the next 7-10 days. Daytona registered a record low high temperature for the date yesterday of 47F, not surprising considering how 'cool' the intra-coastal of Brevard was yesterday. Temperature bottomed out in Cape Canaveral about 2 hours after sunset and held steady the remainder of the overnight hours, indicative that a change was in the offering for most of Brevard. High and mid-level clouds over South Florida (once again as was the case the night before) streamed over that region, holding temperatures up a bit overnight there.

TODAY-WEEKEND: High pressure at the surface will expand east and north from the southern Mississippi River Valley region and across the Deep South with the axis running initially over Central Georgia toward the FL/GA border at times in the low levels. Northerly winds near noon time veering to NNE-NE and eventually ENE and weakening through tomorrow as the axis settles in, relaxing the pressure gradient. Warmest overnights from Port Canaveral south to Miami and the Keys east of I-95 with ultimately the warmest from West Palm and south closer to the Gulf Stream's warm water influence. Coolest next few mornings remains well to the west and north of Brevard County, edging the Orlando area and over/southwest toward Sarasota. Morning lows in the low-mid 50s (coastal) with a gradual increase to mid-upper 50s; highs in the low-mid 60s North, mid-upper 60s South, warming to upper 60s (all) and some low 70s further south toward Miami before the weekend is over. Coolest mornings/warmest afternoons inland over the weekend with the area from West Palm toward Naples pretty much coming out even across the boards (warmest spot SW Florida near Naples). Coolest afternoons along A1A from SR 520 to Jacksonville.

No rain chances noted, although the North American Model is showing shower chances in the warmest area outlined above (from the 'Port of Canaveral' to the 'Port of Miami') beginning overnight tonight. Believe this is over done though, and will leave this as an indicator of periodic greater enhancement (vertical depth) of stratocumulus clouds instead.

MONDAY-THURSDAY: Will generalize this time frame since there will be an opportunity for rain chances in the late-day Monday through Wednesday (at least) time frame. The trend has been to temper down coverage of actual rainfall as well as longevity, but it's too soon to tell if this is a trend or fluke. Outside of the rain chances, though, continuous mild/near normal or a few degrees below normal temperatures at times is the trend for everyone. Best chance for rain appears to be afternoon Monday through Tuesday, so obviously some fine tuning is required for a period that is still a good 3-4 days away. During late weekend a short wave trough riding across the ridge axis may result in a more northerly wind component for 12 hours or so and a minor temperature fluctuation accompanied by more clouds from the trend, but this impulse, should it occur, will have little other affects....and will likely occur unbeknowst to anyone outside of the "Weather Critics".

Rain chances will be associated with a cold front, or two of them, which will cross the state during mid-week in similar fashion to our last event. The first front bringing the rain chances then clearing out the mid-level, rain inducing moisture, with the second front bringing the more pronounced drier/colder air mass. The difference this time is that there will not be a surface low over the Northern Gulf traversing North Florida, but rather much further north. Correspondingly, all the thermodynamics and strong wind profiles ( and colder/drier air associated with ) stays further north as well. Looks like a Northern Plains to the Great Lakes winter to me for the next 5 days.

Side note: Thinking of taking up a new career. We have Food Critics, Movie Critics, Book Critics, Media Critics, Politically Based Critics ad-naseum...why not a Weather Critic!?

No comments:

Wednesday, January 12, 2011

Coldest Today through Thursday Night - Gradual Warm Up Through Weekend


Image shows a forecast for 2 meter morning low temperatures Thursday morning. We see a vast expanse of freezing or near freezing degree temperatures over Central / South Florida toward Lake Okeechobee and west-southwest toward Sarasota/Naples. Warmest location Thursday morning from near Cocoa Beach south along A1A to Miami (increasingly warmer the further south one gets toward Miami/Venice/Keys).

TODAY: Morning low at my place was 40F while MLB was showing 42F with similar readings on the west side of the state at the same latitude. In comparison, the panhandle was in the mid-upper 20F's with much drier dew point air. Forecast of yesterday remains on track so not much to add this morning. Second cold front is still clearing extreme South Florida this morning with the final one, composed of the driest of air crossing the state today and also clearing the state by tonight. Driest and coldest of air for this event will occur (for the most part) Thursday morning.

But for today, little change throughout the day as a continuous stream of surface wind from the NW ushers the final 'front' through (consisting of greater extensive drying at all atmospheric levels more than anything else). There are some cirrus streams over head, but they will gradually shift south of Central Florida during the afternoon. Extreme South Florida has some stratus clouds abundant (being still ahead and along the second front). Continuous feed (cold air advection) throughout the day will keep the afternoon temperature very close to the 50F degree isotherm along 520 to Tampa Bay within 2-3 degrees, with mid 50s increasing to upper 50s further south and finally low-mid 60s across the Keys. Winds NW at 15mph perhaps gusting to 25mph along the causeways and near open bodies of water elsewhere.

TONIGHT/THURSDAY MORNING: Final thrust of the cold air arrives with advection freezing level temperatures very close to US1 at sunrise. The Barrier Islands should escape a short-duration freeze tonight with mainly mid 30s as a NNW wind blows down the intracoastal waterways along their length. Again, warmest along A1A from Port Canaveral - Miami and warmer the further south, but still pretty cold down there for them. Afternoon temperatures on Thursday will again be similar to what we will feel today, but do believe it will be 3-6F degrees warmer than today under full sunshine.

THURSDAY NIGHT-FRIDAY: Phase 1 of initially only gradual warm up begins, especially at the coast as winds become due north and eventually NNE-NE into Friday. Coastal lows in the mid-upper 40s but continued much cooler/cold in the morning west of I-95 over and down toward Sarasota. Afternoon high Friday in the low-mid 60s with some patchy clouds or close to 10F degrees warmer on Friday than what will be reached Thursday afternoon. The area around Miami may even see a rain shower before Friday is over, but that remains a big question mark in my mind with a great temptation to squash that notion altogether.

SATURDAY-MONDAY: Phase II warm up. Coastal lows by Saturday morning might not be much different from what the temperature will be at sunset Friday night up and down the east coast as winds become more easterly and eventually southeast during the weekend. Coolest afternoons east of US1 but upper 60s and low 70s will be the rule Saturday. Warmer away from the coast. No big rain events, or any rain at all for that matter through the weekend as the warming trend expands in coverage of real estate statewide returning to seasonable norms Sunday. Stratocumulus clouds likely to become an ever-increasing factor for afternoon high temperatures in some locations but extensive overcast conditions not anticipated currently, but does bear watching for the east coast from the Cape and points south as we go into the overnight hours of Friday into Saturday.

TUESDAY: Perhaps the warmest day yet with very mild, non-impact temperatures in either the freezing or sweltering category as winds shift from southeast to eventually southwest over night Monday into Tuesday ahead of the next frontal system. We should lose the onshore component wind on Tuesday which will permit us to feel the warmest temperatures, albeit cooler than west of the rivers due to the cooling affect of wind blowing across water.

No comments:

Tuesday, January 11, 2011

"Un-Civil War" To Break Out NYC to New England - Country Enslaved by Cold Air


Images: (1) This image roughly shows the current synoptic situation. We see a low pressure system that departed NE Florida yesterday riding up the eastern seaboard just offshore getting reading to phase with what was a Central Plains System yesterday 2) Thursday morning temperatures (7am EST).




SYNOPISIS: Moisture laden low pressure that exited NE Florida yesterday is trekking NNE as a cold low pressure center crosses the Ohio Valley today. "South" will meet "North" just off the coast of New Jersey overnight tonight. The low pressure area just off the coast will become the dominant feature as pressures fall rapidly and 'bomb' out. Artillery will fall from the sky as a result! Both systems have plenty of moisture to work with and as such a broad swath of snow across the Ohio Valley and Pennsylvania will broaden during the next 24-36 hours, becoming most prolific in the purple shaded area where the combination of most abundant moisture, strong surface winds, and cold air combine in "Civil Warfare" of uncivilized nature.

Meanwhile, a series of short-waves will rotate around this complex war zone bringing colder and drier air into the Deep South as a series of wave intrusions rather than all at once. We see that by Thursday morning the war will have ended for the most part leaving a fast expanse of cold air casualties in its wake. Should add at this point (speaking of causalities) that those folks in the Deep South are in for it tonight. Given the recent snowfall, and temperatures in the 30s today and another front soon to pass, those temperatures will fall into the low 20s tonight which will re-freeze the melted snow making for dangerous driving (and in some cases walking) conditions there. The net result by Thursday is the much of the country will be enslaved by cold air.

LOCALLY: The first front that was in the Gulf of Mexico has crossed all but extreme South Florida today after lingering across Central Florida until mid-morning, where it is little more than a wind shift. This was Phase 1, mainly a wind shift and some drier air -- but not by much. North Florida is feeling the front much more though where temperatures in the low 40s have persisted. During the afternoon Central and South Florida will remain in somewhat of a 'lull' before the next front moves in around sunset with much cooler air following. Rapid clearing late this morning has ensued during the past hour but more high clouds could be on the way until the last and final front crosses later on Wednesday. No rain in the outlook, although some showers over extreme South Florida remain possible until the second front clears the state. The second front will cross Central Florida around or just after sunset bringing in drier low level air and much cooler air.

WEDNESDAY: Much cooler Wednesday morning with temperatures in the mid-upper 50s from North to South by afternoon and lows in the low-mid 40s, but considering the timing of the second front, South Florida from Lake Okeechobee and south won't realize the full impact of this front until after peak heating, thus it will remain relatively warm there tomorrow, albeit a bit cooler than today. High level clouds could become a problem as well for Central and South Florida until the final front pulls through which further complicates just exactly how warm it will be in both zones. But do expect mid-50s along 520 to low 50s along I-4 with upper 50s to near 60 from Melbourne and south. Much warmer South Florida Further complicating the forecast is that cold air advection will ongoing throughout the day, somewhat doggedly but nonetheless it will be occurring.

THURSDAY: The final front will clear Central Florida during the afternoon Wednesday allowing the driest and coldest air to finally move in. Looks like Thursday will be the coldest day 'round the clock' from sunrise to set with widespread mid-30s and the freezing line being teased all across Central Florida toward Ft Myers. Highs comparable to that of Wednesday, but colder over South Florida. At this time, do not foresee any nights with prime radiational cooling under near calm winds to occur for a wide spread freezing event although many locales could be below freezing for a time. It seems this will again be a 'spine of the state' event with NNW winds prevailing throughout the duration, which will advect cold air southward from snow and ice covered grounds now over Georgia. This looks to be much more of a 'spine of the state' cold event, favoring the west side as has been alluded to in the posts made several days ago now given what will be the prevailing NW-NNW wind direction.

FRIDAY: Another cold start to the day but not as cold as Thursday and a bit warmer in the afternoon, but not by much. Need to watch the Barrier Islands beginning this time frame for some clouds contingent upon a minor veering of the wind. Winds remain NNW becoming more northerly during the day, with a possible hint of NNE overnight. From Friday night and beyond the temperature and cloud forecast is nearly impossible to ascertain for the barrier islands especially south to Miami so will go so far as to omit this time frame out in today's post until a greater level of certainty is grasped. But in general, moderating temperatures will be the rule across the state with the cold snap ending.

No comments:

Monday, January 10, 2011

Deep South Begins To Recover - Northeast Braces

















Images: First image is the 85omb pattern forecast for this afternoon with current surface features overlaid for the SE states near Florida. These features are better depicted in the 4th image. Second image shows current radar with thunderstorms/lightning strikes showing up across the GOM and North Florida. Third image shows the current 'mean' steering flow. Anticipated areas of best rain chances are north of the 'highlighted' line.

CURRENT: Weakening low pressure just south of Panama City, FL is moving ENE toward Jacksonville with the warm front having just cleared them. Thunder reported last hour at JAX and Gainesville near the front. As expected, over night lows never really fell much if at all along the coast due to cloud cover and onshore flow, with the warmest spot east of US1 up and down the coast due to onshore flow and what one could argue as being a pseudo-thermally induced coastal trough / warm front and then passage of the warm front itself.

GENERAL SYNOPSIS/FORECAST: Now that we're up to the current time of this writing (9AM), we'll observe the low pressure system to track across the panhandle with accompanying surface boundaries pivoting east to the NE-NNE and weakening around the main player low pressure system now over the South Central Plains (shown in first image). Perhaps the post from Saturday better depicted the next few days ahead. The Southeast system will ride up the eastern seaboard and merge with the Plains system on Tuesday as that one crosses the Ohio Valley. Net result will be some very active winter weather over all of the NE states Tuesday and Wednesday.

LOCALLY: As we see by the mid-upper level winds and in observing radar trends, all storm motion is uniform from the WSW - ENE and this is not expected to change today. As such, any thunder today should remain along and north of the highlighted line within this flow. The temperature observations showed cool 50 degree readings inland this morning with low-mid 60s at the coast, but for the most part all things will become equal south of the warm front before noon with everyone in the mid-upper 70s. The coolest spot will be along A1A north of Melbourne Beach due to the expected slight onshore, breezy wind component from a predominant SSE direction where closer to 70F-73F will be felt.

Skies are cloudy this morning, but some breaks in the low level deck may develop by noon for a brief time. But for the most part mostly cloudy to cloudy skies prevail. Should some breaks occur, we might see a quick moving rainshower along the Beach Line, especially from 2pm -8pm. Otherwise, SE-SSE winds will veer to due south by dark and remain elevated in the15-25mph range. Once again, the Beach Line prevails as the demarcation line to where it merges with I-4.

TUESDAY: The dashed 'cold front' shown in the Gulf will move into Central Florida and linger through the day very close to the I-4 to 528 corridor as all upper level dynamics and support for it move well away into the mid-Atlantic states and eventually just offshore the NE states. With all dynamics and deep layer moisture having exited the area, looking for mainly partly cloudy to cloudy skies continuing Tuesday , patchy at times and no rain. Another mild night tonight and Tuesday along/ahead of the stalled boundary with highs again in the mid-upper 70s very close to the Beach Line and points south.

Meanwhile, the low over the South Central Plains will be crossing the Ohio Valley with its attendant cold front moving rapidly toward Florida. The two fronts eventually merge over Central Florida overnight Tuesday into Wednesday morning making for a cool start to the day with clearing skies. True cold frontal air advection throughout the day Wednesday on the wings of a WNW-NW wind.

WEDNESDAY/SATURDAY: Front clears the state with a cool day in store all day Wednesday and much cooler to cold Thursday through Saturday morning round the clock. As opposed to previous thinking, could be some freezing temperatures for many folks except those along the barrier islands Thursday and Friday mornings (at least). I have not waited for morning model runs for today's post, being more focused on the short-term to tackle what appeared could have been a severe weather event too close to home for comfort.

Winds will be more northerly though during this next cold spell as opposed to previous events which may spare the outer islands and down A1A toward Miami, with the worst of it all along and north of I-4 (at least at the beginning). It will be interesting to see what happens in the temperature department though as the northerly winds move in and persist as they advect cold air from the region that will be impacted by more snow (Tuesday and Wednesday) come Friday and Saturday. Temperatures may struggle to break the mid-upper 50s across much of Central Florida Thursday and Friday northh of the magic latitude of the Beach Line.

No comments:

Sunday, January 9, 2011

Evolving Storm System Just Beginning To Be Felt - MUCH More To Come










This morning's images: (1) Current surface plot shows cold front having cleared Florida with developing storm complex affecting SE Texas with thunderstorms/rain (2) 8AM this morning colorized/general temperatures across the state. Note NE winds in the making with and temp gradient along the east coast. Wind barbs show a NE wind along the coast which are just offshore the Cape in reality (3) *Forecast for 7AM Monday morning. By this time 'everything weather' will be underway from Central Florida to the Central Plains. Those yellow areas are zones of contention (particularly nasty).

TODAY: The forecast from yesterday's post remains on track with a few (and should add, beneficial) timing discrepancies with a slight thunderstorm threat thrown in for kicks Monday. But in the short term, all parameters remain on track. As expected, overnight lows were coldest west of A1A with Patrick AFB reporting a morning low of 50F while Orlando International was at 42F. A northeast wind is already blowing at the Mayport Naval Air Station south to Daytona (where it's also 50F this hour), but hasn't quite made it to NE Brevard County and points south where winds were light from the N-NNW. I think there was a brief period last night when the atmosphere decoupled, so these winds are more of a land breeze more than anything else. The NNE-NE wind should develop by 10AM though up and down the east coast and encompass much of the state as well. Cool day regardless in the wake of the cold front, with highs across Central Florida in the mid-60s and lower further north, upper 60s south and 70s far Southeast Florida under partly cloudy skies.

At this point (and of potential later importance as we'll read below), will also add that southerly winds a few thousand feet overhead will begin to develop well in advance of the approaching storm system (just moving off the Texas Coast) as a warm front gathers moment to the south and moves rapidly north overnight. This front is shown in the first image still very far away.

MONDAY: Very mild overnight and post-midnight. As shown in Image (3) the warm front will be across Central Florida at daybreak. As noted Friday, our cold front of late yesterday would return as a warm front, and that still seems to will be the case. Expect some cloud cover as well as developing ESE winds will keep temperatures tonight from bottoming out much beyond 11pm tonight, then hold steady and maybe even warm a bit by sunrise along the coast from Miami to the Cape as the warm front passes. Winds from the S-SW just overhead at 20-25mph with surface winds from the ESE-SE and increased moisture could induce rain showers along the east coast along the front itself, which will slow its northward trek during the day. Low level convergence along the front due to the shearing wind profiles, coupled with increasing winds at the surface and just overhead coupled with increasing moisture throughout the boundary layer near the front could result in a strong thunderstorm with some rotation from near Cape Canaveral to Daytona and inland along SR 528 toward Orlando and Ocala during a critical time frame between noon-3pm before the warm front gets its second thrust of moment to move further north of Jacksonville.
Timing is all critical. If things do not come together "just right" the risk of a strong thunderstorm (or any thunderstorm for that matter) quickly dwindles. But do keep the time frame from around 6AM - 2pm in mind for the chance of rain or a thunderstorm with gusty winds possible. Winds become SSE-S during the day in the 15-22mph range under partly cloudy to mostly cloudy skies by late afternoon once the warm front clears north of I-4 and quickly passes the Jacksonville area. Afternoon highs on Monday in the mid-70s with even some upper 70s across much of the state other than the I-10 corridor. Maybe even a low 80 or two over South Florida.

LATE MONDAY-TUESDAY: As expected, the cold front will be slow to sink south into Central Florida which is where the timing disparity from yesterday's post bears mention. Anticipated it would take all day Tuesday to clear the area, but that might have not been slow enough! That's the beneficial part. Granted, we'll be hearing all about winter weather woes not too far to the north, but for folks south of a Daytona - Brooksville line it'll be a totally different animal. North of that line is where the greater chance of persistent cloud cover and light rain will increase, getting increasingly worse (wetter and colder) the further north one goes, particularly north of the Florida/Georgia border as was alluded to two days ago. Another mild-night over night Monday and warm on Tuesday with highs in the mid-upper 70s despite cloud cover. Winds SSW-SW all day.

TUESDAY: Continued very mild. It was previously thought the cold front would be slowly crossing Central Florida during the first half of the day, but it now appears it will be delayed by a good 18-24 hours. Another warm day but cloudy or mostly cloudy with minimal rain chances. By now the low pressure area will have cleared the east coast and will be riding along or close to the mid-Atlantic coast line with all the dynamics stretched out. This system though, will begin to phase somewhat with a separate system that will have greatly impacted the Central Plains from Colorado, Kansas, Northern Oklahoma east across Tennessee...net result will be a broad expanse of snow cover and cold air for much of the NE states and around the Great Lakes as very cold air sinks south out of Canada across that same area setting the stage for a very cold second half of the week across these locations.

WEDNESDAY: With all the dynamics and bulk of the moisture concentrated about the complex storm encompassing the Northeast Quadrant of the U.S., the front will eventually cross Central Florida in a much dilapidated state. Timing would have it now crossing Central Florida the first half of the morning hours on Wednesday. Will it take even longer? Very hard to believe so at this point, but a further delay toward noon time isn't totally out of the question. Wednesday is very sketchy in regards to cloud cover as well. A secondary impulse will provide the momentum to give the front the necessary shove south, but may also produce increased cloud cover and holding temperatures below what we will have bask in on Monday and Tuesday.

THURSDAY-SATURDAY: Front will finally move south one way or the other, and barely affect extreme South Florida. No humongous temperature drops. This morning might very have well been the coldest morning we'll feel for the next 5-6 days. That wasn't so bad now was it? Looking at lows in the mid-upper 40s and highs in the mid-upper 60s and 70s to the far South. Coldest of locations for Central and South Florida will be on the west side of the state, permeating into the Orlando area and south toward Naples.

No comments:

Saturday, January 8, 2011

"Manic Monday For Most" - Central/South Florida 'Relatively' Unscathed












Images: First image is a mid-level (700mb) forecast for 7pm EST tonight. Note the circled red area. This is the wind field (and trough) of a storm system that sat off the California coast last week bringing them rains. It has moved on shore and is crossing SW Texas now and approaching the East Central Texas Coast today. There's almost nothing there now, but just watch and see what happens Sunday morning through Monday afternoon! The second image is for Monday morning. Yellow shows a very generalized area of the zone where initial winter impacts will hit hard from this system as it moves E-ENE with weak cyclogensis (formation of a surface low) having already occurred. Note that Florida is in the warm sector south of the warm front Monday morning.

TODAY: Dry, cold front approaching Central and South Florida tonight. The front has crossed the Panhandle already, but will likely get hung up to our north during day light hours, then push through between 7-10pm and clear the state after midnight. Before that time (during daylight), brisk WSW-W winds continue with partly cloudy skies and temperatures 70-mid 70s, upper 70s South Florida. Meanwhile, a storm system starts to take shape over South Central Texas moving east toward the Gulf Coast as all the ingredients for a wintry stew gather over the Deep South.

TONIGHT: Front clears Central Florida with a quick wind shift to the NW, then N to NNE all over night. No change in previous line of thinking from yesterday. A1A from Port Canaveral and south may escape the majority of temperature impacts from the front due to the rapid change of wind direction, but everyone west of the rivers will go down into the low 40s and upper 30s in Central Florida. It's a very close call. Best bet is to hope for the best, but be prepared for a chilly beach walk in the morning, just in case. Additionally, the quick wind shift off the shelf waters further north could induce some clouds along the coast mitigating a sharp temperature drop. Very close call though for A1A south of the Space Center in regards to sunrise temperatures. Given the situation and the small zone that might not be all so cold in the morning, we'll never hear about it on the TV or radio, with low 40s and upper 30s being the rule for the majority of the populace.

SUNDAY: Regardless, by mid-morning the wind will be NNE-NE, but the day will remain cool give the recent frontal passage, wind shift early or not as the wind blows off cool Atlantic Shelf waters from that northerly component. Stratocumulus clouds off the Atlantic may inhibit daytime heating to a small degree, with high level cirrus streamers more likely beginning to pass over head by late afternoon from the West in advanced of the developing storm system that will be approaching the Mississippi River Delta area. Highs in the low 60s along SR528 and mid-upper 60s further south, some 70s South Florida. Another point to make is that even if A1A manages to eke out of this short-lived very cool blast, it may also end up being the coolest spot during the afternoon given the NE wind direction. Rats.

SUNDAY-NIGHT/MONDAY: But all's far in love and war as they say. Wind shift continues over night with winds continuing to swing around toward the ESE by day break, shifting to southerly (and brisk) by sunset. It'll be a "Mild Monday Morning" for Florida, but a "Manic Monday Morning" north of I-10, with a mixture of freezing rain along a thin band, and snow just north of that across the Northern half of Alabama, Louisiana, Mississippi, and Georgia (very roughly speaking). Big cities will be impacted. We could see a light shower along the coast, put expect mainly lots of clouds at various levels. The temperature may actually warm a bit overnight toward Monday morning as the wind gains the more southerly component along A1A and US1. So there you go, it could go from being the coolest afternoon spot Sunday, to the warmest Monday morning location. Widespread 70+ degree readings for all but the Panhandle and very close to I-10 where a very, VERY sharp temperature gradient will exist. But again, A1A although warmer in the morning won't see the big increases in afternoon temperatures, especially north of Melbourne, due to a slight component off the water, this time from the south.

MONDAY: As noted above, mild over night going into Monday, particularly along the entire East Coast east of I-95, but warm everywhere by late morning under partly cloudy to cloudy skies. Chance of a low end shower, especially east of I-95 from Sebastian to Jacksonville (trace amounts). Weather headlines will be scrolling for folks from Louisiana east to Georgia and eventually the Carolinas though with the entire gamut of winter woes occurring there while we remain untouched by ongoing drudgery further north through the entire day. Some folks will walk out the door in the morning, particularly in the Carolinas under just cloudy skies, only to have full on snow happening when its time to head home. Locally, though, winds SSE and veering to SSW after dark and remaining in the 12-18mph range overnight as the low pressure system exits the east coast near Jacksonville and the fronts drags back toward the WSW-SW.

MONDAY NIGHT/TUESDAY: Mild again Monday night through early Tuesday. Looks now like the cold front will cross Central Florida much like the one last week in regards to timing, that being, half-doggedly. It will take all day to finally clear the Miami area just after sunset. Could take a good portion of the first half of the day to clear Central Florida...with wrap around moisture providing for cloud cover for the remainder of the day. Also need to consider that low level winds will be blowing across the now rain, snow, and ice covered grounds further north directly at Central Florida, complicating the cloud parameter forecasting portion of this time frame. The clearing line might very well be on our Northern horizon (for folks from the Cape to Orlando) as the sun sets Tuesday night, hopefully sooner.

The chance of rain along the front itself still looks very meager. The only dynamics in place will be limited thermal instability due to deep layered cloud cover before hand and nearly unidirectional winds limiting shear. The only mechanism I see to instigate rainfall would be speed shear induced lift and covergence right along the front itself. I'd say maybe 10-15% of folks might see something falling with the front, but nothing measurable or if so less the 1/4" of rain, since what little does fall will also be moving fast and not linger. South Florida similar, maybe even less chance of wet stuff. Tempting to say no chance down there, but there's still a good 2 days to re-evaluate.

TUESDAY NIGHT-FRIDAY: Clearing for sure overnight (if it had not cleared by afternoon, Tuesday). Winds swing around rapidly to due north and remain such through Wednesday, gradually becoming more NNE on Thursday. The coldest locations will be West of I-95 toward SSW Florida. Jacksonville area might get bit bad by this one. But again believe, that although it will be only very cool in the morning, comparably speaking in regards to other folks to our north, the 'least cold' place to be will be east of a line from near Port Canaveral - SSW toward Naples/Venice. For example, several mornings it could be colder at Punta Gorda than in Cocoa Beach which is much further north (but on the east side of the state).

BEYOND: No change in the extended per the 0z (last night) and 06z (overnight) model runs. Very active, near zonal flow over nearly the entire Southern U.S, but thank goodness the core of the jet stream will be just to the north. But the majority of the country will be under if not north of the jet stream. Many areas will be frigid cold, and we'll be hearing plenty about THAT! Look out North Texas-Kansas-Oklahoma and everywhere East and north of there. The southern stream will remain active both from impulses riding along it from Southern Cal..as well as it being fed by impulses/storm systems riding south out of the Arctic. These precipitation inducing systems will further aggravate a cold ground level temperature, ice, and snow cycle.

It'll become a self-perpetuating machine. Expect bigger fronts to cross Florida during the remainder of January roughly every 5 days, but untimely secondary systems could also hit on a '3rd day' as well. Too early to say if another big freeze is in store for Central / South Florida, but at this point it is not apparent one will occur, at least not with any duration. Active time ahead for the enter eastern 3/4 of the country, and forecasters over much of the country will have their hands full for quite some time to come.

No comments:

Friday, January 7, 2011

This Weekend At a Glance







Images: 1st image shows the forecast for 12pm (noon) today. Second image is a forecast for 7pm, Sunday night. The expanse of the weekend.

NOW: Nice weather statewide through the' majority' of the weekend. Currently at noon time, there is an amazingly very small temperature gradient (difference) over the entire state from extreme North to the Keys, with temperatures varying from high-end upper 50s at and north of SR520 to lower and some mid-60s to the south with mostly clear skies with the exception of a few stratocumulus advecting toward the West Coast near Sarasota off of what appears to be a thermally induced Loop Current trough. But everywhere I'm finding low 60s. So in essence, everyone is within about 5 degrees of one another.

We see in the first image high pressure over the Southwest Gulf of Mexico that will be moving east (and mainly south of the state) in tangent with a weak trough (the dashed blue line) today and into tonight. The only affect these two items of interest will have is to keep winds elevated from the WNW to W due to the air pressure gradient between them...with perhaps a brief backing to the WSW in the wind direction as the trough passes. No big 'cloud or temperature' event is foreseen. In essence, unless one is closely monitoring the weather this will occur unnoticed unless engaging in activities dictated by wind strength (such as kite boarding or kite flying). Good day for both.

TONIGHT-SATURDAY: Winds remain elevated primarily from the west at 10-20mph (strongest during the afternoon as mixing with daytime heating occurs), but little worth mentioning other than perhaps some passing bands of high cirrus clouds ahead of the next 'dry front' late Saturday. This front is shown in the first image to be roughly located across the South Central Plains states. Although this front will have minimal impact here, it is setting up for some hellacious forecast problems in other parts of the Southeast as the next system (yet to form) approaches. One way to look at it would be to say that it will lay the foundation (in the form of cold air near the ground) that will making for a complex meteorological scenario by the end of the weekend up there. But that's their problem. Closer to home (Central and South Florida)....Saturday will be perhaps 5 degrees warmer across the boards than today, if not by more than that of this afternoon. A few high clouds, but no biggy.

OVERNIGHT SATURDAY-SUNDAY: This is when the first crux of weather changes in store for all of Florida during the period of Sunday morning to Tuesday morning will begin. The front will cross late Saturday (more likely Saturday night) with the first big change. Namely, a wind shift to the NW-NNW-N over the period of a few hours if not less. This is different from the westerly direction we've experienced since yesterday. This veering of the wind direction will continue throughout the day on Sunday, becoming easterly by afternoon. Temperature forecast is a bit tricky for those along A1A from Daytona and points south with morning low temperatures dependant on how quickly the wind gains a semblance of an onshore component.

But when everything comes out of the wash, believe the end result will be that this area (A1A corridor) will end up with a low temperature similar to what was felt this Friday morning, which varied depending on one's location. For instance, I saw Patrick AFB was reading 48F this morning while my porch in Cape Canaveral was 43F (close to if not cooler than the Melbourne area and Orlando). But hey, that's 5F degrees. Believe Sunday morning will be similar along the coast, but folks from US1 and west will be in the low 40s to start the day, Sunday. (side note: will watch for cloud potential right at the coast at sunrise, Sunday)

The remainder of Sunday. Interesting day from a meteorological perspective, considering we could start the day very cool to cold and clear, and end the day nearly cloudy and almost 'warm'.
We see in the second image included in this post that a low pressure system will have formed off the Texas Coast, as a warm front begins to form along the receding air mass (from the south)... that which passed through yesterday. This boundary will assert itself with a vengeance as it gets fully developed along or just north of I-10 (near the Florida/Georgia border) and conflicts with much colder air already residing to the north.

Remember now that front that I mentioned earlier leaving cold air in its tracks up there? Now's the time to retroflect. I circled that area in black just to depict a very generalized zone of potential future weather impacts in that area which will consist of freezing rain, sleet, and/or snow. Must say, the folks in the Tallahassee NWS office will have their hands full in dealing with lots of "whens, wheres, ifs, ands, or buts" as the zone will be close to if not within part of their area of responsibility. But getting ahead of myself.

SUNDAY NIGHT-MONDAY: Modifications continue Sunday night through Monday. Surface winds overnight shift to the southeast, ushering in warmer air behind (south) of the northward moving warm front over night. But the front won't get too far beyond I-10. As such, in the temperature department it will be a "Mild Monday", with lots of clouds at various levels. Winds ESE to start the day, Monday, and becoming southerly by day's end. Lows in the mid-upper 60s at the coast with high temperatures in the low 70s state wide and some mid 70s with everyone being in 'the warm sector' now (south of the warm front). The surface low will traverse a path similar to that of the previous system, namely close to I-10, although it is beginning to look like it will track a bit further south from near Inverness or Crystal River on the west coast near the Big Bend and across North Central Florida somewhere between Ocala and Gainesville, with the cold front trailing off to the SW-WSW.

The low will track across the state all day Monday with the trailing front then finally passing through Central Florida across all zones nearly simultaneously after sunrise Tuesday through noon time, accompanied by clouds-a-plenty. This system will be different from the last one though. As hypothesized yesterday, our atmosphere will have had little time to become fully entrenched in deep moisture throughout, additionally, the majority if not all of the upper level dynamics will be stretched horizontally and along the warm front before the cold front gets here. End result, little to no rain. I see The Weather Channel as I type showing "thunderstorms' for Monday. So, some rethinking in those regards and continued close observation of future model runs will be maintained with any changes (or none) to my current line of thinking being made known in future posts.

POST COLD FRONT (NEXT WEEK): Subject to change (wink)... Looks like the majority of next week, from Tuesday afternoon to week's end will consist of morning temperatures below normal, but nothing extreme or comparable to what occurred last month. Obviously when it comes to nailing down temperatures to the "Nth" degree it's too soon to say. But the general impression going into mid-late week next week is that the coldest location in the state will be along and north of I-4, or roughly from just south of Daytona Beach, to just north and west of downtown Orlando (by a smidge)on through to South Tampa Bay. I've seen entire winters hold this general temperature regime so it's not abnormal. Could see lots of mornings where the Tampa area is a good 10F degrees colder than the Space Coast (in general). This results from surface winds being from more directly from the North rather than the WNW-NW as now appears will be the case. The warmest, but still somewhat cool zone, will run east of a line from Port Canaveral SSW through Lake Okeechobee toward Naples.

Morning temperatures west of the line could be in the 30s (with some freezing possible, particularly further north), with mainly morning lows in the mid 40s east of the line (warmer along A1A). Warmer south of Vero/Ft Pierce of course along the East Coast 'round the clock.

BEYOND: Perhaps I should include a 'Future-cast" every other post or so, if only to point out how varied the models are when it comes to the long range. For instance, no longer seeing "snow" for Central Florida, but the trend continues for a cold spell heading into the 2nd and 3rd week of January. On the flip side, look at it this way - - get through the last week of January and its all uphill from there (not to say there won't be some bumps or even ditches in the road ahead). What we need is some good rain in here...the drought continues, worsens, and spreads.

No comments:

Thursday, January 6, 2011

January Thunder Preludes Cool End To The Week






















Images: These images depict 'actuals' at 7AM, during which time we still had light rain across Central Florida with embedded thunder. We see the cold front pushing slowly down the peninsula which has since cleared Cape Canaveral as of 9AM when the temperature went from 64F to 59F on the porch here.

RECAP: The weather radio went off at 7AM as large spatters of rain bounced off the bedroom window and thunder had just rolled overhead less than a minute earlier. It was for a Special Marine warning in regards to wind gusts. A few other alerts have since been sounded for the same reason. This was expected to be possible (the stronger wind gusts) as written yesterday with the stronger mid-level winds racing overhead. For example (as issued by the National Weather Service (NWS)):

LZ053-054-058-059-061330-
INDIAN RIVER-OKEECHOBEE-OSCEOLA-ST. LUCIE-
729 AM EST THU JAN 6 2011

...A SIGNIFICANT WEATHER ADVISORY IS IN EFFECT FOR STRONG WIND GUSTS BETWEEN 45 AND 55 MPH OVER INDIAN RIVER COUNTY...OKEECHOBEE COUNTY...SOUTHERN OSCEOLA COUNTY...ST. LUCIE COUNTY...* UNTIL 830 AM EST.


TODAY: Story of the day is simply gradually improving weather conditions for Central Florida from North to South, with deteriorating conditions over South Florida during the late morning and into the afternoon as the front pushes southward toward that area. They are in for more of the same as what Central Florida experienced during the wee hours of this first Thursday in January.

Satellite animation/timing estimates to my best guess shows the most significant clearing line of clouds to be along SR528 between 11:30AM-12:30pm. However, the driest of air is still well to the north. With this in mind, hard to discount that with the initial cloud breaks occurring at or near peak sunshine time, any heating on the still somewhat moist air mass will result in re-development of stratocumulus clouds in scattered to maybe even broken fashion until sunset over the immediate Central Florida area, much more assuredly only widely scattered north of I-4 to nearly clear.

As noted yesterday, believed the warmest time of day would be before the front passed, and that temperatures would hold near steady from the point at which the rain hit overnight. The temperature has fallen since sunrise with the FROPA (frontal passage) by 3-5F degrees (which just occurred at 8:50AM), and with clearing to commence during the time the sun is near its peak azimuth this leaves little time for heat to accumulate. With expected strength of afternoon west to WNW winds this afternoon mixing in the lowest levels could regenerate more clouds and prevent a good warm up, so shooting for a high in the low-mid 60s this afternoon with a breezy WNW wind. But the rain is over now north of 520.

TONIGHT: Drier air and a more NW wind component will usher in a temperature drop beginning at sunset as skies rapidly start to clear in accordance with the drier air. Temperatures will fall throughout the night with a continued NW wind all night bringing them to just above 40F at sunrise with a nearly clear sky. In short, it'll be chilly Friday morning with wind chills being a big factor as well.

FRIDAY: Below normal temperature day in store with the low just above 40F and a high right near 60-62F along a Cape Canaveral to South Tampa Bay line, but warmer the further south one goes. From North Brevard to North Tampa Bay the temperature might only be in the mid-upper 50s tomorrow with winds beginning to back toward the west but remaining elevated until late day.

SATURDAY: Another very cool day to start with mid-40s wide spread, but winds decrease. Highs in the low-mid 60s for the most part across the dead center line from west to east across the state and warmer south into the mid-upper 60s with low 70s restricted to the East Coast from near West Palm to Miami and the Keys. Winds continuing generally from the west but of less strength.

SUNDAY: Another cool start similar to Saturday but warmer in the afternoon by about 5 degrees. The GFS is still quick to swing the winds around to onshore overnight which would mean significantly warmer air east of I-95 or US1 (mid-50s) by sunrise. Didn't wait to see the morning model run to make this post to see if it is still latching on to this early onset of an onshore wind shift, but no rains. Additionally, either way (whether the wind shifts by morning or not), the afternoon will again be even warmer than that from Saturday afternoon. Mainly in the upper 60s with 70s further south.

By late in the day our next storm system will have already taken shape in the far Western Gulf off the Texas Coast. This system will move rapidly east along the northern Gulf during the day as it approaches the Florida Panhandle coast line Monday morning. Very mild weather overnight Sunday into Monday ahead of this system. It appears the low pressure system will take a similar track as this last one (namely, from west to east and exiting off the Florida East coast close to, or just north of Jacksonville).

On the weather map, the cold front that will be lying dormant south of the Florida Keys could very well return 'as a warm front' Sunday night into Central Florida as heights rise ahead of the surface and mid-level low pressure area. The system will provide another quick shot of rain, but a somewhat 'active event' comparable to this last system does not seem to be in the making. The atmosphere probably won't have had enough time to recover from the air mass that is still moving in today and tonight. This will definitely need to be watched though since it's not assured this will be the case. At this point, it does not look as if we will see the statewide temperature warm up as was experienced prior to the system of today, so instability will be lacking even more. Intensity of the low, warm air advection ahead of it, and mid-level winds all will require close scrutiny as the time approaches, considering none of the above has yet to even evolve.

MONDAY: Probably cloudy all day with temperatures holding steady in the upper 60s with shot of rain. Naturally turning a bit colder once again once the front passes. Hate to say it, but the trend going into the 2nd and 3rd week of January is for each successive frontal passage to be colder than the previous one. With the said, the system next week will provide cold temperatures in the 30s by Tuesday/Wednesday. Just how low into the 30s is beyond predictability. It also appears that it will ride closer to the U.S. east coast bringing a big snow event for the folks in the Northeast States by next Tuesday/Wednesday.

PRELUDE: 3rd Week of January. Winter could hold 'true to form' with the coldest nation wide event to occur from the 17th - 23rd. This falls right in line from what we learned in school, that being the coldest time of the year occurs 1 month after the sun has reached its lowest point (December 21st). The pattern looks very active with much of the country being in the cold air for a prolonged time. Central/South Florida, the Gulf Coast, and California escape the worst of it though...which would be typical. But I DO NOT like what the GFS is showing around the 20th for Florida. Now really, snow?!! Maybe Mother Nature has been reading up.

Naturally, this is well beyond the scope of reason, but the general trend is for a persistent upper level gyre to remain over the Great Lakes to James Bay (as has already begun). Would not want to live north of the Mason-Dixon Line that's for sure beginning about now.


No comments:

Wednesday, January 5, 2011

Best Rain Chance From After Sunset to Sunrise - North of SR520






















Images: First three images are 'actuals'. Satellite image clearly shows the southern extent of mid-level cloud coverage just north of 528 early this afternoon. We also see a forecast for moisture content (Integrated Liquid) in the last image for 1pm which matches nicely with satellite. The third image shows the average mid-level winds and greatest moisture, and lastly the first image shows an analysis of the current low pressure location near the Panhandle with a warm developing across North Central Florida with the warmer air to its south.

TODAY: Warm this afternoon everywhere south of the warm front (in the warm sector) where it is also most free of concentrated cloud cover. Warm front won't lift much further north than its current location, so things are very touch and go just along and north of The Beach Line this afternoon, particularly after 4:30pm. Further north, a strong bowing line segment (thunderstorm) is generating severe thunderstorm warning or two out of the Tallahassee NWS Office...this could put a kink in the forecast locally late today, amongst other numerous kinks.

But for the time being, sunny to partly cloudy sky conditions will prevail into at least mid-afternoon with highs in the mid-upper 70s south of the warm front. Winds are light and variable early this afternoon, but a more assured SSW-SW wind will develop around sunset or shortly thereafter as the cold front and low pressure system push east across the Western and Central Panhandle toward Jacksonville. I have noted some patches of ACCAS (altocumulus castellnus) clouds since late morning over my area, indicative of some mid-level instability. Might be important for the over night hours in regards to the strength of rain showers or maybe even some thunder.

In noticing the latest satellite trend, the sunniest spot was generally East Central Florida, with afternoon bubbly stratocumulus clouds forming to the S-WSW under the afternoon sun, heading this way. They should be here in an hour or two, with others filling in almost directly over head.

TONIGHT: Overcast over night with very mild temperatures holding into the low-mid 60s as SW-WSW pick up in the 15-20mph range. Good bet of rain from near Patrick AFB to just north of a Tampa Bay line anytime after 8pm through sunrise. Currently appears the heaviest (and best chance) of which will fall between 2AM - 6AM early Thursday morning. I do believe the region of most active weather tonight into early Thursday will occur right along and 20-30 miles either side of a line of where that warm front was drawn, namely very close to or just north of SR528. It is also along this area that some strong storms (due to wind gusts) could result from any isolated heavy activity. Rain accumulations could add up pretty good in one spot toward one inch, but such amounts aren't anticipated for more than a tiny sliver/zone due to the fact that storm motion will be a quickly paced from west to east at a good 30mph+.

It is worth noting that" forecast winds" from near 3000 - 10,000ft from around 2am - 7am will be from 30 to near 60kts right along the same area described above, which just so happens to be where I've seen the ACCAS clouds since late this morning. Actually, I've noticed that radar is showing rogue rain echoes over Central Florida which might actually be those ACCAS patches. Any true convection overnight will likely remain somewhat elevated , although per chance should a bubble of activity get more rooted in the boundary layer we'll be hearing thunder and maybe a warning for strong wind gusts will be issued while we're 'under the sheets'. Just a heads up. It will be worth watching the weather segment on the news tonight and/or the weather channel late today into tonight to monitor the latest and greatest (emphasized!). Also, I mentioned that bowing storm line segment earlier. Outflow from that system as it passes north of near Gainesville could have a ripple affect on timing of precipitation or intensity many hours from now. It's too early to speculate but that will be the first harbinger of several causes to pause in any reasonably good forecasters mind. At least for those along and north of the BeeLine.

THURSDAY: The front will be sinking south down the peninsula as the low moves off more toward the east rather than the northeast as zonal flow over the Southeast States prevails on the day Thursday. As such, the front will only go through in piece-meal fashion rather than with one big simultaneously occurring wind shift, drying, clearing, and shoving cold air blast as we often see happen in the winter. Thus, clouds and light rain chances could persist into early afternoon from near the 'magic 538' line and more certainly further south toward South Central Florida. In this regard, the high temperature tomorrow will probably never break into the 70s but rather hold steady from where it will be the time any rain begins or is near by (for those who do not get rain). In other words, mid-60s as a rule for now, but wouldn't be surprised to see even lower readings.

Do believe that any rain chances will go close to nil by 3pm, although one model shows that chance lingering until dark. I'm taking that as a sign of more significant clouds rather than actual rain though. The further south one goes toward South Central and South Florida the lesser the chance of rain will get, namely south of Vero Beach - Sarasota but there later also will be the clearing of clouds and lingering rain chances.

More definitive cooler air begins to finely make its presence none shortly after sunset and throughout all of Thursday night into Friday morning as clouds finely scour out and a minor kink in the zonal flow permits a northwest wind to develop and colder air to move in.

FRIDAY: Very cool day with lows very close to 41F and a high in the low 60s with ample sunshine. Winds will remain somewhat elevated from the WNW-NW for a time but back more toward the W for a brief time as another impulse passes to the north of little impact other than to reassert that indeed, a cold front has passed.

SATURDAY: Another cool start, but maybe not as cold as was previously feared. These systems are riding high and mighty (fast) in the ever changing nearly zonal (generally speaking) pattern, and as a result the changes are also rapidly paced. Regardless, another cool day with lows pretty much the same inland as Friday morning, but the coast might fare much better near 50F. The afternoon will again be cool though with another low 60 degree reading, perhaps some mid-60s. Some high cirrus streamers well overhead could pass from time to time with more west wind. This will also be the coolest morning for South Florida with mostly 50s.

SATURDAY NIGHT-SUNDAY: BIG UNCERTAINTY (exclamation point spelled out). Like the previous GFS run (only faster this go around) we do see a warm up on Sunday afternoon toward the 70F isotherm with another cool morning. This was mentioned yesterday. The biggest change for this period from the previous model run is a sooner over night wind shift to light onshore well before sunrise. End result, the A1A corridor could actually warm up during the overnight hours or hold steady most of the night. Otherwise, no big changes as temperatures begin to return toward normal readings after two full days of below normal for everyone Sunday afternoon. BUT...

LATE SUNDAY AND BEYOND: At this point, don't believe a word you hear until at least you see the news Saturday night, point blank. There's as many different possibilities by late Sunday as there is models. All of which could have a pretty significant impact for the weather all across Central and North Florida in regards to cloud cover and chances of rain already returning (depending on what one chooses to believe). As it stands now, South Florida again escapes the atrocious variabilities no matter what the outcome at this point...at least for now. What we will hear/see is what one particular forecaster favors, the end result will likely not end being any of what we hear today or even through Friday. Additionally, you could probably switch from one channel to the other and receive a different message.

Just to paint one scenario-cast: Another low pressure forms in the East Central Gulf late Sunday with a warm front stretched across Central Florida and isentropic lift along the boundary produces cloud cover and eventually showers. Which of course will affect the temperature. Not biting into any one solution for now, and thus will not project. That's one benefit of having a mere blog post (of few readers). I'm not obligated to come off sounding definitive or having to be oh so sure about a situation in which the true reality is that no one really knows (like the TV Weather Guy/Gal must). They don't get paid to say, "The truth is, we don't know what's going to happen".

I just happen to have The Weather Channel on right now, and they seem to be trending (quite flakily if that's a word) toward the scenario I just described. Noticed they left out any details in regards to related weather events though (how convenient), but they did show a similar placement of a warm front and low pressure system sometime late Sunday into Monday as was just written. There should be a little caption on the screen , "Just for kicks, this might happen by Monday. But not for sure. We'll get back with you on that one".

No comments: