"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 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 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.

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