Images Depict: A weak mid-level short wave, namely a manifestation of the upper level support for the cold front over the panhandle outrunning the surface features showing as a wind shift, cloud band (with very light rain in spots), and very warm dew points over the central Gulf Of Mexico (3rd image). Note in the first image that the averaged mid-level winds behind the front are westerly and not from the north, indicating no big cold air invasion from the Arctic but rather one of Pacific origin.
SYNOPSIS: A weak band of spotty light rains and enhanced cloudiness raced from NNW-SSE down North and Central Florida around sunrise this morning and is currently dissipating just south or along Route 60 or from near Vero to Sarasota; meanwhile, the surface feature delineating the true surface cold front remains over the Panhandle at noon time.
Interestingly, the temperature at PAFB bottomed out just as the feature approached and winds went from SSE to calm and the temperature fell for a brief time to 60F. As soon as the boundary approached the wind picked up and the temperature went back up to 68F by 9AM. Ahead of the boundary the winds over SE Florida are from the SE, but behind the boundary they are from the SSW-SW as reported last hour (11AM) over North Brevard and points to the west and north. Cape Canaveral is near calm right now, so that wind direction will hopefully be here shortly. The boundary passing over appears has enough umpf to it to have helped erode the western edge of the high pressure area located to our east and out in the Atlantic that has been palguing the East Central Florida Coast the past few days. And as such, with this minor dissipation the surface wind will veer ever so slightly as to help the folks from Vero north to loose the onshore wind this afternoon, and allow one of the coolest afternoon locations of recent days (namely, the Barrier Islands) to warm up to those levels that everyone else has been experiencing the past day or two this afternoon before clouds advect in and/or down right form over the region.
We see in the 3rd image very warm dew point air (of high moisture content) in the West Central Gulf preceding the cool front which will move across Central and South Florida in sporadic fashion during the mid-late afternoon and through the evening. The presence of greater moisture in the atmosphere and cloud breaks allowing the sun to shine through and heat the earth's surface should aid in cloud development early this afternoon off setting what otherwise could be temperatures reaching widespread 80F readings, but do believe they will be found most likely over East Central Florida (at least, that's my line of thinking right now). In the meantime, widespread mid-upper 70s will prevail south of the cold front today during peak heating, which essentially is all of peninsular Florida. But clouds will be an ever increasing reality during the course of the afternoon hours, and with the low sun angle at this time of year, believe whatever temperature is reached by 2pm -3pm is where it will level off but hold steady with only a slow fall near dark preceding the front with cloud cover and winds preventing any radiational cooling to occur.
MIDNIGHT-MONDAY: Looks like the front will pass cross Central Florida between 11PM - 2AM, accompanied by a solid cloud cover with the best chance of rain on the West side of the Central Peninsula near Tampa. Winds will veer more toward the west just ahead and along the front before midnight then quickly gain a due northwest - north component with its passage, and eventually more of NNE direction by mid-morning Monday as the front clears the Florida Straits at that time. The models are clearing the clouds out nicely for tomorrow, but I'm not so sure. The saving grace may be that surface and mid-level winds will remain light which would prevent significant mixing at the mid-levels, thus preventing cloud formation. But there will still be plenty of moisture to work with for this time of year -- as such, I'm sticking with at least a partly cloudy sky tomorrow with a cooler daytime high (mid-upper 60s) either way. Again, the coolest spot will be along A1A from near JAX to the south end of the Barrier Islands with the light onshore component wind advecting even cooler shelf waters to the coast from what has occurred in this location during a SE wind event --considering the greater distance the air will be trajected across cold shelf waters from the warm Gulf Stream waters at this direction as opposed to when the wind is from the SE.
MONDAY-WEDNESDAY: Very docile temperature regime for A1A with the warmest overnight lows and coolest afternoon high temperatures under variable sky conditions with a nondescript wind in the strength department as high pressure in the mid-levels remains anchored over the South Central Gulf and across South Florida generating a W-WNW north wind just over head and a light sea breeze at the surface during the day. In essence, temperatures will be around or just below normal during the day, and above normal at night. Of course, away from the coast it will be both cooler by night and warmer by day, closer to 'normal', 'average', whatever.
Another mid-level impulse may brush over North and Central Florida which will go mainly un-noticed by most Tuesday/Wednesday with little impact other than to disrupt the generalized pattern described above, but otherwise of little consequence. But it will be a harbinger of things to come.
THURSDAY-BEYOND: The main focus on this period is increasingly cooler temperatures state wide. During the first half of the week a zonal flow pattern aloft over the eastern 3/4 of the country will be the rule; however, an ever deepening trough of low pressure will be fed almost continuously in the broad brush by short wave ripples migrating from Central and Southern California which will quickly skirt across the country's mid-section. As such, each consecutive shot off dynamics will aid in sinking the standard height levels from 850mb-300mb east of the Mississippi, meaning colder air aloft will sinking toward the surface with the surface temperature to respond accordingly.
No big chances of rain are noted, but clouds will remain an on again/off again issue throughout the week. This is both good and bad. It won't be totally cloudy for any one period too long, but then again it won't be totally sunny too long for any one period either. But expect some of both, often several times in any one given day.
NEXT WEEKEND: As it stands now, in following the trend that has been implied by the GFS and ECMWF models and as just described above, next weekend will be about 10-15F degrees cooler than this one has been, with morning lows falling into the low-mid 40s and highs in the mid-upper 50s north of a Vero Beach to Sarasota line. But that's still a week away and obviously the temperature regime will require great scrutiny as the time approaches. No big freezes are shown to occur, but it could get generally much cooler to the point of it 'not being fun anymore' in the shorts and flip-flops department. Then again, as I've observed over many years, we're entering the coldest time of year. Meaning, the time of year when it is most likely to be uncomfortably cool/cold for an extended amount of time rather than in piece meal shots or blasts of air. Then again, has that yet to occur this winter season? Barely. This little 'warm period' we are having now might be the last prolonged one until around the end of the 3rd week of January, but who knows.
'Tis the Winter Season.
Side Note: Still watching the extreme SW Gulf for any big weather makers, given the time of year. Weather makers, that is, in the severe weather department. We will be entering Tornado Valley Season in the next couple of weeks as well.