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.