(Image: Wall of rain moves in on Cocoa Beach late this morning)
SYNOPSIS: High pressure at the surface over the Western Atlantic is sinking south and simultaneously retreating further East as a trough enters the Mid-Atlantic region this afternoon. Central Florida is positioned on the extreme western extent of its direct influence, where as South Central and more so South Florida remains under its influence more directly. With weak winds aloft, afternoon sea breezes are acting as a the primary influential factor for where it will rain this afternoon. It was noted this morning that a weak southwest flow aloft was developing at the mid level over NE Florida ahead of the trough approaching the mid-Atlantic region, and apparently this entity is working south into Central Florida. Although winds right on the coast are quite discernibly from generally the east to southeast, showers over Brevard County are clinging to the western county border east of Orlando while others fill in further west. The coast from Volusia, south, is totally scoured out by the sea breeze. Further north to Jacksonville, those SW winds aloft are having a greater influence and the sea breeze is almost non-existent up that way. Hence, showers and storms are occurring nearer the coast north of Daytona, but nothing of much interest as far as intensity goes. Looks like the sea breeze might be winning out on whatever has managed to form up that way as well...barely.
TONIGHT-THURSDAY: Winds aloft remain quite light but begin to assume a westerly component at 10 mph or less after midnight over Central and South Central Florida. Winds along the coast of most of Eastern Florida should wane by daybreak to allow a light land breeze to develop by daybreak Thursday with light westerlies aloft, mainly north of Fort Pierce. Further south, the winds aloft remain very light from the east. Models are depicting SW-W surface winds tomorrow over Central Florida, but these will be offset by a sea breeze that will develop by noon and progress toward I-95 by afternoon. Due to light and gradually shifting surface winds near noon time...early shower/thundershower activity could develop anywhere from near Jupiter to St. Augustine, with the intracoastal land strips of Brevard the preferred location due solely to its unique geography, especially north of Cape Canaveral over North Merritt Island and the Cape. With daytime heating, a light sea breeze will develop against the light/perpendicular mid level west flow. Thus, storms should be on the upswing in the US-1 to I-95 corridor after 2:00pm-3:00pm along this boundary. Meanwhile, expect the west coast sea breeze to make better east ward penetration than recent days with an eventual collision up and down the Central Peninsula, more likely between I-95 and the Florida Turnpike. As is the case with such weak steering flows, storm motions will be essentially based on propagation with pre-established Lake/Sea breezes and Outflow Boundaries basically north of Vero and south of Ormond Beach on the east coast and North of Bradenton on the west coast. Further south toward West Palm expect more of a diurnal pattern of late evening to mid-morning activity to begin along the immediate east coast to progress toward the west and strengthen as the day wears on. Due to slow storm motions, some big rain fall accumulations could be anticipated well west of I-95 tomorrow, but due to a return to upper level temperatures where they've been all summer of 2010 overall coverage will be just at or below normal.
FRIDAY: Expect the pattern to continue into the first half of Friday with a land breeze more likely to develop from Daytona Beach south to Ft. Lauderdale or maybe even Miami. Once again, showers could form over and near the intracoastal around noon time from the Cape to Sebastian Inlet. Motion will be close to non-existent, with both coastal sea breezes coming into play but slow to work inland...with an eventual collision over the spine of state after 6pm. Same story as far as coverage is concerned.
ALSO LATE FRIDAY: By this time, a high pressure center will be building somewhere near the Georgia/Alabama border with a light NW mid-upper level flow developing with the trough by this time moving further off the Mid-Atlantic Coast. Circulation around the ridge will come off the Carolina Coast and will be composed of drier air. Eventually, this high pressure will retrograde further North and west toward Arkansas and merge with the Atlantic High trying to push back over Florida in the wake of the trough that will have moved well into the Atlantic. The result will initially be a drier NW flow aloft with an east then northeast surface wind developing Saturday into Sunday. During this transition East Central Florida will have one last gasp of receiving a thunderstorm, from somewhere around Sanford to Central Brevard before sunset. This scenario will most likely not unfold...with the aforementioned NE-E winds at the surface and aloft being the sole event to occur sometime near sunset to after dark along the coast. This could manifest as a very weak backdoor boundary through NE Florida but that's about as far as it gets.
THROUGH THE WEEKEND: NE surface winds prevail over most of the peninsula with moisture being mostly likely squeeze out from roughly Sarasota to Naples late in the afternoons against the west coast sea breeze. Temperatures inland remain in the low 90s and upper 80s along the immediate coast with little in the way of showers anticipated on the eastern 1/3 of the state, and even that might be generous.
TROPICS: Storm Igor looks as though it will be quite the sight to see on satellite imagery for a number of days. It currently looks like this could end up being a large hurricane by the beginning of next week, but it seems at this point it will be picked up by a second front that will be moving off the U.S. East Coast sometime in the Monday-Tuesday time frame...which wouldn't even begin to occur until about this time next week..or later.
If Igor does not get picked up by this second trough...all bets are off and some serious eye-balling for the folks from Florida to the Carolinas will have to begin. That's a long time from now, so not dropping any loose ends. Leave it to say for now, the models indicate the coast will be clear of Igor...but as we all know by this point the tropical season (lest some haven't already learned from previous seasons)...the models are what they are...I'll believe it when we are talking no more that 48 hours out..at best.