TODAY: Upper level trough from the west is slowly approaching Florida (for some possible 'eventful weather Wednesday and/or Thursday' as surface ridge axis which had been north of Central Florida begins to drop to Central and even South Central (weakly) late in the day. Best overall atmospheric moisture is so far shown (and forecast) to be north of Lake Okeechobee today. Strongest 'west to east steering will be from near Melbourne and north though quite weak and not strong enough to overcome the east coast sea breeze from Brevard and South.
The west coast sea breeze appears will be the dominate feature today and to press eastward the most and first across the northern third of the state. First activity overall for mid afternoon could initiate across NE Florida sending outflow southward and regenerating / propagating more activity southward with time..as more activity along the east coast sea breeze presses down I95 across Flagler / Volusia Counties and then back to the east more into Seminole/Osceola Counties late day along the east/west coast sea breeze collision. Some of this activity might be able to press off shore with thunder mainly north of the Cape but some shower activity with 'rumbles aloft' might make it to the beaches from MLB and north.
Further south and much later toward the 6-8PM time frame activity will be strongest west of I-95 (as it appears now) near Seminole/Osceola Counties and Central/Eastern Orange county as well (perhaps). Guidance differs on how far South true thunder along I95 will manage. The 4KM NAM shows storms as far south as St. Lucie County whereas the latest HRRR prefers Central into Osceola County as the southern most activity. The HRRR was way off earlier today though and seems to be latching on to what the 4KM NAM is seeing (which on the other-hand might be over-done) which liked the idea of storms even further south.
Will compromise between the two as written / drawn (image) above. Elsewhere, sea breezes from both coasts accompanied by Lake Okeechobee Breeze convergence could manifest some thunder over the general Glades area as well.
TUESDAY: For now guidance implies even more favorable for thunderstorms up and down the east coast in regard to the wind parameters but lack of moisture might mean 'no dice' on storms Tuesday ; might require revisiting this tomorrow to see if that is still the case.
WEDNESDAY: Highly unusual pattern aloft for Florida is in the making. Upper level trough in a position that looks more like winter (with a 100kt jet stream as well) with strong wind aloft over Florida and appears ample instability resulting in bulk shear sfc-500mb of about 40Kts with temps running around -8 to -10C could produce storms with strong wind / small hail. GFS implies it is possible the east coast sea breeze if it can form will remain pinned right at the coast and have little effect an adding an additional boost to the storms if they can manifest.
Precedent cloud cover is going to be a problem for storms to form is the big fly in the ointment (suspect) especially south of I-4. The Storm Prediction Center has taken a broad brush on this day as a result of the synoptic scale situation placing much of Florida in "Slight Risk" for severe category storms on Wednesday already.
THURSDAY: Timing big issue this day, but appears instability will be sufficient from Oak Hill (well south of I4) for a storm chance again from Brevard County and South as long as the surface trough axis associated with the upper level trough does not press too far south over night Wednesday and early Thursday. Wind aloft this day in the jet stream up to 100kts. Could be an 'early onset' day if storms get going this day..and will be interesting to see if it doesn't end up being 'the day after the day' that ends up being the 'most interesting' in regard to strong storms (particularly for parts of South Central/ South Florida). The Storm Prediction Center so far is not 'out-looking' this day.
BEYOND: Drying out a bit and so far the Memorial Day weekend looks warm and dry though Sunday especially from Central Brevard and South along the East Coast might begin to see shower activities. Too soon to say at this point and will work on that as later (and more accurate) model guesses come out during coming days ahead.