At the surface, the low level ridge axis remains across Far South Florida with low level moisture feeding around its stronger western periphery along the SW Coast and as per guidance will be pressing NE ward during the day. Latest analysis is showing sufficient moisture in place from SW Florida to North Brevard in the lower levels, but above those twoard 10,000 feet it is quite dry in all locations except in the western Panhandle. The west coast sea breeze has already begun and seems to be taking off eastward faster than would be normally expected, perhaps due to the 700mb trough actually pressing east just a bit. In any case, beyond that mere speculation the greatest instability today is unevenly dispersed with the only consistency being just along the Atlantic Coast. Chances are, more low level moisture, hence atmospheric buoyancy will be lifted North and East as sea breeze circulations meet and squeeze moisture NE ward along the 850-700mb flow.
With those rough and sketchy depictions showing on models, some thunderstorms and showers should be spreading NE ward from the South as the afternoon progresses with an isolated shower or storm possible toward Western or Central Volusia, although that one is the big question. What seems a tad more certain is thunder and showers working as far north as I-4 in the Orlando Area and eastward toward the Eastern Osceola County area and possibly showers and thunder almost as far east as the Sanford into the Mims or even Titusville area by 6 or 7pm. This all being the 'worst case' scenario for those not wanting their picnic rained on.
The graphic shows one general area where a stronger storm could exist due to down draft winds..a result of the dry upper levels cooling upon decent into the more moist air in thunder or even heavy rainstorm down drafts. Temperatures aloft are not all that cold, but any storm (if there be one) that punches through the dry layer on its own devices along converging low level wind fields could put on a spectacle, then back trace southward beyond dark into Osceola County. "Could" being the operative word in all cases. The final 'could' or 'might' is thunder after dark south of Orlando. As noted earlier, all of the above depends upon when the sea breezes meet. If it is too early, all bets are off.
BEYOND: Saturday looks a bit like a variation of today with Sunday through Tuesday going up and down on the rains chances near these same locations as time will tell.
WEDNESDAY: As would be expected, it is summer and the dry air cannot last forever over Florida (one hopes). Moisture only increases or varies in small increments from day to day into Wednesday but from there on out the GFS and the latest ECMWF (Euro) indicate a tropical wave to cross near Puerto Rico and arc NW toward Florida (previously the ECMWF was showing a possible depression but is now amazingly close to the GFS, which given that is a good 5 days away is sure to change several times if only over the weekend).
In any case, per what is given today, increasing rain chances Wednesday but much more so toward NEXT weekend for a few days with two moisture surges.