TODAY: Relatively dry easterly breezes reign supreme today through tonight as a frontal boundary approaches the Western Florida Panhandle. Skies are mostly clear to partly cloudy across the state other than the panhandle where some showers are developing closer to the approaching front.
WEDNESDAY: The front will be located across NW Florida at sunrise. This boundary will progress east-southeastward during the late morning into North Central Florida by mid-late morning. Meanwhile aloft, the supporting mid-upper level trough will pass on east to ENE ward toward the mid-Atlantic coast (well North of Florida), leaving the sprawling surface front to enter all of North Central Florida between 9-11AM with the greatest moisture convergence right on and behind the boundary. The front is expected to be roughly across Volusia County at 9AM and into North Brevard by 11AM. Accompanying the boundary will be some light showers earlier in the day, transitioning to some moderate showers and isolated thunder after 11AM - noon time over North Brevard, Seminole, far Southern Volusia, and Northern Orange Counties. Most of this activity it appears could be accompanied by more extensive cloud cover.
If we take the 'union' of GFS and NAM forecast precipitation subsets...the best chance of thunder tomorrow will occur near West Osceola and Polk Counties after 1pm- 5pm where greater surface heating/instability will be permitted to mount;however, the previous NAM and the latest GFS place the better chances of thunder over North Brevard from near Cape Canaveral to Mims into Seminole County after 1pm. Given the wind fields portrayed by all models, severe weather is not likely.
The models do agree though that at the lowest levels the immediate surface front will reach into South Central Florida by early afternoon, but is nothing more than a wind shift, whereas just above the surface the mid-upper level troughs lag by a good 6-12 hours. Not sure what the net affect will be, but given that surface winds will be NE behind the front, rain chances on the East Side of the state beyond 1pm should be simply showers, with the better thermodynamics further south and west toward Western portions of South Central Florida. It does not appear that South Florida will receive any rain tomorrow from the front. Rain chances could continue as late as sunset over the East Side of the state south of Daytona if the GFS verifies, but this will likely end up being simply cloud cover.
THURSDAY: The remaining surface boundary will skirt the east coast as high pressure over laps from the the west and north...all features...similar to the previous front, become non-entities over far South Florida. The best chance of Storms on Thursday and Friday look to be far SW Florida, Broward, Dade Counties, and the Keys, with mainly Dade and the Keys highlighted into Friday as moisture beings to return to the north overnight into Saturday.
SATURDAY: Model disagreement abounds per the author's observation and backed up by NWS forecast discussions. Saturday could end up being a bit like a modified summer day type pattern favoring inland showers and isolated thunder for South Central and South Florida as surface winds begin to swing around to the gradient SE-SSE direction but with sea breezes generated from both coasts and moisture lifts back to the north. Very typical for mid-Spring/pre-thunderstorm season (for Central/South), and more in line with the earlier onset of thunderstorms over South Florida, although it might be one or two more fronts before the full onset becomes even more evident.
In Summary, it's starting to look more and more since the previous system that the Thunderstorm season is starting right where it left off in 2010, over SW Florida at some point in time during the next two weeks. On the far far out there. The GFS is starting to show very high Precipitable water values of 2"+ down in the Caribbean and trying to approach the southern Gulf going into mid portions of May. This would be the missing ingredient needed to get the Florida Storm Season underway going into June...and potential act to ignite the Southern Plains State's Severe Weather activity from that perspective going later into May (outside of other moisture sources that region draws from).