With those factors in mind 1) Divergence aloft 2) strong 500mb wind core 3) instability and finally, the big question mark, 4) an east coast sea breeze which seems most likely north of St. Lucie County, and 5) coldest temperatures aloft from 10000 ft up are from Brevard and North. South Florida might be contending with outflow backlash from early day activity, but things could change down there quickly, as often seems to be the case. Regardless, without a doubt the region further north, as it stands now at least, holds the better chance of severe weather today . So with those factors in mind:
Low to mid level helicity values along the coast, especially from Brevard and North are shown to be the most consistent in guidance, with a concerning higher value running from near Southern Volusia toward Cocoa Beach, and again further north toward Ormond Beach give or take 50 miles north/south. Another factor is that latest guidance is showing stronger downdraft CAPE values encroaching in on the entire west side of the state from the Gulf. Downdraft CAPE tends to limit overall coverage, but that which can form , that is to say, can work against the downdraft cape into updrafts, can result in storms that rapidly build vertically, resulting in hail and/or strong downburst winds. Thus the area in red as well. Such downdraft CAPE would also, if it is true to form as a mere 'mortal model' can show, would INHIBIT activity over South Florida already covered in High Clouds.However, guidance is showing rainfall down that way, the type for lightning production. Best best at this point down there would be from Port Charlotte and South inland toward Lake Okeechobee and the Everglades for any potential strong storms,.
THUS: The purple area would be considered for this post to be a zone to watch for rotating thunderstorms and maybe even a brief waterspout or tornado, especially South of St. Augustine and North of Vero Beach, with a possible highlight north 1/2 of Brevard County east of I-95 closest to the boundary, convergence, instability, divergence, and 500mb wind core (IF IT IN FACT WILL EXIST). Any activity especially after 4:30Pm near the coast (if it manifests) is worth monitoring today, especially for deviant right or left moving activity. Storms or showers could continue in isolated fashion after 9pm. toward midnight.
FRIDAY: With today's "Potential Soap Opera Drama" on the line, tomorrow per the latest NAM model shows yet more, thus today / tonight could fold with... "...To Be Continued". Today's boundary gets 'locked up' in the quick upper level winds and has a hard time dropping, at least permanently, much further south than Southern Brevard, if even that. Net result is the same sort of set up on Friday only this time from Brevard County and South toward Palm Beach County. See no reason why high clouds again might not be a factor further south, toward Dade County at least. Otherwise, might need to watch mostly inland toward West Central and SW Florida, as winds gain more of an east ward yet light component in higher levels of the atmosphere.
Beyond Friday is a big TBD, but based on what I'm seeing the previous post looks valid yet still, namely early day activity east side translating toward the interior mid-late afternoon, with activity attempting to migrate back east yet again toward or after sunset through Tuesday.