TODAY: During the course of today the trough shown above will move slowly east north east in general into the weekend and be a rain and potential severe weather maker from time to time along its course. An associated cold front will be a very slow mover as a consequence, considering today is only Tuesday.
Weather appears fairly juiced up for eastern Texas into Louisiana later today and northward to a limited extent for severe thunderstorms and possible tornadoes, but a outbreak of any sort is not anticipated. Meanwhile, high pressure circulation continues the Florida east coast onshore flow. The pressure gradient will be holding its own tonight through tomorrow as winds become a bit more SE toward tonight. Additionally, forecast model trends are sticking closely together, depicting a well defined 'bubble pocket' of high precipitable water (PWAT) air to move in after sunset to after midnight toward the southeast coast which is then to work north and west through the course of Wednesday.
WEDNESDAY: As noted above, higher moisture content air to spread in over night. This moisture appears to be getting drawn toward that humongous trough to the west as it steadfastly shifts east ever-so-slowly toward the Mississippi River. Below is a hand-made graphic showing where this moisture and potential showers will work in. I did not include thunder for the early morning activity, although I could be selling the weather short. Latest NAM forecast weather balloon soundings do not appear to exemplify an atmospheric structure which would be support a cause to argue for thunder producing showers early on, or not at least until later in the day. By that time, the leading edge of the bubble of elongated moisture will be well inland during the course of daytime heating. The SPC (Storm Prediction Center) is not indicating thunder tomorrow other than toward Gainesville, but I am not prepared to deny areas further south some thunder as well as shown in orange below:
Above graphic for Wednesday. Green along east coast shows better moisture for producing clouds and showers spreading WNW per the black arrows during the day, reaching NW Interior toward western lake County, Ocala (perhaps) toward Gainesville after 2pm. Meanwhile, the east coast areas should be ending with the rain chances by mid-late afternoon, although clouds will remain present to a certain degree. The moisture for these showers, coming off the Atlantic appears it could work toward Alabama or Georgia in the next two days.
SATURDAY/SUNDAY: The deep elongated trough will be 'cutting -off' in the next 48 hours. Meaning, a closed low will form. Although model guidance is in fairly good agreement right now, closed lows are messy business to contend with in regard to how fast they will press onward, and in what direction. However, given the present circumstances combined with those yet forecast toward next week (more below), it seems relatively safe to assume they have nipped this closed bugger in the nip.
Given that notion, best now to stick with model agreement but no-thing is dead pan certain concerning the weekend weather in regard to rain chances for Florida as a consequence.
Lest we be left slap jawed and dumb happy, latest guidance indeed shows for a chance of thundershowers and/or showers, especially on Sunday as by now the cut off low is moving off the east coast or near to close to it. A weak frontal boundary will be entering the area of Central mid Afternoon Sunday. Winds by Saturday will have already started to become much more southerly on Saturday if not SW-WSW on Sunday. There is a chance there will be an east coast sea breeze pegged east of the spine of the state if not closer to the coast Sunday afternoon as the front sinks down the state. Best chances of thunder appears to be North Central to Central east side and south to Dade County beyond 2pm Sunday...
BEYOND: History repeats itself in more ways than one. Another deep trough to move into the West coast akin to a pattern we might see in a La Nina January, or reflective of it. That combined with a negative Atlantic Oscillation (AO) would be the culprit I am 'thinking' for the "double dose of deep upper level troughs parade" toward the U.S. east coast. It is this approaching trough that will boot the prior cut off low as just noted out of the picture toward the early portions of next week, yet to make room for the next one to the western U.S.
And now, the rest of the story...This next one could be even more extreme than the previous, so be ready to hear more weather ready recaps on the national news networks, The Weather Channel, onward and upward...up through next week...