"But seeing they could not See; hearing they could not Hear"
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"From its chamber comes the whirlwind, and cold from the scattering winds." - Job 37:9.

"The wind blows to the south and turns to the north; round and round it goes, ever returning on its course".

Thursday, April 21, 2011

Review of Electrified Yesterday NW Florida - Much More Quiet Today

Areas of most active weather on Wednesday. Rainfall of up to 2.20" and numerous reports of pea to 1.00" hail received. Very little in wind reports which is not completely surprising. I've seen nothing written concerning this area of activity, but it looks to qualify as a Mesoscale Convective Complex (MCC). See next image.

In these images above we see that the activity in Florida was not the only weather maker. It was actually one of four other complexes that were ongoing during the late afternoon and early evening. None of these systems moved very much at all during their lifespans except for those over Mississippi and Arkansas. The ones in Texas and Florida were nearly stationary. Lightning in the Florida Complex was just as, if not more so, prolific than the other systems at one point in time. Due to the developmental nature of the system in Florida, this might have been a mesoscale convective complex (MCC) since it did not seem to be related to sea breezes and was mostly focused in the mid-upper levels by colder air and fairly steep mid-level lapse rates. Surface parameters would not have warranted such an active day as was experienced in this area. However, I've seen no mention out of any of the official weather services alluding to this possibility so perhaps the notion is pure conjecture. Either way, it was organized, strong, and never exhibited outflow boundaries on the south end as would be seen with generic summer like thunderstorms.

Now we see the graphic, hand-paint from yesterday's post:
We see the area circled in black. Almost matches the actual area in the images above doesn't it? Note the other areas that were in question at the time this was created. I had added verbiage to include Thunder in SW Florida with  sea-breeze convergence down there. The areas in the Central portions were too dry as peak heating came into play and never recovered. Additionally, the sea breezes never met until dark if ever. The higher dew points never reached much further west from the east coast as is depicted they were located in this image during the afternoon; therefore, there was not an active sea-breeze front. Cold air aloft over NW Florida with a feed of heat from the south kept the system further north alive and well, with the only outflow boundary from the entire complex evident while I watched to occur to the Northwest of the system in the early evening (which prompted a severe warning) and up toward Jacksonville (also severe warning).
No outflow boundaries were ever evident to plunge southward, which might have also been additionally 'causative' to preclude any chance of thunderstorms/showers over Central Florida altogether.

TODAY: Much less active day today appears at first glance to be at hand. Best chance for showers /thunder appears to be near the Tallahassee area to just east of there,so not going to go into any details regarding an other wise pleasant day.

FRIDAY: Could be active again tomorrow in nearly the same area as yesterday. A chance of thunderstorms will exist primarily west of I-95 and north of I-4, with the axis running along I-75 to the Florida Turnpike. Activity could begin over Western or even Central Volusia County as showers and perhaps some thunder and converge with the west coast sea breeze further west during the late afternoon. Colder air aloft could again warrant some big lightning makers. Activity it appears will move off the west coast near Cedar Key only slowly. Slow movers again over the Jungles. The NAM and GFS wildly diverge on this forecast though, with the NAM showing nothing but a rain shower/thunder near Tampa Bay. I'm hedging more toward the GFS solution.

SATURDAY: More model divergence. On this day the NAM favors the Jungle Region down to Sarasota, whereas the GFS shows nothing. I'm favoring the NAM this time. (Note that favoring toward an area of storms everyday somewhere? .  

SUNDAY/BEYOND THRU THURSDAY: Too great of disparity between the ECMWF/GFS/last leg of the NAM. There are indications by the GFS that morning shower activity could begin as soon as Sunday morning along the east coast, translating to thunder over NE Florida into Daytona, NAM shows nothing. 

By Monday/Tuesday time frame moisture from the sub-tropical system north of Puerto Rico is expected to reach Florida in near underhanded fashion Central and North, more directly South Florida/Keys, ahead of an approaching continental frontal system.  Wednesday is depicted to be a showery day everywhere, with thunder focused on East Central Florida (the GFS already has a CAPE bull's-eye over East Brevard during the afternoon.  The front is depicted to cross the peninsula during the afternoon - early evening on Thursday.

Temperatures aloft during this time frame are not forecast to be cold at all, so it looks like generic thunder and showers, but too soon to say for sure. Given that the moisture would originate from the Atlantic, for it to reach the state I'm inclined to believe this would be more of a sub-tropical/near tropical set up, very pre-early-season type scenario, so just exactly how it would manifest over the state is somewhat up in the air to myself.  Most activity on Tuesday would be the South Half of Florida with late day thunder further north.

THURSDAY: Too far out in time for even the official offices to mention, especially considering the great uncertainties involved two days prior. For now, just to throw it out there (and that is all), Thursday per the GFS is a slight risk for Severe Thunderstorms and possible eye toward a tornado threat for North Central and North Florida from Central Brevard -Tampa and North with very cold air aloft as well as many other features we look for in a late winter/early spring set up such as Bulk Shear (stronger winds aloft in layers), combined with some low level thermal instability.  South Florida looks to get in the game too, but I'd leave it a "See Text" for strong, organized storms (if the exact same set up were shown in the GFS, say..tomorrow..they'd probably stick the whole state in a "Slight Risk" though). It does look like something 'organized' could be in the making though. Given the time of year , it is all so very questionable, but the GFS has been consistent with this to occur now for nearly 3 full days of model runs in various forms.

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