"But seeing they could not See; hearing they could not Hear"
“The views expressed herein are those of the author and do not necessarily represent those of the National Weather Service or affiliate/related organizations. Please consult .gov sites for official information”

"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, July 12, 2012

Another day for Good Rain Chances Central and North

Threatening Storm Clouds Approaching Cape Canaveral
 from the SSE Tuesday Afternoon

TODAY: Persistence in thinking might be the best rule of thumb today despite most model guidance; however, there is a fly in the ointment if the short term Rapid Refresh (formally Rapid Update Cycle model), is hitting on something correctly. As sup-positioned, early rains occurred "somewhere along the east coast south of Daytona Beach" prior to sunrise in the form of a thunderstorm across North Central Brevard County and a bit to the west as it slid ashore, peaking up as the weak wind fields converged along the land/coast.

This radar image was saved at 5:10AM. During the rains (which are lightly falling still as of 7:35AM) dropped over one inch of rain accompanied by in-cloud (IC) lightning.  This area appears to have formed as a result in part due to a weak low pressure area manifesting in the 2000-5000 ft level above ground (AGL)  which showed up nicely in infrared satellite imagery and an accompanying boundary (shown further below). The area appears per satellite animation and supposedly per model guidance (at least) to be moving toward the WNW-W and will continue to do so only slowly the remainder of the day. The NAM might be hyper-reacting to this low by its implication of a much stronger mid-level low forming along the west coast later today. For now, will rest with the GFS which implies a drift toward the WNW but no change in strength. Another low also resides of similar nature off the west coast a good 120NM offshore.  Much of south Florida appears to be blanketed in mainly lower clouds this morning, and whether those clouds will remain or not with such high precipitable water values in place remains a flat out mystery. Most guidance indicates a slow burn off and thus little to no rain in the region south of the Lake today. However, the other opt out is that the moisture going into those clouds begins to lift and transform directly back into more clouds of the rain and thunder producing variety. For now, will opt out on that scenario since mid level winds over the South are forecast to shift from a more westerly direction solution  ..perhaps resulting in only more clouds. Too hard to say.

Two images depict the approaching storm cluster yesterday. Image 1 is clearly from a more distant perspective
Today's First Guess, not likely accurate.
Image shows location of the two low pressure areas, both are a bit 'elevated' and weak so far. Thunder central and North interior.

Running with short term guidance and extrapolated analysis data, it appears a good feed of sufficient moisture and instability is poised toward the region off near West Palm and north to Southern Volusia County. With little change in low to mid level winds, would expect a break in activity until temperatures can reach Convective Temperature which would not be until early into mid- afternoon (in support of thunderstorms). South Florida might end up receiving debris clouds from activity off of the SW coast as light west winds take part in the mid-levels (assuming they do).  

Therefore, for this post and without trying to read too much more into an already problematic situation, have left this area out until very late toward or after dark (yellow) for rainfall. Coverage of storms might very well end up mainly near and west of I-95 in the Central region, but given that sea breezes will be weak cannot count out the barriers 'just in case'.  One or two strong storms could occur near the Brooksville area into Lake County it appears, maybe even Osceola, with that region to the north also  in question. Looks more like a standard late day sea breeze collision set up for that region, but if the mid level circulation would be even sooner (if at all) .

FRIDAY-SUNDAY: Although forecast discussions refer to some drying over the weekend, I'm not changing previous thinking, for rebel's sake. East coast could still see isolated activity (especially Friday from JAX to Boyton) sometime between 11am toward 3pm. Guidance has indicated an 'open disturbance ' or trough to wash ashore accompanied by low level convergence and higher PWAT sometime on Friday, but there is big timing differences with the GFS holding off until mid-afternoon. This will make all the difference in the world for the east coast for sure, but more so the west coast. If it holds off until late, the west coast might not see as much rain tomorrow as expected (which as of this hour at a very good chance threshold). Otherwise, continued mostly to partly cloudy skies all regions.

Saturday and Sunday and even into Monday is a very slow transitional process period with little change in thinking. Early east coast and later West Coast rain/storm chances, except Monday is going to have to be 'let's wait and see'. Transitional periods can be accompanied by a periodic dry spell in the pattern shift as parameters and moisture fields get realigned. Better chances of rain many areas appears to be in the cards on Tuesday.
Green Seas and Dark Skies wash ashore in Cape Canaveral Storm

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