"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".

Wednesday, April 20, 2011

A Strong Popcorn Storm or Two Possible Interior Central Late Afternoon

Initial Guess for a thunderstorm today is shown in the image above. Note all areas are north of the Beach line. Now See Figure 2.

Figure 2: Note the additional area in Dark Green. This area is a little more questionable but of more importance for later this afternoon in regard to stronger storms. Not shown is an slightly better chance to change the area in SW Florida to a Lightning Icon.

RECAP: A few strong storms yesterday, with dangerous lightning (isn't it always?), and a report of nickel sized hail in the Narcoosee area around prime time (6 pm).  Orange and Lake County (after dark) and a portion of Polk seemed to bear the brunt of the active weather, although Okeechobee had a whopper down there too. I could see the overshooting top from way up in Brevard...time lapse would have shown it to go up and collapse within 6 minutes. After that point, I saw radar shortly thereafter and the storm had nearly already dissipated in rapid fashion. A true pulse, strong storm.

Out flow from that storm triggered more activity northward as it road NNW up the east coast sea breeze and while other activity was getting started further north on its own accord. Lightning lingered in Lake County to near Ocala until late in the evening that disappeared quite quickly by 10:30pm. The atmosphere yesterday was quite unstable prior to onset of the storms.

TODAY: Different day altogether today, but it may end up that we'll end up with activity in much the same locations as yesterday as is often the case when steering currents are weak and not much has changed in the synoptic (larger ) scale pattern.  Rainfall from the previous day's rainfall aids in speeding up the atmosphere's instability  above during the trans-evaporation process unless dry air is being advected into the area. Such is the case over South Florida today, not so sure about far SW Florida though in regards to thunder, but I'd think that anything that can generate rain today will also generate lightning. It seems there could be a little bubble of moisture to move in during the late afternoon. The more focused area today though will be further north, at least that's how it looks now as a few models are depicing upper level energy to sweep from East to west across the North Half of the state today.

THIS AFTERNOON: Note the second image. A lot of this area highlighted is based on GUT FEELING...with little to back it up other than 1) unusual cloud lines through late morning along both the intracoastal waterways. Haven't seen that since last summer!  This means that higher dew-points just off shore and higher instability could be there ; 2)  High 70F+ dewpoint air (and CAPE) aligning the coast  (now analyzed as I write) almost on the coast just waiting for the sea breeze to come in.  Therefore, at this time instability is not high at all except for over North Central-North Florida at noon time...and not over South Central Florida, but the air mass further south is very warm (just not as moist/buoyant) . I'm very skeptical about the area South of the Beach Line today but will monitor since if it goes up, it would be the strongest of activity today.

Otherwise, the winds aloft are almost non-existent , so expect storm motion will be dictated by outflow boundaries and/or propagation along the sea breeze/lake breezes...with over-all-encompassing globular mass appeal toward the west slowly toward sunset while anvil debris has a mind of it's own and heads ESE/SE ward.   The east coast from Indian River and Brevard County into Southern Volusia  might again be overrun with high cirrus anvil debris after 5pm into sunset from activity further to the NW-W.

Expect mid-afternoon activity to being  in the first area in the light triangle into Western Volusia...ending by 5pm.

The second area further south would be from 4:30pm -7:00pm (note I wrote Would or Could) , as would something that might go up over far SW Florida.  Both of these two areas are wild cards though, so keep in mind. Should the second area in dark green go up this afternoon, I believe this is where the strong storms would occur, if they do. Do not expect strong storms further north, but still could be lightning producers (and as such, dangerous).

A good thernal gradient down in this area (South)  might set up should activity further north spread anvils east ward..not affecting the area to the south like the West Half of Osceola County into Okeechobee County (where again a Lake Shadow will aid in moisture convergence). These areas will have all afternoon to heat up.
 I'm only talking 1 -3 storms that might produce a few wind gusts of 40-48mph and pea-dime hail for a very brief time as they pulse or pop upward into the very cold air aloft still in place.  Showers will be widely dispersed as was the case the past two days due to the overall low atmospheric moisture content.  But at least they won't be competing with each other.

Therefore, more people will not see rain than will in those areas as has been the case the past two days. Keep in mind, these storms could be big lightning makers once again, and are capable of sparking fires when the lightning strikes in rain free areas which has occurred the past two days down in the Glades region along the Lake Okeechobee Shadow.

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