"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".

Saturday, June 8, 2013

Storms Today 'Could' Produce Frequent to Excessive Lightning

Thunder Possible in Orange, In Purple where there appears to be a
 chance of EXCESSIVE Lightning
in a few Storms as of noon time guidance
TODAY: Huge buckets of rainfall occurred over SE Florida yesterday along a trailing vorticity lobe of Andrea even though the storm was well far away. A remnant of that boundary is now, per visible satellite imagery (or at least appears to be) located along a line from near the tip of the Cape west to just north of Tampa Bay; another boundary is further north yet still running east to west, and one that has been active all morning over Palm Beach County extending west toward Sarasota or just south of there. Steering winds although now are about 15 mph from WSW - ENE , are forecast per short term RAP model information to weaken to 8-10mph much later today except in the tallest of storms, in which case up to 12-15 mph could occur.

Sea breeze inland penetration is iffy, as cloud coverage in certain areas could offset it (such as over far East Central Florida). 

It should be noted that the least favorable area for storms at the current time of this writing is East Central Florida. Lifted parcel levels (LPL) are way too high, there is virtually no lifted index values (LIs), and CAPE (convective available potential energy) is weak compared to other locations . Thus, it is with a bit of hesitancy that such a brazen statement of high lightning threat is being made in today's Blog post; however, all indications in short range high resolution guidance (HRRR) insist this will be the case as the stable area of East Central erodes in the next few hours.  Additionally, lake breezes interacting with a west coast sea breeze working east combined with outflows from South Florida activity currently ongoing could result in a surging northward of interacting outflow boundaries working up the interior with a secondary area along the east coast sea breeze, especially and only if the timing is right (that is to say, after 4:30pm if not 5:30pm). 

It is possible with the chance that the steering will have weakened later today that storms further north of the Southern more counties will not press off shore, but rather anvil debris tops and/or light to moderate rainfall from decaying thunderstorms would be the result mainly East of I-95 with little more to speak of. Much depends on how far inland the east coast sea breeze can penetrate even though it should be a very shallow sea breeze. The other questionable detail is that the morning KSC Sounding showed a convective temperature of 92F, which is going to be a bit hard to come by in almost all locations with the cloud cover currently in place ; thus, unless that changes to somewhere around 86F storms in general would be hard to come by, but again, that sounding early today was also in the most unfavorable area as of early today as already point out. 

Winds at only 2000 ft today alone is expected to remain from the SW all today regardless of any seabreeze which would lead me to believe that the HRRR might be off on something in this regard.  Point is, high lightning threat remains so far today, which includes bolts well removed from storms and innitial bolts that can come down before rain even appears in certain locations. Lightning Safety Rules apply.

SUNDAY-MONDAY: Ridge axis near South Florida will be lifting toward Central Florida which will limit afternoon activity to well away from the east coast over Central Florida toward Orlando and west but closer to the coast along and north of I-4.

TUESDAY: The next trough from the Mid West region will begin to press the ridge axis back south on Tuesday or Wednesday as it enters the SE states coincident with the approach of a Tropical Upper Tropospheric Trough  (TUTT Low). Guidance has shown this to be the case for about 2 days now. It has been my observation that such interactions can result in isolated storms due to some drying but also stronger ones as well. That will be yet a new story and a totally different weather pattern to contend with from that of today and to a smaller degree, Sunday and Monday.

The ECMWF is showing steering to become again more from the SW rather than away from the East Coast as has the GFS in previous runs. It appears the GFS is trending toward there emerging somewhat of a 'backdoor like' front or mid level trough working down the the East Coast on Tuesday into Wednesday that could result in even early day activity near Volusia County working only slowly south with time (a bit like what is happening over Palm Beach County today). But that is still far away and will likely change.

TUESDAY/WEDNESDAY: TUTT low shown is at JET STREAM LEVEL, winds below this low will remain as if a trough is approaching through the lower 20,000 feet of the atmosphere.  TUTTs are notoriously difficult to forecast several days in advance at times as are the interactions with other subliminal lower level features.

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