"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".

Tuesday, June 18, 2019

Just like that, Pattern Change ! : Heavy Thunderstorms East Coast Mid-Late Afternoon

On This Day, 2015 ..Thunderhead offshore Cape Canaveral
TODAY:  Big change today from the past two days. 

While all slept winds aloft and at the surface became uniformly  more SW to WSWerly...shifting from Southeast to SSE from the past two days. 

Today will be quite a different day for most experientially along the east coast especially, no longer being daunted by early day cloud cover (for the most part) and/or wet grounds. Instead, today will take on the tenor of an 'early onset of storms with many areas being periodically affected by a rain shower or storm'.

Steering is from the 'west to east' at about 20 mph, but from the looks of the KSC Sounding they might not be strong enough at 2000 -3000 feet to offset the sea breeze from forming, or at least it appears a  'side shore' type component sea breeze might be able to establish near Central Brevard through 'the outer regions of the Cape'. Such set ups with a easterly steering often sets up for 'stronger' and/or heavier thunderstorms in the Oak Hill - Sanford - Port St. John triangle to as far south as 'Canaveral' at times.

Assuming that the modified sea breeze will be able to form ( and that is conditional   that the west coast sea breeze holds off it's eastward march across the state to reach I-95 not until around 3-4 pm) that could be the case today. if it does form anywhere along the east coast, it will not make much inland progress. This is relatively crucial for just exactly what nature storm activity will take as it cross the east coast communities. if a sea breeze does form all kinds of unpredictable things can suddenly happen. If not, activity will just slide off shore rather inconsequential with out anything beyond the 'norm'.

Temperatures aloft at 500mb are running around -7 C ; 700 mb ,7.5-8 C --  just a bit below (cooler) than a 'summer day'. 

With good heating and moderately strong Convective Available Potential Energy (CAPE) to build up and mount with ample heating and a convective temperature of 88F per the KSC sounding, it will be easy in the absence of convective inhibition and PWAT air running around 2.15" to get the clouds and showers going.

Storm motion speed could limit overall rainfall totals in any one location, but with such HIGH PWAT air-mass in place, I would not be surprised if some rainfall totals come in to over 1.5" in a short amount of time, especially if the sea breeze sets up and outflows meet resulting in a back building cluster somewhere. 

Some of the water table seems to have gone down (at least it has in the Canaveral area) thankfully, but any area prone to localized ponding/flooding from heavy rainfall and poor drainage might be effected today. Granted,  the majority of locations will not see such kind of rainfall (most will not).

The bigger 'threat' as usual, will  be lightning. 

Severe weather does not look likely but isolated gustier winds from water loading might be an issue as storms initially usher forth from above their 'watery downspouts', especially in areas with the longest heating prior to onset of storm activity.

WEDNESDAY: Similar scenario might well take place. There will be a 'drying out ' period over night and the overall PWAT air mass will depart to the east; but another air mass of richer moisture is poised to approach the state early in the day; all this will be transparent to the GP. 

Tomorrow again looks to be a 'storms from the west moving to the east, reaching each coast by mid-afternoon' scenario. Hit and miss as they go.

THURSDAY-FRIDAY: Sketchy time period. Thursday-Friday look to be the driest of days statewide, though some areas in South and Far North could see some activity. Delayed sea breezes will mean warm at the coast (assuming they form).

By Saturday the remnants of a frontal boundary could sink down to south of the I-10 toward Ocala - Ormond Beach zone. The Latest GFS implies that said activity with it by then will result in SE Steering winds (from NW to Southeast)  which could bring activity propagating down the East Coast Sea breeze to Central Florida by early evening with colder air aloft. Thus, Saturday could see storms mainly north of Vero Beach late in the day after a full day of solid heat.

Thus, for now am watching for 'Strong Storms' North - North Central on Saturday . and some variation of the same on Sunday. 

NOTE: Saturday and Sunday look like 'anomalies of summer' for now. Guidance implies NW-NNW winds but warm with Thunder and cold air aloft. A strange combination. But ifa sea breeze forms, it would likely be from the southeast regardless of the overall synoptic scale pattern. Latest forecasts were calling for 'dry' over the weekend but that has been will it be? A few days to clarify. 

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