"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".

Tuesday, September 6, 2011

Strong/Marginally Severe Wind Gusts in Storms Today

(1)Image shows mid and upper level support for storms . Divergence (purple)well overhead sustains storms, whereas mid-and lower level convergence (red) creates and holds them intact. Note the lack of rains and cloud cover toward Southern Volusia and South. Also to watch for lightning prone storms near the Lake Okeechobee Shadow in Martin/Palm Beach Counties..and Indian River toward Southern Brevard Counties

Images 2 through 4 (below) (1 is above) and  1 above reflects the upper levels. Not too often we see those purple and red lines overlapped in Florida this time of the lower levels, Surface:

(2) Original image shows 0-3km helicity, looks to be caused by wind speed shear (vs. directional shear).
The greatest thermal instability will mount where skies stay clearer longest which is more into Brevard (Central/South)..and Indian River. But synoptic scale wind shear is not quite fully in the southern most area..but could work in after 4-5pm.  Additional highlights: Storms could regenerate further north in Flagler County later as well despite early day cloud cover and nearby showers. Purple Boxes are for the synoptic scale winds (North) and Lake Shadow (South, particularly the one for near MLB to Vero Beach/Sebastian Inlet)

The above image is mainly showing the best wind profiles will be over Central Florida, but greatest instability will likely mount a bit further south of the best winds for manifesting strong/severe storms. Thus, storms could be active out of those winds as well, along the northern side of the Lake Okeechobee shadow'...assuming there is one. If skies stay clearer long enough, a near neutral sea breeze/vs gradient wind could develop at the coast south of MLB Beach. Either way, that should not make a difference.  Also to watch, is toward Coastal Palm Beach County. 

(3)Latest visible satellite image shows extent of clear sky vs. cloudy.
The leading edge is progressing at a rate it should reach the area around KSC by noon which time heating will have begun to increase instability. It is also unsure if the leading edge  will slow down as heating commences. It looks like pure 'outflow' right now..with the true leading edge running back toward Flagler County. Other showers to develop along the SW Coast and work ENE-NE during the late morning hours.

In summary, the same boundary that absorbed Tropical Storm Lee is moving into North Florida. In fact, the temperature across the panhandle was only 60F last hour or two up there. Meanwhile, the boundary extends well into the Mid-Atlantic states and south toward the Bay of Campeche..but might not get much further east in the next few days. The reason being the approach of Hurricane Katia. High pressure surrounding that system could work as a 'blocking mechanism' preventing further east ward progress of the trough. For Florida (other than the panhandle), it could get as Far South as North or Central Brevard. The NoGAPS, latest GFS, and SREF models agree on this scenario through Thursday.  

The Storm Prediction Center has placed Central Florida in a Slight Risk for Severe Thunderstorms today due to winds gusting to in excess of 58mph. There will likely be more fast moving rain showers than thunderstorms...but even heavy rain-showers could generate some gusty winds in the area noted ..which matches closely to the area highlighted in the above images:

(4) SPC FORECAST from 

BEYOND TODAY: Expect that the boundary will work toward Central Florida and struggle against approaching Katia and high pressure beginning to build westward across South Florida in the mid-levels. This in turn would create a 'deformation zone' across Central Florida of closely opposing winds at the same level side by side.  Additionally, low pressure development along the far south end of the boundary will generate an area of low pressure in the bay of Campache area which would also slow further eastward progression. Between that area, the deformation zone..and then the remnants of Lee (which is expected to retrograde..or rather, be forced back toward the WNW rather than advancing on to the NE) toward the Ohio Vally.. these three low pressure areas will generate:

A Menage A Trois' of Low Pressure areas:

IMAGE FORECAST FOR THURSDAY: Strength of low in Bay of Campeche highly uncertain but is not likely to impact Florida directly in the next 5 days, if ever. Note that Former Lee, Katia, and this low are loosely 'connected'.  
 THURSDAY: Wednesday might be more of a 'rainy' or showery day..but we'll cross theat bridge tomorrow. On Thursday, the initial surface boundary will begin to wash out. It is possible a low pressure area will form along it either in the Gulf WSW of  Naples or over Central . Either way, it would cross the Central to South Central Peninsula and again create a potential severe weather threat...mainly Southern Volusia toward Ft Pierce on the east coast with general thunder south to Key Largo.

FRIDAY:  Another Sea Breeze day with SW Steering. Thunder again possible South of Titusville to Miami/ Key Largo Area

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