408 
fxus62 ktae 190717 
afdtae 


Area forecast discussion 
National Weather Service Tallahassee Florida 
317 am EDT Friday Mar 19 2010 


Synopsis... 
the 03 UTC regional surface analysis showed a 1020 mb high off the 
la coast and a weak trough from central Georgia to the NC coast. Unlike 
the past few nights...local radars were quiet as our forecast area 
is now under the subsidence side of a broad trough lifting 
northeastward off the southeast U.S. Coast. 


&& 


Short term... 
(today through sunday) fair weather is in store for our region today 
and Saturday. High temperatures will be near average (mid 70s) but 
low temperatures will be slightly below average (lower 40s) in our 
normally coldest inland locations outside of the cities. Afternoon 
temperatures will be cooler along the coast today and 
Saturday...with high temperatures only reaching the middle to upper 60s 
due to the close proximity of the cool waters (lower 60s) along the 
Florida Panhandle shelf. A cold front is forecast to move east across our 
area on Sunday...accompanied by a band of showers and isolated 
thunderstorms. All the numerical guidance forecast ample deep layer 
moisture and lift to support rain...but thunderstorms will be harder 
to come by due to a rather stable boundary layer. It appears that 
this system will not have enough time to tap into the maritime 
tropical airmass over the central Gulf to properly moisten and 
destabilize the local boundary layer before the upward forcing 
develops. Despite strong wind fields aloft...the lack of instability 
will greatly limit the overall severe weather threat. Because of the 
projected rapid movement of this cold front...storm total rainfall 
amounts will likely be an inch or less...which should not create a 
significant flood threat. 


Long term... 
(sunday night through thursday) the extended period begins with 
ridging over western half of Continental U.S. And a positively tilted trough over 
eastern Continental U.S. With low over western Tennessee Valley. At surface...front had 
exited County Warning Area and was located over north/Central Peninsula with drier air 
filtering in at the surface. However...we may see lingering 
low/middle level wrap around cloudiness into Monday afternoon/evening as the 
upper low translating eastward into the Middle Atlantic States. 
Then...models continue to show a strong high pressure ridge and 
cool/stable northwest flow bringing much drier conditions through Tuesday. At 
this time northern and southern stream impulses...originating in the Pacific northwest 
and Baja California respectively...move eastward and phase helping to develop a 
strong trough/low over Southern Plains/Texas Panhandle by Wednesday afternoon. This 
trough to approach lower MS valley by end of extended period. As a 
result...eastern surface high shifts progressively into the western 
Atlantic with low level flow veering to east and then onshore 
providing increasing moisture and warming local temperatures. Approaching 
upper system will move further eastward dragging a cold front east-southeast. This 
will bring our next chance of rain on late Thursday ahead of 
front. 


Probability of precipitation will show small chance of lingering rain Sun night...mainly southeast 
third of County Warning Area. Then...none probability of precipitation rest of period. Following the passage 
of the front...minimum temperatures will again drop 5 to 10 degrees 
below climatology (climo is upper 40s) sun-Tuesday nights then as next 
weather maker begins to form and local winds veer...mins rise to 
around climatology Wednesday-Thursday night. Maximum temperatures on Monday will be 10-12 
degrees below climatology (climo middle 70s) and 5-7 degrees below climatology on 
Tuesday before rising to seasonal levels Wednesday and Thursday. 


&& 


Aviation... 
through 06z Sat. Expect VFR through period except may see some brief 
visibility/ceiling restrictions around sunrise at ktlh and kvld. Light northwest 
winds will shift to onshore by afternoon. 


&& 


Marine... 
as the high pressure system becomes centered over the marine area 
this afternoon...the sea breeze circulation will become the dominant 
driver of local winds. Winds and seas will rapidly increase Saturday 
night and Sunday with the approach of the cold front...and advisory 
conditions will be possible...along with tides about 1 foot above 
normal around the time of high tide Sunday afternoon. The surf may 
reach 5 to 7 feet along the Florida Panhandle beaches Sunday 
afternoon. 


&& 


Fire weather... 
in the wake of exiting upper level disturbance...dry air will 
filter into the area today and and Sat. A red flag warning remains 
in effect for this afternoon into early evening for all of the Florida Panhandle 
and Big Bend...except coastal Walton... Bay...Gulf and Franklin 
counties...due to long durations of low relative humidity. A watch remains in 
effect on Sat after for these same Florida zones due to low relative humidity coupled 
with high dispersions. On Sunday...another low pressure system 
will impact the region increasing the chance for rain and 
storms...and ending any fire weather concerns. However... 
pronounced dry air builds in rapidly on Monday and red flag 
humidities are again expected for portions of North Florida Monday 
into Tuesday. 


&& 


Preliminary point temps/pops... 
Tallahassee 73 41 73 51 68 / 0 0 0 10 70 
Panama City 68 49 68 57 65 / 0 0 0 20 70 
Dothan 74 44 74 52 67 / 0 0 0 30 70 
Albany 73 44 75 50 68 / 0 0 0 10 70 
Valdosta 73 43 75 51 72 / 0 0 0 10 60 
Cross City 72 41 75 51 71 / 0 0 0 10 60 
Apalachicola 67 47 66 56 66 / 0 0 0 20 60 


&& 


Tae watches/warnings/advisories... 
Alabama...none. 
Georgia...none. 
Florida...red flag warning from 2 PM EDT /1 PM CDT/ this afternoon to 7 PM 
EDT /6 PM CDT/ this evening for the following zones: 
Calhoun...Dixie...Gadsden...Holmes...inland Walton... 
Jackson...Jefferson...Lafayette...Leon...Liberty... 
Madison...Taylor...Wakulla...Washington. 


Fire Weather Watch from Saturday afternoon through Saturday 
evening for the following zones: Calhoun...Dixie... 
Gadsden...Holmes...inland Walton...Jackson...Jefferson... 
Lafayette...Leon...Liberty...Madison...Taylor...Wakulla... 
Washington. 


GM...none. 


&& 


$$ 


Long term/aviation/fire excessive...block 
rest of discussion...Fournier 

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