Weather

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Area forecast discussion 
National Weather Service Tampa Bay Ruskin Florida 
240 am EDT Thursday Aug 28 2008 


Synopsis...high pressure at the surface and aloft is centered 
roughly over the southern half of the state. Tropical Storm Gustav 
is well southwest of the region...between Haiti and Jamaica. 


&& 


Short term (today-saturday)...the ridge will lift slowly north as 
Gustav is forecast to strengthen and travel west across the 
central Caribbean. Over the last couple of days the ridge aloft has 
limited storm activity...especially with the initial push 
of the seabreeze inland. Expect a similar day today. Friday 
however the flow aloft will start to become more easterly. This 
pattern will bring showers and storms back to the coast. In this 
case however the ridge may strengthen depending on how strong 
Gustav becomes by then. At this time feel the best subsidence 
would be over the southern half of the region...and have gone with 
slightly lower probability of precipitation there for now. 


Saturday...expect the easterly flow to be a little stronger. The 
ridge is forecast to be over the northern half of the state. With 
moisture starting to come in from the east...expect the best 
chance for storms to return to the southern half of the region. 
Have gone with 40 probability of precipitation north and 50 south. 


Temperatures will be above normal for the week...then start 
dropping to normal Saturday as cloud cover increases. 


Long term (saturday night-wednesday)...a lot of uncertainty still 
remains in the forecast during the long term period given various 
medium range model solutions regarding Gustav and other possible 
tropical features to the east over the Atlantic. Current GFS/European model (ecmwf) now 
keep Gustav well west of the forecast area and close to the official 
NHC track...taking Gustav northwest into the central Gulf through early 
next week. Even though the GFS/European model (ecmwf) keep Gustav well west of the area 
at this time...a plume of deep moisture (pw's >2.25") on the eastern 
side of Gustav is forecast to overspread the region from the south on 
a developing southeast to southerly wind flow which will enhance rain 
chances Sunday through Tuesday...which is currently reflected in the 
higher mex pop values (60-70% range) during this time frame. 


Another possibility would be if Gustav tracks even further to the 
west or southwest as advertised by the NAM...with another tropical 
feature or low over the Atlantic (being advertised by the GFS/European model (ecmwf) 
for the last few days) staying well to our east...then high pressure 
and associated drier air/subsidence in between the two systems would 
significantly limit rain chances. Given the differences in the models 
confidence in any one solution still remains rather low at this time 
so will again opt to keep inherited climatology probability of precipitation (~40%) in place for 
now with scattered showers/storms developing along the sea breeze 
each afternoon...but will increase cloud cover/rain chances...winds 
and seas some especially over the adjacent Gulf waters due to the 
forecast track of Gustav currently being advertised by NHC. 


During Wednesday latest model runs of the GFS/European model (ecmwf) now show much drier 
air moving in from the northeast as strong high pressure builds in 
over the middle Atlantic region with a dry northeast wind flow supporting 
a lower pop (~30%) regime. Temperatures will be near normal with 
daytime highs ~90 to the lower 90s with overnight lows in the lower 
to middle 70s. 


Note...residents and visitors of Florida should continue to closely 
monitor the progress of Gustav through the upcoming weekend and early 
next week. For additional information on Gustav...see the latest 
advisories being issued by the National Hurricane Center. 


&& 


Aviation...brief MVFR/IFR ceilings and visibilities from showers 
and thunderstorms developing along the sea breeze may impact Fort 
Myers and regional southwest terminals during the afternoon. Further 
north showers/storms should develop just inland from Sarasota...Tampa 
and Saint Petersburg terminals...so will handle with thunderstorms in the vicinity for now. 
Outside of the showers/storms VFR conditions will be the rule. 


&& 


Marine...expect a couple more good days for boating. By the 
weekend however winds will start to pick up...perhaps to advisory 
levels over at least the southern waters this weekend. The 
offshore flow will also allow any showers and storms that form 
over the land areas to the waters...so coverage will pick up 
compared to the last several days. 


&& 


Fire weather...no concerns with relative humidity values. Will start to see 
transport winds on Friday increase from the east as Gustav begins 
to influence our weather. Thus expect dispersions to increase as 
well. 


&& 


Preliminary point temps/pops... 
tpa 92 77 92 77 / 30 20 40 20 
fmy 94 77 93 76 / 40 20 30 30 
gif 94 75 93 75 / 40 20 40 20 
srq 91 76 92 76 / 30 20 40 20 
bkv 93 71 93 72 / 30 20 40 20 
spg 91 80 91 80 / 30 20 40 20 


&& 


Tbw watches/warnings/advisories... 
Florida...none. 
Gulf waters...none. 
&& 


$$ 


Short term...rjs 
long term/aviation...jcm