Weather

516 
fxus62 kkey 070913 
afdkey 


Area forecast discussion for the Florida Keys 
National Weather Service Key West Florida 
515 am EDT sun Sep 7 2008 


Discussion...in the middle and upper levels...(700-200 mb) latest 
satellite imagery overlaid with streamline analysis as of 300 am 
this morning depict a very large trough encompassing much of the 
eastern two thirds of the Continental U.S.. on the regional scale...a 593 dm @ 
500 mb area of high pressure is situated over South Florida and 
the Keys. Hurricane Ike is well to the east of this regional scale 
anticyclone...moving across the far southeastern Bahamas. 


In the lower to middle levels...surface to 700 mb...satellite 
imagery...surface observations...and analysis as of 500 am...the 
center of Hurricane Ike was located near latitude 21.1 
north...longitude 72.2 west or about 65 miles...east of Great Inagua 
Island...which is 650 miles east southeast of Key West. A weak ridge 
extends from the central Atlantic west southwestward to the northern 
Bahamas. Last evenings 00z analysis detected a very weak low level 
weakness/trough...analyzed at 850 mb positioned over the Florida 
Straits and central Cuba. Presently...integrated precipitable water 
(ipw) sensors at Geiger Key are detecting 2.00 inches...indicative 
of further moistening in the boundary layer this morning. 


Currently...as of 400 am...short term...today through 
Wednesday...the main story of course will be the impact of Hurricane 
Ike. As of this writing...there are no watches and warnings in 
effect for the Keys. On the current forecasted NHC track...Hurricane 
Ike is forecasted to move across a lengthy section of the Cuban 
island landmass by late tonight or tomorrow morning...with movement 
of the hurricane today continuing between just south of due west 
and westward today and tonight before reaching the north coast of 
eastern Cuba. Thereafter...movement of the hurricane is forecast 
between west and westnorthwestward as it move across Cuba during 
Monday and Monday night. On Tuesday...models are detecting enough 
of a weakness in the ridge to allow the hurricane to move west 
northwestward as the weakened hurricane reemerges over the extreme 
southeastern Gulf of Mexico...and eventually moves west 
northwestward to northwestward across the southeastern Gulf of 
Mexico on Wednesday. 


For today through Monday night...gradually freshening and moistening 
of the boundary layer is on tap for the first three periods. A 
gentle east flow and precipitable water near 2 inches will allow for cumulus cloud 
line formation today. By tonight and Monday...winds will freshen up 
with winds near 20 knots early on Monday. Conditions will 
deteriorate by late in the day...with numerous showers and squalls 
associated with tropical storm force winds possible by Monday night. 
Have maintained low chance probability of precipitation today and tonight...with the outer 
rainbands beginning to impact the area on Monday justifying 50 
percent. Tropical storm conditions will be possible by Monday night 
as rainbands begin to move across the area. Have likely probability of precipitation in 
place for Monday night. Stay tuned for more information about 
possible severe weather threats from the Storm Prediction 
Center...and for rainfall information form the Hydrometeorological 
Prediction Center. Residents should access the latest hurricane 
local statement from the National Weather Service website. 


Tuesday through Wednesday...based on the latest NHC track...tropical 
storm warnings appear likely Monday night...Tuesday...and Tuesday 
night across much of the Keys and adjoining waters. Hurricane 
conditions are possible on Tuesday. Have categorical rain chances in 
place over the islands on Tuesday and likely on Tuesday night. Based 
on the current forecast...weather conditions would steadily improve 
by Wednesday...but low level convergence within rainbands would 
still generate fast moving showers and thunderstorms to move across 
the Keys. 


Extended...Thursday through Saturday...forecasts are based on 
climatology. There are no other tropical items of concern at this time 
expected to impact the Keys. 


&& 


Marine...as Hurricane Ike continues to move along the current 
forecasted track...breezy conditions should arrive very late tonight 
or tomorrow morning. Tropical storm force winds appear to be 
possible across the waters by Monday night continuing Tuesday and 
even Tuesday night. Hurricane conditions will be possible on 
Tuesday. By Wednesday winds should be diminishing and seas 
subsiding. More detailed information should be available by tonight 
or tomorrow. Although weakening is indicated on this track...bear in 
mind that as with this latest track...any small deviations north or 
even south of this track will make a large difference in all of the 
significant meteorological impacts. 


&& 


Aviation...Key West International Airport and Florida Keys Marathon 
Airport will remain open for all commercial flights and general 
aviation through this evening. 


VFR conditions will prevail at eyw and mth through 18z with only a 
few low-level cumulus clouds expected. After 18z...low-level cumulus 
will become scattered over land areas with bases near fl025. 
Scattered showers will develop over Mainland South Florida and 
portions of the Lower Keys and move from about 050/12kt from 
18-24z...then increasing to 060/20kt through 08/06z. Showers will 
produce areas of MVFR and IFR ceilings and visibilities with wind 
gusts up to 25kt. Isolated thunderstorms are possible after 18z. 


&& 


Preliminary point temps/pops... 
Key West 90 81 90 78 / 30 30 40 70 
Marathon 91 81 91 78 / 30 30 40 70 


&& 


Key watches/warnings/advisories... 
Florida...none. 
GM...none. 


&& 


$$ 


Public/marine/grids...futterman/Jacobson 
aviation/nowcasts.....Kasper 
data acquisition......hovorka 
coord/media/hls.......Jacobson/rizzo 


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