698 
fxus62 kkey 230850 
afdkey 


Area forecast discussion for the Florida Keys 
National Weather Service Key West Florida 
350 am EST Monday Nov 23 2009 


Discussion... 
considerable middle and high level cloudiness within the subtropical 
jet stream is covering our region...while light southeast winds are 
keeping temperatures in the middle and upper 70s along the island 
chain. Across the marine district...C-man station platforms indicate 
southeast winds of 5 to 10 knots...while local radars are not 
detecting any precipitation echoes in our region. 


Short term (today through thursday) 
a weakening area of low pressure over the Florida Panhandle will 
lift northeastward along the southeast and middle Atlantic 
coast...pulling an associated cold front into south central Florida 
and the adjacent Gulf and Atlantic waters tonight before becoming 
stationary on Tuesday. Meanwhile...a very formidable sub-tropical 
jet will remain aligned from old Mexico to across the Gulf of Mexico 
and Florida Peninsula. Within the strong flow aloft...a couple of 
middle level disturbances over old Mexico will eject eastward helping 
low pressure to develop along the stationary boundary. Although the 
intensity and exact position of low pressure is uncertain...our 
region will lie in a very warm and moist sector where precipitable water values 
will likely reach 2.0 inches Wednesday into Thursday morning. Given 
the abundance of moisture...the combination of isentropic lift and 
large scale lift associated with deep cyclonic flow will prompt well 
above normal probability of precipitation beginning late Tuesday night into early Thursday 
morning. But until then...weak subsident flow aloft combined with 
precipitable water values of less than 1.25 inches will pose only isolated 10 to 
20 percent probability of precipitation. Thereafter...the deepening middle and upper level 
trough over the eastern United States will finally kick the cold 
front through our region late Thursday or Thursday evening. 


Long term (thursday night through sunday)... 
in wake of the departing cold front...cooler and drier air will 
slowly filter into our region with the coolest temperatures 
expected Friday night into Sunday morning. Outside of isolated 
showers Thursday night...no precipitation is expected Friday through 
Sunday. 


&& 


Marine... 
light to gentle winds will predominate on Keys waters through 
tonight...with gentle to moderate winds Tuesday into Wednesday. 
Scattered to numerous showers and isolated thunderstorms will cover 
Keys waters Wednesday into Thursday morning...before a cold front 
pushes through our area Thursday afternoon or evening. In wake of 
the cold front...fresh to strong northwest to north winds will 
likely prompt a Small Craft Advisory on Friday. 


&& 


Aviation... 
VFR conditions will continue through this evening...with fairly 
light southeast winds. There should be a few low topped clouds 
around 2kft. 
&& 


Preliminary point temps/pops... 
Key West 83 76 83 75 / 10 10 20 50 
Marathon 85 76 85 75 / 10 10 20 50 


&& 


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


$$ 


Public/marine.................Apa 
aviation/nowcasts/climate.....MS 




Visit US on the web at www.Weather.Gov/keywest