373 
fxca62 tjsj 211952 
afdsju 


Area forecast discussion 
National Weather Service San Juan PR 
352 PM AST Sat Nov 21 2009 


Synopsis...locally driven showers and isolated thunderstorms will 
dominate the weather across Puerto Rico and the U.S Virgin 
Islands for the next several days. 


&& 


Discussion...the surge in moisture entering the eastern Caribbean 
this afternoon is expected to remain mainly south of the local 
islands as it passes by overnight and on Sunday. Even so...may see 
an increase in shower and thunderstorm activity over the local 
Caribbean waters...however...weather across Puerto Rico and the 
U.S. Virgin Islands is expected to remain mainly diurnal driven 
in nature. While ridging is expected to dominate the middle to upper 
levels of the atmosphere over the next week...expect some shower 
development over the interior of the island each day...as 
sufficient low level moisture and daytime heating should provide 
enough of a trigger for some shower activity. No large scale 
weather features are expected to impact the local area through the 
end of the forecast period. 


&& 


Aviation...periods of MVFR and brief IFR conds will remain possible 
across tjsj...tjbq and tjmz through 21/22z...with VFR conds expected 
at the rest of local taf sites. Thereafter...prevailing VFR forecast 
for the entire flying area overnight at least through 22/04z... 
followed by prob30 of passing rain showers in and around tjsj... tisx... 
tist...tncm...and tkpk from 22/04z-22/06z. Elsewhere...Virginia emissions 
continue from trpg...with low to middle level steering from the east 
southeast during the next 24 hours. Based on latest satellite imagery... 
faint ash an gas emissions are still expected to remain over water 
just east northeast of the tist airdrome by the way tist and tupj. 


&& 


Climate...the high temperature reached 91 degrees at the luis 
munoz international Airport in San Juan today. This broke the 
previous high temperature for November 21st...which reach 90 
degrees back in 2006. 


&& 


Preliminary point temps/pops... 
sju 76 87 76 87 / 40 40 40 40 
stt 78 87 77 87 / 40 50 40 40 


&& 


Sju watches/warnings/advisories... 


PR...none. 
Vi...none. 


&& 


$$ 


09/04