922 
fxca62 tjsj 231327 
afdsju 


Area forecast discussion 
National Weather Service San Juan PR 
927 am AST Monday Nov 23 2009 


Update...latest satelite images as well as tpw product from 
CIMSS indicated an area of drier air moving across the U.S. Virgin 
Islands late this morning. This slot of dry air will move west 
during the rest of the afternoon limiting the shower activity 
across the local area. However...exist the probability of some 
shower development across the western interior and southwest sections of 
Puerto Rico late this afternoon. Also...some passing showers are 
expected across the eastern half of Puerto Rico the rest of the 
morning hours. No changes to short term grids needed at this time. 


&& 


Aviation...VFR all sites next 24 hours except tjmz which could 
see a MVFR ceiling 18-22z in vcsh. 




&& 


Previous discussion... /issued 253 am AST Monday Nov 23 2009/ 


Synopsis...middle level high pressure to dominate through the 
forecast period...only allowing for only isolated typical afternoon 
showers and thunderstorms over western Puerto Rico each afternoon 
and nocturnal passing showers over the waters. The majority of the 
area will enjoy plenty of sun for the next 7 days. 


Discussion...quiet week in store as middle level ridge keeps a cap 
on any larger scale systems to penetrate the region. No 
significant moisture advection expected next 7 days...so looking 
for very isolated activity each afternoon...with favored locations 
for afternoon convection to be limited over western Puerto Rico. 
The majority of the islands will experience ample sunshine and a 
return to climatology easterly winds 10-15 knots. GFS steadily backing off 
of front sweeping into region by end of forecast period...so kept 
climatology grids in the extended. 


Aviation...VFR all sites next 24 hours except tjmz which could 
see a MVFR ceiling 18-22z in vcsh. 


Marine...weak northeasterly swell energy to persist through 
this afternoon when much longer period energy (12-14 seconds) 
arrives from the same direction. This will result in higher 
breakers and coastal run up for about 24 hours. Another set of 
weak northeasterly swells for Thursday before northwesterly swells behind middle 
latitude system arrive early the following week. 


&& 


Preliminary point temps/pops... 
sju 87 76 86 74 / 20 20 30 30 
stt 87 77 87 76 / 20 20 20 20 


&& 


Sju watches/warnings/advisories... 
PR...none. 
Vi...none. 
&& 


$$ 


71/09