655 
fxca62 tjsj 220928 
afdsju 


Area forecast discussion 
National Weather Service San Juan PR 
528 am AST Sat Nov 22 2008 


Discussion...broad upper ridge continues across the east Caribbean and 
adjacent tropical Atlantic this morning while Omega block persists at 
higher lats spanning the entire Atlantic. Frontal remnants remain 
strung out across the regional Atlantic from the north coast of Hispaniola 
NE into the central Atlantic...with latest East Coast middle to upper low 
shifting off of the coast and supporting another frontal system 
extending from near Bermuda into S Florida. The local islands are 
presently sandwiched in an area of drier air...between moisture to 
our north and northwest associated with frontal remnants...and a late season 
tropical wave and associated tropical moisture across the southern 
Caribbean. This next cold front across the west Atlantic is forecast to move 
southeast next few days...and will force whatever remains of the first 
frontal trough across the local area late Sunday through Sunday 
night...with second reinforcing frontal system then expected to 
move across the local area in a weakened state Mon-Tue. This will 
all maintain the fresh and breezy conditions across the region 
through this time period before winds turn more north-northeast and weaken Tuesday 
into Wednesday...followed by decidedly cooler and drier air filtering in 
from the NE. Another frontal system is then forecast to sweep 
across the west and SW Atlantic middle week and sweep remnant moisture 
lingering to our north and northwest...back towards the east and southeast by the end 
of the week for a likely wet and showery period Friday into 
Saturday...and possibly the first cold frontal passage of the year. 


For today look for a more NE wind flow to prevail and produce 
scattered showers along the north coastal sections through noon...with 
afternoon showers and a possible tstorm or two across the 
interior...southern slopes...and SW sections of the island...with 
leeward streamers likely off of the Spanish...U.S. And British 
Virgin Islands. 


&& 


Aviation....VFR conditions to continue overnight across all local 
taf sites. Brief passing showers and subsequent MVFR conditions 
may affect tjbq overnight...however probability of occurrence will 
be less than 50 percent. This will preclude any tempos for the 
overnight tafs. Additionally...western and southwestern Puerto 
Rico /tjps and tjmz vicinities/ may experience possible MVFR 
conditions in the form of ceilings/visibilities and mountain obscurations due 
to afternoon convection between 18z-22z. 


&& 


Marine...coastal observation from yesterday suggest that northwest swells was no 
larger than 7 feet during the daylight hours...and peak northwest energy 
may have missed Puerto Rico just to the east...as buoy 41043 peaked 
near 12 feet...suggesting 8 or 9 feet would reach the local Atlantic 
coasts. Swells have since turned more northerly and subsided to 6 feet 
overnight and similar lessening of swell should be expected 
locally. However...fresh NE wind flow continues to produce NE wind 
waves mixing with this swell and maintaining rough and shifting 
seas and sca's remain in effect for all Atlantic waters and Caribbean 
passages. Another pulse of moderate northwest swell is expected Sunday 
night through Monday and will reinforce current rough conditions. 
High surf advisories remain in effect for all north coasts except St 
Croix due to northerly swells...but is likely marginal at this time...and will 
be allowed to expire at noon today. 


&& 


Preliminary point temps/pops... 
sju 84 78 84 74 / 50 50 20 40 
stt 85 77 85 75 / 40 20 30 40 


&& 


Sju watches/warnings/advisories... 
PR...high surf advisory until noon AST today for Culebra-Mayaguez and 
vicinity-north Central-Northeast-northwest-San Juan and 
vicinity-Vieques. 


Vi...high surf advisory until noon AST today for St. Thomas/St. 
John/adjacent islands. 


&& 


$$ 


02/70/