Good morning. Good weather is expected this weekend in the NE Caribbean so enjoy it.
AFDSJU
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
454 AM AST FRI DEC 14 2012
.SYNOPSIS...AT UPPER LEVELS...AN APPROACHING SHORT WAVE WILL
FLATTEN OUT THE RIDGE OVER THE LOCAL AREA. THE TROUGH WILL PASS
SATURDAY AND SATURDAY NIGHT AND WILL BE FOLLOWED BY ANOTHER WEAK
RIDGE AND LIGHT WINDS. SOUTHWEST FLOW WILL BEGIN MID WEEK NEXT
WEEK AND CONTINUE THROUGH MUCH OF THE WEEKEND.
AT MID LEVELS...A CUT-OFF LOW IN THE WESTERN TROPICAL ATLANTIC
WILL DRIFT TO THE NORTHEAST AND WEAKEN WHILE A SHORT WAVE FROM THE
NORTHWEST ERODES THE RIDGE OVER THE AREA DURING THE WEEKEND. HIGH
PRESSURE THEN SPREADS OVER THE GREATER ANTILLES AND INTO THE
TROPICAL ATLANTIC NEXT WEEK.
AT LOWER LEVELS...COOL FLOW OUT OF THE CENTRAL ATLANTIC CONTINUES
UNTIL EARLY NEXT WEEK WHEN FLOW SHIFTS TO THE EAST SOUTHEAST AND
MOISTURE INCREASES. SEVERAL FRONTS APPROACH THE AREA...ONE NEXT
THURSDAY AND ONE DURING CHRISTMAS WEEK. AT THIS TIME NEITHER IS
EXPECTED TO PASS THROUGH.
&&
.DISCUSSION...PATCHES OF MOISTURE VISIBLE IN THE INFRARED
SATELLITE IMAGERY HAVE FUELED SHOWERS OVER EASTERN PUERTO RICO AND
THE ADJACENT ATLANTIC AND CARIBBEAN WATERS OVERNIGHT...BUT DRIER
AIR IS ON TAP FOR MUCH OF THE DAY TODAY AS LOW LEVEL FLOW BECOMES
MORE NORTHEASTERLY DUE TO AN INVERTED TROUGH AND LOW PRESSURE CENTERED NEAR
19 DEGREES NORTH 50 DEGREES WEST. THIS WILL ALSO ALLOW THE
ADVECTION OF SOMEWHAT COOLER AND DRIER AIR TODAY AND TOMORROW.
SHOWERS WILL BE FEWER...BUT SOME RAIN CHANCES WILL
CONTINUE...ESPECIALLY IN SOUTHWEST PUERTO RICO. THE LOW PRESSURE
IS NOT EXPECTED TO CONTINUE WEST TO CROSS THROUGH THE WINDWARD
ISLANDS BUT INSTEAD WEAKEN AND MOVE NORTHEAST. LATER IN THE WEEK
MOISTURE FROM THE TROPICAL ATLANTIC WILL BE ABLE TO MOVE IN AND AN
APPROACHING SHORT WAVE WILL INCREASE SHOWER ACTIVITY. NEVERTHELESS
NO MAJOR EVENTS OR DEEP CONVECTION ARE EXPECTED DURING THE NEXT 10
DAYS AND COLD FRONTS WILL NOT REACH THE FORECAST AREA ACCORDING TO
LATEST MODEL GUIDANCE. THIS WILL ALLOW THE ON AGAIN OFF AGAIN
SHOWERS TO CONTINUE...ALBEIT IN SOMEWHAT WEAKER FORM.
&&
.AVIATION...MAINLY VFR CONDITIONS ARE EXPECTED ACROSS MOST OF THE
LOCAL TAF SITES THROUGH AT LEAST 14/18Z. HOWEVER...SOME PASSING
SHOWERS ARE POSSIBLE IN THE VICINITY OF TJSJ...TJMZ...TJBQ..AND TIST
FROM TIME TO TIME. WINDS WILL CONTINUE MAINLY NORTHEAST AT 10 TO 15
KTS AT THE SURFACE...WITH OCCASIONAL HIGHER GUSTS.
&&
.MARINE...WINDS AND SEAS WILL CONTINUE TO DIMINISH THROUGH WEDNESDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
SJU 84 72 82 73 / 20 10 10 10
STT 86 72 85 73 / 20 10 10 10