Area Forecast Discussion
Issued by NWS San Juan, PR

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FXCA62 TJSJ 200932 CCA
AFDSJU

AREA FORECAST DISCUSSION...CORRECTED
NATIONAL WEATHER SERVICE SAN JUAN PR
531 AM AST MON OCT 20 2014

.SYNOPSIS...AT UPPER LEVELS...A WEAK LOW PRESSURE JUST NORTH OF PUERTO
RICO WILL MOVE EAST NORTHEAST TODAY AND TOMORROW. ANOTHER WEAK
TROUGH WILL PASS THROUGH THE LOCAL AREA ON TUESDAY. THEN HIGH
PRESSURE WILL BUILD OVER THE WESTERN CARIBBEAN AND A RIDGE WILL
EXTEND INTO THE ATLANTIC JUST NORTH OF THE AREA DURING THE COURSE
OF THE WEEK. LOW PRESSURE JUST NORTH OF THE WESTERN TROPICAL
ATLANTIC ON THURSDAY WILL STRENGTHEN OVER THE WEEKEND AS IT MOVES
SOUTHWEST AND INTO THE SOUTHEASTERN CARIBBEAN EARLY NEXT WEEK.

AT MID LEVELS...HIGH PRESSURE WILL DOMINATE THE LOCAL AREA. AN
INVERTED TROUGH IN THE WESTERN TROPICAL ATLANTIC ON SATURDAY WILL
MOVE INTO THE CARIBBEAN MONDAY AND PASS SOUTH OF THE AREA TUESDAY
AND WEDNESDAY OF NEXT WEEK. THIS WEEK LIMITED MID-LEVEL MOISTURE
WILL CONTINUE UNTIL TUESDAY AND THEN RETURN ON FRIDAY.

AT LOWER LEVELS...HIGH PRESSURE IN THE WESTERN ATLANTIC AND
LOWER PRESSURE OVER SOUTH AMERICA WILL GENERATE LIGHT TO MODERATE
TRADE WIND FLOW UNTIL MID WEEK. GENERALLY GOOD MOISTURE WILL BRING
SHOWERS AND SCATTERED THUNDERSTORMS TODAY AND TUESDAY. WEAK LOW
PRESSURE ALSO CONTINUES TO WOBBLE AROUND IN A BOX BOUNDED BY 50
AND 60 WEST LONGITUDE AND 20 AND 30 NORTH LATITUDE UNTIL THURSDAY.
LATER THIS WEEK HIGH PRESSURE IN THE CENTRAL ATLANTIC WILL SPREAD
SOUTH INTO THE TROPICAL ATLANTIC AND SOUTHWEST INTO THE LOCAL
AREA. LOOK FOR GENERALLY WARMING TEMPERATURES WEDNESDAY THROUGH
MONDAY OF NEXT WEEK.

&&

.DISCUSSION...SCATTERED SHOWERS WERE SEEN ACROSS MOST OF THE LOCAL
WATERS EXCEPT IN THE SHADOW OF PUERTO RICO GENERATED BY THE EAST
NORTHEAST FLOW. A FEW OF THESE SHOWERS MADE IT INLAND ON THE
COASTS AROUND PUERTO RICO FROM DORADO AND SAN JUAN THROUGH FAJARDO
AND YABUCOA. A FEW SHOWERS WERE ALSO SEEN IN PARTS OF THE U.S.
VIRGIN ISLANDS. RELATIVELY GOOD MOISTURE AROUND 1.7 INCHES OF
PRECIPITABLE WATER AND LIFTED INDEX VALUES AROUND MINUS 5 TO MINUS
6 WILL GENERATE ANOTHER ROUND OF SHOWERS AND SCATTERED
THUNDERSTORMS ACROSS PUERTO RICO IN MUCH THE SAME AREAS AS
YESTERDAY WITH LITTLE EXPECTED ON THE NORTH COAST AND HEAVY RAINS
AT TIMES IN THE WESTERN CENTRAL PORTIONS OF THE ISLAND. SOME
STREAMERS MAY ALSO BE GENERATED DOWNWIND FROM THE THE U.S. VIRGIN
ISLANDS. CURRENTLY THE GFS KEEPS THE MOISTURE AT THESE ABUNDANT
LEVELS THROUGH TUESDAY WITH WINDS VEERING VERY SLIGHTLY TOWARD THE
EAST. THIS SHOULD CONTINUE SHOWERS AND AFTERNOON THUNDERSTORMS IN
THE INTERIOR THROUGH TOMORROW. WIND FLOW BEGINS TO VEER DEVELOPING
A SOUTHERLY COMPONENT THAT SHOULD HELP TO WARM TEMPERATURES ON THE
NORTH COAST BY SEVERAL DEGREES WEDNESDAY THROUGH SUNDAY. MOISTURE
LEVELS DIMINISH CONSIDERABLY ON WEDNESDAY AND EXPECT MUCH LESS
SHOWER ACTIVITY THEN AND THURSDAY. HOWEVER MOISTURE RETURNS FRIDAY
THROUGH SUNDAY...AND SHOULD HELP MODERATE TEMPERATURES
SOMEWHAT...BUT WILL LIKELY SEE THE SAN JUAN METROPOLITAN AREA 2 TO
4 DEGREES ABOVE NORMAL AT THE PEAK OF THE WARMING.

&&

.AVIATION...VFR CONDITIONS ARE EXPECTED THRU THE FCST PERIOD
EXCEPT AS FOLLOWS. PSBL VCSH ACROSS TJSJ/TIST/TISX FROM 20/09Z-20/16Z.
LIGHT AND VARIABLE WINDS EARLY IN THE MORNING...INCREASING TO
8-12 KTS FM THE EAST AFT 20/13Z. SHRA/TSRA EXPECTED ACROSS THE
INTERIOR AND WESTERN PORTIONS OF PR BETWEEN 20/18-22Z CREATING
MOUNTAIN OBSCURATIONS AND BRIEF MVFR/IFR CONDITIONS OVER THE
INTERIOR AND...IMPACTING MAINLY TJMZ/TJBQ WITH BRIEF MVFR.
ALSO...VCTS PSBL AT TJSJ AND TJPS BY MID AFTERNOON.

&&

.MARINE...SEAS WILL GENERALLY DIMINISH THROUGH THE WEEK WITH THE
EXCEPTION OF ONE MORE BURST OF SWELL FROM THE NORTH NORTH EAST ON
TUESDAY OF UP 3 TO 4 FEET. WINDS WILL INCREASE A LITTLE OVER THE
WEEK BUT WILL BECOME MORE EAST SOUTHEAST AFTER TUESDAY. NO SMALL
CRAFT ADVISORIES ARE EXPECTED DURING THE NEXT 7 DAYS.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU  89  77  88  77 /  30  30  30  30
STT  89  78  87  77 /  40  20  30  30

&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...NONE.
VI...NONE.
COASTAL WATERS...NONE.
&&

$$

27/12




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