Area Forecast Discussion
Issued by NWS San Juan, PR

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FXCA62 TJSJ 010208
AFDSJU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
1008 PM AST FRI OCT 31 2014

.UPDATE...UPPER LEVEL RIDGE IS FORECAST TO ESTABLISH ACROSS THE
NORTHEAST CARIBBEAN ISLANDS DURING THE WEEKEND. THEREFORE...WEATHER
CONDITIONS WILL GRADUALLY IMPROVE DURING THE WEEKEND. HOWEVER...BRIEF
MORNING SHOWERS ACROSS EASTERN PORTIONS OF PUERTO RICO AND ISOLATED
TO SCATTERED CONVECTION OVER WESTERN PR IN THE AFTERNOON CAN BE EXPECTED
SATURDAY AND SUNDAY. NO CHANGES WERE INTRODUCED TO THE FORECAST PACKAGE
THIS EVENING.

&&

.AVIATION...PREVAILING VFR CONDS ACROSS THE LOCAL FLYING AREA AND
ALL TAF SITES DURG THE PRD. PASSING -SHRA/SHRA WILL AFFECT PARTS OF
THE COASTAL WATERS BTW ERN PR AND THE NRN LEEWARDS WITH FEW CU/TCU
EN ROUTE MAINLY OVR S-SE CARIBBEAN WATERS. SOME SHOWERS MAY AFFECT
PARTS OF E INTERIOR SECTIONS OF PR WITH PSBL LOW SCUD CLDS AND SOME
PATCHY EARLY MORNING FOG WHICH MAY OBSCR MTN TOPS BTW 01/06-01/12Z.
GENERAL WND FLOW LGT BUT MAINLY FM THE SOUTH AT 5-10 KNOTS BLO FL100
BCMG SW-W ABV AND UP TO FL250...THEN FM N AT 10-15 KTS UP TO FL350.
NO OTHER SIG OPERATIONAL WX IMPACTS AT THIS TIME.

&&

.MARINE...SEAS WILL RANGE BETWEEN 2-4 FT UNTIL SUNDAY. THEN...
LONG PERIOD NW SWELLS WILL IMPACT THE ATLANTIC WATERS AND PASSAGES
EARLY NEXT WEEK...WAVE HEIGHT WILL RANGE BETWEEN 5-7 FT FROM MONDAY
THROUGH AT LEAST WEDNESDAY. DANGEROUS RIP CURRENTS WILL BE LIKELY
EARLY NEXT WEEK ACROSS THE NORTH FACING COASTLINES OF PR AND USVI.

&&

.PREV DISCUSSION... /ISSUED 303 PM AST FRI OCT 31 2014/

SYNOPSIS...UPPER LEVEL RIDGE WILL BUILD THROUGH THE WEEKEND. DEEP
CUTOFF LOW EXPECTED TO EVOLVE OVR THE WINDWARD PASSAGE/CONTROL
CARIBBEAN MID NEXT WEEK AND BRING COOLER AND UNSETTLED WEATHER.

DISCUSSION...VERY ACTIVE AFTERNOON OVER PUERTO RICO...MAINLY
ALONG THE NORTH COAST OF PUERTO RICO. VERY HEAVY RAINFALL OCCURRED
OVER THE SAN JUAN METROPOLITAN AREA WITH RAINFALL ACCUMULATIONS
BETWEEN 2 TO 3 INCHES OBSERVED IN SOME AREAS. MOST OF THIS
ACTIVITY WAS PRIMARILY ASSOCIATED WITH THE COMBINATION OF A TROUGH
OF LOW PRESSURE COMBINED WITH STRONG DAYTIME HEATING AND LOCAL
EFFECTS. SHOWERS AND THUNDERSTORMS WILL CONTINUE TO AFFECT MAINLY
THE SOUTHEAST...EAST AND NORTH SECTIONS OF PUERTO RICO THROUGH AT
LEAST 7 PM AST. FOR TONIGHT...A DRY AIR MASS IS EXPECTED TO MOVE
ACROSS THE REGION.

FOR THE WEEKEND...AN UPPER LEVEL RIDGE IS EXPECTED TO BUILD ACROSS
THE REGION WHICH WILL LIMIT THE SHOWER ACTIVITY ACROSS THE REGION.
HOWEVER...AVAILABLE MOISTURE WILL COMBINE WITH DAYTIME HEATING AND
LOCAL AFFECTS WILL PRODUCE SCATTERED SHOWERS WITH ISOLATED
THUNDERSTORMS MAINLY OVER THE WESTERN INTERIOR AND NORTHWEST
SECTIONS OF PUERTO RICO.

FOR THE MIDDLE OF NEXT WEEK...A CUTOFF LOW IS EXPECTED TO DEVELOP
WEST OF THE AREA WHICH WILL PROMOTE UNSTABLE ATMOSPHERIC
CONDITIONS ACROSS THE REGION. THEREFORE...A RETURN TO A WETTER
PATTERN IS EXPECTED FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS.

AVIATION...SHRA/TSRA WILL CONTINUE TO AFFECT THE TJSJ...TJBQ...TJMZ
AND TIST UNTIL AT LEAST 31/22Z WITH CIGS AROUND FL020-040 AND
REDUCTION IN VISIBILITY TO AROUND 4 MILES AS THE ACTIVITY AFFECTS
THESE TERMINALS. THE REST OF THE LOCAL FLYING AREA WILL REMAINS
MOSTLY VFR WITH ONLY VCSH. FOR TOMORROW...AFTERNOON CONVECTION
EXPECTED AGAIN ACROSS NW-PR WHICH MAY BRIEFLY AFFECT TJBQ AND TJMZ
BETWEEN 01/18Z AND 01/22Z.

MARINE...SEAS UP TO 4 FEET AND WINDS UP TO 14 KNOTS ARE EXPECTED
OVER THE COASTAL WATERS.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU  80  88  81  87 /  10  10  10  10
STT  82  89  82  88 /  20  20  10  10

&&

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

$$

09/11





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