Area Forecast Discussion
Issued by NWS San Juan, PR

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866
FXCA62 TJSJ 120957
AFDSJU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
557 AM AST FRI FEB 12 2016

.SYNOPSIS...UPPER LEVEL RIDGE WILL HOLD ACROSS THE ANEGADA PASSAGE
THROUGH TONIGHT. A DEEP POLAR LOW WILL MOVE INTO THE WESTERN ATLANTIC
ERODING THE RIDGE DURING THE WEEKEND. FAIR WEATHER WILL PREVAIL THROUGH
TONIGHT...THEN ENVIRONMENTAL CONDITIONS BECOME MORE FAVORABLE FOR
SHOWERS AND THUNDERSTORMS AS UPPER RIDGE FLATTENS FROM SATURDAY
THROUGH EARLY NEXT WEEK.

&&

.DISCUSSION...EASTERLY TRADE WINDS HAVE PUSHED PATCHES OF LOW
LEVEL MOISTURE ACROSS THE ISLANDS SINCE MIDNIGHT. THESE PASSING
SHOWERS FAVORED THE WINDWARD AREAS...WHERE UP TO ONE QUARTER OF
AN INCH HAVE BEEN OBSERVED IN ISOLATED SPOTS OF NORTHEAST PR SO
FAR THIS MORNING. SATELLITE IMAGERY INDICATES ADDITIONAL LOW
LEVEL MOISTURE UPSTREAM OF THE ISLANDS. AS A RESULT...THESE
MORNING SHOWERS WILL CONTINUE TO AFFECT PORTIONS OF THE USVI AND
THE EASTERN THIRD OF PR THROUGH MID-MORNING. STILL EXPECTING
LIMITED SHOWER ACTIVITY LATER THIS MORNING AND IN THE AFTERNOON AS
OPERATIONAL MODELS CONTINUE TO SUGGEST A CAP INVERSION HOLDING
THROUGH TONIGHT. A FEW SHOWERS OVER MAYAGUEZ AND VICINITY CAN NOT
RULED OUT THIS AFTERNOON DUE TO LOCAL EFFECTS.

A WETTER AND MORE UNSTABLE PATTERN IS FORECAST FROM SATURDAY TO
EARLY NEXT WEEK AS THE UPPER RIDGE COLLAPSES AND SHORT WAVE ENERGY
PROVIDES FAVORABLE CONDITIONS FOR SHOWERS AND THUNDERSTORMS. AS
THE RIDGE FLATTENS...MOISTURE WILL SURGE ACROSS THE NORTHEAST
CARIBBEAN ISLANDS. AT THIS TIME...THE WETTEST DAY APPEARS TO BE
ON MONDAY WHEN AN EASTERLY PERTURBATION WILL CROSS THE ISLANDS.

&&

.AVIATION...MAINLY VFR CONDS AT ALL TERMINALS DURG THE NEXT 24 HOURS.
HOWEVER...SHRA EMBEDDED ON TRADE WINDS WILL CONTINUE TO MOVE FM THE
NORTHERN LEEWARD ISLANDS INTO EASTERN PR THRU AT LEAST 12Z. SCT CLD
LYRS FL030...FL070 AND MTN TOP OBSCD AT EASTERN PR LIKELY WITH THIS
ACTIVITY. BETWEEN 17Z-22Z SHRA DEVELOPING OVER WESTERN INTERIOR OF
PR...IMPACTING MAINLY JMZ/JBQ. LOW LEVEL WINDS WILL CONTINUE FM THE
EAST AT 10-20 KTS. SEA BREEZE VARIATIONS WITH HIGHER GUSTS AFTER
14Z.

&&

.MARINE...WINDS OF 10-15 KT AND SEAS OF 4-7 FT CAN BE EXPECTED
ACROSS THE ISLANDS THROUGH AT LEAST SATURDAY. THIS WILL RESULT IN
HAZARDOUS MARINE CONDITIONS FOR SMALL CRAFT IN THE OUTER ATLANTIC
WATERS. BREAKING WAVES UP TO 7 FEET ALONG THE NORTH COAST OF PR
AND CULEBRA WILL KEEP THE HIGH RISK OF RIP CURRENT FOR THE NORTH
FACING BEACHES THROUGH LATE TONIGHT. MODELS ARE CURRENTLY INDICATING
INCREASING WINDS AND SEAS BEGINNING MONDAY AND CONTINUING THROUGH
TUESDAY AS A STRONG HIGH DEVELOPS IN THE CENTRAL ATLANTIC.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU  86  73  85  73 /  30  30  30  30
STT  84  74  84  73 /  30  50  50  40

&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...HIGH RIP CURRENT RISK THROUGH LATE TONIGHT FOR CULEBRA-NORTH
     CENTRAL-NORTHEAST-NORTHWEST-SAN JUAN AND VICINITY-SOUTHEAST-
     WESTERN INTERIOR.

VI...HIGH RIP CURRENT RISK UNTIL 5 AM AST EARLY THIS MORNING FOR ST.
     THOMAS/ST. JOHN/ADJACENT ISLANDS.

AM...HIGH RIP CURRENT RISK UNTIL 5 AM AST EARLY THIS MORNING FOR
     COASTAL WATERS OF SOUTHERN USVI VIEQUES AND EASTERN PUERTO
     RICO OUT 10 NM.

     SMALL CRAFT ADVISORY UNTIL 2 PM AST SATURDAY FOR ATLC WATERS OF
     PUERTO RICO AND USVI FROM 10NM TO 19.5N.

&&

$$

13/11



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