Small Craft Advisory 32, NWS JSJ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
252 PM AST SAT APR 24 2010

.SYNOPSIS...MID TO UPPER LEVEL SHORT WAVE AND ASSOCIATED JET
STREAK WILL MOVE ACROSS THE LOCAL AREA EARLY TONIGHT...BEFORE
LIFTING SLOWLY OUT TO THE NORTHEAST LATE TONIGHT SUNDAY. BEHIND
THIS FEATURE...A MID TO UPPER LEVEL RIDGE WILL GRADUALLY BUILD
ACROSS THE LOCAL AREA SUNDAY AND MONDAY AND SHOULD LINGER THROUGH
AT LEAST THE MIDDLE AND POSSIBLY END OF NEXT WEEK.

&&

.DISCUSSION...OLD FRONTAL TROUGH/CONVERGENCE ZONE AND ASSOCIATED
MOIST AND UNSTABLE AIR MASS WILL CONTINUE NEARLY STATIONARY
ACROSS THE LOCAL AREA TONIGHT THROUGH MOST OF SUNDAY AS WELL...
BEFORE A GRADUAL...OVERALL AIR MASS DRYING TAKES PLACE EARLY NEXT
WEEK. FOR TONIGHT...ABUNDANT MOISTURE AND INSTABILITY SHOULD
COMBINE WITH FAVORABLE DYNAMICS AND LOCAL EFFECTS TO MAINTAIN A
GOOD DEAL OF CLOUDINESS...SHOWERS AND ISOLATED THUNDERSTORMS OVER
PARTS OF THE LOCAL ISLANDS...ESPECIALLY THE INTERIOR...NORTHEAST
AND SOUTH SECTIONS OF PUERTO RICO. ADDITIONAL AREAS OF HEAVY
RAINFALL AND SOME LOCALIZED FLOODING ARE EXPECTED IN A FEW
LOCATIONS. FOR SUNDAY...BUILDING HIGH PRESSURE SHOULD BEGIN TO
CAP CONVECTION A BIT...BUT STILL SHOULD BE ENOUGH MOISTURE IN
COMBINATION WITH LOCAL EFFECTS...TO PRODUCE LOCALIZED
CLOUDINESS...SHOWERS AND POSSIBLY A COUPLE OF THUNDERSTORMS.
LOOKING AHEAD...FOR MONDAY AND TUESDAY AND PROBABLY WEDNESDAY AND
THURSDAY ALSO...COMBINATION OF MID TO UPPER LEVEL RIDGE AND AN
OVERALL DRIER AND MORE STABLE AIR MASS...SHOULD ALLOW FOR A
GENERALLY FAIR WEATHER PATTERN ACROSS THE FA. HOWEVER...LOCAL
EFFECTS WILL STILL BE ABLE TO PRODUCE SOME LOCALIZED CONVECTION
EACH DAY...PARTICULARLY ON WEDNESDAY AND THURSDAY AFTERNOONS.
ADDITIONALLY...THE SURFACE WIND FLOW IS EXPECTED TO BE SOUTHEAST
DURING THIS TIME AND IF ENOUGH SUNSHINE OCCURS...NORTH COASTAL
TEMPERATURES MAY ONCE AGAIN REACH THE LOWER 90S...AS ONCE AGAIN
INDICATED BY 12Z MEXJSJ GUIDANCE.

&&

.AVIATION...EXPECT PREVAILING VFR CONDITIONS ACROSS THE LOCAL
ISLANDS AND AT MOST LOCAL TAF SITES DURING THE NEXT 24 HOURS.
HOWEVER...BRIEF PERIODS OF MVFR OR EVEN IFR CONDITIONS AND
MOUNTAIN OBSCURATIONS ARE EXPECTED...ESPECIALLY ALONG THE
CORDILLERA CENTRAL AND ACROSS TJPS AND POSSIBLY TJMZ AND TJSJ DUE
TO SHOWERS AND ISOLATED THUNDERSTORMS. MOST SHOWERS AND
THUNDERSTORMS ARE EXPECTED TO DISSIPATE BY 25/01Z. ALSO...BASED
ON VISIBLE SATELLITE DATA...A SMALL PLUME OF VOLCANIC ASH OR
STEAM IS MOVING MAINLY WEST FROM MONTSERRAT AND IS EXPECTED TO
REMAIN MAINLY SOUTH OF THE LOCAL ISLANDS AND TAF SITES TONIGHT.

&&

.MARINE...GENERALLY EXPECT WINDS OF 20 KNOTS OR LESS AND SEAS OF
8 FEET OR LESS ACROSS THE REGIONAL WATERS THROUGH TUESDAY. LONG
PERIOD...NORTH NORTHEAST SWELLS WILL BEGIN TO AFFECT THE LOCAL
ATLANTIC WATERS AND THE CARIBBEAN PASSAGES SUNDAY NIGHT AND WILL
LINGER THROUGH AT LEAST MONDAY NIGHT. SMALL CRAFT ADVISORIES MAY
BE REQUIRED FOR PARTS OF THE LOCAL ATLANTIC WATERS AND THE
CARIBBEAN PASSAGES BEGINNING SUNDAY NIGHT.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU  75  85  76  89 /  30  30  30  30
STT  75  84  77  87 /  40  40  30  30

&&

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

BCS

HAZARDOUS WEATHER OUTLOOK FOR PUERTO RICO AND THE U.S. VIRGIN
ISLANDS
NATIONAL WEATHER SERVICE SAN JUAN PR
619 AM AST SAT APR 24 2010

AMZ710>745-PRZ001>013-251030-
SAN JUAN AND VICINITY-NORTHEAST-SOUTHEAST-EASTERN INTERIOR-
NORTH CENTRAL-CENTRAL INTERIOR-PONCE AND VICINITY-NORTHWEST-
WESTERN INTERIOR-MAYAGUEZ AND VICINITY-SOUTHWEST-CULEBRA-VIEQUES-
THE NEARSHORE AND OFF SHORE ATLANTIC AND CARIBBEAN COASTAL WATERS-
619 AM AST SAT APR 24 2010

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PUERTO RICO AND THE
ADJACENT COASTAL WATERS.

.DAY ONE...TODAY AND TONIGHT

A MOIST AND UNSTABLE WEATHER PATTERN IS EXPECTED TO CONTINUE
ACROSS THE LOCAL ISLANDS TODAY AND TONIGHT. SHOWERS AND ISOLATED
THUNDERSTORMS ARE EXPECTED TO DEVELOP THIS AFTERNOON ESPECIALLY
ACROSS WESTERN...CENTRAL AND INTERIOR SECTIONS OF PUERTO RICO.
THIS ACTIVITY WILL CONTINUE INTO THE MID EVENING HOURS. AREAS OF
LOCALLY HEAVY RAINFALL CAN BE EXPECTED ACROSS PARTS NORTHEAST...
NORTH CENTRAL AND SOUTHWEST SECTIONS OF PUERTO RICO...WITH GOOD
CHANCE OF URBAN AND SMALL STREAM FLOODING IN SOME AREAS...AS WELL
AS POTENTIAL FOR MUDSLIDES IN AREAS OF STEEP TERRAIN...WHERE
SIGNIFICANT AMOUNTS OF RAINFALL HAD OCCURRED IN RECENT DAYS.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY

CLOUDINESS...SHOWERS AND ISOLATED THUNDERSTORMS ARE EXPECTED MAINLY
OVER THE WESTERN INTERIOR OF PUERTO RICO SUNDAY AFTERNOON. THESE
SHOWERS WILL BE CAPABLE OF PRODUCING HEAVY RAIN...THEREFORE URBAN
AND SMALL STREAM FLOODING WILL ALSO BE LIKELY.

.SPOTTER INFORMATION STATEMENT...

RAINFALL AND RIVER FLOODING REPORTS WILL BE WELCOME.

AMZ715-725-VIZ001-002-251030-
ST. THOMAS ST. JOHN ADJACENT ISLANDS-ST CROIX-
NEARSHORE ATLANTIC AND ADJACENT CARIBBEAN COASTAL WATERS-
619 AM AST SAT APR 24 2010

THIS HAZARDOUS WEATHER OUTLOOK IS FOR THE U.S. VIRGIN ISLANDS AND
THE ADJACENT COASTAL WATERS.

.DAY ONE...TODAY AND TONIGHT

A MOIST AND UNSTABLE WEATHER PATTERN IS EXPECTED TO CONTINUE ACROSS
THE LOCAL ISLANDS THROUGH AT LEAST TONIGHT. SHOWERS...SOME
POSSIBLY HEAVY ARE EXPECTED THIS AFTERNOON AND TONIGHT.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION WILL NOT BE NEEDED.