Flash Flood Warning 149, NWS JSJ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
1118 PM AST WED DEC 15 2010

.UPDATE...PERSISTENT SHOWERS AFFECTED MUCH OF NORTHERN AND
NORTHEASTERN PUERTO RICO THIS EVENING. WITH A LIGHT NORTHERLY FLOW
AND AMPLE LOW LEVEL MOISTURE EXPECTED TO PERSIST OVERNIGHT...
ADDITIONAL SHOWERS ARE EXPECTED TO DEVELOP AND AFFECT NORTHERN
COASTAL SECTIONS OF THE LOCAL ISLANDS THROUGH TOMORROW AFTERNOON.
AS A RESULT...WENT AHEAD AND INCREASED POPS IN SHORT TERM...BUT NO
OTHER CHANGES NECESSARY TO INHERITED FORECAST THIS EVENING.

&&

.AVIATION...THE REMNANTS AN OLD COLD FRONT ARE EXPECTED TO PUSH
FURTHER SOUTHWARD ACROSS THE CARIBBEAN WATERS TONIGHT AND
TOMORROW. SHRAS WILL PERSIST ACROSS MUCH OF NORTHERN PUERTO
RICO...WITH MVFR CONDS POSSIBLE ACROSS TIST...TJSJ...AND TJSJ
THROUGH AT LEAST 16/14Z. MTN OBSCURATIONS WILL ALSO CONTINUE
ACROSS THE INTERIOR OF PR AND HIGHER ELEVATIONS OF THE USVI
THROUGH ABOUT 16/20Z. LLVL FLOW WILL BE NORTHERLY 10 KT TO 15 KTS
WITH GUSTY WINDS 20 KT NEAR HEAVIER SHOWERS.

&&

.MARINE...LONG PERIOD NORTHWEST SWELLS WILL SLOWLY SUBSIDE ACROSS
THE REGIONAL WATERS THROUGH FRIDAY AFTERNOON. THIS WILL RESULT IN
HAZARDOUS MARINE CONDITIONS ACROSS MUCH OF THE LOCAL ATLANTIC
WATERS AND CARIBBEAN PASSAGES THROUGH AT LEAST NOON FRIDAY. IN
ADDITION...LARGE BREAKING WAVES WILL RESULT IN DANGERS RIP
CURRENTS OVERNIGHT AND THURSDAY...AND A HIGH SURF ADVISORY REMAINS
IN EFFECT FOR THE NORTHERN EXPOSED COASTLINES OF PUERTO
RICO...CULEBRA...AND THE NORTHERN U.S. VIRGIN ISLANDS THROUGH 4 PM
AST THURSDAY AFTERNOON.

&&

.CLIMATE...WITH OVER THREE INCHES OF RAINFALL ACCUMULATING AT THE
LUIS MUNOZ MARIN INTERNATIONAL AIRPORT AS OF 11 PM AST THIS
EVENING...OVER 87 INCHES OF RAINFALL HAS NOW ACCUMULATED AT THE
AIRPORT SINCE THE FIRST OF THE YEAR. WITH PRECIPITATION TOTALS
DATING BACK TO 1898 FOR THE SAN JUAN AREA...2010 IS ONLY ABOUT ONE
QUARTER OF AN INCH AWAY FROM ESTABLISHING A NEW ANNUAL
PRECIPITATION RECORD FOR THE SAN JUAN AREA. SEE THE LATEST NEWS
HEADLINES AT WWW.WEATHER.GOV/SANJUAN FOR INFORMATION ABOUT THIS
AND OTHER HISTORICAL RECORDS.

&&

.PREV DISCUSSION... /ISSUED 410 PM AST WED DEC 15 2010/

SYNOPSIS...MID TO UPPER LEVEL TROUGHINESS WILL CONTINUE ACROSS THE
WEST AND SOUTHWEST ATLANTIC THROUGH TONIGHT OR EARLY THURSDAY...
BEFORE SLOWLY LIFTING OUT TO THE EAST NORTHEAST LATER THURSDAY
THROUGH FRIDAY...AS MID TO UPPER LEVEL RIDGE BUILDS ACROSS THE
CARIBBEAN. THIS RIDGE IS GENERALLY EXPECTED TO HOLD THROUGH
SATURDAY AND POSSIBLY SUNDAY.

DISCUSSION...A COLD FRONT WILL CONTINUE TO SINK SLOWLY SOUTHEAST
ACROSS THE LOCAL AREA THE REST OF THIS AFTERNOON THROUGH THURSDAY.
KUDOS TO NCEP TROPICAL DESK AND MODEL PROJECTIONS FOR CORRECTLY
SHOWING AREAS OF HEAVY RAINFALL THAT HAVE AFFECTED PARTS OF NORTH
PUERTO RICO SINCE LATE WEDNESDAY NIGHT...WITH LOCALIZED 3 TO 5
INCH AMOUNTS ALREADY REPORTED. AS THIS BOUNDARY CONTINUES
DRIFTING SOUTHEAST TONIGHT THROUGH EARLY THURSDAY...EXPECT
ADDITIONAL RAINFALL...WITH LOCALIZED HEAVY AMOUNTS...OVER THE
NORTH...NORTHEAST AND INTERIOR SECTIONS OF PUERTO RICO EASTWARD
ACROSS CULEBRA AND THE NORTHERN U.S. VIRGIN ISLANDS...WITH A
GRADUAL SHIFTING TREND MORE AND MORE TOWARD THE EAST AND
SOUTHEAST OVERNIGHT TONIGHT THROUGH THURSDAY. STILL THINK THAT
THE REMNANTS OF THE BOUNDARY WILL LINGER ACROSS THE LOCAL ISLANDS
THROUGH THURSDAY NIGHT AND POSSIBLY EARLY FRIDAY...BEFORE IT IS
FAR ENOUGH SOUTH OF THE LOCAL ISLANDS AND WEAK ENOUGH THAT IT
SHOULD NOT HAVE A BIG EFFECT ON THE LOCAL SENSIBLE WEATHER. AT
THIS TIME...GENERALLY FAIR AND DRIER CONDITIONS ARE INDICATED FOR
SATURDAY AND SUNDAY.

A HIGH SURF ADVISORY REMAINS IN EFFECT FOR THE NORTHWEST THROUGH
NORTHEAST COASTS OF PUERTO RICO...CULEBRA AND THE NORTHERN U.S.
VIRGIN ISLANDS AND HAS BEEN EXTENDED UNTIL 4 PM AST THURSDAY.

AVIATION...EXPECT PREVAILING VFR CONDITIONS ACROSS MOST OF THE
LOCAL TAF SITES THROUGH TONIGHT...BUT WITH BRIEF MVFR CONDITIONS
AND LOCAL MOUNTAIN OBSCURATIONS EXPECTED IN SCATTERED PASSING
SHOWERS. HOWEVER...OVER THE INTERIOR AND NORTH SECTIONS OF PUERTO
RICO...INCLUDING TJSJ AND TJNR...EXPECT PREVAILING MVFR
CONDITIONS AND MOUNTAIN OBSCURATIONS...WITH OCCASIONAL IFR
CONDITIONS...IN NUMEROUS SHOWERS AND ISOLATED THUNDERSTORMS.

MARINE...LARGE...LONG PERIOD NORTHWEST SWELLS HAVE GENERALLY
PEAKED ACROSS THE LOCAL ATLANTIC WATERS AND THE CARIBBEAN
PASSAGES...BUT WILL CONTINUE TO AFFECT THE WATERS THROUGH AT
LEAST THURSDAY NIGHT...WHILE SLOWLY SUBSIDING. THESE SWELLS WILL
CONTINUE TO PRODUCE ROUGH AND HAZARDOUS MARINE CONDITIONS. SMALL
CRAFT ADVISORIES REMAIN IN EFFECT FOR ALL OF THE LOCAL COASTAL
WATERS TONIGHT.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU  72  79  73  81 /  80  50  30  30
STT  72  82  74  84 /  50  50  40  40

&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...HIGH SURF ADVISORY UNTIL 4 PM AST THURSDAY FOR CULEBRA-MAYAGUEZ
     AND VICINITY-NORTH CENTRAL-NORTHEAST-NORTHWEST-SAN JUAN AND
     VICINITY.
     SCA AMZ710-712-715-722-725-732-741-742.

VI...HIGH SURF ADVISORY UNTIL 4 PM AST THURSDAY FOR ST. THOMAS/ST.
     JOHN/ADJACENT ISLANDS.
     SCA AMZ710-715-722-725-732.

&&

10/04

HAZARDOUS WEATHER OUTLOOK FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS
NATIONAL WEATHER SERVICE SAN JUAN PR
523 AM AST WED DEC 15 2010

AMZ710>745-PRZ001>013-160930-
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-
523 AM AST WED DEC 15 2010

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

.DAY ONE...TODAY AND TONIGHT

A WEAKENING FRONTAL BOUNDARY JUST ACROSS THE REGION TODAY...WILL
CONTINUE TO INDUCE THE DEVELOPMENT OF SHOWERS AND A FEW
THUNDERSTORMS ACROSS PUERTO RICO TODAY AND TONIGHT. A COMBINATION
OF LONG PERIOD NORTHWEST SWELLS...AND MODERATE NORTHEAST
SWELLS WILL CONTINUE TO CREATE HAZARDOUS SURF CONDITIONS ALONG THE
NORTH FACING COASTLINES...WITH A MODERATE TO HIGH RISK OF RIP
CURRENTS.

.DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY

A COMBINATION OF LONG PERIOD NORTHWEST SWELLS...AND MODERATE NORTHEAST
SWELLS WILL CREATE HAZARDOUS SURF CONDITIONS ALONG THE NORTH FACING
COASTLINES...WITH A MODERATE TO HIGH RISK OF RIP CURRENTS.

.SPOTTER INFORMATION STATEMENT...
SPOTTER ACTIVATION WILL NOT BE NEEDED AT THIS TIME.

AMZ715-725-VIZ001-002-160930-
ST. THOMAS ST. JOHN ADJACENT ISLANDS-ST CROIX-
NEARSHORE ATLANTIC AND ADJACENT CARIBBEAN COASTAL WATERS-
523 AM AST WED DEC 15 2010

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

.DAY ONE...TODAY AND TONIGHT
A WEAKENING FRONTAL BOUNDARY JUST ACROSS THE REGION TODAY...WILL
CONTINUE TO INDUCE THE DEVELOPMENT OF SHOWERS AND A FEW
THUNDERSTORMS ACROSS THE LOCAL ISLANDS TODAY AND TONIGHT. A
COMBINATION OF LONG PERIOD NORTHWEST SWELLS...AND MODERATE
NORTHEAST SWELLS WILL CONTINUE TO CREATE HAZARDOUS SURF CONDITIONS
ALONG THE NORTH FACING COASTLINES...WITH A MODERATE TO HIGH RISK
OF RIP CURRENTS.

.DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY

A COMBINATION OF LONG PERIOD NORTHWEST SWELLS...AND MODERATE NORTHEAST
SWELLS WILL CREATE HAZARDOUS SURF CONDITIONS ALONG THE NORTH FACING
COASTLINES...WITH A MODERATE TO HIGH RISK OF RIP CURRENTS.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION WILL NOT BE NEEDED AT THIS TIME