Flood in Puerto Rico, March 27, 2004

PUERTO RICO AND U.S. VIRGIN ISLANDS FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
900 PM AST SAT MAR 27 2004

.UPDATE...500 MB SHORTWAVE TROUGH CROSSING LOCAL AREA THIS EVENING
TO CONTINUE AFFECTING LOCAL WEATHER THROUGH SUNDAY MORNING...BEFORE
IT MOVES EAST. UPDATED EARLIER FORECAST AS BANDS OF SHOWERS AND
ISOLATED THUNDERSTORMS ENTERED THE NORTH COAST OF PUERTO RICO. NEXT
12 TO 24 HOURS WILL REMAIN UNDER THE INFLUENCE OF MODERATE BUT GUSTY
NORTHEASTERLIES AND WITH MOISTURE LADEN AIR TO CAUSE SCATTERED TO
NUMEROUS SHOWERS ALONG THE NORTH HALF OF PUERTO RICO. UPDATED
FORECAST TO ALLOW FOR SCATTERED SHOWERS ALONG CARIBBEAN
WATERS./RM

.SYNOPSIS...MID TO UPPER LEVEL LOW PRESSURE CENTERED ACROSS THE WEST
ATLANTIC NEAR 36N 59W WITH TROUGH EXTENDING SOUTHWEST ACROSS CUBA. A
100 KT SUBTROPICAL JET MAXIMA AT THE BASE OF THE TROUGH STREAMING
EAST ACROSS THE ATLANTIC WATERS JUST NORTH OF HISPANOLA AND PUERTO
RICO AND INTO THE CENTRAL ATLANTIC. THE RIGHT REAR QUADRANT OF JET
MAX IS NOW SITUATED OVER THE OFFSHORE ATLANTIC WATERS WHERE SHOWERS
AND ISOLATED THUNDERSTORMS HAVE BEGUN TO DEVELOP. A ZONAL WESTERLY
UPPER LEVEL FLOW CONTINUES ACROSS THE LOCAL REGION. IN THE LOW
LEVELS...HIGH PRESSURE CONTINUES OVER THE WEST ATLANTIC WITH A LOW
PRESSURE SYSTEM AND INDUCED TROUGHING OVER THE CENTRAL ATLANTIC WHICH
EXTENDS SOUTH TO JUST EAST OF THE LEEWARD ISLANDS. THIS PATTERN HAS
MAINTAINED A NORTHEASTERLY WIND FLOW ACROSS THE LOCAL REGION.

&&

.PREVIOUS DISCUSSION...AS DEPICTED BY THE LATEST SATELLITE IMAGERY
AND THE DOPPLER RADAR...CLOUDINESS AND SHOWERS ASSOCIATED WITH AND
OLD FRONTAL BOUNDARY/SHEARLINE ACROSS THE REGIONAL ATLANTIC WATERS
WILL CONTINUE TO BE TRANSPORTED ACROSS THE LOCAL AREA BY THE
MODERATE TO STRONG NORTHEAST WIND FLOW. THESE CONDITIONS WILL
CONTINUE AT LEAST THROUGH SUNDAY. THE GFS MODEL HAS INITIALIZED
FAIRLY WELL WITH THE PRESENT CONDITIONS AND HAS SO FAR HANDLED THE
CURRENT WEATHER PATTERN WELL. I WILL THEREFORE LEAN TOWARD THIS
MODEL FORECAST. THE 12Z SOUNDING SHOWED A SLIGHT INCREASE IN LOW
LEVEL MOISTURE ACROSS THE REGION...A LIFTED INDEX NEAR -4 WITH
NORTHEAST WIND FLOW UP TO 700 MILLIBARS. THEREFORE EXPECT THE
OCCASIONAL SHOWER ACTIVITY TO PERSIST OVERNIGHT THROUGH MORNING
HOURS AS MOISTURE WILL CONTINUE TO BE BROUGHT IN ACROSS THE LOCAL
AREA.

&&

.MARINE...SOME ISOLATED SHIP REPORTS JUST BEYOND THE OFFSHORE
ATLANTIC EARLIER INDICATED SEA HEIGHTS OF 10 TO 13 FEET AND CURRENT
WEB CAMERAS INDICATED CONTINUED ROUGH SEA CONDITIONS. THE PRESSURE
GRADIENT OVER THE LOCAL REGION REMAINS MODERATE SO THIS WILL
MAINTAIN THE GUSTY NORTHEAST WIND FLOW AT LEAST THROUGH SUNDAY. THE
GRADIENT IS THEN EXPECTED TO WEAKEN MONDAY AND TUESDAY ACROSS THE
AREA. THE REMNANTS OF THE WEAK FRONTAL BOUNDARY WILL CONTINUE TO
MOVE EAST SOUTHEAST TOWARD THE LEEWARDS ISLANDS THROUGH TUESDAY. AS
A RESULT OF THE CURRENT SEA CONDITIONS...AN SCA AND HIGH SURF
ADVISORY ALONG WITH A COASTAL FLOOD WATCH WILL REMAIN IN EFFECT AT
LEAST THROUGH TOMORROW. IN AGREEMENT WITH THE WAVE WATCH III MODELS
WHICH PEAKED WAVE HEIGHTS EARLIER THIS MORNING AND THEREFORE EXPECT
TO SEAS TO SLOWLY SUBSIDE STARTING ON SUNDAY.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU  72  84  72  84 /  40  40  40  40
STT  73  83  72  83 /  40  40  40  40

&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...SCA AMZ710-720 AND PARTS OF AMZ730-740. CFW AND HSA NW THRU NE
     COASTS OF PRZ001-002-005-008-010-012-013.
VI...SCA AMZ710-720 AND PARTS OF AMZ730. CFW AND HSA NW THRU NE
     COASTS OF VIZ001-002.

&&

MITCHELL

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE SAN JUAN PR
630 AM AST SAT MAR 27 2004

PRZ001>013-AMZ710>750-281000-
630 AM AST SAT MAR 27 2004

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PUERTO RICO.

.TODAY AND TONIGHT...NUMEROUS SHOWERS...OF MODERATE INTENSITY...ARE
EXPECTED ACROSS PUERTO RICO...MAINLY DURING THE MORNING AND
AFTERNOON HOURS...WHERE THERE IS A RISK OF ISOLATED THUNDERSTORMS.
SOME AREAS MAY RECEIVE MODERATE AMOUNTS OF RAIN...BETWEEN ONE AND
TWO INCHES. A SMALL CRAFT ADVISORY...HIGH SURF ADVISORY...AND
COASTAL FLOOD WATCH  ARE IN EFFECT FOR THE LOCAL ATLANTIC WATERS AND
COASTS DUE TO LARGE NORTHEAST SWELLS. THESE SWELLS ARE EXPECTED TO
BE 10 TO 12 FEET...AND ARE LIKELY TO PRODUCE COASTAL FLOODING AND
SIGNIFICANT BEACH EROSION ALONG EXPOSED COAST LINES.

.SPOTTER CALL TO ACTION STATEMENT...
MARINE SPOTTER ACTIVATION IS REQUESTED TODAY.

.SUNDAY THROUGH FRIDAY...A WET AND UNSTABLE WEATHER PATTERN WILL
PREVAIL ACROSS MOST OF THE LOCAL ISLANDS THROUGH THE
WEEKEND. THAT MEANS..MORE CLOUDINESS AND SHOWER ACTIVITY....WITH
ISOLATED THUNDERSTORMS...AND POTENTIAL FOR ISOLATED AREAS OF VERY
HEAVY RAIN. LARGE AND LONG PERIOD SWELLS FROM THE NORTHEAST WILL
AFFECT OUR ATLANTIC COASTAL WATERS THROUGH MONDAY. THIS WILL PRODUCE
VERY DANGEROUS SURF CONDITIONS...AND A GOOD CHANCE FOR COASTAL
FLOODING AND BEACH EROSION ALONG THE NORTH AND NORTHEAST COASTS.

VIZ001-002-AMZ710>730-281000-
630 AM AST SAT MAR 27 2004

THIS HAZARDOUS WEATHER OUTLOOK IS FOR THE U.S. VIRGIN ISLANDS.

.TODAY AND TONIGHT...SCATTERED SHOWERS...OF MODERATE INTENSITY...ARE
EXPECTED ACROSS THE U.S. VIRGIN ISLANDS...WITH RAINFALL AMOUNTS OF
ONE HALF TO TWO INCHES POSSIBLE. A SMALL CRAFT ADVISORY...HIGH SURF
ADVISORY...AND COASTAL FLOOD WATCH  ARE IN EFFECT FOR THE LOCAL
ATLANTIC WATERS AND COASTS DUE TO LARGE NORTH NORTHEAST SWELLS.
THESE SWELLS ARE EXPECTED TO BE 10 TO 12 FEET...AND ARE LIKELY TO
PRODUCE COASTAL FLOODING AND SIGNIFICANT BEACH EROSION ALONG EXPOSED
COAST LINES.

.SPOTTER CALL TO ACTION STATEMENT...
MARINE SPOTTER ACTIVATION IS REQUESTED TODAY.

.SUNDAY THROUGH FRIDAY...A WET AND UNSTABLE WEATHER PATTERN WILL
PREVAIL ACROSS MOST OF THE LOCAL ISLANDS THROUGH THE WEEKEND. THAT
MEANS..MORE CLOUDINESS AND SHOWER ACTIVITY....WITH ISOLATED
THUNDERSTORMS...AND POTENTIAL FOR ISOLATED AREAS OF VERY HEAVY RAIN.
LARGE AND LONG PERIOD SWELLS FROM THE NORTHEAST WILL AFFECT OUR
ATLANTIC COASTAL WATERS FRIDAY THROUGH MONDAY. THIS WILL PRODUCE
VERY DANGEROUS SURF CONDITIONS...AND A GOOD CHANCE FOR COASTAL
FLOODING AND BEACH EROSION ALONG THE NORTH AND NORTHEAST COASTS.

FOR ADDITIONAL INFORMATION...VISIT THE NATIONAL WEATHER SERVICE WEB
SITE FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS AT (ALL LOWERCASE
LETTERS): HTTP://WWW.SRH.NOAA.GOV/SJU.