Flood in Puerto Rico, May 11, 2004

PUERTO RICO AND U.S. VIRGIN ISLANDS FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
824 PM AST MON MAY 10 2004

.UPDATE...
SATELLITE IMAGES SHOW UPPER LEVEL CLOUDS ADVECTING FROM THE WEST TO
THE FA ATTM. GFS MODEL IN AGREEMENT WITH THIS UPPER LEVEL MOISTURE
IN ASSOCIATION OF AN UPPER LEVEL SHORT WAVE AND JET STREAM.
THEREFORE...INCREASE CLOUD COVER FOR THE REST OF TONIGHT AND
TOMORROW.

IN ADDITION...SINCE MOST SOILS ACROSS THE NORTHERN HALF OF PUERTO
RICO ARE SATURATED DUE TO THE RAINFALL DURING THE PAST FEW DAYS...
AND THE POSSIBILITY OF ADDITIONAL RAINFALL TOMORROW...DECIDED TO
EXTENDED AND EXPANDED THE FLASH FLOOD WATCH TO INCLUDE THE NORTH
CENTRAL...SAN JUAN AND VICINITY...NORTHEAST ...EASTERN AND CENTRAL
INTERIOR SECTIONS THROUGH AT LEAST 11 AM.

/ROCHE

.245 PM DISCUSSION...
12Z SOUNDING MEASURED MAINLY LOW LEVEL MOISTURE OVER THE LOCAL AREA.
THIS LOW LEVEL MOISTURE IS CONVERGING ALONG THE NORTHERN SLOPES OF
THE ISLAND OF PUERTO RICO RESULTING IN A PERSISTENT PATTERN OF
SHOWERS ALONG THE EAST AND CENTRAL SECTIONS OF THE CORDILLERA
CENTRAL. THE SHOWERS ARE NOT AS HEAVY AS THEY WERE YESTERDAY BUT THE
PATTERN IS A VERY SIMILAR ONE.

TUESDAY AN UPPER LEVEL TROUGH IS GOING TO APPROACH FROM THE
SOUTHWEST AND MAY BRING MORE SHOWERS TO THE LOCAL AREA ESPECIALLY
PUERTO RICO. AFTER THAT MODEL GUIDANCE SUGGEST A SERIES OF SHORT
WAVES MOVING THROUGH THE LOCAL AREA CAUSING INSTABILITY AND
PRODUCING DIFLUENCE AND STRONG DIVERGENCE ALOFT AS WELL AS A MORE
SATURATED AIRMASS FROM THE SURFACE TO THE UPPER LEVELS. STRONG
DIVERGENCE AND DIFLUENCE ALOFT TOGETHER WITH ENOUGH MOISTURE WILL
PRODUCE HEAVY RAINFALL AND THUNDERSTORMS. ALTHOUGH THE EXACT TIME OF
OCCURRENCE FOR THESE EVENTS HAVE UNCERTAINTIES...LOOKS LIKE A VERY
WET PATTERN IS AHEAD WITH GOOD CHANCES FOR SEVERE WEATHER.

&&

.MARINE...SURFACE HIGH PRESSURE ACROSS THE W ATLC TO THE WEST OF
CENTRAL ATLC LOW AND LOCAL FRONTAL TROUGH WILL SHIFT EASTWARD INTO
CENTRAL ATLANTIC NEXT 48 HOURS TO MAINTAIN SUFFICIENT PRESSURE
GRADIENT AND FRESH TRADE WIND FLOW...AND LOCALLY ROUGH SEAS OFF
SHORE ATLC. SCA NOW IN EFFECT OFF SHORE ATLC AND PROBABLY SHOULD
HAVE REMAINED IN EFFECT OVERNIGHT. OBSERVATIONS WOULD COME IN HANDY
HERE.

&&

.AVIATION...A WIDE AREA OF UPPER LEVEL CLOUDS OVER THE CARIBBEAN
WATERS IN A CORRIDOR FROM SOUTH OF PUERTO RICO AND HISPANIOLA SOUTH
TO VENEZUELA SHOWS A WAVELIKE PATTERN WHICH SUGGEST SOME TURBULENCE.

&&

.HYDROLOGY...LOCAL SOILS ALONG NE AND N COASTAL MUNICIPALITIES
REMAIN SATURATED WITH MOST RIVER LEVELS HIGH OR NEAR BANKFULL.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU  73  84  73  84 /  40  20  40  40
STT  73  83  73  83 /  40  40  40  40

&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...SCA AMZ730-740.
VI...SCA AMZ730.

&&

RIVERA

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE SAN JUAN PR
610 AM AST MON MAY 10 2004

PRZ001>013-AMZ710>750-111000-
610 AM AST MON MAY 10 2004

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PUERTO RICO.

.TODAY...MOISTURE ASSOCIATED WITH THE REMNANTS OF A COLD FRONTAL
BOUNDARY...WILL COMBINE WITH STRONG NORTHEAST WINDS AND LOCAL
EFFECTS TO PRODUCE SCATTERED TO NUMEROUS SHOWERS AND ISOLATED
THUNDERSTORMS. SHOWERS WILL INITIALLY AFFECT THE NORTHERN SLOPES
FROM THE NORTHEAST THROUGH THE NORTH CENTRAL...AND THEN WILL BECOME
MORE GENERALIZED THIS AFTERNOON. LOCALIZED HEAVY RAINS WILL CONTINUE
ALONG THE NORTHEAST THIS MORNING WITH THE POTENTIAL FOR FLASH
FLOODING AND SMALL STREAM FLOODING. HEAVIER RAINS THIS AFTERNOON
WILL SHIFT TO THE INTERIOR AND WEST PART OF PUERTO RICO. RIVERS
ACROSS THE NORTH CENTRAL WILL EXPERIENCE SIGNIFICANT RISES THROUGH
THIS EVENING.

MARINE CONDITIONS WILL REMAIN UNSETTLED DUE TO STRONG AND GUSTY
NORTHEAST WINDS.

.SPOTTER CALL TO ACTION STATEMENT...
SPOTTER ACTIVATION MAY BE REQUIRED.

.DAYS TWO THROUGH SEVEN...

TYPICAL WET CONDITIONS FOR THE MONTH OF MAY SHOULD BE EXPECTED WITH
SCATTERED TO NUMEROUS SHOWERS AND ISOLATED AFTERNOON THUNDERSTORMS.
CONDITIONS WILL DETERIORATE EVEN MORE THURSDAY THROUGH FRIDAY AS
UPPER LEVEL CONDITIONS BECOME MORE FAVORABLE FOR SHOWERS AND
THUNDERSTORMS.

A MODERATE TO FRESH WIND FLOW AND CHOPPY SEAS WILL PREVAIL ACROSS
THE LOCAL WATERS UNTIL WEDNESDAY.

VIZ001-002-AMZ710>730-111000-
610 AM AST MON MAY 10 2004

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

.TODAY...SCATTERED SHOWERS WILL OCCUR ACROSS THE TERRITORY. LIGHT TO
MODERATE RAINFALL ACCUMULATIONS SHOULD BE EXPECTED. ASSOCIATED
RAINFALL COULD RESULT IN SOME URBAN AND GUT FLOODING. STRONG AND
GUSTY NORTHEAST WINDS WILL MAINTAIN UNSETTLED MARINE CONDITIONS.

.SPOTTER CALL TO ACTION STATEMENT...
SPOTTER ACTIVATION IS NOT ANTICIPATED.

.DAYS TWO THROUGH SEVEN...

SCATTERED SHOWERS WILL OCCUR ACROSS THE U.S. VIRGIN ISLANDS DURING
THE REST OF TIS WEEK. SHOWERS SHOULD BECOME MORE NUMEROUS ON
THURSDAY AND FRIDAY AS A MID TO UPPER LEVEL TROUGH APPROACHES FROM
THE NORTHWEST.

A MODERATE TO FRESH WIND FLOW AND CHOPPY SEAS WILL PREVAIL ACROSS
THE LOCAL WATERS UNTIL WEDNESDAY.

STAY TUNED TO NOAA WEATHER RADIO AND OTHER LOCAL MEDIA FOR FURTHER
DETAILS OR UPDATES.

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.

RM