Debris Flow in Puerto Rico, May 15, 2004

PUERTO RICO AND U.S. VIRGIN ISLANDS FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
312 AM AST SAT MAY 15 2004

.DISCUSSION...
NWS DOPPLER RADAR SHOWS NUMEROUS SHOWERS WITH EMBEDDED THUNDERSTORMS
JUST NORTH OF PUERTO RICO FROM FAJARDO...WEST THROUGH ARECIBO.
EXPECT SOME OF THIS RAINFALL ACTIVITY TO MOVE INLAND TO AFFECT THE
NORTHERN COASTS AND SLOPES THIS MORNING. WITH SATURATED SOILS...ANY
MODERATE TO HEAVY RAINFALL WITH ACCUMULATIONS OF TWO OR MORE INCHES
WILL PRODUCE FLASH FLOODING. A FLASH FLOOD WATCH REMAINS IN EFFECT
FOR THE EASTERN HALF OF PUERTO RICO...INCLUDING THE ISLANDS OF
VIEQUES...CULEBRA AND THE U.S. VIRGIN ISLANDS THROUGH 600 PM.

GFS MODEL INDICATED THAT ABUNDANT LOW LEVEL MOISTURE WILL CONTINUE
OVER THE LOCAL REGION AT LEAST THROUGH LATE SUNDAY. LOW LEVEL
THETA-E FIELD SHOWS A RIDGE ACROSS THE LEEWARD ISLANDS EXTENDING
WEST THROUGH THE CARIBBEAN ADJACENT COASTAL WATERS. THE BULLS EYE OF
THIS RIDGE WILL SLOWLY MOVE OVER PUERTO RICO AND THE U.S. VIRGIN
ISLANDS THROUGH SUNDAY. SOME MID LEVEL RISING MOTION WILL ACCOMPANY
THIS SURGE OF MOISTURE TODAY INCREASING CONSIDERABLE TONIGHT THROUGH
SUNDAY. ALSO...MODELS SUGGEST SOME UPPER LEVEL DIVERGENCE BY LATE
TONIGHT...INCREASING CONSIDERABLY THROUGH SUNDAY EARLY AFTERNOON. AN
UPPER LEVEL TROPICAL JET IS RESPONSIBLE FOR THIS VERY UNSTABLE
ATMOSPHERIC CONDITIONS.

THESE THREE INGREDIENTS ARE ENOUGH TO PRODUCE A MAJOR FLASH FLOOD
EVENT ACROSS PUERTO RICO AND THE ADJACENT ISLANDS ESPECIALLY ON
SUNDAY. EVEN WORST...SOILS ACROSS MOST PARTS OF PUERTO RICO ARE
SATURATED... INCREASING EVEN MORE THE POTENTIAL FOR A MAJOR FLASH
FLOOD EVENT.

THEREFORE...INCREASED WEATHER...POPS AND QPF ACCORDINGLY FOR TODAY
AND EVEN MORE FOR SUNDAY INCLUDING TORRENTIAL RAIN AND FLOODING IN
THE FORECAST.

&&

.MARINE...
NEAR NORMAL MARINE CONDITIONS WILL PERSIST TODAY WITH SEAS MAINLY
FROM 4 TO 6 FEET ACROSS THE ADJACENT WATERS. HOWEVER...CHOPPY SEAS
AND STRONG GUSTY WINDS WILL OCCUR NEAR THUNDERSTORMS. WINDS ARE
EXPECTED TO INCREASE ON SUNDAY WITH STRONG GUSTY WINDS...TORRENTIAL
RAIN...FREQUENT LIGHTNING AND CHOPPY SEAS. SMALL CRAFT OPERATORS
SHOULD EXERCISE CAUTION TODAY...AND A SMALL CRAFT ADVISORY MAY BE
REQUIRED FOR SUNDAY. MARINERS SHOULD REMAIN IN PORT ON SUNDAY UNTIL
THE THUNDERSTORM ACTIVITY DIMINISH OR MOVE AWAY FROM THE AREA.

/ROCHE

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU  82  75  83  75 /  70 100 100 100
STT  81  74  82  74 /  50 100 100 100

&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...FFA PRZ001>006-012-013.
VI...FFA VIZ001-002.

&&

ROCHE

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE SAN JUAN PR
610 AM AST SAT MAY 15 2004

PRZ001>013-AMZ710>750-161000-
610 AM AST SAT MAY 15 2004

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PUERTO RICO.

.TODAY...THE LOCAL AIRMASS STILL VERY MOIST AND UNSTABLE. RAINFALL
AMOUNTS EVEN IN SMALL QUANTITIES MAY BE SIGNIFICANT SINCE SOILS ARE
VERY SATURATED ESPECIALLY OVER THE NORTH HALF AND EAST SECTIONS.
RIVERS AND STREAMS LEVELS ARE VERY HIGH AND THESE WILL FLOOD WITH
LESSER AMOUNTS OF RAIN OVER THEIR BASINS. LANDSLIDES ARE LIKELY OVER
STEEP TERRAIN. HEAVY RAIN IS EXPECTED ONCE AGAIN TODAY RESULTING IN
FLOODING.

MARINE CONDITIONS WILL CONTINUE ROUGH AND CHOPPY ALONG THE ATLANTIC
AND CARIBBEAN WATERS WITH GOOD CHANCES FOR WATERSPOUTS TO DEVELOP
TOGETHER WITH VERY HEAVY DOWNPOURS AND REDUCED VISIBILITIES.

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

.DAYS TWO THROUGH SEVEN...

ALTHOUGH THE POTENTIAL FOR HEAVY PRECIPITATION AND CHANCES FOR FLASH
FLOODING WILL REMAIN HIGH THROUGH THE WEEK NOW SUNDAY SEEMS TO BE
THE DAY WITH MORE SEVERE WEATHER. THIS INCLUDES VIEQUES AND CULEBRA.
WEATHER THIS DAY MAY BECOME SEVERE. LANDSLIDES ARE LIKELY OVER STEEP
TERRAIN.

A MODERATE TO FRESH WIND FLOW AND CHOPPY SEAS WILL PREVAIL ACROSS
THE LOCAL WATERS WITH GOOD CHANCES FOR WATERSPOUTS....HEAVY
DOWNPOURS AND REDUCED VISIBILITIES.

VIZ001-002-AMZ710>730-161000-
610 AM AST SAT MAY 15 2004

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

.TODAY...CONTINUOUS MODERATE TO HEAVY PASSING SHOWERS WILL LEAD TO
URBAN FLOODING AND POSSIBLE FLASH FLOODING.

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

.DAYS TWO THROUGH SEVEN...

CHANCES FOR PRECIPITATION WILL REMAIN HIGH BUT SUNDAY WEATHER
CONDITIONS MAY BECOME SEVERE. OVER THE WATERS THERE ARE GOOD CHANCES
FOR WATERSPOUT DEVELOPMENT AND VERY HEAVY DOWNPOURS.

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.

RIVERA