Flash Flooding in Puerto Rico, June 11, 2005

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
615 AM AST SAT JUN 11 2005

.DISCUSSION...
FLASH FLOOD WATCH WAS DISCONTINUED FOR W AND NW SECTIONS OF P.R.
OVERNIGHT AND FOR THE REMAINDER OF THE LOCAL AREA THIS MORNING AS
DOPPLER RADAR INDICATING A DECREASING TREND IN WEATHER OVER THE
ISLANDS...WHILE CONVECTION PERSISTS OVER PORTIONS OF THE OFF SHORE
WATERS. A QUIET MORNING WITH PERIODS OF FILTERED SUN SHOULD GIVE WAY
TO ANOTHER ACTIVE AFTERNOON...WITH A CHANCE FOR ACTIVE NOCTURNAL
WEATHER TONIGHT.

LOCAL AREA NOW FALLS IN BETWEEN TWO VERY WET LLVL TROUGHS. ONE...THE
LLVL TROUGH OF WHATEVER ORIGIN THAT MOVED THROUGH YESTERDAY...
LEAVING A SOUTHEASTERLY LLVL WIND FLOW IN ITS WAKE...AND THE SECOND
A TROPICAL WAVE APPROACHING THE LESSER ANTILLES AND GETTING SHEARED
STRONGLY. THIS HAS LEFT DRIER SLIGHTLY MORE STABLE LLVL AIR ACROSS
THE LOCAL AREA IN BETWEEN THESE TWO FEATURES...ALSO BEING STABILIZED
BY DRY MID LVL AIR ADVECTING IN FROM THE NORTH AND ASSOCIATED WITH
TUTT LOW TO OUR NNE THIS MORNING. FURTHER...A JET STREAK DIVING
THROUGH THE BASE OF A BROAD UPPER TROUGH ACROSS THE REGION HAS
PRODUCED UPPER CONVERGENCE ACROSS PUERTO RICO AND THE MONA PASSAGE
OVERNIGHT...AND HAS SHEARED BANDS OF SHOWERS AND THUNDERSTORMS
MOVING NW INTO THE E AND SE COAST OF P.R. SO STRONGLY THAT THEY HAVE
DISSIPATED UPON REACHING THE ISLAND. DEEP CONVECTION PERSISTS THIS
MORNING TO THE NORTH OF THE VIRGIN ISLANDS UNDER THE RIGHT REAR QUAD
OF THIS JET STREAK...AND ACROSS THE CARIB WATERS SOUTH OF THE MONA
PASSAGE AND SANTO DOMINGO...UNDER DIFFLUENT UPPER FLOW...AND IN THE
VICINITY OF THE SOUTH PORTION OF THE ABOVE FIRST LLVL TROUGH. THE
GFS CONTINUES TO FORECAST THE TUTT TO SINK SW OVER THE NEXT COUPLE
OF DAYS...AND OUR UPPER FLOW SHOULD VEER TO A MORE WESTERLY
DIRECTION...LESSENING THE SHEAR...WITH UPPER DIVERGENCE DEVELOPING
MUCH CLOSER TO THE LOCAL AREA. INCREASING MID LVL MOISTURE AND
ASSOCIATED INSTABILITY COUPLED WITH DAYTIME HEATING AND LOCAL
EFFECTS...BOTH DIURNAL AND NOCTURNAL...SHOULD LEAD TO THE MORE
ACTIVE WEATHER THAT WE HAVE FORECAST...BEGINNING THIS AFTERNOON...
AND CONTINUING IN SPURTS TONIGHT THROUGH SUNDAY. DUE TO THIS...A
FLASH FLOOD WATCH IS LIKELY TO BE REISSUED FOR PORTIONS OF THE LOCAL
AREA BY THIS AFTERNOON.

&&

.MARINE...
SE LLVL WIND SURGE DID ACCOMPANY THE LLVL TROUGH MOVING THROUGH THE
AREA YESTERDAY AFTERNOON AND LAST NIGHT BUT WAS LARGELY CONFINED TO
THE LOCAL CARIBBEAN WATERS AS SUGGESTED BY EVENING QUIKSCAT PASS.
WINDS WILL LIKELY REMAIN STRONGER ACROSS OUR SW CARIB WATERS NEXT 2
DAYS AS WE REMAIN IN THIS SE LLVL WIND FLOW PARTLY INDUCED BY THE
SYNOPTIC PATTERN OF ARLENE IN THE GULF AND HIGH PRESSURE IN THE
CENTRAL ATLANTIC. GFS CONTINUES TO FORECAST STRONG SE WIND SURGES
MOVING THROUGH THE CARIBBEAN WITH EACH PERTURBATION AND FIND THIS
HARD TO SWALLOW...SO HAVE GONE WITH A BLEND OF THE ETA AND GFS FOR
WIND FORECASTS THE NEXT 3 DAYS. LAST 2 RUNS OF GFS ALSO FORECASTING
ANOTHER TROPICAL CYCLONE LIFTING OUT OF THE DEEP CENTRAL CARIB AND
INTO THE SW ATLC MONDAY THROUGH WEDNESDAY...BUT PREFER TO WAIT ON A
CONCRETE FEATURE TO EVOLVE BEFORE GOING WITH THIS.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU  88  77  89  77 /  70  60  60  30
STT  87  80  87  80 /  70  60  60  40

&&

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

&&

70

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE SAN JUAN PR
PRZ001>013-AMZ710>750-121000-
600 AM AST SAT JUN 11 2005

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PUERTO RICO.

.TODAY AND TONIGHT...UNSTABLE ATMOSPHERIC CONDITIONS AND ABUNDANT
MOISTURE WILL CONTINUE TO PRODUCE ACTIVE WEATHER OVER PUERTO
RICO...CULEBRA AND VIEQUES FOR SATURDAY AND SUNDAY.
HOWEVER...SATELLITE IMAGERY THIS MORNING SHOWS DRIER AIR TRYING TO
COME IN FROM THE NORTH OF PUERTO RICO. THIS FEATURE WILL LIMIT THE
SHOWERS ACTIVITY DURING THE MORNING EARLY HOURS. EXPECT A MIX OF
CLOUDS AND SUNSHINE DURING THE FIRST PART OF THE DAY...THEN AN
INCREASE OF CLOUDINESS IN THE AFTERNOON WITH THE COMBINATION OF
DIURNAL HEATING AND OROGRAPHIC EFFECTS TO RESULT IN SHOWERS AND
ISOLATED THUNDERSTORMS MOVING ACROSS THE LOCAL AREA.

.SPOTTER CALL TO ACTION STATEMENT...
SPOTTER ACTIVATION NOT ANTICIPATED AT THIS TIME.

.DAYS TWO THROUGH SEVEN...
A DRIER AND MORE STABLE ATMOSPHERE IS EXPECTED FOR THE UPCOMING
WEEK. HIGH PRESSURE WILL BE IN DOMAIN. EXPECT NORMAL AFTERNOON
SHOWERS ACTIVITY DUE TO LOCAL EFFECTS AND DIURNAL HEATING. NO SIGN
OF HAZARDOUS WEATHER FOR THE NEXT 7 DAYS IS IN THE FORECAST.

VIZ001-002-AMZ710>730-121000-
600 AM AST SAT JUN 11 2005

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

.TODAY AND TONIGHT...UNSTABLE ATMOSPHERIC CONDITIONS AND ABUNDANT
MOISTURE WILL CONTINUE TO PRODUCE ACTIVE WEATHER OVER THE U.S.
VIRGIN ISLANDS ON SATURDAY AND SUNDAY. HOWEVER...SATELLITE IMAGERY
THIS MORNING SHOWS DRIER AIR TRYING TO COME IN FROM THE NORTH OF
PUERTO RICO. THIS FEATURE WILL LIMIT THE SHOWERS ACTIVITY DURING THE
MORNING EARLY HOURS TO THE LOCAL ISLANDS.

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

.DAYS TWO THROUGH SEVEN...
EXPECT A DRIER AND STABLE ATMOSPHERE FOR THE UPCOMING WEEK...WHILE
HIGH PRESSURE DOMINATES THE WEATHER CONDITIONS OVER THE U.S. VIRGIN
ISLANDS. IF POSSIBLE TO SEE SOME SHOWERS MAINLY IN THE AFTERNOON
HOURS...BUT NO SIGN OF HAZARDOUS WEATHER FOR THE NEXT 7 DAYS IS
IN THE FORECAST.

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.