Severe Thunderstorm Warning 5, NWS JSJ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
308 PM AST THU OCT 8 2009

.SYNOPSIS...
MID TO UPPER LEVEL RIDGE ACROSS THE WESTERN ATLANTIC...
WILL CONTINUE TO BUILD EASTWARD ACROSS THE NORTHEAST CARIBBEAN
THROUGH THE UPCOMING WEEKEND. TROPICAL DEPRESSION HENRI LOCATED
NEAR 19.8 NORTH 62.0 WEST AT 11 AM AST...CONTINUED TO WEAKEN AND
BECOME MORE DISORGANIZED WHILE MOVING WEST AROUND 13 MPH. MAXIMUM
SUSTAINED WIND WERE NOW NEAR 35 MPH BASED ON INFORMATION FROM THE
NATIONAL HURRICANE CENTER IN MIAMI. HENRI IS STILL EXPECTED TO
DISSIPATE AND BECOME OPEN AREA OF LOW PRESSURE AS IT CONTINUES
WESTWARDS OVER THE NEXT FEW DAYS. A TROPICAL WAVE NOW NEAR 56 WEST
WILL CROSS THE LESSER ANTILLES OVERNIGHT THROUGH FRIDAY MORNING...
THEN MOVE ACROSS THE EASTERN CARIBBEAN FRIDAY AFTERNOON THROUGH
SATURDAY. SATELLITE IMAGERY SHOWED LARGE AREA OF SAL/DRY AIR
TRAILING THE ABOVE MENTIONED FEATURES ACROSS THE TROPICAL
ATLANTIC. MEANWHILE REMNANTS OF A COLD FRONT CONTINUED TO SINK
SOUTHWARDS ACROSS THE WEST CENTRAL ATLANTIC AS STRONG HIGH
PRESSURE QUICKLY BUILDS INTO THE SOUTHWEST ATLANTIC.

&&

.DISCUSSION...
OVERALL DRY AND SUBSIDENCE AIR ALOFT OVER THE REGION...AND NO
SIGNIFICANT LOW LEVEL MOISTURE ADVECTION OVER AREA TODAY...LIMITED
SHOWERS AND ISOLATED THUNDERSTORMS DEVELOPMENT TO THE SOUTHWEST
AND SOUTHERN SLOPES OF PUERTO RICO AS WELL AS IS ISOLATED SPOTS
OVER THE VIRGIN ISLANDS TODAY.

AFTERNOON CLOUDINESS AND CONVECTION IS EXPECTED TO DISSIPATE AND
DIMINISH AFTER SUNSET LEAVING CLEAR TO PARTLY CLOUDY SKIES FOR THE
REST OF THE EVENING AND AT LEAST THROUGH FRIDAY MORNING. ONLY
PASSING SHOWERS ARE FORECAST TO REACH THE NORTH AND NORTHEAST
COASTAL AREAS OF PUERTO RICO...AND PARTS OF THE VIRGIN ISLANDS
DURING THE EARLY MORNING HOURS.

HOWEVER...EXPECT INCREASING TROPICAL MOISTURE ACROSS THE AREA BY LATE
FRIDAY AFTERNOON AND INTO SATURDAY AS REMNANTS FROM HENRI MERGES
WITH THAT OF THE TROPICAL WAVE FORECAST TO MOVE ENTER THE EASTERN
CARIBBEAN ON FRIDAY. THIS WILL LEAD TO INCREASED CLOUDINESS WITH
BETTER CHANCES FOR DAYTIME AND EARLY MORNING CONVECTION ACROSS THE
ISLANDS AND SURROUNDING WATERS. THIS IN TURN WOULD INCREASE THE
POTENTIAL FOR URBAN AND SMALL STREAM FLOODING ACROSS PARTS OF
PUERTO RICO AND THE VIRGIN ISLANDS ESPECIALLY LATE FRIDAY AND
OVERNIGHT THROUGH AT LEAST SATURDAY AFTERNOON.

THEREAFTER...GRADUAL DRYING TREND IS EXPECTED ON SUNDAY THROUGH
BEGINNING OF THE NEXT WORK WEEK AS THE LOCAL LEVEL WIND FLOW
BECOMES MORE NORTHEASTERLY AND A SLIGHTLY COOLER AND DRIER AIR
MASS FILTERS IN ACROSS THE AREA AND WILL PREVAIL THROUGH AT
LEAST WEDNESDAY.

&&

.AVIATION...OVERALL VFR CONDITIONS ARE EXPECTED ACROSS ALL LOCAL
TAF SITES FOR THE NEXT 12 TO 24 HOURS WITH ONLY PASSING ISOLATED
TO SCATTERED SHOWERS FROM TIME TO TIME THAT COULD BRIEFLY REDUCE
VISIBILITIES AND CEILINGS TO MVFR CONDITIONS MAINLY OVER THE USVI.

FOR NOW THROUGH 08/22Z...TEMPO MVFR CONDITIONS ARE EXPECTED ACROSS
AND AROUND TJMZ...AND THE SOUTHERN SLOPES OF PR...AS SHRA AND
ISOLD TSTMS WILL AFFECT THE WESTERN COAST OF PR.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU  78  88  78  87 /  30  60  60  60
STT  79  87  80  86 /  30  70  70  70

&&

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

17/09

HAZARDOUS WEATHER OUTLOOK FOR PUERTO RICO AND THE U.S. VIRGIN
ISLANDS
NATIONAL WEATHER SERVICE SAN JUAN PR
433 AM AST THU OCT 8 2009

AMZ710>745-PRZ001>013-091000-
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-
433 AM AST THU OCT 8 2009

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

.DAY ONE...TODAY AND TONIGHT

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY

MOISTURE FROM REMNANTS OF TROPICAL DEPRESSION HENRI MAY LEAD TO AN
INCREASE IN THUNDERSTORM ACTIVITY AND MINOR FLOODING THREATS
FRIDAY AND SATURDAY.

.SPOTTER INFORMATION STATEMENT...

AMZ715-725-VIZ001-002-091000-
ST. THOMAS ST. JOHN ADJACENT ISLANDS-ST CROIX-
NEARSHORE ATLANTIC AND ADJACENT CARIBBEAN COASTAL WATERS-
433 AM AST THU OCT 8 2009

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

.DAY ONE...TODAY AND TONIGHT

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY

MOISTURE FROM REMNANTS OF TROPICAL DEPRESSION HENRI MAY LEAD TO AN
INCREASE IN THUNDERSTORM ACTIVITY AND MINOR FLOODING THREATS
FRIDAY AND SATURDAY.

.SPOTTER INFORMATION STATEMENT...