Heavy Rain in Puerto Rico, June 8, 2009

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE SAN JUAN PR
1217 PM AST MON JUN 8 2009

.UPDATE...EXPECT A MIXTURE OF CLOUDINESS AND SOME SUNSHINE ACROSS
THE LOCAL ISLANDS THIS AFTERNOON. SCATTERED TO NUMEROUS SHOWERS
AND ISOLATED TO LOCALLY SCATTERED THUNDERSTORMS WILL CONTINUE TO
DEVELOP...AS MOISTURE ASSOCIATED WITH PASSING TROPICAL WAVE
INTERACTS WITH LOCAL EFFECTS. WE HAVE HIGHEST POPS OVER THE
CENTRAL AND WESTERN INTERIOR...NORTH CENTRAL...WEST AND NORTHWEST
SECTIONS OF PUERTO RICO AND ACROSS PARTS OF THE SAN JUAN METRO
AREA. PERIODS OF HEAVY RAINFALL AND MINOR LOW LYING FLOODING ARE
EXPECTED IN A FEW LOCATIONS...WITH SOME FLASH AND RIVER FLOODING
POSSIBLE AND WE HAVE ISSUED A FLASH FLOOD WATCH FOR PARTS OF ZONES
1...5...6...8...9 AND 10 UNTIL 600 PM AST TO ACCOUNT FOR THIS.
INHERITED SHORT TERM GRIDS AND ZFP HAD A GOOD HANDLE ON EXPECTED
CONDITIONS FOR THIS AFTERNOON...BUT SENT A QUICK UPDATE TO BOTH
TO ALTER WEATHER...SKY COVER...POPS AND WINDS IN SEVERAL ZONES AND
TO HEADLINE AFOREMENTIONED FFA. FOR THE COASTAL WATERS...MADE A
COUPLE OF SEMANTIC ALTERATIONS TO THE PREVIOUS CWF...MAINLY TO THE
SYNOPSIS...OTHERWISE NO CHANGES. AVIATION-WISE...PREVAILING VFR
CONDITIONS WILL CONTINUE ACROSS THE LOCAL ISLANDS AND AT ALL LOCAL
TAF SITES THIS AFTERNOON...EXCEPT BRIEF MVFR CONDITIONS AND LOCAL
MOUNTAIN OBSCURATIONS WILL OCCUR IN SHRA AND TSRA./ BCS

REMAINDER BELOW UNCHANGED FROM THE MIDNIGHT SHIFT.

&&

.PREV DISCUSSION... /ISSUED 620 AM AST MON JUN 8 2009/

SYNOPSIS...TROPICAL WAVE MOVING SOUTH OF THE LOCAL AREA TODAY.
HIGH PRESSURE ACROSS THE CENTRAL ATLANTIC WILL SHIFT SLOWLY EAST
THE NEXT COUPLE OF DAYS. UPPER LEVEL LOW WILL WEAKEN NORTHEAST OF THE
LOCAL AREA. UPPER LEVEL RIDGE WILL DOMINATE THE LOCAL AREA THROUGH
AT LEAST FRIDAY.

DISCUSSION...SHOWERS AND ISOLATED THUNDERSTORMS HAVE BEEN
INCREASING EARLY THIS MORNING ACROSS THE LOCAL WATERS...MAINLY
SOUTH OF THE LOCAL AREA. OVERNIGHT...A LINE OF HEAVY SHOWERS WITH
EMBEDDED THUNDERSTORMS WAS ALIGNED EAST OF SAINT CROIX...EXTENDING
NORTHWEST THROUGH SAINT THOMAS AND SAINT JOHN...IN THE U.S. VIRGIN
ISLANDS. HOWEVER...DURING THE MORNING HOURS JUST BEFORE
SUNSET...THIS LINE OF SHOWERS HAS WEAKEN CONSIDERABLY...LEAVING
THE AREA WITH SCATTERED SHOWERS. ACROSS PUERTO RICO...DOPPLER
RADAR DETECTED SOME SHOWERS BRUSHING THE NORTHEAST
COAST...AFFECTING FROM TIME TO TIME THE MUNICIPALITIES OF
FAJARDO...LUQUILLO...AND RIO GRANDE. THIS ACTIVITY IS ASSOCIATED
WITH A TROPICAL WAVE LOCATED EARLY THIS MORNING NEAR 66W
LONGITUDE. THIS WAVE DOESNT LOOK TOO IMPRESSIVE IN INFRARED
SATELLITE IMAGES. HOWEVER...LATEST CIMSS MIMIC TPW PRODUCT SHOWS
AMPLE MOISTURE ASSOCIATED WITH THIS WAVE...WITH PRECIPITABLE
WATER VALUES RANGING BETWEEN 1.80-2.15 INCHES. MOST OF THIS
MOISTURE WILL REMAIN SOUTH OF THE LOCAL AREA. ALTHOUGH LATEST
WATER VAPOR IMAGES SHOWS SOME SUBSIDENCE AIR INTRUSION ACROSS THE
LOCAL AREA FROM THE NORTHEAST...LOW LEVEL MOISTURE WILL BE ENOUGH
ACROSS THE LOCAL AREA...TO COMBINE WITH DAYTIME HEATING AND
OROGRAPHIC EFFECTS...TO PRODUCE SCATTERED TO NUMEROUS SHOWERS WITH
ISOLATED THUNDERSTORMS ACROSS THE LOCAL AREA. AFTER THE PASSAGE OF
THIS WAVE...SURFACE HIGH PRESSURE WILL BUILD ACROSS THE NORTH
CENTRAL ATLANTIC...WHICH WILL PRODUCE A MODERATE TO FRESH TRADE
WIND FLOW ACROSS THE LOCAL AREA.

IN THE LONG TERM...AN UPPER LEVEL LOW CURRENTLY NORTHEAST OF THE
LOCAL AREA...IS EXPECTED TO MOVE SLOWLY NORTHEAST...AND WEAKENING.
IN THE MEANTIME...UPPER LEVEL RIDGE IS EXPECTED TO DOMINATE THE
LOCAL AREA AT LEAST THROUGH FRIDAY. FOR NEXT WEEKEND...COMPUTER
MODELS SUGGEST THAT THIS UPPER LEVEL RIDGE WILL BE REPLACE BY AN
UPPER LEVEL THROUGH THAT IS FORECAST TO DEVELOP ACROSS THE WESTERN
ATLANTIC. THE POSITION OF THIS THROUGH WILL BE A KEY PLAYER IN THE
WEATHER FORECAST FOR NEXT WEEK. OVERALL...LOOKS LIKE THE WEATHER
PATTERN ACROSS THE LOCAL AREA WILL BE DOMINATE BY LOCAL EFFECTS
WITH ISOLATED SHOWERS DURING THE MORNING HOURS...WITH SCATTERED
SHOWERS WITH THUNDERSTORMS EVERY AFTERNOON MAINLY ACROSS THE
CORDILLERA CENTRAL.

AVIATION...A WEAK TROPICAL WAVE IS PASSING SOUTH OF THE AREA AND
WILL SPREAD MOISTURE AND CLOUDS OVER THE ISLAND OF PUERTO RICO.
CONDITIONS WILL BEGIN VFR...BUT UNSTABLE CONDITIONS WILL GENERATE
SHOWER AND THUNDERSTORMS OVER MUCH OF THE INTERIOR AND NORTHWEST
SECTIONS OF PUERTO RICO BEGINNING ABOUT 08/15Z OVER PARTS OF THE
ISLAND AND CAUSING MVFR CONDITIONS AT TJMZ AND TJBQ AND MOUNTAIN
OBSCURATIONS BY 08/17Z LASTING THROUGH 09/04Z.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU  86  78  87  78 /  60  40  50  50
STT  86  78  83  78 /  40  30  30  40

&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...FLASH FLOOD WATCH UNTIL 6 PM AST THIS EVENING FOR CENTRAL
     INTERIOR-MAYAGUEZ AND VICINITY-NORTH CENTRAL-NORTHWEST-SAN
     JUAN AND VICINITY-WESTERN INTERIOR.

VI...NONE.
&&

HAZARDOUS WEATHER OUTLOOK FOR PUERTO RICO AND THE U.S. VIRGIN
ISLANDS
NATIONAL WEATHER SERVICE SAN JUAN PR
602 AM AST MON JUN 8 2009

AMZ710>745-PRZ001>013-091015-
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-
602 AM AST MON JUN 8 2009

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

.DAY ONE...TODAY AND TONIGHT
A WEAK TROPICAL WAVE WILL SPREAD INCREASED MOISTURE OVER PUERTO
RICO BRINGING LOCALLY HEAVY RAINS TO PARTS OF NORTHWEST AND NORTH
CENTRAL PUERTO RICO AND INTERIOR ZONES. SHOWERS WILL BE ACCOMPANIED BY
SOME THUNDERSTORMS. SOME SMALL STREAM AND URBAN AREAS WILL SEE
FLOODING TODAY.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY
MOISTURE CONTINUES BEHIND THE WAVE IN A SIMILAR WIND FLOW SO THAT
SHOWERS AND THUNDERSTORMS WILL CAUSE LOCAL FLOODING OF SMALL
STREAMS AND URBAN AREAS. SHOWERS WILL DECREASE AFTER WEDNESDAY BUT
SOME AREAS WILL STILL RECEIVE LOCALLY HEAVY RAIN EACH DAY.

.SPOTTER INFORMATION STATEMENT...SPOTTER ACTIVATION MAY BE
NECESSARY. RAIN REPORTS ARE WELCOME.

AMZ715-725-VIZ001-002-091015-
ST. THOMAS ST. JOHN ADJACENT ISLANDS-ST CROIX-
NEARSHORE ATLANTIC AND ADJACENT CARIBBEAN COASTAL WATERS-
602 AM AST MON JUN 8 2009

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

.DAY ONE...TODAY AND TONIGHT
NO HAZARDOUS WEATHER IS EXPECTED.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY
SOME LOCALLY HEAVY RAIN MAY OCCUR ON WEDNESDAY...BUT NO HAZARDOUS
WEATHER IS EXPECTED.

.SPOTTER INFORMATION STATEMENT...SPOTTER ACTIVATION IS NOT EXPECTED.