Flash Flood Warning 85, NWS JSJ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
335 PM AST FRI NOV 7 2008

.SYNOPSIS...A LOW LEVEL TROUGH JUST NORTH OF HISPANIOLA WITH AXIS
EXTENDING SOUTHEASTWARD INTO THE VI HAS REMAINED NEARLY STATIONARY
OVER THE LAST FEW DAYS. THIS TROUGH AXIS IS ON THE EASTERN EDGE OF
AN U/L HIGH PRESSURE SYSTEM OVER THE CENTRAL CARIBBEAN...WHICH
WILL SHIFT SLOWLY WESTWARD AND WEAKEN OVER THE NEXT FEW DAYS AS
HURRICANE PALOMA MOVES NORTH TOWARD CUBA. EXPECT A VERY WEAK
SOUTHEASTERLY WIND FLOW OVER THE NEXT TWO DAYS...WITH SCATTERED SHOWERS
AND ISOLATED THUNDERSTORMS OVER THE VI AS WELL AS INTERIOR PUERTO
RICO FOR THE REMAINDER OF THIS AFTERNOON AND SATURDAY AFTERNOON.
THESE STORMS WILL BE VERY SLOW MOVING AND LIKELY TO PRODUCE
ISOLATED AREAS OF HEAVY RAINFALL. A DRIER AIR MASS WILL MOVE OVER
THE LOCAL AREA TUESDAY...AND LIMIT SHOWER ACTIVITY.

&&

.DISCUSSION...LATEST SATELLITE IMAGERY SHOWS WEAK LOW LEVEL
CYCLONIC TURNING OVER THE ATLC WATERS JUST NORTH OF HISPANIOLA
THIS AFTERNOON WITH CONVERGENT AXIS EXTENDING SE OVER THE VI. GUIDANCE
HAS BEEN TOO FAST TO BRING THIS TROUGH AXIS WESTWARD ACROSS PR FOR
A DAY OR SO. ALSO OF NOTE IS THAT THE NAM12 MODEL SPINS UP AN LOW
LEVEL VORT SOUTH OF THE ISLAND OVER THE CARIBBEAN WATERS...AND
TAKES THE BULK OF THE MOISTURE WITH IT...SOUTH OF THE AREA THROUGH
SATURDAY. THIS SCENARIO DOES NOT APPEAR TO BE INITIALIZING
WELL...AS BEST MOISTURE APPEARS TO BE NORTH OF THE FORECAST AREA.
WILL GO WITH A VERY WEAK SOUTHEASTERLY FLOW REGIME WITH MOISTURE
ADVECTION CONTINUING TO MOVE WESTWARD...VERY SLOWLY OVER THE
FORECAST AREA THROUGH AT LEAST SUNDAY...MAYBE EVEN MONDAY.
CONSIDERING THE WEAK FLOW...MOISTURE CONVERGENCE WILL CONTINUE TO
SETUP ALONG MOST OF INTERIOR PR AND THE VI WITH ISOLATED AREAS OF
HEAVY RAIN EACH AFTERNOON THROUGH SUNDAY OR MONDAY. SEVERAL RIVERS
ALONG INTERIOR AND WESTERN PUERTO RICO WERE NEAR MINOR FLOOD STAGE
WITH YESTERDAYS HEAVY RAINS...SO EXPECT ADDITIONAL RAINFALL TO
RAPIDLY RESULT IN FLOODING OF RIVERS...STREAMS AND LOW LYING
AREAS.

HEADING INTO TUESDAY NEXT WEEK...A PATTERN CHANGE IS EXPECTED AS A
TUTT DIGS INTO THE TROPICAL ATLANTIC NEAR 50W/20N AND ADVECTS A
MUCH DRIER AIR MASS INTO THE REGION.

&&

.AVIATION...SCT AFTERNOON MVFR RW/TRW WILL PERSIST ACROSS PUERTO
RICO THROUGH 23Z WHILE DRIFTING WNW NEAR 5 KT...ISOLD IFR CONDS AND
TOPS AOA 40K FT. WHILE VFR CONDS ARE DOMINATING AT MOST PR SITES
ATTM... PERIODS OF MVFR CONDS ARE LIKELY TO AFFECT TJSJ..TJBQ..AND
TJMZ THRU 23Z. SCT MVFR RW CURRENTLY SPREAD NNW TO SSE ACROSS THE
VIRGIN ISLANDS AND ADJACENT WATERS WILL ALSO INDUCE BRIEF MVFR CONDS
AT TIST AND TISX THROUGH 02Z BEFORE CLEARING OCCURS. THIS MVFR RW
ACTIVITY WILL GRADUALLY SHIFT W THROUGH THE EVENING AND POTENTIALLY
AFFECT TJSJ 00-06Z.

&&

.MARINE...TRANQUIL SEAS EXPECTED NEXT 7 DAYS...WITH A VERY LIGHT
WIND FLOW OVER THE LOCAL WATERS. ONLY CHANGE OF NOTE IS A MINOR
NORTHEASTERLY SWELL OF ABOUT 4 FEET AT 10 SECONDS WHICH WILL MOVE
ACROSS THE ATLC WATERS AND ANEGADA PASSAGE DURING THE DAY SUNDAY.
NOT EXPECTING ANY SCA OR HIGH SURF ADVISORY CRITERIA NEXT 7 DAYS.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU  76  87  76  86 /  40  20  30  30
STT  75  87  75  87 /  50  40  40  30

&&

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

70/93/

HAZARDOUS WEATHER OUTLOOK FOR PUERTO RICO AND THE U.S. VIRGIN
ISLANDS
NATIONAL WEATHER SERVICE SAN JUAN PR
624 AM AST FRI NOV 7 2008

AMZ710>745-PRZ001>013-081030-
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-
624 AM AST FRI NOV 7 2008

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

.DAY ONE...TODAY AND TONIGHT
A SLOW MOVING TROUGH TO THE EAST OF PUERTO RICO WILL SPREAD
MOISTURE ACROSS THE LOCAL AREA TODAY CAUSING SHOWERS AND
THUNDERSTORMS...ESPECIALLY IN WESTERN PUERTO RICO. THERE LOCAL
URBAN AND SMALL STREAM FLOODING COULD BE A PROBLEM AND MAIN STEM
RIVERS COULD FIND THE ADDITIONAL WATER SUFFICIENT TO PRODUCE MINOR FLOODING.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY
A SLOW MOVING TROUGH TO THE EAST OF PUERTO RICO WILL SPREAD
MOISTURE ACROSS THE LOCAL AREA SATURDAY AND SUNDAY CAUSING SHOWERS AND
THUNDERSTORMS...ESPECIALLY IN WESTERN PUERTO RICO. THERE LOCAL
URBAN AND SMALL STREAM FLOODING COULD BE A PROBLEM AND MAIN STEM
RIVERS COULD FIND THE ADDITIONAL WATER SUFFICIENT TO PRODUCE MINOR FLOODING.

.SPOTTER INFORMATION STATEMENT...REPORTS OF FLOODED STREAMS AND
RIVERS ARE WELCOME.

AMZ715-725-VIZ001-002-081030-
ST. THOMAS ST. JOHN ADJACENT ISLANDS-ST CROIX-
NEARSHORE ATLANTIC AND ADJACENT CARIBBEAN COASTAL WATERS-
624 AM AST FRI NOV 7 2008

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...SATURDAY THROUGH THURSDAY

NO HAZARDOUS WEATHER IS EXPECTED.

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