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000
FXCA62 TJSJ 100002
AFDSJU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
802 PM AST TUE FEB 9 2010

.UPDATE...TOP CONCERN OVER NEXT FEW DAYS WILL BE POTENTIAL FOR MAJOR
SWELL EVENT SETTING UP FOR THIS FRIDAY AND SATURDAY. LOW PRESSURE
SYSTEM OVER EASTERN UNITED STATES WILL EXIT EASTERN SEABOARD AND
RAPIDLY DEEPEN OVER THE OPEN W ATLC DURING NEXT FEW DAYS. STRONG
NORTHWESTERLY WINDS...POSSIBLY APPROACHING 50KT WILL WRAP AROUND THE
SYSTEM THURSDAY AND CREATE A FETCH OF LARGE LONG PERIOD WAVE
ENERGY DESTINED FOR THE LOCAL AREA. FETCH SHOULD BE SUFFICIENT TO
PRESENT GOOD PROBABILITY OF NEARLY 15 FOOT SWELLS AT 15 SECONDS TO
REACH THE LOCAL WATERS. TIMING AND PLACEMENT OF THE FETCH WILL
DETERMINE WHICH AREAS RECEIVE THE GREATEST THREAT...BUT CONDITIONS
LOOK PRIMED FOR 10 TO 15 FOOT SWELLS AT AT LEST 12 TO 15 SECONDS
FOR FRIDAY. IF THAT SITUATION PANS OUT...ITS POSSIBLE THAT LOCAL
REEFS AND STEEP COASTLINES CAN SEE BREAKING WAVES GREATER THAN 20
FEET...WITH EXTREME RIP CURRENT DANGER. 2 TO 3 FEET WAVE RUN UP
IN ADDITION TO A HIGH TIDE OF ABOUT 1.3 FT WILL ALSO CREATE THE
POTENTIAL FOR MODERATE COASTAL FLOODING ALONG THE NORTH COAST.

DECIDED TO ISSUE PNS AND MWS TO GIVE SOME EXTRA LEAD TIME FOR THE
EXPECTED THREAT. WILL EVALUATE THE NEED FOR COASTAL FLOOD WATCH
NEXT FEW SHIFTS.

&&

.AVIATION...VFR CONDITIONS WILL CONTINUE TO PREVAIL ACROSS ALL THE
LOCAL TAF SITES FOR THE NEXT 24 HOURS.THE LOW LEVEL EASTERLY FLOW IS
EXPECTED TO BECOME MORE SOUTHEASTERLY TOMORROW AFTERNOON...BUT FOR
NOW VOLCANIC ASH FROM MONTSERRAT IS EXPECTED TO REMAIN MAINLY SOUTH
OF THE FLYING AREA.



&&

.PREV DISCUSSION... /ISSUED 304 PM AST TUE FEB 9 2010/

SYNOPSIS...BROAD TROUGH WILL DOMINATE THE WESTERN AND CENTRAL ATLANTIC
WITH SUBTROPICAL RIDGE REMAINING SOUTH OF THE AREA. A COLD FRONT
WILL SWEEP THROUGH THE AREA EARLY FRIDAY WITH LARGE NORTH SWELLS
RESULTING IN HAZARDOUS SEAS AND VERY DANGEROUS SURF CONDITIONS
ALONG THE ATLANTIC COASTLINE.

DISCUSSION...MOSTLY SUNNY SKIES PREVAILED ACROSS PUERTO RICO AND
THE U.S. VIRGIN ISLANDS THIS AFTERNOON. DRY CONDITIONS WILL
CONTINUE AT LEAST THROUGH FRIDAY AS A SUBTROPICAL RIDGE CONTINUE
DOMINATING THE LOCAL WEATHER. A COLD FRONT IS EXPECTED TO APPROACH
THE LOCAL AREA FRIDAY...HOWEVER...NO SIGNIFICANT RAINFALL
ACCUMULATION IS EXPECTED AT THIS TIME WITH THIS FEATURE. AFTER THE
PASSAGE OF THIS FRONT...IN THE LONG TERM...NO SIGNIFICANT WEATHER
FEATURE IS NOT EXPECTED TO AFFECT THE LOCAL AREA.

AVIATION...VFR CONDITIONS WILL CONTINUE TO PREVAIL ACROSS ALL THE
LOCAL TAF SITES FOR THE NEXT 24 HOURS. LOW LEVEL EASTERLY WINDS OF
10-15 KTS AND LITTLE SHOWER ACTIVITY EXPECTED.

MARINE...VERY LARGE...AND LONG PERIOD NORTHERLY SWELLS...WILL
GENERATE HAZARDOUS SURF CONDITIONS ALONG THE NORTHERN EXPOSED
COASTLINES OF PUERTO RICO BOTH FRIDAY AND SATURDAY.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU  74  87  73  85 /   0  10   0  20
STT  75  83  76  83 /   0   0   0  20

&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...HIGH SURF ADVISORY UNTIL 10 PM AST THIS EVENING FOR CULEBRA-
     MAYAGUEZ AND VICINITY-NORTH CENTRAL-NORTHEAST-NORTHWEST-SAN
     JUAN AND VICINITY.

VI...HIGH SURF ADVISORY UNTIL 10 PM AST THIS EVENING FOR ST.
     THOMAS/ST. JOHN/ADJACENT ISLANDS.

&&

$$

09/93