Area Forecast Discussion
Issued by NWS San Juan, PR

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FXCA62 TJSJ 111437
AFDSJU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
1037 AM AST THU FEB 11 2016

.UPDATE...SOME LIGHT PASSING SHOWERS WERE NOTED OVER THE CARIBBEAN
COASTAL WATERS. MEANWHILE...MOSTLY SUNNY SKIES PREVAILED OVER LAND
AREAS. NO CHANGES WERE NEEDED TO FORECAST GRIDS THIS MORNING AS
FORECAST IS ON TRACK WITH ONGOING WEATHER SITUATION.

&&

.AVIATION...VFR CONDITIONS ARE EXPECTED TO PREVAIL DURING THE NEXT
24 HOURS AT ALL TERMINALS. HOWEVER...SHOWERS POSSIBLE IN AND AROUND
TJBQ/TJMZ AFT 11/17Z. LOW LEVEL WINDS FM THE EAST TO SOUTHEAST AT
10 TO 15 KNOTS...WITH SEA BREEZE VARIATIONS AFTER 15Z.

&&

.MARINE...LOCAL BUOY ARE SHOWING SEAS BETWEEN 5-7 FEET STILL
PERSIST ACROSS THE LOCAL WATERS. BUOY 41043 AROUND 170 MILES
NORTHEAST OF SAINT THOMAS CONTINUES TO SHOW SWELLS OF 7 FEET.
SMALL CRAFT ADVISORY CONTINUES IN EFFECT FOR THE OFFSHORE ATLANTIC
WATERS.


&&

.PREV DISCUSSION... /ISSUED /

SYNOPSIS...MID TO UPPER LEVEL RIDGE WILL CONTINUE TO DOMINATE
THE LOCAL WEATHER PATTERN THROUGH FRIDAY. A DEEP POLAR LOW/TROUGH
WILL MOVE INTO THE NORTHWEST ATLANTIC ERODING THE RIDGE DURING THE
WEEKEND. AT THE SAME TIME...EASTERLY PERTURBATIONS ARE FORECAST TO
MOVE ACROSS THE FORECAST AREA BETWEEN SATURDAY AND MONDAY...RESULTING
IN GENERALLY UNSTABLE CONDITIONS ACROSS THE LOCAL ISLANDS.

DISCUSSION...WATER VAPOR IMAGERY SHOW A DRY AND STABLE AIR MASS
AT MID-UPPER LEVELS COVERING THE LESSER ANTILLES AND PUERTO RICO.
STRONG CAP INVERSION AND A SUBSIDENCE AIR MASS WILL KEEP THE LOCAL
AREA WITH LIMITED SHOWER ACTIVITY TODAY. THE DRIEST DAY OF THE
NEXT 7 DAYS APPEARS TO BE TODAY. GFS FORECAST SOUNDINGS SUGGEST
THAT THE PRECIPITABLE WATER WILL DROP BELOW ONE INCH AROUND 18Z...
THIS IS A 20%-25% PERCENT BELOW NORMAL FOR THIS TIME OF THE YEAR.

A WETTER AND MORE UNSTABLE PATTERN IS FORECAST FOR THE UPCOMING
WEEKEND AS THE UPPER RIDGE COLLAPSES AND A SERIES OF SURFACE
TROUGHS MOVE ACROSS THE LOCAL ISLANDS. GOOD UPPER DYNAMICS
ASSOCIATED WITH THE PROXIMITY OF THE SUBTROPICAL JET WILL INCREASE
THE RISK OF THUNDERSTORMS FROM SATURDAY THROUGH EARLY NEXT WEEK.
LOOKS LIKE THE BEST MOISTURE CONVERGE WILL OCCUR ON MONDAY WHEN AN
EASTERLY PERTURBATION/SURFACE TROUGH WILL CROSS THE ISLANDS.

AVIATION...VFR CONDITIONS ARE EXPECTED TO PREVAIL DURING THE NEXT
24 HOURS AT ALL TERMINALS. HOWEVER...SHOWERS POSSIBLE IN AND AROUND
JBQ/JMZ AFT 11/17Z. LOW LEVEL WINDS FM THE EAST TO SOUTHEAST AT 10
TO 15 KNOTS...WITH SEA BREEZE VARIATIONS AFTER 14Z.

MARINE...OFFSHORE BUOY 41043 REGISTERED ANOTHER PULSE OF LONG
PERIOD NORTHERLY SWELL OF 7-8 FT DURING OVERNIGHT HOURS. SOME OF
THIS SWELL ENERGY WILL FILTER ACROSS THE LOCAL ATLANTIC WATERS AND
CARIBBEAN PASSAGE LATER TODAY. THIS WILL MAINTAIN HAZARDOUS MARINE
CONDITIONS ACROSS THE OUTER ATLANTIC WATERS AS WELL AS A HIGH RISK
OF RIP CURRENTS ALONG THE NORTH FACING BEACHES OF PUERTO RICO...CULEBRA
AND NORTHERN USVI THROUGH THIS AFTERNOON/EVENING. THE REST OF THE
WEEK...SEAS WILL REMAIN AROUND 4-6 FEET ACROSS MOST OF THE LOCAL
WATERS.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU  88  74  85  74 /  10  20  20  30
STT  85  74  84  74 /  20  20  20  40

&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...HIGH RIP CURRENT RISK UNTIL 5 PM AST THIS AFTERNOON FOR CULEBRA-
     NORTH CENTRAL-NORTHEAST-NORTHWEST-SAN JUAN AND VICINITY-
     SOUTHEAST-WESTERN INTERIOR.

VI...HIGH RIP CURRENT RISK UNTIL 5 PM AST THIS AFTERNOON FOR ST.
     THOMAS/ST. JOHN/ADJACENT ISLANDS.

AM...HIGH RIP CURRENT RISK UNTIL 5 PM AST THIS AFTERNOON FOR COASTAL
     WATERS OF SOUTHERN USVI VIEQUES AND EASTERN PUERTO RICO OUT
     10 NM.

     SMALL CRAFT ADVISORY UNTIL 8 PM AST THIS EVENING FOR ATLC WATERS
     OF PUERTO RICO AND USVI FROM 10NM TO 19.5N.

&&

$$

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