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000
FXCA62 TJSJ 150859
AFDSJU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
459 AM AST SAT JUN 15 2013

.SYNOPSIS...AT UPPER LEVELS...A RIDGE OVER THE CARIBBEAN JUST
SOUTH OF PUERTO RICO WILL BUILD WESTWARD AS A TROUGH BRUSHING CUBA
MOVES TO THE NORTH OF THE LOCAL AREA NOW THROUGH MONDAY. A CUT OFF LOW
FORMS IN THE TROUGH SUNDAY NIGHT AND CONTINUES NORTHEAST OF THE
LEEWARD ISLANDS THROUGH MUCH OF NEXT WEEK. THIS ALLOWS A WEAK
TROUGH TO REMAIN JUST WEST OF THE FORECAST AREA FOR MUCH OF THE
WEEK.

AT MID LEVELS...A RIDGE EXTENDS NORTHEAST TO HIGH PRESSURE IN THE
CENTRAL ATLANTIC. WEAK TROUGHING FORMS OVER THE LOCAL AREA
BEGINNING ON SUNDAY DUE TO THE UPPER LEVEL TROUGH UNTIL HIGH
PRESSURE BUILDS BACK IN FROM THE EAST LATE NEXT WEEK. EXCEPT FOR
SOME MOISTURE TODAY...MOISTURE IS GENERALLY LIMITED EXCEPT FOR
WEDNESDAY AND THURSDAY.

AT LOWER LEVELS...A WEAK TROUGH WILL MOVE THROUGH THE LOCAL AREA
THIS MORNING FOLLOWED BY A NARROW SLOT OF SOMEWHAT DRIER AIR. LOW
LEVEL MOISTURE PERSISTS HOWEVER UNTIL LATE MONDAY AND RETURNS
AGAIN ON TUESDAY. A TROPICAL WAVE MOVES THROUGH THE AREA ON
WEDNESDAY AND THURSDAY OF NEXT WEEK FOLLOWED BY MUCH DRIER AIR
THROUGH SATURDAY.

&&

.DISCUSSION...MOISTURE INCREASED OVERNIGHT AS PRECIPITABLE WATER...
AS MEASURED BY THE SOUNDER IN BAYAMON...SURPASSED TWO INCHES. HEAVY
SHOWERS MOVED WEST NORTHWEST AT 18 TO 28 KNOTS THROUGH PUERTO
RICO AND SAINT CROIX. RAIN AMOUNTS WERE GENERALLY UNDER ONE INCH
OVER LAND AND WERE HEAVIEST IN YABUCOA...SAN LORENZO AND CAGUAS.
THUNDERSTORMS FORMED IN THE LOCAL WATERS NORTH OF ARECIBO JUST
BEYOND 10 NAUTICAL MILES IN A STREAM THAT WAS STILL ACTIVE AS OF
4:45 AM AST. MOISTURE CONTINUES THROUGH THE DAY...AND THE BEST
MOISTURE EXITS INTO THE MONA PASSAGE BY 16/00Z TAKING MOST OF THE
SHOWERS WITH IT.

DURING THE NEXT 7 TO 10 DAYS HIGH PRESSURE AT THE SURFACE IN THE
MID ATLANTIC RETREATS TO THE NORTHEAST SOMEWHAT...BUT STRENGTHENS.
HENCE MODERATE TO FRESH TRADE WINDS CONTINUE THROUGHOUT THE PERIOD
WITH LITTLE CHANGE IN STRENGTH. MOISTURE DURING THIS PERIOD
CONTINUES RICH UP TO ABOUT 6 KFT...BUT EXCEPT FOR A SHORT BREAK
WEDNESDAY AND THURSDAY THE ATMOSPHERE AT MID LEVELS IS DRY. DEEP HIGH
CLOUDS ARE GENERALLY PRESENT EXCEPT MONDAY AND TUESDAY JUST BEFORE A
TROPICAL WAVE COMES THROUGH ON WEDNESDAY. THE WAVE SHOULD BRING
SIGNIFICANT RAIN AMOUNTS TO THE AREA AND IS FOLLOWED IMMEDIATELY
BY 25 TO 35 KNOT WINDS AT 850 MB AND MORE SAHARAN DUST. SHOWERS
ARE EXPECTED TO CONTINUE INTO THURSDAY WITH THIS WAVE...HOWEVER
MID LEVELS DRY CONSIDERABLY THURSDAY NIGHT AND REMAIN VERY DRY
THROUGH SATURDAY. THIS WILL LIMIT CONVECTION AFTER THE PASSAGE OF
THE WAVE AND LEAD TO SOMEWHAT DRIER WEATHER OVERALL TOWARD THE END
OF NEXT WEEK.

&&

.AVIATION...VFR COND DURING OVERNIGHT HOURS FOR ALL SITES...WITH
CHANCE OF VCSH ACROSS ISLANDS. BRIEF MVFR COND POSSIBLE FOR TJMZ AND
TJBQ AFT 15/17Z DUE TO SHOWERS AND THUNDERSTORMS NEAR THE AREA. WIND BLO
FL100 ESE-SE 15-25 KT THRU SAT. SHRA WILL BRING VERY GUSTY WINDS.
GUSTS IN SAINT CROIX WERE MEASURED TO 29 KNOTS THIS MORNING.

&&

.MARINE...MODERATE TO FRESH TRADE WINDS BROUGHT HIGHER SEAS TO THE
ATLANTIC WATERS YESTERDAY AND TODAY. SEAS ARE EXPECTED TO BEGIN
TO COME DOWN TODAY. NEVERTHELESS...SEAS IN MOST OF OUR EXPOSED
WATERS WILL CONTINUE AT 4 TO 6 FEET AND SMALL CRAFT WILL NEED TO
EXERCISE CAUTION.


&&

.PRELIMINARY POINT TEMPS/POPS...
SJU  88  79  89  78 /  40  10  10  10
STT  88  80  88  80 /  40  10  10  10

&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...NONE.
VI...NONE.
COASTAL WATERS...SMALL CRAFT ADVISORY UNTIL 6 PM AST THIS EVENING FOR ATLC WATERS
     OF PUERTO RICO AND USVI FROM 10NM TO 19.5N.

&&

$$

15/12