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000
FXCA62 TJSJ 180050
AFDSJU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
850 PM AST FRI MAY 17 2013

.UPDATE...SHOWERS LINGERED OVER SOUTHWEST PUERTO RICO...BUT WILL BE
MOVING OFFSHORE BY ABOUT 10 PM AST. OTHERWISE PREVIOUS FORECAST
HOLDS. DRIER AIR IS JUST EAST OF PUERTO RICO AND WILL MOVE OVER
THE AREA DURING THE MORNING. ALSO STILL EXPECTING AFTERNOON
CONVECTION IN THE WEST AND SOUTHWEST...SHOULD NOT LAST AS LONG AS
TODAY HOWEVER. WILL NOT UPDATE ZONE PACKAGE.

&&

.AVIATION...VFR CONDITIONS ARE EXPECTED AT ALL TAF SITES UNTIL
18/16Z. MVFR/IFR CONDS ARE LIKELY BTWN 18/17Z-21Z ALONG THE
CORDILLERA CENTRAL AND TJMZ IN AREAS OF +SHRA/TSRA. MOUNTAINS WILL
BE OBSCURED OVER WESTERN INTERIOR OF PR. FOR THE LEEWARD
ISLANDS...VFR CONDITIONS ARE EXPECTED. 00Z TJSJ SOUNDING INDICATES
MAINLY EAST WINDS AT 18 KNOTS OR LESS UP TO 2 KFT.

&&

.MARINE...SEAS STILL HOLDING AT NO MORE THAN 5 FEET...EVEN AT BUOY
41043. WINDS WILL INCREASE NEXT WEEK.

&&

.PREV DISCUSSION... /ISSUED 256 PM AST FRI MAY 17 2013/

SYNOPSIS...A MID TO UPPER LEVEL TROUGH ACROSS THE CENTRAL ATLANTIC
INTO THE EASTERN CARIBBEAN WILL CONTINUE TO MOVE EAST AND AWAY FROM
THE LOCAL ISLANDS. LOCAL PRESSURE GRADIENT WILL TIGHTEN AS SURFACE
HIGH BUILDS AND RELOCATES TO THE NORTH OF THE FORECAST AREA. A
BETTER CHANCE OF SHOWER AND THUNDERSTORM ACTIVITY IS EXPECTED NEXT
WORK WEEK.

DISCUSSION...A GENERALLY FAIR WEATHER PATTERN WILL CONTINUE TO
PREVAIL TONIGHT INTO THE WEEKEND AS TROUGH ALOFT CONTINUES TO MOVE
AWAY FROM THE LOCAL AREA. AS AFOREMENTIONED TROUGH MOVES TO THE
EAST...A WEAK MID LEVEL RIDGE WILL CONTINUE TO BUILD FROM THE
WEST. AT LOW LEVELS...LOCAL PRESSURE GRADIENT WILL TIGHTEN AS
HIGH BUILDS AND RELOCATES TO THE NORTH OF THE FORECAST AREA.

AS RESULT...FOR THE NEXT TWO DAYS OR SO...UNDER THE PREVAILING
WIND FLOW...EXPECT PASSING SHOWERS EMBEDDED IN THE TRADES ACROSS
THE EAST COASTAL SECTIONS OF THE ISLANDS ESPECIALLY DURING THE
MORNING HOURS...FOLLOWED BY AFTERNOON CONVECTION WHICH WILL BE
MAINLY FOCUSED ACROSS WESTERN PUERTO RICO DUE TO DIURNAL HEATING
AND LOCAL EFFECTS.

FOR THE UPCOMING WORK WEEK...A HIGHER AMPLITUDE TROUGH IS FORECAST
TO EXTEND FROM THE BAHAMAS INTO THE WESTERN CARIBBEAN...WITH
DIVERGENT SIDE OF ASSOCIATED JET OVER THE AREA. THIS WILL BRING
DEEP MOISTURE AND FAVORABLE UPPER LEVEL DYNAMICS OVER PUERTO RICO
AND U.S. VIRGIN ISLANDS...RESULTING IN CLOUDY AND WET CONDITIONS
WITH A GOOD CHANCE OF SHOWER AND THUNDERSTORM ACTIVITY ESPECIALLY
THE MIDDLE/LATTER PART OF NEXT WEEK.

AVIATION...VFR CONDITIONS EXPECTED ACROSS THE LOCAL TERMINALS
THROUGH THE FORECAST PERIOD WITH THE EXCEPTION OF TJMZ AND THE
VICINITY OF TJBQ WHERE SHRA/TSRA MAY CAUSE MVFR/IFR CONDITIONS UNTIL
AROUND 18/22Z. EASTERLY WINDS WITH SEA BREEZE VARIATIONS AT AROUND
10 TO 15 KTS GUSTING TO 25KTS UNTIL 18/00Z...BECOMING LIGHTER
THEREAFTER.

MARINE...LOCAL PRESSURE GRADIENT WILL TIGHTEN DURING THE WEEKEND
AS SURFACE HIGH BUILDS AND RELOCATES TO THE NORTH OF THE FORECAST
AREA. SEAS UP TO 5 FEET AND WINDS UP TO 21 KNOTS EXPECTED FOR
THE NEXT FEW DAYS.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU  77  87  77  87 /  10  20  20  20
STT  76  88  76  88 /  10  10  30  30

&&

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

$$

13/12