AFDSJU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
1011 PM AST WED AUG 17 2011

.UPDATE...PASSING SHOWERS AND AN ISOLATED THUNDERSTORM OR TWO ARE
STILL EXPECTED OVERNIGHT...HOWEVER NO SIGNIFICANT RAINFALL OR
FLOODING IS ANTICIPATED. MINOR CHANGES WERE MADE TO THE SHORT TERM
GRIDS AT THIS TIME...JUST TO MATCH THE CURRENT WEATHER CONDITIONS.

LOOKING AHEAD...A VIGOROUS TROPICAL WAVE LOCATED ACROSS THE CENTRAL
ATLANTIC IS FORECAST TO MOVE WESTWARD AND MAY REACH THE LESSER
ANTILLES SUNDAY NIGHT OR EARLY MONDAY. REGARDLESS OF DEVELOPMENT...
SQUALLY WEATHER CONDITIONS ARE POSSIBLE SUNDAY NIGHT THROUGH
TUESDAY.

&&

.AVIATION...VFR CONDITIONS WILL PREVAIL ACROSS ALL TAF SITES THROUGH
AT LEAST 18/16Z. BETWEEN 18/16Z-18/22Z...PERIODS OF MVFR CONDITIONS
CAN BE EXPECTED ACROSS TJBQ AND TJMZ IN SHRA/TSRA.

&&

.PREV DISCUSSION... /ISSUED 310 PM AST WED AUG 17 2011/

SYNOPSIS...TROPICAL WAVE THAT AFFECTED THE AREA YESTERDAY KEEPS
MOVING WEST. AVAILABLE MOISTURE WILL INCREASE SLIGHTLY TOMORROW
AND DECREASE ON FRIDAY. WINDS WILL BECOME MORE NORTHEASTERLY FOR
FRIDAY.

DISCUSSION...FORECAST SOUNDINGS SHOW THAT THE PW VALUES SHOULD
REMAIN CLOSE TO 2.0 INCHES FOR THE REST OF TODAY AND INTO THURSDAY
AFTERNOON. THEN A SLIGHT DECREASE IN PW IS SHOWN FOR FRIDAY AND
SATURDAY WITH A SLIGHT DECREASE IN OVERALL INSTABILITY AS WELL.
HOWEVER...THERE IS STILL A CHANCE OF SHOWERS AND
THUNDERSTORMS...ESPECIALLY IN THE AFTERNOON TOMORROW ACROSS THE
WESTERN SECTIONS OF PUERTO RICO.

A MORE STABLE AIR MASS IS FORECAST TO ENTER OUR AREA BY FRIDAY AND
INTO SATURDAY. FORECAST SOUNDINGS NOT ONLY SHOW A DECREASE IN PW
BUT ALSO IT SHOWS A DECENT CAP. THEREFORE...THUNDERSTORM DEVELOPMENT
FOR THE WEEKEND MAY BE LIMITED.

AVIATION...VFR CONDS TO PREVAIL AT MOST TAF SITES THIS AFTERNOON
WITH SOME VCSH...VCTS AND THE CHANCE FOR A PERIOD OF MVFR AT TAF
SITE...TJMZ AS TS MOVE THROUGH THAT AREA BETWEEN 1718/1721. GUSTY
CONDITIONS CONTINUE...GENERALLY EAST 15-22 KT WITH LOCALIZED GUSTS
OF 20-30 KT.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU  78  89  78  89 /  20  20  30  30
STT  79  89  80  90 /  30  30  50  50

&&

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

$$