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000
FXCA62 TJSJ 160102
AFDSJU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
902 PM AST WED MAY 15 2013

.UPDATE...MOST OF THE HEAVY SHOWER ACTIVITY DISSIPATED AROUND 530
PM AST. CLOUDY SKIES HAS PREVAILED ACROSS ALL THE LOCAL ISLANDS
SINCE THIS AFTERNOON. LIGHT RAIN WAS REPORTED EARLY IN THE EVENING
ACROSS THE SOUTHWEST AND SOUTH SECTIONS OF PUERTO RICO BUT NO RAIN
IS OBSERVED OVER THE ISLANDS AT THIS TIME. EVENING TJSJ SOUNDING
INDICATED VERY MOIST AIR MASS WITH PRECIPITABLE WATER AROUND 2.1
INCHES. THIS HIGH MOISTURE CONTENT COMBINED WITH THE PROXIMITY OF
THE UPPER TROUGH...WILL PRODUCE ANOTHER ACTIVE WEATHER DAY TOMORROW
WITH THE POTENTIAL FOR HEAVY SHOWERS AND A FEW POSSIBLE THUNDERSTORMS
ACROSS THE LOCAL ISLANDS...ESPECIALLY ACROSS PUERTO RICO IN THE
AFTERNOON. MINOR CHANGES WERE INTRODUCED TO THE FORECAST PACKAGE
TONIGHT.

&&

.AVIATION...VFR CONDITIONS ARE EXPECTED AT ALL TAF SITES UNTIL ARND
16/16Z. MVFR/IFR CONDS WILL BEGIN DEVELOPING AFT 16/16Z ALONG THE
CORDILLERA CENTRAL AND ARND TJMZ IN AREAS OF +SHRA/TSRA. MOUNTAINS
WILL BE OBSCURED. CONDS WILL IMPROVE EAST TO WEST AFT 16/21Z AS
DRIER AIR MOVES IN. FOR THE LEEWARD ISLANDS...MVFR CONDS ARE PSBL
AFT 16/21Z AT TKPK OTHERWISE EXPECT VFR. WINDS ESE 12 TO 18 KNOTS UP
THROUGH 7 KFT...THEN LIGHT AND VARIABLE TO 17 KFT. MAX WINDS WEST
ARND 60 KT AT 200 MB OR FL400.

&&

.MARINE...SEAS OF 4 FEET ARE EXPECTED THROUGH EARLY THURSDAY. A
SLIGHT INCREASE IN WINDS AND SEAS IS ANTICIPATED FOR LATE THURSDAY
AND FRIDAY AS A SURFACE HIGH PRESSURE RELOCATES NORTH OF THE AREA.

&&

.PREV DISCUSSION... /ISSUED 305 PM AST WED MAY 15 2013/

SYNOPSIS...UPPER LEVEL TROUGH PASSING JUST NORTH OF PUERTO
RICO..WILL KEEP UNSTABLE ATMOSPHERIC CONDITIONS THROUGH AT LEAST
FRIDAY. SURFACE HIGH PRESSURE WILL BUILD ACROSS THE LOCAL AREA
DURING THE WEEKEND. ANOTHER UPPER LEVEL TROUGH WILL MOVE ACROSS THE
AREA EARLY NEXT WEEK.

DISCUSSION...VERY ACTIVE DAY ACROSS PUERTO RICO...WITH VERY HEAVY
RAIN REPORTED ACROSS THE EAST AND SOUTHEAST SECTIONS OF PUERTO
RICO...WHERE U.S.G.S RIVER SENSOR INDICATED OVER 3 INCHES IN ONE
HOUR FELL OVER LAS PIEDRAS. ALSO...ANOTHER AREA WHICH RECEIVED
BETWEEN 1 TO 3 INCHES OF RAINFALL WAS THE WESTERN INTERIOR AND
WEST SECTION OF PUERTO RICO.  AN UPPER LEVEL THROUGH COMBINED WITH
DAYTIME HEATING AND GOOD MOISTURE AT THE SURFACE...TO PRODUCE
SCATTERED TO NUMEROUS SHOWERS WITH THUNDERSTORMS.

THE AFOREMENTIONED UPPER LEVEL TROUGH WILL MOVE AWAY FROM THE AREA
THURSDAY. HOWEVER...LINGERING MOISTURE WILL COMBINE ONCE AGAIN WITH
LOCAL EFFECT TO PRODUCE ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS
MAINLY ALONG AND NORTH OF THE CORDILLERA CENTRAL UN THE AFTERNOON
HOURS. A SURFACE HIGH PRESSURE IS THEN EXPECTED TO BUILD ACROSS
THE AREA DURING THE WEEKEND..WHICH WILL LIMIT SOMEWHAT THE CHANCES
FOR SHOWER ACTIVITY. BUT IN GENERAL...CONDITIONS WILL REMAIN
FAVORABLE FOR SOME KIND OF SHOWER DEVELOPMENT EACH AFTERNOON.

FOR NEXT WEEK...COMPUTER MODELS INDICATED ANOTHER UPPER LEVEL
THROUGH WILL APPROACH THE LOCAL REGION. WET CONDITIONS WILL
RETURN TO OUR LOCAL AREA BY MID WEEK...AS THIS TROUGH ESTABLISHES
CLOSE TO OUR AREA.

AVIATION...MVFR/IFR CONDITIONS ARE POSSIBLE UNTIL AROUND 15/23Z
ACROSS TJMZ...TJBQ...AND TJSJ SUE TO SHOWERS AND THUNDERSTORMS OVER
PR. WINDS WILL CONTINUE FROM THE EAST SOUTHEAST WITH SEA BREEZE
VARIATIONS AT AROUND 10 KTS AND GUSTY NEAR SHRA/TSRA. MOUNTAIN
OBSCURATIONS AND VARIABLY GUSTY WINDS CAN BE EXPECTED. WEATHER
CONDITIONS EXPECTED TO IMPROVE AFTER 16/00Z BUT CEILINGS WILL REMAIN
GENERALLY AROUND FL040-060 UNTIL 16/02Z. SCATTERED CLOUDS AND WINDS
FROM THE EAST AT 10 KTS OR LESS EXPECTED THEREAFTER.

MARINE...SEAS OF 5 FEET OR LESS AND WINDS OF 15 KNOTS OR LES ARE
EXPECTED TO PREVAIL ACROSS THE COASTAL WATERS.

HYDROLOGY...SEVERAL RIVERS REMAINS AT HIGH LEVEL...AN WILL
CONTINUE TO RISE MAINLY OVER THE EASTERN HALF OF PUERTO RICO...AND
OVER THE WESTERN INTERIOR AND WEST SECTIONS OF PUERTO RICO. PEOPLE
LIVING AT OR CLOSE TO RIO ESPIRITU SANTO...IN RIO GRANDE... RIO
BLANCO IN NAGUABO...RIO ANASCO...RIO CULEBRINAS AND RIO GRANDE DE
ARECIBO BE ALERT IN CASE OF A FLASH FLOOD WARNING IS ISSUED.
ELSEWHERE...RESIDENTS AND MOTORISTS SHOULD BE ALERT TO PONDING OF
WATER ON ROADWAYS AND ALLOW TIME FOR STREAMS...CREEKS AND RIVERS
TO RETURN TO NORMAL LEVELS...AS RUNOFF WILL CONTINUE TO AFFECT
THESE AREAS DURING THE NEXT HOUR OR SO.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU  76  86  77  86 /  20  40  20  20
STT  79  87  79  85 /  20  30  20  20

&&

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

$$

12/11