Area Forecast Discussion
Issued by NWS San Juan, PR

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037
FXCA62 TJSJ 300142
AFDSJU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
942 PM AST FRI APR 29 2016

.UPDATE...MOSTLY CLOUDY SKIES WERE OBSERVED THIS EVENING ACROSS
THE FORECAST AREA. AFTERNOON SHOWERS AND THUNDERSTORMS ACROSS THE
ISLANDS TAPERED OFF JUST AROUND SUNSET. WHILE THEY MAINLY
REMAINED OFFSHORE...WITH THE EXCEPTION OF AN ISOLATED THUNDERSTORM
THAT MADE IT INLAND ACROSS CABO ROJO. HOWEVER...THE HEAVIEST
ACTIVITY WAS OBSERVED OVER VIEQUES BY MID AFTERNOON...AS A STRONG
THUNDERSTORM PRODUCED SMALL HAIL...GUSTY WINDS AND TORRENTIAL
RAINFALL LEADING TO URBAN FLOODING. FOR THE REST OF THE OVERNIGHT
INTO THE EARLY MORNING HOURS...SHOWERS SHOULD CONTINUE OVER THE
REGIONAL WATERS...WITH SOME REACHING THE SOUTHEASTERN AREAS OF PR.
LATEST 30/00Z TJSJ UPPER AIR SOUNDING INDICATED A MOIST ATMOSPHERE
AT 2.03 INCHES OF PRECIPITABLE WATER AND SOUTHEAST WINDS BELOW
4000 FT AT LESS THAN 11 KNOTS...WESTERLIES ABOVE AND INCREASING
W/HEIGHT. ANOTHER RAINY DAY IS EXPECTED ON SATURDAY ACROSS THE
REGION.

&&

.AVIATION UPDATE...UNSTABLE WEATHER CONDITIONS WILL CONTINUE TO PRODUCE
SHRA/TSRA OVER THE LOCAL AREA DURING THE FORECAST PERIOD. SHRA/TSRA
WILL REMAIN POSSIBLE ACROSS THE LOCAL REGION WITH MOUNTAIN
OBSCURATIONS BETWEEN UNTIL 30/08Z. WINDS WILL CONTINUE FROM THE SE
AT 5 TO 10 KT.

&&

.MARINE UPDATE...BUOYS ACROSS PR AND THE USVI ARE INDICATING SEAS
UP TO 3 FEET AND SOUTHEAST WINDS AT 10 KNOTS OR LESS. SEAS SHOULD
CONTINUE BELOW SMALL CRAFT ADVISORY CRITERIA. ISOLATED
THUNDERSTORMS CONTINUE OVER THE MONA PASSAGE...BUT THEY SHOULD
DISSIPATE LATER TONIGHT.

&&

.PREV DISCUSSION... /ISSUED /

SYNOPSIS...A SERIES OF MID TO UPPER SHORT-WAVE TROUGH WILL CONTINUE
STREAM OVER THE LOCAL REGION THROUGH NEXT WEEK. AMPLE AREA OF
MOISTURE WILL REMAIN OVER THE NORTHEAST CARIBBEAN REGION OVER THE
NEXT SEVERAL DAYS. AS A RESULT...HIGHLY UNSTABLE AND MOIST
ATMOSPHERE REMAINS OVER THE FORECAST AREA...FAVORING THE
DEVELOPMENT OF SHOWERS AND THUNDERSTORMS EVERYDAY. UNSETTLED
PATTERN WILL LIKELY PREVAIL UNTIL AT LEAST MIDWEEK NEXT WEEK.

DISCUSSION...VERY UNSTABLE AND MOIST AIR MASS OVER THE FORECAST
AREA HAVE RESULTED IN THE DEVELOPMENT SHOWERS AND THUNDERSTORMS
WITH HEAVY RAINFALL ACROSS PORTIONS OF PUERTO RICO. THE HEAVIEST
RAINFALL OCCURRED IN PORTIONS OF EAST...NORTHEAST AND NORTH
CENTRAL PUERTO RICO. AREAS OF FAJARDO...LUQUILLO AND CEIBA
RECEIVED IN EXCESS OF 3 INCHES AND CONTINUED TO RAIN. OTHER AREAS
OF THE WEST AND NORTH PR EXPERIENCED AT LEAST ONE INCH OF RAIN SO
FAR THIS AFTERNOON. NEW SHOWERS AND THUNDERSTORMS WILL CONTINUE TO
DEVELOP ACROSS PORTIONS OF THE EASTERN THIRD OF PUERTO RICO
THROUGH THIS EVENING.

VERY MOIST SOUTHEASTERLY FLOW ACROSS THE EASTERN CARIBBEAN WILL
CONTINUE TO PROMOTE MOISTURE CONVERGENCE ACROSS PUERTO RICO AND
THE US VIRGIN ISLANDS THROUGH THE END OF THE WEEK. THIS COMBINES
WITH INFLOW OF MID LEVEL ENERGY AND FAVORABLE JET DYNAMICS TO SUSTAIN
UNSETTLED CONDITIONS OVER THE NEXT SEVERAL DAYS.

PATTERN WILL REMAIN HIGHLY FAVORABLE AND CONDUCIVE TO ORGANIZED
DEEP CONVECTION THROUGH MID-WEEK NEXT WEEK. HIGH MOISTURE CONTENT
AND ADDITIONAL PERTURBATIONS AT MID-UPPER LEVELS WILL KEEP THE
CHANCES OF SHOWERS AND THUNDERSTORMS HIGH THROUGH THE FORECAST
PERIOD.

AVIATION...UNSTABLE WEATHER CONDITIONS WILL CONTINUE TO PRODUCE
SHRA/TSRA OVER THE REGION DURING THE FORECAST PERIOD. SHRA/TSRA WILL
REMAIN POSSIBLE AT TJSJ/TJPS AND TJMZ WITH MOUNTAIN OBSCURATIONS
BETWEEN UNTIL 30/02Z. WINDS WILL CONTINUE FROM THE SE AT 10 TO 15 KT.

MARINE...WINDS OF 10-15 KT AND SEAS OF 3-5 FEET CAN BE EXPECTED ACROSS
MOST OF THE WATERS OVER THE NEXT SEVERAL DAYS. SMALL CRAFT ADVISORIES
ARE NOT EXPECTED OVER THE NEXT 5-7 DAYS. THUNDERSTORMS ACROSS THE
WATERS WILL BE THE MAIN HAZARD THROUGH EARLY NEXT WEEK.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU  75  87  74  88 /  20  40  40  40
STT  78  83  76  86 /  40  40  30  30

&&

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

$$

10/13



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