FXCA62 TJSJ 221939
AFDSJU
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
339 PM AST TUE MAY 22 2012
.SYNOPSIS...AT MID AND UPPER LEVELS...HIGH PRESSURE WILL REMAIN
CENTERED OVER OR JUST WEST OF PUERTO RICO THROUGH SUNDAY.
BEGINNING ON SATURDAY LOW PRESSURE WILL DROP SOUTH SOUTHEAST FROM
NOVA SCOTIA BRINGING NORTHWEST FLOW TO THE AREA MONDAY THROUGH
WEDNESDAY OF NEXT WEEK.
AT LOWER LEVELS...HIGH PRESSURE WILL DOMINATE THE CENTRAL
ATLANTIC...WEAKENING THURSDAY THROUGH SUNDAY. BUT EAST SOUTHEAST
TO SOUTHEAST TRADE WINDS WILL CONTINUE THROUGH THE MIDDLE OF NEXT
WEEK.
&&
.DISCUSSION...SOUTHEAST FLOW AND MODERATE MOISTURE ALONG WITH A
BAND OF CONVECTION THAT MOVED INTO THE AREA EARLIER THIS MORNING
KEPT SHOWERS OVER THE U.S. VIRGIN ISLANDS AND THE EASTERN PORTION
OF PUERTO RICO THIS MORNING...AND ALLOWED SHOWERS AND WEAK
THUNDERSTORMS TO FIRE UP OVER NORTHWEST PUERTO RICO THIS
AFTERNOON. A FEW SHOWERS ALSO CONTINUED IN THE ATLANTIC NORTH OF
FAJARDO AND CULEBRA. MIMIC PRODUCT SHOWED A BAND OF MOISTURE
MOVING INTO THE AREA EARLY THIS MORNING AND CONTINUING TO THE WEST
OVERNIGHT THAT WILL LEAVE LOCAL WATERS ACTIVE WITH SCATTERED
SHOWERS EVEN AFTER SHOWERS OVER PUERTO RICO HAVE ENDED. OTHER
PATCHES OF MOISTURE ARE ON TRACK TO CROSS THROUGH THE AREA
TONIGHT AND TOMORROW BEFORE AN AREA OF DRIER AIR MOVES THROUGH
WEDNESDAY NIGHT THROUGH SATURDAY. AT THIS TIME IT DOES NOT LOOK
LIKE THE AIR MASS WILL BE DRY ENOUGH TO ELIMINATE AFTERNOON
CONVECTION IN THE FORM OF SCATTERED SHOWERS AND THUNDERSTORMS IN
NORTHWEST PUERTO RICO AND ISOLATED SHOWERS IN THE INTERIOR...ALTHOUGH IT
MAY REDUCE THE SHOWERS SEEN IN THE USVI CONSIDERABLY. ALSO WHEN
THIS HAPPENS SOUTHEAST FLOW CONTINUES AND MAY BE ENOUGH TO BOOST
THE TEMPERATURES ON THE NORTH COAST BY 2 TO 4 DEGREES DURING THAT
TIME. THE GFS HAS BEEN SOMEWHAT ERRATIC THERE...EVEN SHOWING 90
DEGREES IN CHARLOTTE AMALIE THURSDAY AND SATURDAY. IT LOOKS MORE
LIKELY THAT SAN JUAN METRO AREA WILL HAVE SOME LOWER 90S THURSDAY
THROUGH SUNDAY...ALTHOUGH THE AIRPORT MAY JUST MAKE 90 ON SOME OF
THOSE DAYS. WINDS WILL BE WEAKER IN THE LOWER LEVELS DURING THE
WEEKEND AND EARLY NEXT WEEK...BUT SOUTHEAST WINDS STRENGTHEN
ACCORDING TO THE GFS AFTER WEDNESDAY OF NEXT WEEK AND TEMPERATURES
WILL WARM AGAIN.
MOISTURE WILL PEAK TOMORROW...AND THEN DECLINE BUT MOISTURE FROM A
TROPICAL WAVE...PERHAPS THE STRONGEST THIS YEAR SO FAR...IS
FORECAST TO WIND AROUND THE HIGH PRESSURE IN THE CENTRAL ATLANTIC
AND MOVE NORTH NORTHWEST OVER THE AREA SUNDAY NIGHT OR MONDAY AND
SHOULD REPRESENT A MOISTENING TREND THAT WILL CONTINUE INTO NEXT
WEEK. THE THREAT OF URBAN AND SMALL STREAM FLOODING IS EXPECTED
TO RETURN NEXT WEEK...ALTHOUGH LOCAL STORMS MAY YIELD VERY HEAVY
RAIN DUE TO THE WARMER TEMPERATURES.
&&
.AVIATION...
BRIEF PERIODS OF MVFR CONDITIONS WILL REMAIN POSSIBLE IN AND
AROUND TJBQ AND TJMZ IN SHRA/TSRA THROUGH ABOUT 22/22Z. MVFR CONDS
THAT HAVE BEEN PREVALENT DURING THE DAY IN THE LEEWARD ISLAND TAF
SITES OF TNCM AND TKPK SHOULD LIFT EARLY TONIGHT. OTHERWISE EXPECT VFR
CONDS WILL CONTINUE. AFT 02Z...VFR CONDITIONS ARE EXPECTED THROUGH
23/16Z. LLVL WINDS WILL BE MAINLY FROM THE EAST SOUTHEAST AT 10 TO
20 KTS.
&&
.MARINE...SEAS WILL CONTINUE TO REMAIN JUST BELOW SMALL CRAFT
ADVISORY CONDITIONS FOR SEAS IN MOST OF THE OPEN WATERS OF THE
ATLANTIC AND CARIBBEAN THROUGH THE NEXT 7 DAYS. WINDS WILL BE EAST
SOUTHEAST FOR MOST OF THE TIME EXCEPT NEAR SHORE WHERE LAND AND
SEA BREEZES MAY INTERVENE.
&&
.PRELIMINARY POINT TEMPS/POPS...
SJU  77  86  78  87 /  50  50  30  30 
STT  78  86  79  90 /  40  40  20  20 
&&
.SJU WATCHES/WARNINGS/ADVISORIES...
PR...NONE.
VI...NONE.
COASTAL WATERS...NONE.
&&
$$
23/12