Issued by NWS San Juan, PR
000 FXCA62 TJSJ 211952 AFDSJU AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SAN JUAN PR 352 PM AST SAT NOV 21 2009 .SYNOPSIS...LOCALLY DRIVEN SHOWERS AND ISOLATED THUNDERSTORMS WILL DOMINATE THE WEATHER ACROSS PUERTO RICO AND THE U.S VIRGIN ISLANDS FOR THE NEXT SEVERAL DAYS. && .DISCUSSION...THE SURGE IN MOISTURE ENTERING THE EASTERN CARIBBEAN THIS AFTERNOON IS EXPECTED TO REMAIN MAINLY SOUTH OF THE LOCAL ISLANDS AS IT PASSES BY OVERNIGHT AND ON SUNDAY. EVEN SO...MAY SEE AN INCREASE IN SHOWER AND THUNDERSTORM ACTIVITY OVER THE LOCAL CARIBBEAN WATERS...HOWEVER...WEATHER ACROSS PUERTO RICO AND THE U.S. VIRGIN ISLANDS IS EXPECTED TO REMAIN MAINLY DIURNAL DRIVEN IN NATURE. WHILE RIDGING IS EXPECTED TO DOMINATE THE MID TO UPPER LEVELS OF THE ATMOSPHERE OVER THE NEXT WEEK...EXPECT SOME SHOWER DEVELOPMENT OVER THE INTERIOR OF THE ISLAND EACH DAY...AS SUFFICIENT LOW LEVEL MOISTURE AND DAYTIME HEATING SHOULD PROVIDE ENOUGH OF A TRIGGER FOR SOME SHOWER ACTIVITY. NO LARGE SCALE WEATHER FEATURES ARE EXPECTED TO IMPACT THE LOCAL AREA THROUGH THE END OF THE FORECAST PERIOD. && .AVIATION...PERIODS OF MVFR AND BRIEF IFR CONDS WILL REMAIN POSSIBLE ACROSS TJSJ...TJBQ AND TJMZ THROUGH 21/22Z...WITH VFR CONDS EXPECTED AT THE REST OF LOCAL TAF SITES. THEREAFTER...PREVAILING VFR FORECAST FOR THE ENTIRE FLYING AREA OVERNIGHT AT LEAST THROUGH 22/04Z... FOLLOWED BY PROB30 OF PASSING SHRA IN AND AROUND TJSJ... TISX... TIST...TNCM...AND TKPK FM 22/04Z-22/06Z. ELSEWHERE...VA EMISSIONS CONTINUE FM TRPG...WITH LOW TO MID LEVEL STEERING FROM THE EAST SOUTHEAST DURG THE NEXT 24 HRS. BASED ON LATEST SATELLITE IMAGERY... FAINT ASH AN GAS EMISSIONS ARE STILL EXPECTED TO REMAIN OVR WATER JUST EAST NORTHEAST OF THE TIST AIRDROME BTW TIST AND TUPJ. && .CLIMATE...THE HIGH TEMPERATURE REACHED 91 DEGREES AT THE LUIS MUNOZ INTERNATIONAL AIRPORT IN SAN JUAN TODAY. THIS BROKE THE PREVIOUS HIGH TEMPERATURE FOR NOVEMBER 21ST...WHICH REACH 90 DEGREES BACK IN 2006. && .PRELIMINARY POINT TEMPS/POPS... SJU 76 87 76 87 / 40 40 40 40 STT 78 87 77 87 / 40 50 40 40 && .SJU WATCHES/WARNINGS/ADVISORIES... PR...NONE. VI...NONE. && $$ 09/04
