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000 FGCA72 TJSJ 110001 ESFSJU PRC001-003-005-007-009-011-013-015-017-019-021-023-025-027-029- 031-033-035-037-039-041-043-045-047-049-051-053>055-057-059-061- 063-065-067-069-071-073-075-077-079-081-083-085-087-089-091-093- 095-097-099-101-103-105-107-109-111-113-115-117-119-121-123-125- 127-129-131-133-135-137-139-141-143-145-147-149-151-153-VIC010- 020-030-120000- HYDROLOGIC OUTLOOK NATIONAL WEATHER SERVICE SAN JUAN PR 800 PM AST FRI OCT 10 2008 ...A SLOW MOVING TROPICAL WAVE WILL BEGIN A WEEK LONG RAINY PERIOD FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS... AN UPPER LEVEL LOW HAS INDUCED AN AREA OF TROPICAL MOISTURE BETWEEN 50 AND 60 DEGREES WEST LONGITUDE EAST OF THE WINDWARD ISLANDS AND A WAVE THAT IS NOW NEAR 60 DEGREES WEST THAT WILL CONTINUE TO MOVE AT ABOUT 9 MPH TOWARD PUERTO RICO AND THE U.S. VIRGIN ISLANDS. THIS WAVE WILL APPROACH THE U.S. VIRGIN ISLANDS AND PUERTO RICO DURING THE DAY ON SATURDAY AND PASS THROUGH PUERTO RICO SATURDAY NIGHT. SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WILL GRADUALLY INCREASE IN COVERAGE AND INTENSITY OVER THE AREA SATURDAY NIGHT...SUNDAY AND SUNDAY NIGHT AS MOISTURE IN CONVERGING FLOW OVER THE FORECAST AREA BEHIND THE WAVE FORMS A WIDE BAND OF SHOWER AND THUNDERSTORM ACTIVITY THAT FLOWS FROM THE SOUTHEAST OVER THE LOCAL AREA. BY MONDAY THE WAVE WILL BE OVER THE DOMINICAN REPUBLIC. THE AREAS MOST AFFECTED BY THESE SHOWERS WILL BE IN THE SOUTHEAST OF PUERTO RICO...BUT RAINFALL WILL SPREAD ACROSS THE ISLAND DURING THE PERIOD. MAXIMUM RAINFALL IN SOUTHEAST PUERTO RICO FROM SATURDAY NIGHT THROUGH MONDAY COULD RANGE FROM 8 TO 15 INCHES AND WILL LIKELY DIMINISH TO LESS THAN 1 INCH IN THE NORTHWEST PORTION OF THE ISLAND. THE POTENTIAL EXISTS FOR MAJOR RIVER FLOODING IN THE SAME AREAS THAT WERE HIT SO HARD DURING THE LATTER PART OF SEPTEMBER 2008 INCLUDING THE COASTAL MUNICIPALITIES FROM NAGUABO TO JUANA DIAZ. MOST AREAS THERE ARE STILL FAIRLY SATURATED AND AREAS OF STEEP TERRAIN WILL BE SUBJECT MUDSLIDES AND DEBRIS FLOWS. DANGER EXISTS THAT DEBRIS IN RIVER CHANNELS WILL CAUSE WIDER FLOODING WITH LESS WATER THAN WOULD HAVE HAPPENED PREVIOUSLY. LOW LEVEL LOW PRESSURE PERSISTS THROUGH THE WEEK FROM HISPANIOLA TO PUERTO RICO AND THE U.S. VIRGIN ISLANDS AND WILL BE THE FOCUS ON CONTINUING RAINS TUESDAY AND WEDNESDAY AS WELL. UNUSUAL SOUTHWESTERLY WIND FLOW DURING THIS TIME PERIOD MAY BRING THE FOCUS OF THE HEAVIEST RAINS TO THE SOUTHWEST WHERE 6 TO 12 INCHES OF RAIN COULD ALSO FALL IN AREAS WHERE RAINS ARE THE HEAVIEST. ALTHOUGH LESS CERTAIN...NATIONAL WEATHER SERVICE FORECAST MODELS SHOW ABUNDANT MOISTURE AND FAVORABLE UPPER LEVEL CONDITIONS...SOMETIMES WITH LOCAL LOW PRESSURE VORTICES FORMING... THAT WILL PROLONG THIS EXTENDED WET PERIOD THROUGH THE WEEKEND OF 18-19 OCTOBER. AREAS WORST HIT RUN THE RISK OF 15 TO 40 INCHES OF RAINFALL BETWEEN 10 OCTOBER AND 19 OCTOBER...NEVERTHELESS SOME AREAS OF PUERTO RICO MAY RECEIVE LESS THAN 2 TO 3 INCHES DURING THE SAME PERIOD. AREAS IN THE U.S. VIRGIN ISLANDS MAY SEE AS MUCH AS 6 TO 8 INCHES BY 19 OCTOBER. LOCAL EMERGENCY MANAGERS SHOULD REVIEW STAFFING AND RESOURCE REQUIREMENTS. CITIZENS SHOULD CHECK EMERGENCY SUPPLIES...AND FLOOD PROCEDURES AND MAKE PRIOR ARRANGEMENTS TO LEAVE FLOOD PRONE AREAS SHOULD RAINFALL DEVELOP AS EXPECTED. AREA RESIDENTS SHOULD LOOK FOR ALTERNATE ROUTES IN CASE THEY ARE STRANDED BEHIND FLOODING IN LOW LYING AREAS. IT IS NEVER SAFE TO CROSS A FLOODED ROAD. EVERYONE SHOULD REMAIN ABREAST OF THE DEVELOPMENT OF THIS SITUATION EITHER BY NOAA WEATHER RADIO OR LOCAL MEDIA. ALTHOUGH CONVECTION IN THE AREA OF INTEREST IS NOT AS DEEP OR AS STRONG AS LAST MONTH...FAVORABLE CONDITIONS FOR HEAVY RAIN WILL LAST LONGER AND THE WEATHER-PRODUCING TROUGH WILL MOVE AS SLOWLY AS THE WAVE IN THE PREVIOUS EVENT...WHICH COULD PROLONG THE FLOODING FOR A LONGER PERIOD. $$ SNELL