An elongated area of moisture associated with a surface trough moving across the area produced scattered to numerous showers and a few thunderstorms during the late afternoon and evening. The heaviest shower activity occurred in sections of the northeast, central interior, southwest, and San Juan.
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Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS SJU wrote it up.
An elongated area of moisture associated with a surface trough moving across the area produced scattered to numerous showers and a few thunderstorms during the late afternoon and evening. The heaviest shower activity occurred in sections of the northeast, central interior, southwest, and San Juan.
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS San Juan, PR wrote its last area forecast discussion before the first event at May 12, 3:37 PM AST, 1 hour 8 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SAN JUAN PR 337 PM AST TUE MAY 12 2009 .SYNOPSIS...FRESH TRADES WILL PERSIST ACROSS THE NORTHEAST CARIBBEAN THROUGH THE END OF THE WEEK. WEAK TROUGH ALOFT AND ABUNDANT MOISTURE WILL KEEP WET CONDITIONS THROUGH THE END OF THE WEEK. MID LEVEL RIDGE WILL BUILD FOR THE WEEKEND BRINGING DRIER CONDITIONS. && .DISCUSSION...LATEST MICROWAVE IMAGERY SHOWS PLUME OF MOISTURE WITH 2.0+ INCHES PRECIPITABLE WATER EXTENDING FROM 60W WNW THROUGH THE LEEWARDS TO THE USVI/PR AND THE EASTERN PORTION OF THE DOMINICAN REPUBLIC IS FCST TO REMAIN OVR THE NORTHEAST CARIBBEAN OVR THE NEXT FEW DAYS. THIS IN COMBINATION WITH A SURFACE TROUGH LOCATED ALONG 64W IN ADDITION TO LOW-LVL VORTICES AS SEEN ON RECENT VISIBLE IMAGERY WILL KEEP A VERY WET FORECAST FOR THE NEXT 24 HRS. ABUNDANT MOISTURE AND WEAK TROUGH ALOFT LIKELY TO KEEP WET CONDITIONS THROUGH THE END OF THE WORK WEEK. CONTEMPLATED ISSUING A FLASH FLOOD WATCH FOR TOMORROW HOWEVER MODEL SOUNDINGS SHOW WINDS IN THE BDRY LYR IN THE 20-25 KT RANGE WHICH SHOULD KEEP SHOWERS MOVING ALONG AND PREVENTING RAINS FROM BECOMING TOO EXCESSIVE. RAIN GAGES ACROSS NORTHEAST PR SHOW RAINFALL RATES OF UP TO AN INCH IN ONE HOUR. LOCALIZED FLOODING LIKELY IN SOME AREAS BUT DONT THINK WILL SEE WIDESPREAD FLOODING ATTM. DRIER WILL WORK INTO THE NORTHEAST CARIBBEAN ON SAT ON BACKSIDE OF UPPER LOW OVR THE CNTRL ATLC BRINGING A SIGNIFICANT IMPROVEMENT TO THE WX CONDITIONS. && .AVIATION...EXPECT MVFR CONDITIONS IN PASSING SHRA ACTIVITY AT ALL SITES UNTIL AROUND 22Z. TSRA POSSIBLE TJMZ AND TJBQ 18Z TO 22Z WITH TEMPO IFR LIKELY TJBQ. OTHERWISE...EXPECT SHOWERY CONDITIONS TO CONTINUE WITH TEMP MVFR IN PASSING SHRA ACTIVITY...AND LOW LEVEL WINDS TO 20 KNOTS DURING THE DAY TODAY AND TOMORROW. && .MARINE...SCA IN EFFECT FOR SEVERAL MARINE ZONES. PLEASE REFER TO MARINE WEATHER MESSAGE FOR MORE DETAILS. && .PRELIMINARY POINT TEMPS/POPS... SJU 75 83 75 83 / 80 80 40 30 STT 75 81 75 81 / 70 60 20 20 && .SJU WATCHES/WARNINGS/ADVISORIES... PR...NONE. VI...NONE. && 93/64
HAZARDOUS WEATHER OUTLOOK FOR PUERTO RICO AND THE U.S. VIRGIN...CORRECTED ISLANDS NATIONAL WEATHER SERVICE SAN JUAN PR 1018 AM AST TUE MAY 12 2009 AMZ710>745-PRZ001>013-131430- SAN JUAN AND VICINITY-NORTHEAST-SOUTHEAST-EASTERN INTERIOR- NORTH CENTRAL-CENTRAL INTERIOR-PONCE AND VICINITY-NORTHWEST- WESTERN INTERIOR-MAYAGUEZ AND VICINITY-SOUTHWEST-CULEBRA-VIEQUES- THE NEARSHORE AND OFF SHORE ATLANTIC AND CARIBBEAN COASTAL WATERS- 1018 AM AST TUE MAY 12 2009 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PUERTO RICO AND THE ADJACENT COASTAL WATERS. .DAY ONE...TODAY AND TONIGHT AN AREA OF LOW TO MID LEVEL MOISTURE...ASSOCIATED WITH A SURFACE TROUGH...ACROSS THE NORTHERN LEEWARD ISLANDS EARLY THIS MORNING WILL CONTINUE TO PRODUCE SCATTERED SHOWERS AND A FEW THUNDERSTORMS ACROSS EASTERN SECTIONS OF PUERTO RICO DURING THE REST OF THE MORNING HOURS. THIS MOISTURE IN COMBINATION WITH DIURNAL HEATING AND LOCAL TERRAIN EFFECTS WILL INDUCE THE DEVELOPMENT OF SHOWERS AND ISOLATED THUNDERSTORMS ESPECIALLY ACROSS WESTERN AND INTERIOR SECTIONS OF PUERTO RICO DURING THE AFTERNOON AND EVENING HOURS. PERIODS OF MODERATE TO LOCALLY HEAVY RAINFALL ARE POSSIBLE. WITH THE ALREADY SATURATED SOIL ACROSS MUCH OF PUERTO RICO...THE POTENTIAL FOR URBAN...SMALL STREAM...AND RIVER FLOODING AS WELL LOCAL MUDSLIDES IN AREAS OF STEEP TERRAIN REMAIN HIGH THIS AFTERNOON AND THIS EVENING. .DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY LINGERING MOISTURE ACROSS THE REGION WILL RESULT IN THE DEVELOPMENT OF SHOWERS AND ISOLATED THUNDERSTORM FOCUSED MAINLY ACROSS WESTERN INTERIOR SECTIONS OF THE ISLAND ESPECIALLY DURING THE AFTERNOONS...WHERE MINOR FLOODING MAY OCCUR ACROSS LOW LYING AND POOR DRAINAGE AREAS...URBAN LOCATIONS AND LOCAL STREET AND HIGHWAYS WEDNESDAY AND CONTINUING THROUGH MONDAY. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION NOT REQUIRED AT THE MOMENT...BUT REPORTS OF RAINFALL AMOUNTS AND FLOODING WOULD BE GREATLY APPRECIATED. AMZ715-725-VIZ001-002-131430- ST. THOMAS ST. JOHN ADJACENT ISLANDS-ST CROIX- NEARSHORE ATLANTIC AND ADJACENT CARIBBEAN COASTAL WATERS- 1018 AM AST TUE MAY 12 2009 THIS HAZARDOUS WEATHER OUTLOOK IS FOR THE U.S. VIRGIN ISLANDS AND THE ADJACENT COASTAL WATERS. .DAY ONE...TODAY AND TONIGHT AN AREA OF LOW TO MID LEVEL MOISTURE...ASSOCIATED WITH A SURFACE TROUGH...ACROSS THE NORTHERN LEEWARD ISLANDS EARLY THIS MORNING WILL CONTINUE TO PRODUCE SCATTERED SHOWERS AND A FEW THUNDERSTORMS ACROSS THE U.S. VIRGIN ISLANDS AND THE SURROUNDING COASTAL WATERS TODAY. .DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY LINGERING MOISTURE ACROSS THE REGION WILL RESULT IN THE DEVELOPMENT OF SHOWERS AND A FEW THUNDERSTORMS ACROSS THE REGION DURING THE PERIOD. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION NOT REQUIRED AT THE MOMENT...BUT REPORTS OF RAINFALL AMOUNTS WOULD BE GREATLY APPRECIATED.
The national radar mosaic for the moment the first event began.
1 flood. Local standard time, as filed.
River Fajardo was reported out of its banks over Highways PR-53 and PR-3, blocking traffic at Los Cilitos.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Puerto Rico in 2009Every state in 2009This day in weather historyWarnings in Puerto Rico, May 2009
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 158712.