Surface trough moving across the area in combination with upper level low and associated trough north of Puerto Rico, produced numerous showers and isolated thunderstorms mainly over north central Puerto Rico.
Every event with a place to put it. Tap one for its entry below.
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.
Surface trough moving across the area in combination with upper level low and associated trough north of Puerto Rico, produced numerous showers and isolated thunderstorms mainly over north central Puerto Rico.
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 4, 4:23 PM AST, 57 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SAN JUAN PR 423 PM AST MON MAY 4 2009 .DISCUSSION...SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS AFFECTED THE ISLANDS OF ST JOHN AND ST THOMAS....PRODUCING RAINFALL ACCUMULATIONS OF AROUND 2 INCHES. ALSO SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS DEVELOPED ALONG THE THE INTERIOR SECTIONS OF PUERTO RICO...THESE SHOWERS MOVED SLOWLY NORTHWARD AFFECTING MOST OF THE NORTHERN HALF OF PUERTO RICO. AT THIS MOMENT...AN AREA OF SHOWERS CONTINUE TO AFFECT WESTERN PORTIONS OF PUERTO RICO. THESE SHOWERS WILL LINGER THROUGH LATE EVENING. A MID TO UPPER LEVEL TROUGH WILL CONTINUE TO PRODUCE A VERY UNSTABLE ATMOSPHERE THROUGH THE INCOMING WEEKEND. A 70 KNOTS JET STREAK OVER THE LOCAL AREA IS ALSO CONTRIBUTING ON THE SHOWER AND THUNDERSTORM ENHANCEMENT. THESE WEATHER FEATURES PROMISE TO GENERATE NUMEROUS SHOWERS AND THUNDERSTORMS THROUGH AT LEAST FRIDAY. SATURATED SOILS AND INCREASING SHOWERS THROUGH THE WEEK WILL INCREASE THE FLOODING POTENTIAL FOR PUERTO RICO AND THE USVI THE NEXT SEVERAL DAYS. RESIDENTS AND VISITORS OF PUERTO RICO SHOULD REMAIN ALERT TO THE LATEST FORECASTS AS FLASH FLOOD WATCHES AND WARNINGS WILL LIKELY BE REQUIRED AT SOME POINT THIS WEEK. && .AVIATION...EXPECT MVFR OR EVEN IFR CONDITIONS ACROSS TIST AND TISX DURING THE REST OF THE AFTERNOON AND THE EVENING HOURS. SHOWER ACTIVITY WILL DIMINISH ACROSS TJBQ AND TJMZ THIS EVENING WITH MAINLY VFR CONDITIONS THIS EVENING AND OVERNIGHT. HOWEVER AN INCREASE IN LOW LEVEL MOISTURE ACCOMPANYING THE PREVAILING EAST TO SOUTHEAST WIND FLOW FOR TOMORROW AFTERNOON...WILL BRING PERIODS OF MVFR CONDITIONS ACROSS TJBQ AND TJMZ. LATEST TJSJ 12Z SOUNDING INDICATED A LIGHT AND VARIABLE WIND FLOW FROM THE SURFACE TO AROUND 10K FEET...BECOMING WESTWARD AND STRONGER ABOVE 10K FEET. && .MARINE...NORMAL MARINE CONDITIONS ARE EXPECTED TO PREVAIL FOR THE REST OF THE WEEK BUT MARINERS SHOULD EXERCISE CAUTIONS FOR THUNDERSTORMS MOVING ACROSS THE LOCAL WATERS. THESE SHOWERS AND THUNDERSTORMS COULD PRODUCE LOCALLY HIGHER WAVES...LIGHTNING STRIKES...AND HEAVY DOWNPOURS. && .PRELIMINARY POINT TEMPS/POPS... SJU 75 85 75 85 / 50 60 50 70 STT 75 86 75 86 / 50 60 60 70 && .SJU WATCHES/WARNINGS/ADVISORIES... PR...NONE. VI...NONE. && 72/10
HAZARDOUS WEATHER OUTLOOK FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS NATIONAL WEATHER SERVICE SAN JUAN PR 1210 PM AST MON MAY 4 2009 AMZ710>745-PRZ001>013-051615- 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- 1210 PM AST MON MAY 4 2009 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PUERTO RICO AND THE ADJACENT COASTAL WATERS. .DAY ONE...THIS AFTERNOON AND TONIGHT PERIODS OF MODERATE TO HEAVY SHOWERS AND ISOLATED THUNDERSTORMS WILL PRODUCE LOCALIZED FLOODING OF URBAN AREAS AND SMALL STREAMS AS HEAVY RAIN BANDS CONTINUE TO MOVE IN FROM THE SOUTH AND EAST. .DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY A NEARLY STATIONARY AREA OF LOW PRESSURE IN THE MID LEVELS OF THE ATMOSPHERE LOCATED NORTH OF HISPANIOLA WILL COMBINE WITH A VERY MOIST EAST SOUTHEAST FLOW TO GENERATE WIDESPREAD HEAVY RAINS AND THE POTENTIAL FOR FLASH FLOODING. .SPOTTER INFORMATION STATEMENT... AMZ715-725-VIZ001-002-051615- ST. THOMAS ST. JOHN ADJACENT ISLANDS-ST CROIX- NEARSHORE ATLANTIC AND ADJACENT CARIBBEAN COASTAL WATERS- 1210 PM AST MON MAY 4 2009 THIS HAZARDOUS WEATHER OUTLOOK IS FOR THE U.S. VIRGIN ISLANDS AND THE ADJACENT COASTAL WATERS. .DAY ONE...THIS AFTERNOON AND TONIGHT PERIODS OF MODERATE TO HEAVY SHOWERS AND ISOLATED THUNDERSTORMS WILL PRODUCE LOCALIZED FLOODING OF URBAN AREAS AND SMALL STREAMS AS HEAVY RAIN BANDS CONTINUE TO MOVE IN FROM THE SOUTH AND EAST. .DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY A NEARLY STATIONARY AREA OF LOW PRESSURE IN THE MID LEVELS OF THE ATMOSPHERE LOCATED NORTH OF HISPANIOLA WILL COMBINE WITH A VERY MOIST EAST SOUTHEAST FLOW TO GENERATE WIDESPREAD HEAVY RAINS AND THE POTENTIAL FOR FLASH FLOODING. .SPOTTER INFORMATION STATEMENT...
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE SAN JUAN PR
1255 PM AST MON MAY 04 2009
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
1253 PM FLOOD COROZAL 18.34N 66.31W
05/04/2009 COROZAL PR EMERGENCY MNGR
URBAN FLOODING AFFECTED HOUSES IN BARRIO CIBUCO AT THE
MUNICIPALTY OF COROZAL.
&&
EMORALESPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE SAN JUAN PR
417 PM AST MON MAY 04 2009
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0407 PM HEAVY RAIN 1 ENE CRUZ BAY 28.04N 81.89W
05/04/2009 U0.00 INCH POLK FL EMERGENCY MNGR
NATIONAL PARK SERVICE FLOODED. ONE LANE OF THE WESTIN
BRIDGE FLOODED. ROUTE 102, 105 AND TENNIS COURT ROAD
FLOODED. MARKET PLACE NEXT TO WAPA FLOODED. ONE BOAT
CAPSIZED.
&&
RMOJICAPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE SAN JUAN PR
417 PM AST MON MAY 04 2009
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0407 PM HEAVY RAIN 1 ENE CRUZ BAY 28.04N 81.89W
05/04/2009 U0.00 INCH SAINT JOHN USVI EMERGENCY MNGR
NATIONAL PARK SERVICE FLOODED. ONE LANE OF THE WESTIN
BRIDGE FLOODED. ROUTE 102, 105 AND TENNIS COURT ROAD
FLOODED. MARKET PLACE NEXT TO WAPA FLOODED. ONE BOAT
CAPSIZED.
&&
RMOJICAThe national radar mosaic for the moment the first event began.
1 flood. Local standard time, as filed.
Roads 620 and 647 were flooded due to overflowing water from small stream Quebrada Ponderosa.
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: 169954.