An upper level trough located over the Western Atlantic, induced a southwesterly wind flow at the surface, which combined with daytime heating, led to heavy rainfall over the San Juan metropolitan area and the North Central sections of Puerto Rico.
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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 upper level trough located over the Western Atlantic, induced a southwesterly wind flow at the surface, which combined with daytime heating, led to heavy rainfall over the San Juan metropolitan area and the North Central sections of 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 27, 3:00 PM AST, 2 hours 6 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SAN JUAN PR 300 PM AST MON MAY 27 2013 .SYNOPSIS...THE BASE OF THE BROAD MID TO UPPER LEVEL TROUGH EXTENDS ACROSS THE NORTHEAST CARIBBEAN INTO THE EASTERN CARIBBEAN FROM THE WESTERN ATLANTIC. THIS FEATURE WILL CONTINUE TO SLOWLY FILL/WEAKEN THROUGH TUESDAY AS IT LIFTS FURTHER EAST NORTHEAST INTO THE CENTRAL ATLANTIC. AS A RESULT...A PREVAILING SOUTHWESTERLY WIND PATTERN WILL BE MAINTAINED ALOFT AT LEAST UNTIL TUESDAY. BY WEDNESDAY HIGH PRESSURE RIDGE IS TO THEN SPREAD WESTWARDS OVER THE FORECAST AREA AND INDUCE A WEST NORTHWEST WIND FLOW ALOFT. IN THE LOW LEVELS...STRONG HIGH PRESSURE SPREAD ACROSS THE NORTH CENTRAL AND WESTERN ATLANTIC WILL MAINTAIN MODERATE TO STRONG EAST SOUTHEAST TRADE WINDS ACROSS THE REGION THROUGH MOST OF THE WEEK. THE PREVAILING WIND FLOW AND WEATHER PATTERN WILL MAINTAIN A HIGH TROPICAL MOISTURE CONVERGENCE ZONE ACROSS THE REGION AND THEREFORE RESULT IN A MOIST AND UNSETTLED WEATHER PATTERN THROUGH MOST OF THE WEEK. && .DISCUSSION...LATEST SATELLITE WATER VAPOR IMAGERY PLACED THE BASE OF THE UPPER LEVEL TROUGH ACROSS PUERTO RICO AND THE VIRGIN ISLANDS AS IT CONTINUED TO SLOWLY LIFT EAST NORTHEAST. THE MOIST SOUTHEASTERLY WIND FLOW IN COMBINATION WITH THIS FEATURE WILL CONTINUE TO ENHANCE CONVECTION ACROSS PARTS OF THE ISLANDS FOR THE NEXT FEW DAYS. THE MIMIC TPW AS WELL AS THE 12Z UPPER AIR SOUNDING DATA FOR BOTH TJSJ AND TFFR ALL SHOWED PRECIPITABLE WATER VALUES AT OR NEAR TWO INCHES ACROSS THE REGION...WITH CONSIDERABLE AMOUNTS OF DEEP LAYERED MOISTURE/CLOUDINESS SPREAD ACROSS THE REGION. THE PROXIMITY OF THE UPPER TROUGH ALONG WITH LOCAL AND DIURNAL EFFECTS WILL LEAD TO AFTERNOON CONVECTION MAINLY ACROSS PARTS OF THE WESTERN INTERIOR AND NORTHWEST SECTIONS OF PUERTO RICO TODAY. SOME THUNDERSTORMS MAY BE INTENSE AT TIMES AND WILL PRODUCE LOCALLY HEAVY DOWNPOURS AND BRIEF GUSTY WINDS. SIMILAR CONDITIONS CAN BE EXPECTED ON TUESDAY...HOWEVER BY TUESDAY AFTERNOON AND POSSIBLE ON WEDNESDAY...THE APPROACH OF THE UPPER LEVEL RIDGE FROM THE WEST WILL PROVIDE MORE FAVORABLE BETTER UPPER LEVEL VENTILATION/DIFFLUENCE FOR FURTHER ENHANCEMENT OF AFTERNOON CONVECTION. THEREFORE THE POTENTIAL FOR LOCALLY HEAVY SHOWERS AND ISOLATED STRONG THUNDERSTORMS WILL REMAIN HIGH AT LEAST THROUGH MID WEEK...ESPECIALLY OVER THE CENTRAL INTERIOR AND WEST SECTIONS OF PUERTO RICO EACH AFTERNOON. MODELS STILL CONTINUE TO SUGGEST CONVECTIVE INSTABILITY AND MOISTURE ADVECTION TO REMAIN HIGH THROUGH MOST OF THE WEEK AS WEAK PERTURBATIONS AND ASSOCIATED TROPICAL MOISTURE EMBEDDED IN THE EASTERLIES WILL CONTINUE TO PROPAGATE WESTWARD ACROSS THE EASTERN CARIBBEAN REGION. ALTHOUGH LOCALLY HEAVY RAINFALL CAN BE EXPECTED AT TIMES ACROSS THE REGION...IT IS NOT EXPECTED TO BE WIDESPREAD...AND SHOULD BE MORE LOCALIZED IN ISOLATED AREAS ACROSS THE ISLANDS FOR THE NEXT SEVERAL DAYS. & .AVIATION...PASSING SHRA AND DEVELOPING ISOLD TSRA WILL CAUSE TEMPO MVFR CONDS EN ROUTE AND VCTY OF TKPK...TNCM...TIST...TISX...AND TJSJ AT LEAST UNTIL 27/23Z. DEVELOPING AFTN TSRA ACROSS THE INTERIOR AND WRN PR WILL ALSO CAUSE MVFR/IFR CONDS FOR TJMZ AND POSSIBLY TJBQ TIL 27/23Z. MTN TOP OBSCR ACROSS THE CORDILLERA CENTRAL OF PR IS ALSO EXPECTED WITH THE DEVELOPING SHRA/TSRA. WINDS WILL REMAIN FROM THE E-SE AT 10-15 KTS WITH SFC WND GUST UP TO 25 KTS. MOSTLY VFR CONDS EXPECTED TO PREVAIL AFT 27/23Z. && .MARINE....MODERATE TO LOCALLY FRESH EASTERLY TRADES WILL PREVAIL ACROSS THE REGIONAL WATERS OVERNIGHT THROUGH TUESDAY. THEREFORE SMALL CRAFT SHOULD EXERCISE CAUTION DUE TO SEAS OF UP TO 6 FEET AND WINDS UP TO 20 KNOTS. && .PRELIMINARY POINT TEMPS/POPS... SJU 77 87 77 87 / 40 40 40 40 STT 78 87 78 88 / 50 50 50 50 && .SJU WATCHES/WARNINGS/ADVISORIES... PR...NONE. VI...NONE. COASTAL WATERS...NONE. && 25/09
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE SAN JUAN PR 610 AM AST MON MAY 27 2013 AMZ710>745-PRZ001>013-281015- 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- 610 AM AST MON MAY 27 2013 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PUERTO RICO AND THE ADJACENT ATLANTIC COASTAL WATERS. .DAY ONE...TODAY AND TONIGHT SHOWERS AND THUNDERSTORMS ARE EXPECTED TO DEVELOP ACROSS THE CORDILLERA CENTRAL EARLY THIS AFTERNOON. THEREFORE...FLOODING OF URBAN AREAS...SMALL STREAMS...CREEKS AND RIVERS ARE POSSIBLE ACROSS THE WEST AND WESTERN INTERIOR SECTIONS OF PUERTO RICO. MUDSLIDES IN AREAS OF STEEP TERRAIN ARE POSSIBLE. .DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME. .SPOTTER INFORMATION STATEMENT... REPORTS OF FLOODING AND HEAVY RAINFALL WILL BE APPRECIATED. AMZ715-725-VIZ001-002-281015- ST. THOMAS ST. JOHN ADJACENT ISLANDS-ST CROIX- NEARSHORE ATLANTIC AND ADJACENT CARIBBEAN COASTAL WATERS- 610 AM AST MON MAY 27 2013 THIS HAZARDOUS WEATHER OUTLOOK IS FOR THE U.S. VIRGIN ISLANDS AND THE ADJACENT COASTAL WATERS. .DAY ONE...TODAY AND TONIGHT NO HAZARDOUS WEATHER IS EXPECTED TODAY. .DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION WILL NOT BE NEEDED.
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE SAN JUAN PR 159 PM AST MON MAY 27 2013 PRC003-005-011-083-097-099-117-131-271900- ANASCO PR-MOCA PR-SAN SEBASTIAN PR-LAS MARIAS PR-RINCON PR- AGUADILLA PR-AGUADA PR-MAYAGUEZ PR- 159 PM AST MON MAY 27 2013 ...SIGNIFICANT WEATHER ADVISORY FOR STRONG THUNDERSTORMS OVER WESTERN PUERTO RICO... AT 153 PM AST...NATIONAL WEATHER SERVICE METEOROLOGIST DETECTED STRONG THUNDERSTORMS ACROSS WESTERN PUERTO RICO...MOVING NORTHWEST AT 10 MPH. THESE THUNDERSTORMS ARE CAPABLE OF PRODUCING HEAVY RAIN...STRONG GUSTY WINDS...INTENSE LIGHTNING...AND SMALL HAIL. INTENSE LIGHTNING IS REPORTED WITH THIS STORM. IF OUTDOORS...STAY AWAY FROM ISOLATED HIGH OBJECTS SUCH AS TREES. MOVE INDOORS IF POSSIBLE. WHEN INDOORS...STAY AWAY FROM WINDOWS AND DOORS AND AVOID USING TELEPHONES UNLESS IT IS AN EMERGENCY. TRY TO UNPLUG UNNECESSARY ELECTRICAL APPLIANCES BEFORE THE THUNDERSTORM APPROACHES. SUDDEN WINDS GUSTS OF 25 TO 35 MPH WILL BE POSSIBLE WITH THE THUNDERSTORMS AS WELL AS FREQUENT LIGHTNING.
COMUNICADO ESPECIAL SOBRE LAS CONDICIONES DEL TIEMPO SERVICIO NACIONAL DE METEOROLOGIA SAN JUAN PR 159 PM AST LUNES 27 DE MAYO DE 2013 PRC003-005-011-083-097-099-117-131-271900- ANASCO PR-MOCA PR-SAN SEBASTIAN PR-LAS MARIAS PR-RINCON PR- AGUADILLA PR-AGUADA PR-MAYAGUEZ PR- 159 PM AST LUNES 27 DE MAYO DE 2013 ...ADVERTENCIA DE TIEMPO SIGNIFICATIVO POR FUERTES TRONADAS SOBRE EL OESTE DE PUERTO RICO... A LA 1:53 PM AST...METEOROLOGOS DEL SERVICIO NACIONAL DE METEOROLOGIA DETECTO TRONADAS FUERTES A TRAVES DEL OESTE DE PUERTO RICO...MOVIENDOSE HACIA EL NOROESTE A 10 MPH. ESTAS TRONADAS SERAN CAPACES DE PRODUCIR FUERTES LLUVIAS...RAFAGAS DE VIENTO...RAYOS INTENSOS Y PEQUENO GRANIZO. SE HA REPORTADO INTENSOS RELAMPAGOS CON ESTAS TORMENTAS. SI SE ENCUENTRA EN EL EXTERIOR...MANTENGASE ALEJADO DE OBJETOS ALTOS COMO LOS ARBOLES. MUEVASE DENTRO DE UNA ESTRUCTURA SI ES POSIBLE. CUANDO ESTE DENTRO MANTENGASE ALEJADO DE PUERTAS Y VENTANAS EVITE USAR TELEFONOS A MENOS QUE SEA UNA EMERGENCIA. TRATE DE DESCONECTAR LOS ENSERES ELECTRICOS ANTES QUE SE ACERQUEN LAS TRONADAS. RAFAGAS REPENTINAS DE ENTRE 25 A 35 MPH PODRAN SER POSIBLES CON ESTAS TRONADAS AL IGUAL QUE RELAMPAGOS FRECUENTES. JJA/KN
The San Juan radar (TJUA), 31 km away, was scanning. The volume nearest the first event began at 21:05 UTC.
3 flood, 1 thunderstorm wind. Local standard time, as filed.
Urban flooding reported at Rio Piedras sector near Monte Hatillo building complex.
Areas of Barrio Machuchal was reported flooded.
Power lines downed at Ramal 8 and Ave Pi ero.
Urban flooding was reported at la Puntilla Sector in Arecibo.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Puerto Rico in 2013Every state in 2013This day in weather historyWarnings in Puerto Rico, May 2013
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: 457206, 457209, 457212, 457211.