An upper level low northeast of Puerto Rico, combined with daytime heating and local effects to produced scattered to numerous showers with isolated strong thunderstorms over the western interior section 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 low northeast of Puerto Rico, combined with daytime heating and local effects to produced scattered to numerous showers with isolated strong thunderstorms over the western interior section 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 Sep 13, 11:02 AM AST, 4 hours 8 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SAN JUAN PR 1102 AM AST THU SEP 13 2012 .UPDATE... SATELLITE IMAGES SHOWS THE TUTT LOCATED TO THE NORTHEAST OF OUR CWA...WHICH WILL COMBINE WITH THE DIURNAL HEATING AND AVAILABLE HUMIDITY TO ENHANCE DEVELOPMENT OF SHOWERS AND THUNDERSTORMS. THESE WILL FOCUS OVER SECTIONS OF WESTERN INTERIOR MOVING TO THE NORTHWEST OF PUERTO RICO...THEREFORE THE FORECAST WAS SHIFT MORE TO THESE AREAS FOR THIS AFTERNOON. && .AVIATION UPDATE... VFR CONDITIONS WILL CONTINUE TO PREVAIL AT ALL TAF SITES TODAY. HOWEVER SHRA/TSRA WILL DEVELOP MAINLY ACROSS WESTERN INTERIOR AND NORTHWEST OF PUERTO RICO AFTER 13/17Z AFFECTING TJMZ AND TJBQ AND POSSIBLY VCTS IN TJPS. SURFACE WINDS WILL CONTINUE MAINLY EAST AT 10 TO 15 KTS. && .PREV DISCUSSION... /ISSUED 517 AM AST THU SEP 13 2012/ SYNOPSIS...AT UPPER LEVELS...THE LOW PRESSURE TO THE NORTHEAST WILL MOVE INTO THE LOCAL ATLANTIC WATERS BY FRIDAY. HOWEVER HIGH PRESSURE ASSOCIATED WITH TROPICAL STORM NADINE AND THAT OVER THE NORTHWEST BAHAMAS WILL SQUEEZE THE LOW OUT BY SATURDAY SUCH THAT HIGH PRESSURE DOMINATES THE GREATER ANTILLES THROUGH MUCH OF NEXT WEEK. AT MID LEVELS...WEAK LOW PRESSURE OVER THE AREA WILL GIVE WAY TO HIGH PRESSURE RIDGING IN FROM THE EAST ONCE NADINE HAS MOVED NORTH OUT OF THE TROPICAL ATLANTIC SATURDAY. HIGH PRESSURE WILL THEN DOMINATE THE NORTHEASTERN CARIBBEAN THROUGH WEDNESDAY. EVEN STRONGER HIGH PRESSURE WILL FORM IN THE WESTERN ATLANTIC NORTH OF THE AREA BY THE FOLLOWING WEEKEND. AT LOWER LEVELS...LOW PRESSURE WILL PERSIST OVER COLOMBIA AND THE SOUTHWEST CARIBBEAN WHILE WEAK HIGH PRESSURE CONTINUES NORTH OF THE LOCAL AREA. THE GFS IS SUGGESTING THAT ANOTHER TROPICAL SYSTEM WILL FORM IN THE TROPICAL ATLANTIC EARLY NEXT WEEK AND MOVE VERY SIMILAR TO THE TRACK OF NADINE. DISCUSSION...THE MIMIC PRODUCT HAS BEEN SHOWING INCREASING MOISTURE OVER THE AREA...SOME OF WHICH APPEARS TO BE ASSOCIATED WITH TROPICAL STORM NADINE OR THE WAVE THAT GENERATED IT. THIS MOISTURE WILL CONTINUE AT LOW LEVELS...ALTHOUGH THERE IS A DECIDED WEAKNESS IN MOISTURE AT MID LEVELS FOR MUCH OF THE NEXT SEVEN DAYS. THE UPPER LEVEL LOW WILL ENHANCE INSTABILITY TODAY AND TOMORROW...BUT MODELS SHOW THE LIFTED INDEX BECOMING MORE STABLE THROUGH MONDAY AFTERNOON. ON TUESDAY A BAND OF MOISTURE MOVES INTO THE AREA WITH A TROPICAL WAVE THAT IS MOVING ACROSS 40 WEST TODAY. THIS MOISTURE CONTINUES THROUGH LATE NEXT FRIDAY AT LEAST...BREAKING A DRIER THAN NORMAL PERIOD AND ADDING MOISTURE NOT JUST TO THE LOWER LEVELS BUT ALSO TO THE REST OF THE ATMOSPHERE. THE NEXT FEATURE IS EXPECTED TO MOVE OFF THE AFRICAN COAST ON FRIDAY AND DEVELOP...ACCORDING TO THE LATEST GUIDANCE...INTO A TROPICAL CYCLONE THAT FOLLOWS CLOSELY IN THE PATH OF T.S. NADINE. SO CLOSELY IN FACT...THAT THE 13/00Z POSITION OF NADINE AND THE 23/00Z POSITION OF THIS CYCLONE ARE BUT 215 MILES APART IN THE GFS. INTERMEDIATE MODEL RUNS HAVE NOT BEEN CONSISTENT...SO AS ALWAYS...THERE IS CONSIDERABLE UNCERTAINTY ABOUT THE FORMATION AND TRACK OF THE NEXT SYSTEM. THERE IS RATHER LESS UNCERTAINTY HOWEVER ABOUT OUR WEATHER WHICH WILL CONTINUE TO BE FAIRLY SIMILAR TO WHAT WE HAVE SEEN...AFTERNOON SHOWERS AND THUNDERSTORMS...MAINLY IN THE WEST. MOS HAS BEEN RUNNING A LITTLE COOL FOR THE LAST SEVERAL DAYS AND WITH NO DAYS UNDER 90 DEGREES SINCE 3 SEPTEMBER HAVE RAISED MAXIMUM TEMPERATURES AT SAN JUAN BACK TO 90 DEGREES THROUGH AT LEAST SATURDAY. SHOULD WINDS TURN A LITTLE MORE TO THE SOUTHEAST THIS AFTERNOON AS THE NAM SUGGESTS...TEMPERATURES MAY REACH 91 OR 92 DEGREES AGAIN. AVIATION... VFR CONDITIONS WILL CONTINUE TO PREVAIL AT ALL TAF SITES THROUGH AT LEAST 13/17Z. SHRA/TSRA WILL DEVELOP MAINLY ACROSS WESTERN INTERIOR AFTER 13/17Z AFFECTING TJMZ AND TJPS AND OBSCURING HIGHER TERRAIN. SURFACE WINDS WILL CONTINUE MAINLY EAST AT 10 TO 15 KTS. MARINE...CURRENT PROJECTIONS DO NOT ANTICIPATE SEAS OF 7 FEET OR GREATER IN THE NEXT 10 DAYS. ALTHOUGH SOME SWELL WILL MOVE INTO THE AREA FROM NADINE TONIGHT...WITH THE BEST HEIGHTS MIDDAY ON FRIDAY...SEAS SHOULD REMAIN JUST UNDER 7 FEET. SHOULD SEAS RISE ABOVE THE MODEL FORECASTS AT BUOYS 41043 OR 41044 THIS FORECAST MAY BE REVISED UPWARD AND WILL...OF COURSE...DEPEND ON THE DEVELOPMENT OF TROPICAL STORM NADINE INTO A HURRICANE. && .PRELIMINARY POINT TEMPS/POPS... SJU 90 78 90 78 / 30 30 20 10 STT 88 78 89 78 / 30 40 20 20 && .SJU WATCHES/WARNINGS/ADVISORIES... PR...NONE. VI...NONE. COASTAL WATERS...NONE. && 23/11/02/DS
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE SAN JUAN PR 533 AM AST THU SEP 13 2012 AMZ710>745-PRZ001>013-140945- 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- 533 AM AST THU SEP 13 2012 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PUERTO RICO AND THE ADJACENT ATLANTIC COASTAL WATERS. .DAY ONE...TODAY AND TONIGHT NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME. .DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION WILL NOT BE NEEDED. AMZ715-725-VIZ001-002-140945- ST. THOMAS ST. JOHN ADJACENT ISLANDS-ST CROIX- NEARSHORE ATLANTIC AND ADJACENT CARIBBEAN COASTAL WATERS- 533 AM AST THU SEP 13 2012 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 AT THIS TIME. .DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION WILL NOT BE NEEDED.
COMUNICADO ESPECIAL SOBRE LAS CONDICIONES DEL TIEMPO SERVICIO NACIONAL DE METEOROLOGIA SAN JUAN PR 115 PM AST JUEVES 13 DE SEPTIEMBRE DE 2012 PRC131-131745- SAN SEBASTIAN PR- 115 PM AST JUEVES 13 DE SEPTIEMBRE DE 2012 ...ADVERTENCIA DE TIEMPO SIGNIFICATIVO POR TORNADAS FUERTES SOBRE SAN SEBASTIAN... A LAS 1:09 PM AST...EL RADAR DOPPLER INDICO UNA FUERTE TRONADA 4 MILLAS AL ESTE DE SAN SEBASTIAN...ESTACIONARIA. LLUVIAS TORRENCIALES Y GRANIZO PEQUENO SE PUEDEN ESPERAR CON ESTA TRONADA. RELAMPAGOS INTENSOS HAN SIDO REPORTADOS CON ESTA TORMENTA. SI SE ENCUENTRA AL AIRE LIBRE...MANTENGASE ALEJADO DE OBJETOS ALTOS COMO LOS ARBOLES. MUEVASE AL INTERIOR SI ES POSIBLE. CUANDO ESTE BAJO TECHO...MANTENGASE ALEJADO DE LAS VENTANAS Y PUERTAS Y EVITE USAR EL TELEFONO A MENOS QUE SEA UNA EMERGENCIA. TRATE DE DESCONECTAR CUALQUIER EQUIPO ELECTRICO INNECESARIO ANTES DE QUE AL TORMENTA SE ACERQUE.
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE SAN JUAN PR 131 PM AST THU SEP 13 2012 PRC081-131-131800- LARES PR-SAN SEBASTIAN PR- 131 PM AST THU SEP 13 2012 ...SIGNIFICANT WEATHER ADVISORY FOR NEAR SEVERE THUNDERSTORMS OVER LARES AND SAN SEBASTIAN COUNTY LINE... AT 128 PM AST...NATIONAL WEATHER SERVICE INDICATED A NEAR SEVERE THUNDERSTORM NEAR THE COUNTY LINE BETWEEN SAN SEBASTIAN AND LARES WITH MARBLE TO PENNY SIZE HAIL...TORRENTIAL RAINFALL AND WIND GUSTS TO 45 MPH WITH MOVEMENT NEARLY STATIONARY. 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.
SPECIAL WEATHER STATEMENT...CORRECTED NATIONAL WEATHER SERVICE SAN JUAN PR 135 PM AST THU SEP 13 2012 PRC081-131-131845- LARES PR-SAN SEBASTIAN PR- 135 PM AST THU SEP 13 2012 ...SIGNIFICANT WEATHER ADVISORY FOR NEAR SEVERE THUNDERSTORMS OVER LARES AND SAN SEBASTIAN COUNTY LINE... AT 128 PM AST...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A NEAR SEVERE THUNDERSTORM NEAR THE COUNTY LINE BETWEEN SAN SEBASTIAN AND LARES WITH MARBLE TO PENNY SIZE HAIL...TORRENTIAL RAINFALL AND WIND GUSTS TO 45 MPH WITH MOVEMENT NEARLY STATIONARY. 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.
COMUNICADO ESPECIAL SOBRE LAS CONDICIONES DEL TIEMPO SERVICIO NACIONAL DE METEOROLOGIA SAN JUAN PR 131 PM AST JUEVES 13 DE SEPTIEMBRE DE 2012 PRC081-131-131800- LARES PR-SAN SEBASTIAN PR- 131 PM AST JUEVES 13 DE SEPTIEMBRE DE 2012 ...ADVERTENCIA DE TIEMPO SIGNIFICATIVO POR TRONADAS CASI SEVERAS SOBRE SAN SEBASTIAN Y LARES... A LAS 1:28 PM AST...EL RADAR DOPPLER INDICO UNA TRONADA CASI SEVERA CERCA DEL LIMITE ENTRE SAN SEBASTIAN Y LAREAS CON GRANIZO DE TAMANO DE CANICA A UN CENTAVO...LLUVIAS TORRENCIALES Y VIENTOS EN RAFAGAS DE HASTA 45 MILLAS POR HORA CON UN MOVIMIENTO CASI ESTACIONARIO. RELAMPAGOS INTENSOS HAN SIDO REPORTADOS CON ESTA TORMENTA. SI SE ENCUENTRA AL AIRE LIBRE...MANTENGASE ALEJADO DE OBJETOS ALTOS COMO LOS ARBOLES. MUEVASE AL INTERIOR SI ES POSIBLE. CUANDO ESTE BAJO TECHO...MANTENGASE ALEJADO DE LAS VENTANAS Y PUERTAS Y EVITE USAR EL TELEFONO A MENOS QUE SEA UNA EMERGENCIA. TRATE DE DESCONECTAR CUALQUIER EQUIPO ELECTRICO INNECESARIO ANTES DE QUE AL TORMENTA SE ACERQUE.
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE SAN JUAN PR 158 PM AST THU SEP 13 2012 PRC039-131830- CIALES PR- 158 PM AST THU SEP 13 2012 ...SIGNIFICANT WEATHER ADVISORY FOR STRONG THUNDERSTORMS OVER CIALES... AT 151 PM AST...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A STRONG THUNDERSTORM OVER CIALES NEARLY STATIONARY OR DRIFTING WEST NORTHWEST. THIS STORMS MAY CONTAIN SMALL HAIL TO THE SIZE OF PEAS AND TORRENTIAL RAINFALL OF ONE TO TWO INCHES OF RAIN PER HOUR.
COMUNICADO ESPECIAL SOBRE LAS CONDICIONES DEL TIEMPO SERVICIO NACIONAL DE METEOROLOGIA SAN JUAN PR 158 PM AST JUEVES 13 DE SEPTIEMBRE DE 2012 PRC039-131830- CIALES PR- 158 PM AST JUEVES 13 DE SEPTIEMBRE DE 2012 ...ADVERTENCIA DE TIEMPO SIGNIFICATIVO POR FUERTES TRONADAS SOBRE CIALES... A LA 1:51 PM AST...EL RADAR DOPPLER INDICO UNA FUERTE TRONADA SOBRE CIALES CASI ESTACIONARIO O MOVIENDOSE HACIA EL OESTE NOROESTE. ESTA TRONADA PUEDE CONTENER PEQUENO GRANIZO DEL TAMANO DE GANDULES Y LLUVIA TORRENCIAL DE UNA A DOS PULGADAS DE LLUVIA POR HORA.
The San Juan radar (TJUA), 87 km away, was scanning. The volume nearest the first event began at 19:11 UTC.
1 tornado. Local standard time, as filed.
A brief F0 tornado was reported at Barrio Minas in the municipality of Lares.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Puerto Rico in 2012Every state in 2012This day in weather historyThe tornado archive for Puerto Rico, 2012Warnings in Puerto Rico, September 2012
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: 414693.