A weak tropical wave passing south of Puerto Rico combined with strong daytime heating and local effects to produce scattered showers with thunderstorms over the interior 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.
A weak tropical wave passing south of Puerto Rico combined with strong daytime heating and local effects to produce scattered showers with thunderstorms over the interior 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 Sep 11, 3:02 PM AST, 2 hours 30 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SAN JUAN PR 302 PM AST TUE SEP 11 2012 .SYNOPSIS...MID TO UPPER LEVEL RIDGE PATTERN IS TO GRADUALLY WEAKEN THROUGH THURSDAY MORNING...ALLOWING TUTT TO SLOWLY RETROGRESS ACROSS THE NORTHEAST CARIBBEAN. A TROPICAL WAVE SOUTH OF THE FORECAST AREA WILL MOVE ACROSS THE EASTERN CARIBBEAN TONIGHT AND INTO THE CENTRAL CARIBBEAN BY WEDNESDAY MORNING. ANOTHER STRONG RIDGE IS EXPECTED TO BUILD OVER THE EASTERN CARIBBEAN/TROPICAL ATLANTIC DURING THE WEEKEND. && .DISCUSSION...VISIBLE IMAGERY SHOWS HIGH CLOUDS DRIFTING SOUTHWESTWARD OVER THE FORECAST AREA. DRY ADVECTION THIS MORNING HAS HELPED TO DELAY THE AFTERNOON CONVECTION...HOWEVER...SOME TOWERING CUMULUS HAVE BEEN OBSERVED ACROSS CENTRAL AND WESTERN PUERTO RICO THIS AFTERNOON. ATTM...RADAR DOPPLER ONLY INDICATES SHOWERS DOWNWIND OF ST THOMAS AND ST CROIX. WATER VAPOR IMAGERY REVEALS A BROAD ANTICYCLONIC CIRCULATION COVERING MOST OF THE GREATER ANTILLES AND A TUTT LOW JUST NORTHEAST OF THE NORTHERN LEEWARD ISLES. AS THE TUTT RETROGRESS OVER THE EASTERN CARIBBEAN...SURFACE FLOW WILL VEER TO THE SOUTHEAST EARLY ON THURSDAY. AS A RESULT...MOISTURE IS EXPECTED TO POOL ACROSS THE ISLANDS FROM THE SOUTHEAST LATER IN THE WEEK. FORECAST MODELS THEN SHOW AN INCREASE IN THE SHOWER ACTIVITY ACROSS THE LOCAL REGION... WITH ORGANIZED CONVECTION TO CLUSTER ACROSS WESTERN INTERIOR/NORTHWEST PORTIONS OF PUERTO RICO ESPECIALLY ON THURSDAY. TROPICAL DEPRESSION FOURTEEN FORMED IN THE CENTRAL ATLANTIC LATE THIS MORNING. IT WAS MOVING MAINLY WEST AT 10 MPH. THE OFFICIAL FORECAST FROM NHC SUGGEST THAT THE DEPRESSION SHOULD BE TURNING WEST-NORTHWEST TONIGHT OR EARLY WEDNESDAY MORNING. THE CYCLONE IS EXPECTED TO PASS WELL NORTHEAST OF THE REGION BY THE END OF THE WORK WEEK. && .AVIATION...VFR CONDITIONS WILL CONTINUE TO PREVAIL AT ALL TAF SITES DURING THE NEXT 24 HOURS. SHRA/TSRA WILL DEVELOP MAINLY ACROSS WESTERN INTERIOR AFTER 1930Z AFFECTING TJMZ AND VICINITY OF TJBQ. && .MARINE...MODERATE WINDS AND SEAS OF 2 TO 4 FEET ARE FORECAST THROUGH AT LEAST FRIDAY MORNING. MEANWHILE...SMALL NORTHEAST GROUNDSWELL OF AROUND 2 FEET ASSOCIATED WITH TS MICHAEL WILL REACH THE LOCAL WATERS WEDNESDAY. THEN...NORTHEAST SWELLS ASSOCIATED WITH TD #14 WILL INVADE OUR WATERS BY FRIDAY MORNING. THIS WILL LEAD TO SLIGHTLY ROUGHER SEAS BUT IT APPEARS NOW THAT CONDITIONS WILL REMAIN BELOW SCA CRITERIA. && .PRELIMINARY POINT TEMPS/POPS... SJU 79 90 79 89 / 20 20 10 20 STT 79 89 79 88 / 30 30 10 10 && .SJU WATCHES/WARNINGS/ADVISORIES... PR...NONE. VI...NONE. COASTAL WATERS...NONE. && 09/11
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE SAN JUAN PR 551 AM AST TUE SEP 11 2012 AMZ710>745-PRZ001>013-121000- 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- 551 AM AST TUE SEP 11 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...WEDNESDAY THROUGH MONDAY NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION WILL NOT BE NEEDED. AMZ715-725-VIZ001-002-121000- ST. THOMAS ST. JOHN ADJACENT ISLANDS-ST CROIX- NEARSHORE ATLANTIC AND ADJACENT CARIBBEAN COASTAL WATERS- 551 AM AST TUE SEP 11 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...WEDNESDAY THROUGH MONDAY NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION WILL NOT BE NEEDED.
The San Juan radar (TJUA), 33 km away, was scanning. The volume nearest the first event began at 21:33 UTC.
1 funnel cloud. Local standard time, as filed.
A funnel cloud was spotted by several members of the public and subsequent photos were forwarded to the broadcast media and the National Weather Service.
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 historyWarnings 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: 414661.