Scattered to numerous showers and isolated thunderstorms developed late in the afternoon across the interior and central sections. An isolated but strong thunderstorm produced strong gusty winds in the Adjuntas municipality, which resulted in downed trees and small hail.
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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.
Scattered to numerous showers and isolated thunderstorms developed late in the afternoon across the interior and central sections. An isolated but strong thunderstorm produced strong gusty winds in the Adjuntas municipality, which resulted in downed trees and small hail.
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 10, 3:51 PM AST, 19 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SAN JUAN PR 351 PM AST THU SEP 10 2009 .SYNOPSIS... WEAK SURFACE HIGH PRESSURE ACROSS THE WEST CENTRAL ATLANTIC SINKING WEAKLY SOUTH ACROSS THE NORTHEAST CARIBBEAN...WILL MAINTAIN FAIRLY LIGHT EASTERLY WINDS ACROSS THE REGION OVER THE NEXT FEW DAYS. UPPER TUTT LINGERING NORTH NORTHEAST OF REGION WILL HELP MAINTAIN A FAIRLY DRY AND SUBSIDENT AIRMASS AS WE REMAIN ON THE CONVERGENT SIDE OF UPPER TROUGH. MID LEVEL HIGH PRESSURE CENTERED NORTHEAST OF THE REGION EXTENDING SOUTHWARD INTO THE NORTHEAST CARIBBEAN WILL REMAIN IN PLACE...AND MAINTAIN A FAIRLY LIGHT EAST NORTHEAST WIND FLOW THROUGH FRIDAY. SATELLITE IMAGERY SHOWED MOSTLY FAIR WEATHER CU LINES DRIFTING WESTWARD ACROSS THE REGIONAL WATERS... WHILE AFTERNOON CONVECTION CONTINUED ACROSS THE INTERIOR SECTIONS OF PUERTO RICO. && .DISCUSSION... OVERALL DRY AND SUBSIDENT CONDITIONS PREVAILED ACROSS THE REGION LIMITING CONVECTIVE DEVELOPMENT ACROSS MOST OF THE ISLANDS TODAY. HOWEVER...LOCAL SEA CONVERGENCE AND LOCAL EFFECTS RESULTED IN LATE AFTERNOON CONVECTION ACROSS THE NORTH CENTRAL SECTIONS OF PUERTO RICO. LATEST TWP PRODUCT FROM CIMMS HOWEVER SHOWED DECREASING PWAT VALUES ACROSS THE REGION...AS WELL AS THE RECENT 12Z TJSJ AND MACM U/A SOUNDINGS. FAIR WEATHER CONDITIONS PREVAILED ACROSS THE U.S. VIRGIN ISLANDS. ON FRIDAY...EXPECT A MID LEVEL VORT MAX TO MOVE SOUTH ACROSS THE REGION DURING THE EARLY MORNING TO ENHANCED SOME TRADE WIND SHOWERS ACROSS THE REGION. SOME ACTIVITY MAY REACH THE EAST COASTAL SECTIONS OF PUERTO RICO...AND THE NORTHERN VIRGIN ISLANDS...BUT DO NOT EXPECT WIDESPREAD RAINFALL. OVERALL FAIR WEATHER CONDITIONS WILL PREVAIL THE REST OF THE DAY WITH SOME INCREASING CLOUDINESS...AND CHANCE OF DIURNALLY INDUCED SHOWER AND POSSIBLE AN ISOLATED THUNDERSTORMS IN WEST SECTION OF PUERTO RICO DURING THE AFTERNOON. MOSTLY FAIR WEATHER SKIES WILL PREVAIL ACROSS THE U.S. VIRGIN ISLANDS. LATEST GFS MODEL GUIDANCE INITIALIZED WILL WITH PRESENT AND EXPECTED WEATHER CONDITIONS. EXPECT THE UPCOMING WEEKEND TO BY MOSTLY SUNNY WITH OVERALL FAIR WEATHER SKIES AND NO SIGNIFICANT WEATHER FEATURE IN SIGHT FOR THE NEXT SEVERAL DAYS. && .AVIATION... VFR CONDITIONS WILL PREVAIL OVERNIGHT THROUGH FRIDAY MORNING AT ALL LOCAL TAF SITES...WITH NO SIGNIFICANT OPERATIONAL WEATHER IMPACTS EXPECTED FOR THE NEXT 24 HOURS. ON FRIDAY...EXPECT SOME DIURNALLY INDUCED SHRA AND ISOLD TSTMS BTW 11/18Z-11/22Z MAINLY ACROSS THE WEST INTERIOR SECTIONS OF PUERTO RICO...WHILE THE REST OF THE ISLANDS && .PRELIMINARY POINT TEMPS/POPS... SJU 79 89 77 88 / 30 30 10 20 STT 79 89 78 88 / 30 30 20 20 && .SJU WATCHES/WARNINGS/ADVISORIES... PR...NONE. VI...NONE. && 04/09
HAZARDOUS WEATHER OUTLOOK FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS NATIONAL WEATHER SERVICE SAN JUAN PR 607 AM AST THU SEP 10 2009 AMZ710>745-PRZ001>013-111015- 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- 607 AM AST THU SEP 10 2009 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PUERTO RICO AND THE ADJACENT COASTAL WATERS. .DAY ONE...TODAY AND TONIGHT RESIDUAL MOISTURE WILL FIRE OFF SOME AFTERNOON THUNDERSTORMS IN NORTHWEST AND WESTERN PUERTO RICO WITH LOCALLY HEAVY RAINS...BUT NO OTHER HAZARDOUS WEATHER IS EXPECTED. .DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY THUNDERSTORM ACTIVITY OVER WESTERN PUERTO RICO DURING THE AFTERNOONS IS THE ONLY HAZARD EXPECTED OVER THE AREA. .SPOTTER INFORMATION STATEMENT...SPOTTER ACTIVATION IS NOT EXPECTED TODAY. AMZ715-725-VIZ001-002-111015- ST. THOMAS ST. JOHN ADJACENT ISLANDS-ST CROIX- NEARSHORE ATLANTIC AND ADJACENT CARIBBEAN COASTAL WATERS- 607 AM AST THU SEP 10 2009 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. .DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY NO HAZARDOUS WEATHER IS EXPECTED. .SPOTTER INFORMATION STATEMENT...SPOTTER ACTIVATION IS NOT EXPECTED TODAY.
The San Juan radar (TJUA), 68 km away, was scanning. The volume nearest the first event began at 19:54 UTC.
1 thunderstorm wind. Local standard time, as filed.
At Barrio Pellejas, one downed tree was reported along Highway 123. At Barrio Tanama, five large downed trees were reported along Highway 526, overturned trash cans, and small hail.
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, September 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: 197363.