A moist airmass produced scattered showers with isolated thunderstorms across the northern half of 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.
A moist airmass produced scattered showers with isolated thunderstorms across the northern half 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 Aug 12, 5:40 AM AST, 3 hours 27 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SAN JUAN PR 540 AM AST FRI AUG 12 2011 .SYNOPSIS...SURFACE HIGH PRESSURE NORTHEAST OF THE LOCAL AREA WILL MAINTAIN A GENTLE TO MODERATE TRADE WINDS ACROSS THE REGIONAL WATERS FOR THE NEXT FEW DAYS. A BROAD AREA OF LOW PRESSURE ACROSS THE CENTRAL ATLANTIC MAY BECOME A TROPICAL CYCLONE OVER THE NEXT SEVERAL DAYS. THIS SYSTEM IS EXPECTED TO PASS NORTHEAST OF THE NORTHERNMOST LEEWARD ISLANDS SUNDAY NIGHT. ANOTHER LOW PRESSURE AREA BEHIND THE AFOREMENTIONED LOW...IS EXPECTED TO BECOME BETTER ORGANIZED DURING THE WEEKEND. && .DISCUSSION...MOSTLY CLEAR SKIES PREVAILED ACROSS THE LOCAL REGION OVERNIGHT. EARLY THIS MORNING...SOME PASSING SHOWERS WERE NOTED MAINLY ACROSS THE EASTERN HALF OF PUERTO RICO. SURFACE HIGH PRESSURE SYSTEM IS THE MAIN WEATHER FEATURE DOMINATING THE LOCAL REGION. THIS HIGH PRESSURE IS PRODUCING MAINLY EASTERLY WINDS ACROSS THE NORTHWEST CARIBBEAN. THIS WEATHER PATTERN IS NOT EXPECTED TO CHANGE TOO MUCH DURING THE NEXT FEW DAYS. HOWEVER...BY THE BEGINNING OF NEXT WEEK...THE MAIN ATTENTION WILL BE ON A VERY ACTIVE TROPICAL WAVE..AND ASSOCIATED LOW...WHICH IS LOCATED THIS MORNING NEAR 30W...FEW HUNDRED MILES SOUTH-SOUTHWEST OF THE CAPE VERDE ISLANDS. COMPUTER MODEL SUGGESTS THIS SYSTEM EVENTUALLY WILL BECOME BETTER DEFINE AND MAY BECOME A TROPICAL CYCLONE. AS A RESULT...WE SHOULD CLOSELY MONITOR THE PROGRESS OF THESE SYSTEMS...AS WE APPROACH THE PEAK OF THE HURRICANE SEASON. PLEASE REFER TO TROPICAL WEATHER OUTLOOK FOR MORE DETAILS. && .AVIATION...VFR CONDITIONS WILL PREVAIL ACROSS ALL TAF SITES DURING THE MORNING HOURS. BRIEF PERIODS OF MVFR CONDITIONS CAN BE EXPECTED ACROSS TJMZ...AND TJBQ THIS AFTERNOON IN SHRA/TSRA. && .PRELIMINARY POINT TEMPS/POPS... SJU 90 78 88 77 / 40 40 40 20 STT 90 79 88 78 / 40 40 40 20 && .SJU WATCHES/WARNINGS/ADVISORIES... PR...NONE. VI...NONE. && 10/71
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE SAN JUAN PR 623 AM AST FRI AUG 12 2011 AMZ710>745-PRZ001>013-131030- 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- 623 AM AST FRI AUG 12 2011 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...SATURDAY THROUGH THURSDAY NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION WILL NOT BE NEEDED. AMZ715-725-VIZ001-002-131030- ST. THOMAS ST. JOHN ADJACENT ISLANDS-ST CROIX- NEARSHORE ATLANTIC AND ADJACENT CARIBBEAN COASTAL WATERS- 623 AM AST FRI AUG 12 2011 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...SATURDAY THROUGH THURSDAY NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION WILL NOT BE NEEDED.
The San Juan radar (TJUA), 43 km away, was scanning. The volume nearest the first event began at 13:04 UTC.
1 thunderstorm wind. Local standard time, as filed.
Downed power lines and blown zinc roofs were reported in Barrios Maricao and Candelaria in southern Vega Alta.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Puerto Rico in 2011Every state in 2011This day in weather historyWarnings in Puerto Rico, August 2011
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: 321989.