Low level moisture combined with strong daytime heating and orographic effects produced scattered showers with isolated strong thunderstorms over the Western Interior and Southwest 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.
Low level moisture combined with strong daytime heating and orographic effects produced scattered showers with isolated strong thunderstorms over the Western Interior and Southwest 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 Aug 4, 3:00 PM AST, 52 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SAN JUAN PR 300 PM AST SUN AUG 4 2013 .SYNOPSIS...SAHARAN DUST EXPECTED TO DIMINISH FOR THE NEXT FEW DAYS. SURFACE HIGH PRESSURE IN THE CENTRAL ATLANTIC IS EXPECTED TO CONTINUE DOMINATING THE AREA AND THE TUTT TO THE NORTH OF THE LOCAL AREA WILL CONTINUE TO SLOWLY MOVE TO THE WEST SOUTHWEST FOR THE NEXT FEW DAYS. RELATIVELY DRY AIR MOVES IN && .DISCUSSION...THE LOCAL AREA REMAINED DRY TODAY WITH ONLY AN ISOLATED SHOWER OR TWO ACROSS THE SOUTHWESTERN QUADRANT OF PUERTO RICO IN THE AFTERNOON. OTHERWISE IT REMAINED PARTLY CLOUDY AND HAZY. SLIGHT IMPROVEMENT IN THE DUST IS EXPECTED TOMORROW AND TUESDAY...HOWEVER A WEAK TROPICAL WAVE IS EXPECTED TO MOVE OVER THE AREA ON WEDNESDAY. PRECIPITABLE WATER VALUES WILL REMAIN RELATIVELY LOW AT AROUND 1.5 INCHES OR SO UNTIL THE TROPICAL WAVE MOVES IN ON WEDNESDAY. HOWEVER...BECAUSE THERE IS LESS DUST EXPECTED FOR MONDAY AND TUESDAY...WITH A WEAKER CAP...THERE IS A SLIGHTLY HIGHER CHANCE OF SHOWERS AND THUNDERSTORMS IN THE AFTERNOONS ACROSS THE INTERIOR AND WESTERN SECTIONS OF PUERTO RICO. SHOWERS AND THUNDERSTORM ACTIVITY MAY ALSO INCREASE ON WEDNESDAY WHILE THE WEAK TROPICAL WAVE PASSES OVER THE AREA. && .AVIATION...PREVAILING VFR CONDS DURG NXT 24 PRD ACROSS LOCAL FLYING AREA. FEW-ISOLD PASSING -SHRA OVR COASTAL WATERS BTW PR AND NRN LEEWARDS...WITH MINIMAL OR NO AFTN CONVECTION ANTICIPATED ACROSS MOST OF THE LOCAL ISLANDS THROUGH 04/23Z. HOWEVER ISOLD -SHRA/-TSRA WILL REMAIN PSBL DURG OVR WRN PR VCTY TJMZ. LVL WINDS MAINLY FM E-NE AT 10-20 KTS BLO FL250. && .MARINE...WINDS WILL BE UP TO 17 KNOTS OVERNIGHT AND SEAS UP TO 5 FEET. ALTHOUGH WINDS MAY INCREASE A BIT TOMORROW OVER THE CARIBBEAN WATERS...SMALL CRAFT ADVISORY CRITERIA IS NOT EXPECTED TO BE MET. && .PRELIMINARY POINT TEMPS/POPS... SJU 78 90 78 89 / 10 10 30 30 STT 79 91 79 89 / 10 30 30 30 && .SJU WATCHES/WARNINGS/ADVISORIES... PR...NONE. VI...NONE. COASTAL WATERS...NONE. && 09/25
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE SAN JUAN PR 554 AM AST SUN AUG 4 2013 AMZ710>745-PRZ001>013-051000- 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- 554 AM AST SUN AUG 4 2013 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...MONDAY THROUGH SATURDAY NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION WILL NOT BE NEEDED. AMZ715-725-VIZ001-002-051000- ST. THOMAS ST. JOHN ADJACENT ISLANDS-ST CROIX- NEARSHORE ATLANTIC AND ADJACENT CARIBBEAN COASTAL WATERS- 554 AM AST SUN AUG 4 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 AT THIS TIME. .DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION WILL NOT BE NEEDED.
The San Juan radar (TJUA), 74 km away, was scanning. The volume nearest the first event began at 19:52 UTC.
2 hail. Local standard time, as filed.
Pea size hail was reported at Barrio Guilarte.
Pea size hail was reported at San German.
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, August 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: 474623, 474624.