Sea breeze convergence combined with low level moisture and diurnal heating to produce afternoon showers and thunderstorms across the San Juan metropolitan area.
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.
Sea breeze convergence combined with low level moisture and diurnal heating to produce afternoon showers and thunderstorms across the San Juan metropolitan area.
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 26, 2:52 PM AST, 40 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SAN JUAN PR 252 PM AST SUN SEP 26 2010 .SYNOPSIS...A MID LEVEL DISTURBANCE WILL CONTINUE MOVING WEST NORTHWEST ACROSS THE LOCAL ISLANDS TONIGHT. A MID TO UPPER LEVEL HIGH PRESSURE WILL EXTEND INTO THE LOCAL AREA MONDAY THROUGH WEDNESDAY. && .DISCUSSION...SEA BREEZE CONVERGENCE COMBINED WITH LOW LEVEL MOISTURE AND DIURNAL HEATING INDUCED AFTERNOON SHOWERS AND THUNDERSTORMS ACROSS THE INTERIOR...NORTHWEST AND WEST SECTIONS OF PUERTO RICO AS WELL AS ACROSS THE SAN JUAN METRO AREA. THIS ACTIVITY IS EXPECTED TO DIMINISH BEFORE SUNSET...LEAVING PARTLY TO VARIABLY CLOUDY SKIES AND ISOLATED SHOWERS ACROSS THESE AREAS. ISOLATED TO SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS STILL EXPECTED ACROSS PORTIONS OF THE SOUTHEAST COAST OF PUERTO RICO AND THE VIRGIN ISLANDS TONIGHT THROUGH THE EARLY MORNING HOURS. COMPUTER MODELS...MIMIC TPW PRODUCT AND PROGNOSTIC SOUNDINGS INDICATED ENOUGH MOISTURE ACROSS THE LOCAL ISLANDS WITH NO SIGNIFICANT DRYING EXPECTED THROUGH THE FORECAST PERIOD. THEREFORE...THE NEXT FEW AFTERNOONS AVAILABLE MOISTURE WILL COMBINE WITH LOCAL EFFECTS AND DIURNAL HEATING TO PRODUCE CLOUDINESS...SHOWERS AND THUNDERSTORMS ACROSS THE LOCAL ISLANDS. THE STEERING FLOW WILL REMAIN MAINLY FROM THE SOUTHEAST TO EAST SOUTHEAST...MAINTAINING THE AFTERNOON CONVECTION ACROSS THE NORTHWESTERN QUADRANT AND INTERIOR SECTIONS OF THE PUERTO RICO EACH AFTERNOON. LOOKING AHEAD...BY THE END OF WEEK...COMPUTER MODELS CONTINUE TO ADVERTISE ADVECTION OF DEEP TROPICAL MOISTURE INTO THE LOCAL ISLANDS AS A LOW PRESSURE SYSTEM DEVELOPS ACROSS THE FAR WESTERN CARIBBEAN. AS A RESULT...BETTER CHANCES OF SIGNIFICANT PRECIPITATION ACROSS THE LOCAL ISLANDS ARE POSSIBLE LATE THIS WEEK THROUGH THE NEXT WEEKEND. && .AVIATION...SHRAS AND TSRAS TO CONT TIL AT LEAST 27/02Z THEN WILL MOVE OFFSHORE AND CONT OVER LOCAL WATERS OVERNIGHT. TOPS BEFORE 26/22Z TO REACH 60 KFT. MTN OBSCURATIONS THRU 27/04Z. OCNL MVFR CONDS AT TJBQ AND TJMZ. LLVL WINDS LESS THAN 20 KTS ESE UP THRU 26 KFT. GUSTY SFC WINDS IN AND NEAR THUNDERSTORMS TO 30 KTS. MVFR PSBL AT TISX AFT 27/08Z IN SHRA. CONVECTION EXPECTED TO RETURN TO LAND AREAS AFT 27/1530Z. && .MARINE...GENERALLY EXPECT WINDS OF 17 KNOTS OR LESS AND SEAS OF 5 FEET OR LESS ACROSS THE REGIONAL WATERS THROUGH AT LEAST TUESDAY. && .PRELIMINARY POINT TEMPS/POPS... SJU 88 78 89 78 / 40 40 40 30 STT 88 78 89 79 / 20 60 60 50 && .SJU WATCHES/WARNINGS/ADVISORIES... PR...NONE. VI...NONE. && 12/23
HAZARDOUS WEATHER OUTLOOK FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS NATIONAL WEATHER SERVICE SAN JUAN PR 526 AM AST SUN SEP 26 2010 AMZ710>745-PRZ001>013-271000- 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- 526 AM AST SUN SEP 26 2010 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PUERTO RICO 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 A MORE SOUTHERLY FLOW IS EXPECTED TO DEVELOP ACROSS THE LOCAL AREA TOWARD THE END OF NEXT WEEK AS PRESSURES FALL IN RESPONSE TO A DEVELOPING AREA OF LOW PRESSURE ACROSS THE WESTERN CARIBBEAN. THIS SHOULD RESULT IN THE TRANSPORT OF DEEP TROPICAL MOISTURE ACROSS THE LOCAL ISLANDS AND INCREASE THE CHANCES FOR WIDESPREAD RAINS. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION NOT ANTICIPATED TODAY. AMZ715-725-VIZ001-002-271000- ST. THOMAS ST. JOHN ADJACENT ISLANDS-ST CROIX- NEARSHORE ATLANTIC AND ADJACENT CARIBBEAN COASTAL WATERS- 526 AM AST SUN SEP 26 2010 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 A MORE SOUTHERLY FLOW IS EXPECTED TO DEVELOP ACROSS THE LOCAL AREA TOWARD THE END OF NEXT WEEK AS PRESSURES FALL IN RESPONSE TO A DEVELOPING AREA OF LOW PRESSURE ACROSS THE WESTERN CARIBBEAN. THIS SHOULD RESULT IN THE TRANSPORT OF DEEP TROPICAL MOISTURE ACROSS THE LOCAL ISLANDS AND INCREASE THE CHANCES FOR WIDESPREAD RAINS. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION NOT ANTICIPATED TODAY. SR
The national radar mosaic for the moment the first event began.
1 heavy rain. Local standard time, as filed.
Road 176 from Rio Piedras to Cupey was reported flooded.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Puerto Rico in 2010Every state in 2010This day in weather historyWarnings in Puerto Rico, September 2010
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 2026-10-01. Each event’s entry at NCEI: 259895.