A tropical wave combined with an upper level low to maintain a moist and unstable air mass across Puerto Rico. This combination led to very heavy rain across the north central section and the San Juan metro area.
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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 tropical wave combined with an upper level low to maintain a moist and unstable air mass across Puerto Rico. This combination led to very heavy rain across the north central section and the San Juan metro 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 Jul 16, 6:44 AM AST, 1 hour 26 minutes earlier.
AREA FORECAST DISCUSSION...DELAYED NATIONAL WEATHER SERVICE SAN JUAN PR 644 AM AST FRI JUL 16 2010 .SYNOPSIS...A TROPICAL WAVE WILL CONTINUE MOVING ACROSS THE LOCAL AREA TODAY AND THEN AWAY FROM THE LOCAL REGION TONIGHT. A SECOND TROPICAL WAVE IS EXPECTED TO MOVE ACROSS THE LOCAL AREA MONDAY THROUGH MONDAY NIGHT. && .DISCUSSION...RATHER BUSY MORNING ACROSS THE LOCAL ISLANDS...AS A TROPICAL WAVE AND ASSOCIATED SURGE OF MOISTURE MOVE ACROSS THE LOCAL AREA AND FAVORABLY INTERACT WITH THE TUTT. THIS WAVE AND MOISTURE WILL CONTINUE TO INTERACT WITH THESE FAVORABLE UPPER LEVEL CONDITIONS THROUGH TODAY AND PART OF TONIGHT...TO PRODUCE ADDITIONAL CLOUDINESS...SHOWERS AND THUNDERSTORMS. SOME OF THESE SHOWERS AND STORMS WILL CONTAIN VERY HEAVY TO TORRENTIAL RAINFALL...STRONG AND GUSTY WINDS AND FREQUENT LIGHTNING. RATHER QUICK CELL MOTION SHOULD KEEP MOST FLOODING LOCALIZED...BUT INTENSE RAINFALL RATES AND TRAINING OF ECHOES HAS ALREADY BEEN AND WILL CONTINUE TO BE A PROBLEM TODAY AND WILL NEED TO BE WATCHED. FOR SATURDAY AND SUNDAY...THE LOCAL AIR MASS SHOULD REMAIN FAIRLY MOIST AND UNSTABLE AND THESE CONDITIONS WILL COMBINE WITH LOCAL EFFECTS AND GENERALLY FAVORABLE UPPER LEVEL WIND CONDITIONS...TO PRODUCE ADDITIONAL CLOUDINESS...SHOWERS AND A FEW THUNDERSTORMS EACH DAY. LOOKING AHEAD...A SECOND TROPICAL WAVE IS EXPECTED TO MOVE ACROSS THE LOCAL AREA MONDAY THROUGH MONDAY NIGHT AND PROBABLY TUESDAY...RESULTING IN ANOTHER ROUND OF VERY ACTIVE WEATHER ACROSS THE LOCAL ISLANDS. && .AVIATION...OUTSIDE OF CONVECTIVE BANDS...MAINLY VFR CONDITIONS ARE EXPECTED. HOWEVER...AS BANDS OF SHOWERS AND INTENSE THUNDERSTORMS MOVE ACROSS THE LOCAL ISLANDS AND TAF SITES...MVFR AND EVEN BRIEF IFR CONDITIONS...MOUNTAIN OBSCURATIONS AND SURFACE WIND GUSTS TO 30 KNOTS WILL CONTINUE TO OCCUR TODAY AND THROUGH AT LEAST PART OF TONIGHT. && .MARINE...GENERALLY EXPECT WINDS OF 15 TO 21 KNOTS AND SEAS OF 4 TO 9 FEET ACROSS THE REGIONAL WATERS THROUGH SUNDAY. LOCALLY ROUGH AND HAZARDOUS MARINE CONDITIONS WILL CONTINUE ACROSS MOST OF THE LOCAL WATERS THROUGH AT LEAST EARLY SATURDAY. PLEASE REFER TO SJUCWFSJU FOR THE LATEST FORECAST DETAILS. && .SITE SUPPORT...THE XXI CENTRAL AMERICAN AND CARIBBEAN SPORT GAMES MAYAGUEZ 2010 KICK OFF IN MAYAGUEZ ON SATURDAY AFTERNOON WITH THE OPENING CEREMONY AT 300 PM AST. THE GAMES WILL THEN RUN THROUGH SUNDAY AUGUST 1. WFO SAN JUAN WILL BE PROVIDING ON SITE AND IN OFFICE SUPPORT TO THE PUERTO RICO EMERGENCY MANAGEMENT AGENCY (PREMA) AND OTHER FEDERAL AGENCIES THROUGH THIS EVENT. && .PRELIMINARY POINT TEMPS/POPS... SJU 89 78 89 78 / 70 40 60 60 STT 89 80 89 79 / 70 40 60 70 && .SJU WATCHES/WARNINGS/ADVISORIES... PR...SMALL CRAFT ADVISORY AMZ710...715...722...725 AND 732. VI...SMALL CRAFT ADVISORY AMZ710...715...722...725 AND 732. && BCS
HAZARDOUS WEATHER OUTLOOK FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS NATIONAL WEATHER SERVICE SAN JUAN PR 702 AM AST FRI JUL 16 2010 AMZ710>745-PRZ001>013-171115- 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- 702 AM AST FRI JUL 16 2010 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PUERTO RICO AND THE ADJACENT COASTAL WATERS. .DAY ONE...TODAY AND TONIGHT A TROPICAL WAVE WILL PRODUCE NUMEROUS SHOWERS WITH THUNDERSTORMS WITH URBAN AND SMALL STREAM FLOODING POSSIBLE. RIVERS AND STREAM ALONG THE NORTH COAST WILL CONTINUE ABOVE NORMAL LEVELS AT LEAST THROUGH TONIGHT. .DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY ENOUGH AVAILABLE MOISTURE WILL COMBINED WITH LOCAL EFFECTS TO PRODUCE SHOWERS WITH THUNDERSTORMS EACH AFTERNOON ACROSS THE WESTERN HALF OF PUERTO RICO. ALSO...A TROPICAL WAVE IS EXPECTED TO AFFECT THE LOCAL AREA ON MONDAY...INCREASING THE CHANCES FOR SHOWERS AND THUNDERSTORMS ONCE AGAIN...WITH HIGH CHANCES FOR AT LEAST URBAN AND SMALL STREAM FLOODING. .SPOTTER INFORMATION STATEMENT...SPOTTER ACTIVATION MAY BE REQUIRED. AMZ715-725-VIZ001-002-171115- ST. THOMAS ST. JOHN ADJACENT ISLANDS-ST CROIX- NEARSHORE ATLANTIC AND ADJACENT CARIBBEAN COASTAL WATERS- 702 AM AST FRI JUL 16 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...SATURDAY THROUGH THURSDAY A TROPICAL WAVE IS EXPECTED TO AFFECT THE LOCAL AREA ON MONDAY...INCREASING THE CHANCES FOR SHOWERS AND THUNDERSTORMS...WITH HIGH CHANCES FOR AT LEAST URBAN AND SMALL STREAM FLOODING. .SPOTTER INFORMATION STATEMENT...SPOTTERV ACTIVATION WILL NOT BE NEEDED AT THIS TIME.
The San Juan radar (TJUA), 39 km away, was scanning. The volume nearest the first event began at 12:07 UTC.
2 flash flood. Local standard time, as filed.
River Cibuco was reported flooding road 647 in Barrio Candelaria.
The bridge over road 620 was impassable due to river Cibuco overflowing its banks.
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, July 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 2026-09-24. Each event’s entry at NCEI: 248228, 248229.