An upper level trough combined with strong daytime heating and very ample moisture to produce numerous showers across the northern half of Puerto Rico. S sensors recorded between 2 to 4 inches across these areas.
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.
An upper level trough combined with strong daytime heating and very ample moisture to produce numerous showers across the northern half of Puerto Rico. U.S.G.S sensors recorded between 2 to 4 inches across these areas. In a 24 hour period, a U.S.G.S sensor recorded 3.29 inches in Isabela, 2.19 inches in Camuy, and 2.25 inches near the Tanama river in Utuado. Heavy rains inland between Orocovis, Barranquitas and Coamo Arriba caused the Coamo river to overflow its banks.
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 30, 2:39 PM AST, 1 minute earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SAN JUAN PR 239 PM AST THU SEP 30 2010 .SYNOPSIS...DEEP TROPICAL MOISTURE AND FAVORABLE ATMOSPHERIC CONDITIONS WILL COMBINE TO RESULT IN A WET/ACTIVE WEATHER PATTERN ACROSS THE LOCAL ISLANDS FRIDAY THROUGH THE UPCOMING WEEK. && .DISCUSSION...SCATTERED TO NUMEROUS SHOWERS DEVELOPED OVER THE INTERIOR SECTIONS AND SLOWLY DRIFTED TOWARD THE NORTHERN HALF OF PUERTO RICO. THESE SHOWERS WILL LINGER AS UPPER LEVEL CONDITIONS ARE FAVORABLE FOR REDEVELOPMENT. THE MID LEVEL TROUGH ASSOCIATED TO NICOLE THAT EXTEND FROM EAST OF FLORIDA TOWARD THE SOUTHWEST OVER THE CARIBBEAN WATERS WILL BEGAN TO LIFT AS NICOLE MOVES TOWARD THE NORTHEAST. A TROPICAL WAVE NOW LOCATED EAST OF THE LESSER ANTILLES WILL MOVE TO THE WEST AND ENTER THE EASTERN CARIBBEAN WATERS. THIS WEATHER FEATURE WILL INTERACT WITH FAVORABLE UPPER LEVEL CONDITIONS TO INCREASE THE SHOWER AND THUNDERSTORM COVERAGE ACROSS THE LOCAL REGION THROUGH AT LEAST LATE SATURDAY. A BETTER ORGANIZED TROPICAL WAVE WILL MOVE OVER THE LOCAL AREA ON SUNDAY NIGHT. THIS TROPICAL WAVE SHOULD BE MONITOR AS SOME MODELS SUGGEST FURTHER DEVELOPMENT. RAINFALL ACCUMULATIONS THAT OCCUR ED IN THE PAST FEW DAY AND RAINFALL THAT WILL OCCUR WITH FIRST TROPICAL WAVE WILL INCREASE THE POTENTIAL FOR FLOODING TO OCCUR BETWEEN SUNDAY NIGHT AND TUESDAY AS THE NEXT TROPICAL WAVE MOVES ACROSS THE AREA. && .AVIATION...MVFR CONDITIONS WILL PREVAIL ACROSS TJBQ...TJMZ AND POSSIBLE TJPS THROUGH AT LEAST 30/23Z IN SHOWERS AND THUNDERSTORMS. VFR CONDITIONS WILL PREVAIL ELSEWHERE...WITH VCSH ACROSS MOST TAF SITES. WINDS WILL BE MAINLY EAST TO SOUTHEAST AT 10 TO 15 KTS..AND GUSTY IN SHOWERS AND THUNDERSTORMS. && .MARINE...MARINERS SHOULD MONITOR THE DEVELOPMENT OF STRONG THUNDERSTORMS ACROSS THE LOCAL WATERS TONIGHT. TONIGHT THESE SHOWERS AND THUNDERSTORMS WILL CONCENTRATE OVER THE CARIBBEAN WATERS AND MONA PASSAGE. FROM NOW THROUGH THE INCOMING WEEK...UNSETTLE WEATHER WILL PREVAIL ACROSS THE LOCAL WATERS. && .PRELIMINARY POINT TEMPS/POPS... SJU 87 78 87 78 / 40 20 50 60 STT 88 79 87 79 / 40 20 60 60 && .SJU WATCHES/WARNINGS/ADVISORIES... PR...NONE. VI...NONE. && 71/10
HAZARDOUS WEATHER OUTLOOK FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS NATIONAL WEATHER SERVICE SAN JUAN PR 642 AM AST THU SEP 30 2010 AMZ710>745-PRZ001>013-011000- 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- 642 AM AST THU SEP 30 2010 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PUERTO RICO AND THE ADJACENT COASTAL WATERS. .DAY ONE...TODAY AND TONIGHT NO HAZARDOUS WEATHER IS EXPECTED. .DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY A PAIR OF TROPICAL WAVES ACROSS THE CENTRAL ATLANTIC HAVE A LOW CHANCE OF DEVELOPING INTO A TROPICAL CYCLONE OVER THE NEXT COUPLE OF DAYS. REGARDLESS OF WHETHER THEY DEVELOP INTO TROPICAL CYCLONES OR NOT...THESE TWO WEATHER SYSTEMS HAVE THE POTENTIAL TO PRODUCE WIDESPREAD HEAVY RAINS ACROSS THE AREA EARLY NEXT WEEK THAT COULD LAST FOR SEVERAL DAYS. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION WILL NOT BE NEEDED. AMZ715-725-VIZ001-002-011000- ST. THOMAS ST. JOHN ADJACENT ISLANDS-ST CROIX- NEARSHORE ATLANTIC AND ADJACENT CARIBBEAN COASTAL WATERS- 642 AM AST THU SEP 30 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. .DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY A PAIR OF TROPICAL WAVES ACROSS THE CENTRAL ATLANTIC HAVE A LOW CHANCE OF DEVELOPING INTO A TROPICAL CYCLONE OVER THE NEXT COUPLE OF DAYS. REGARDLESS OF WHETHER THEY DEVELOP INTO TROPICAL CYCLONES OR NOT...THESE TWO WEATHER SYSTEMS HAVE THE POTENTIAL TO PRODUCE WIDESPREAD HEAVY RAINS ACROSS THE AREA EARLY NEXT WEEK THAT COULD LAST FOR SEVERAL DAYS. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION WILL NOT BE NEEDED.
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE SAN JUAN PR
239 PM AST THU SEP 30 2010
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0238 PM FLOOD COAMO 18.08N 66.36W
09/30/2010 COAMO PR EMERGENCY MNGR
ROAD 556 IN BARRIO TURQUIA IN COAMO WAS REPORTED FLOODED
DUE TO RIO COAMO OUT OF ITS BANKS.
&&
FCASTROThe San Juan radar (TJUA), 28 km away, was scanning. The volume nearest the first event began at 18:39 UTC.
5 heavy rain, 1 flash flood, 1 flood, 1 debris flow. Local standard time, as filed.
River Coamo was reported overflowing its banks at a low crossing bridge in Barrio Turquia.
Urban flooding was reported at Urb. Regional were 3 homes were reported flooded. Road 129 was also reported flooded due to poor drainage.
A car was stranded in water at road 653 Barrio Barranca in the municipality of Arecibo.
Several roads in the Rodriguez Olmo sector of Arecibo were reported flooded.
Road 354, Km 2.4 was reported flooded due to the Yaguez River overflowing its banks.
A landslide was reported along road 352, Km 1.4 in the municipality of Mayaguez.
Road flooding was reported at the intersection of roads 318 and 114 in Hormigueros.
Road 114 was reported flooded at Hormigueros.
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 2026-09-24. Each event’s entry at NCEI: 255082, 258908, 258910, 258911, 258299, 258300, 258917, 258912.