A shear line with its associated trough moved across Puerto Rico, producing scattered to numerous showers across most of the northern half of the island.
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 shear line with its associated trough moved across Puerto Rico, producing scattered to numerous showers across most of the northern half of the island.
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 Dec 27, 2:48 PM AST, 6 hours 15 minutes earlier.
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JUAN PR
248 PM AST MON DEC 27 2010
.SYNOPSIS...A COLD FRONT IS EXPECTED TO MOVE TOWARDS THE FORECAST
AREA EARLY TUESDAY...AND WILL COMBINE WITH AVAILABLE MOISTURE TO
INDUCE AN UNSETTLED WEATHER PATTERN ACROSS THE LOCAL ISLANDS AT
LEAST UNTIL WEDNESDAY. A BROAD RIDGE WILL THEN ESTABLISH ITSELF ACROSS
THE WESTERN ATLANTIC...TO SUSTAIN A FRESH NORTH/NORTHEASTERLY FLOW
ACROSS THE LOCAL ISLANDS.
&&
.DISCUSSION...A PRE-FRONTAL SHEAR LINE WITH ITS ASSOCIATED TROUGH
IS NOW LOCATED OVER HISPANIOLA. THIS SHEAR LINE IS EXPECTED TO
MOVE ACROSS PUERTO RICO TO THE USVI LATER THIS EVENING...WITH THE
FRONT EXPECTED TO ENTER PUERTO RICO ON EARLY TUESDAY MORNING...AND
INTO THE USVI ISLANDS THROUGH WEDNESDAY MORNING. SCATTERED TO
NUMEROUS SHOWERS ARE ANTICIPATED LATER THIS EVENING AS THE SHEAR
LINE REACHES THE FORECAST AREA. THE SHOWER ACTIVITY SHOULD
CONCENTRATE ON WEST/CENTRAL PORTIONS OF THE ISLAND...THEN
SPREAD ACROSS MUCH OF THE NORTHERN HALF OF PUERTO RICO THE REST
OF THE NIGHT...WITH THE POSSIBILITY OF AN ISOLATED THUNDERSTORM OR
TWO AS WELL. AT THIS TIME...THE MOST UNSETTLED DAYS APPEAR TO BE
TONIGHT AND TUESDAY.
A BROAD RIDGE WILL THEN ESTABLISH ITSELF ACROSS THE WESTERN
ATLANTIC...TO SUSTAIN A FRESH NORTH/NORTHEASTERLY FLOW ACROSS THE
LOCAL ISLANDS. THEREFORE...PATCHES OF MOISTURE WILL MOVE ACROSS
THE LOCAL AREA FROM TIME TO TIME...RESULTING IN INTERVALS OF
CLOUDINESS AND A FEW SHOWERS OVER THE LOCAL ISLANDS THURSDAY
THROUGH SUNDAY.
&&
.AVIATION...MAINLY VFR CONDITIONS WILL PREVAIL ACROSS ALL TAF SITES
THROUGH AT LEAST 28/02Z FOLLOWED BY DETERIORATING CONDITIONS FROM
THE NORTHWEST. AN APPROACHING COLD FRONT WILL PRODUCE INCREASING
CLOUDINESS WITH SHOWERS AND LEAD TO PERIODS OF MVFR CONDITIONS
ACROSS TJSJ...TJBQ...AND TJMZ AND WIDESPREAD MTN OBSCURATIONS AFTER
28/06Z OVER PR AND NRN USVI. WINDS WILL BE LIGHT FROM THE SOUTHEAST
SFC TO 12 KFT...BECOMING SOUTHWESTERLY AND STRONGER ALOFT...BUT AFT
28/12Z LLVL WINDS WILL BECOME NELY 10 TO 20 KTS WITH GUSTS PSBL TO
30 KT AT SITES SUCH AS TJBQ AND TIST.
&&
.MARINE...ANOTHER BATCH OF LONG PERIOD NORTHWESTERLY SWELLS WILL
BUILD ACROSS THE LOCAL ATLANTIC WATERS AND THE MONA PASSAGE
TOMORROW. THESE SWELLS WILL RESULT IN ROUGH AND HAZARDOUS SURF
CONDITIONS ALONG THE NORTHERN EXPOSED COASTLINES OF PUERTO RICO
AND THE NORTHERN U.S. VIRGIN ISLANDS. AS A RESULT...A HIGH SURF
ADVISORY WILL BE IN EFFECT FROM 8 AM TUESDAY TO 6 AM AST THURSDAY.
&&
.PRELIMINARY POINT TEMPS/POPS...
SJU 74 80 71 78 / 70 70 70 70
STT 73 83 73 82 / 40 40 50 50
&&
.SJU WATCHES/WARNINGS/ADVISORIES...
PR...HIGH SURF ADVISORY FROM 8 AM TUESDAY TO 6 AM AST THURSDAY FOR
CULEBRA-MAYAGUEZ AND VICINITY-NORTH CENTRAL-NORTHEAST-
NORTHWEST-SAN JUAN AND VICINITY.
SCA AMZ710.
VI...HIGH SURF ADVISORY FROM 8 AM TUESDAY TO 6 AM AST THURSDAY FOR
ST. THOMAS/ST. JOHN/ADJACENT ISLANDS.
SCA AMZ710.
&&
12/23HAZARDOUS WEATHER OUTLOOK FOR PUERTO RICO AND THE U.S. VIRGIN ISLANDS NATIONAL WEATHER SERVICE SAN JUAN PR 611 AM AST MON DEC 27 2010 AMZ710>745-PRZ001>013-281015- 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- 611 AM AST MON DEC 27 2010 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PUERTO RICO AND THE ADJACENT ATLANTIC COASTAL WATERS. .DAY ONE...TODAY AND TONIGHT INCREASING CLOUDINESS WITH SHOWERS ARE EXPECTED ACROSS PUERTO RICO AS A FRONTAL BOUNDARY APPROACH THE LOCAL AREA FROM THE NORTHWEST. .DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY COLD FRONT IS EXPECTED TO MOVE ACROSS PUERTO RICO TUESDAY...MAINTAINING A WET PATTERN ACROSS THE ISLAND AT LEAST THROUGH WEDNESDAY. URBAN AND SMALL STREAM FLOODING WILL BE POSSIBLE EACH DAY. .SPOTTER INFORMATION STATEMENT...SPOTTER ACTIVATION WILL NOT BE NEEDED AT THIS TIME. AMZ715-725-VIZ001-002-281015- ST. THOMAS ST. JOHN ADJACENT ISLANDS-ST CROIX- NEARSHORE ATLANTIC AND ADJACENT CARIBBEAN COASTAL WATERS- 611 AM AST MON DEC 27 2010 THIS HAZARDOUS WEATHER OUTLOOK IS FOR THE U.S. VIRGIN ISLANDS AND THE ADJACENT COASTAL WATERS. .DAY ONE...TODAY AND TONIGHT INCREASING CLOUDINESS WITH SHOWERS ARE EXPECTED ACROSS PUERTO RICO AS A FRONTAL BOUNDARY APPROACH THE LOCAL AREA FROM THE NORTHWEST. .DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY COLD FRONT IS EXPECTED TO MOVE ACROSS PUERTO RICO TUESDAY...MAINTAINING A WET PATTERN ACROSS THE ISLAND AT LEAST THROUGH WEDNESDAY. URBAN AND SMALL STREAM FLOODING WILL BE POSSIBLE EACH DAY. .SPOTTER INFORMATION STATEMENT...SPOTTER ACTIVATION WILL NOT BE NEEDED AT THIS TIME.
The national radar mosaic for the moment the first event began.
2 flood. Local standard time, as filed.
Cibuco river was out of its banks and flooding some portions of road 620 and 647 in the Fatima sector of the municipality of Vega Baja.
Rio Indio, a tributary of the Cibuco river was reported out of its banks and flooding roads 160 and street 4 at sector Arenales.
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, December 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: 275418, 275421.