Upper level trough across the western Atlantic combined with a very weak steering flow at the surface and daytime heating produced numerous showers with thunderstorms across the Cordillera Central. The hardest hit areas were from the central interior to the north coast affecting the Rio Grande de Arecibo and its tributaries, the Rio Manati, Rio Cibuco, Rio de la Plata, Rio Camuy, Rio Fajardo,…
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.
Upper level trough across the western Atlantic combined with a very weak steering flow at the surface and daytime heating produced numerous showers with thunderstorms across the Cordillera Central. The hardest hit areas were from the central interior to the north coast affecting the Rio Grande de Arecibo and its tributaries, the Rio Manati, Rio Cibuco, Rio de la Plata, Rio Camuy, Rio Fajardo, Rio Naguabo and Rio Espiritu Santo. A USGS gage in the Rio Tanama basin (tributary to the Rio Grande de Arecibo) had a 24 hour report of over 12 inches on March 29th. The incredible runoff from this rainfall within the Rio Grande de Arecibo basin in addition to flow from the Rio Grande de Arecibo at Lago Dos Bocas, which rose to almost 303 feet almost 6 feet above the spillway, caused rapid and significant rises in the municipality of Arecibo, downstream from Dos Bocas reservoir to the coast.
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 Mar 27, 10:39 AM AST, 4 hours 1 minute earlier.
AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE SAN JUAN PR 1039 AM AST TUE MAR 27 2012 .SYNOPSIS...LARGE UPPER TROUGH ACROSS THE WRN ATLC WILL CONTINUE TO DOMINATE THE REGION INTO EARLY NEXT WEEK. A SHEARLINE WILL MOVE ACROSS THE AREA TONIGHT BUT ACTUAL CDFNT WILL STALL JUST NORTH OF THE AREA THU NIGHT. && .DISCUSSION...LOCAL AREA UNDER A COL REGION THIS MORNING. HIGH DENSE OVERCAST EARLIER THIS MORNING IS THINING OUT RAPIDLY WITH CU FIELD STARTING TO DEVELOP ACROSS THE SOUTHEAST. STEERING WINDS 0-6KM MEAN WINDS FROM THE WEST AND EXPECT DEEP CONVECTION TO MOVE TO THE EAST OR EAST SOUTHEAST AROUND 10 KNOTS. && .AVIATION...ONLY ARPRT THAT MAY HAVE SHOT AT SOME TSRA TODAY IS JPS TODAY...HOWEVER STEERING WINDS SUGGEST THAT CONVECTION WILL LIKELY REMAIN OVR THE MOUNTAINS AND NOT AFFECT ANY OF THE TAF SITES. SFC WINDS WILL BECOME ONSHORE AROUND NOON AS LAND HEATS UP AND THEN BECOME FROM THE NORTH AS SHEARLINE MOVES ACROSS. && .MARINE...SEAS RATHER TRANQUIL UNDER LIGHT WINDS BUT EXPECTED TO INCREASE THU ON NORTH SWELLS. SCA WILL LIKELY BE NEEDED BY THEN. && .CLIMATE...MARCH 2012 CURRENTLY RANKS AS THE THIRD WETTEST MARCH ON RECORD THE SAN JUAN OFFICIAL CLIMATE STATION WITH A TOTAL OF 6.31 INCHES. THE WETTEST MARCH ON RECORD WAS 1927 WHEN 9.38 INCHES WERE MEASURED. FOR ST. THOMAS...MARCH 2012 CURRENTLY RANKS AS THE FIFTH WETTEST MARCH ON RECORD WITH 3.24 INCHES OF RAIN THUS FAR. THE WETTEST MARCH ON RECORD WAS 1961 WHEN 4.37 INCHES WERE MEASURED. FOR ST. CROIX...MARCH 2012 CURRENTLY RANKS AS THE FOURTH WETTEST YEAR ON RECORD WITH 2.92 INCHES OF RAIN THUS FAR. THE WETTEST MARCH ON RECORD WAS 1985 WHEN 4.15 INCHES WERE MEASURED. && .PRELIMINARY POINT TEMPS/POPS... SJU 85 75 84 74 / 20 30 30 50 STT 78 74 84 74 / 20 30 30 50 && .SJU WATCHES/WARNINGS/ADVISORIES... PR...NONE. VI...NONE. COASTAL WATERS...NONE. && 64/64
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE SAN JUAN PR 529 AM AST TUE MAR 27 2012 AMZ710>745-PRZ001>013-280930- 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- 529 AM AST TUE MAR 27 2012 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PUERTO RICO AND THE ADJACENT ATLANTIC COASTAL WATERS. .DAY ONE...TODAY AND TONIGHT PERIODS OF MODERATE TO LOCALLY HEAVY RAINFALL WILL REMAIN POSSIBLE ESPECIALLY ACROSS THE INTERIOR SECTIONS OF PUERTO RICO AND ALONG THE CORDILLERA CENTRAL THIS AFTERNOON. THE MAIN CONCERN TODAY WILL BE THE SLOW MOVEMENT OF THESE SHOWERS AND THUNDERSTORMS...WHICH COULD PRODUCE HIGH RAINFALL ACCUMULATIONS ALONG THE CORDILLERA CENTRAL. THIS SCENARIO WILL RESULT IN QUICK RISES IN RIVERS...STREAMS AND CREEKS...AS WELL AS INCREASE THE POTENTIAL FOR URBAN FLOODING. ALSO...THE THREAT OF MUDSLIDES WILL ALSO CONTINUE IN AREAS OF STEEP TERRAIN WHERE SIGNIFICANT RAINFALL HAS OCCURRED IN RECENT DAYS. .DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY NO HAZARDOUS WEATHER ANTICIPATED AT THIS TIME. .SPOTTER INFORMATION STATEMENT... ANY REPORTS OF SIGNIFICANT WEATHER OR FLOOD PROBLEMS WOULD BE GREATLY APPRECIATED. AMZ715-725-VIZ001-002-280930- ST. THOMAS ST. JOHN ADJACENT ISLANDS-ST CROIX- NEARSHORE ATLANTIC AND ADJACENT CARIBBEAN COASTAL WATERS- 529 AM AST TUE MAR 27 2012 THIS HAZARDOUS WEATHER OUTLOOK IS FOR THE U.S. VIRGIN ISLANDS AND THE ADJACENT COASTAL WATERS. .DAY ONE...TODAY AND TONIGHT NO HAZARDOUS WEATHER ANTICIPATED AT THIS TIME. .DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY NO HAZARDOUS WEATHER ANTICIPATED AT THIS TIME. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION WILL NOT BE NEEDED.
The San Juan radar (TJUA), 35 km away, was scanning. The volume nearest the first event began at 18:42 UTC.
20 flash flood, 6 flood, 1 debris flow. Local standard time, as filed.
River out of its banks flooded downtown area.
Landslide reported in road 172, kn 3.2 between Cidra to Caguas municipalities.
Small stream out of its banks over road 785.
Water flood house in road 569 in Orocovis.
River was out of its banks and flooded downtown area.
Many Roads were closed due to rivers out of their banks.
Street flooded in 65th Avenue with the intersection with Campo Rico avenue.
Houses flooded with 2 people affected. Also 2 people were trapped in road.
Road 111 was reported flooded and impassable.
Houses and roads flooded in Jesus Maria Lago sector.
Road 10 at Barrio Rio Abajo was reported flooded with people affected.
Road PR-111 at Barrio Hato Arriba was reported flooded.
Road PR-2 was reported flooded and impassable.
Road PR-690 Between Bre as and Cerro Gordo sectors was impassable due to flooding.
Road PR-2, KM 50 was closed due to Rio Manati out of its banks.
Road PR-2 IN Vega Alta was reported flooded and impassable.
Rio Fajardo was reported out of its banks between road 3 and road 53.
Road between Barrio Maricao and Vega Alta downtown was reported flooded.
Road 2, KM 31.6 closed due to Rio Cibuco out of its banks.
Road PR-694 at Monterrey sector was reported flooded and closed.
Road 31 at La Pitina sector was closed due to Rio Blanco out of its banks.
Car stranded in road 160 due to Cibuco river out of its banks.
Roads 620,647,675 AND 690 were closed due to Cibuco river out of its banks.
Road 190 in front of Ines Mendoza school at Sabana Abajo sector was reported flooded.
Several tributaries of La Mina river which feed into the Mameyes river were out of its banks over highway 191 in the upper areas of El Yunque National rainforest.
The 65th Infanteria Avenue was partially flooded.
Road PR-3 with intersection with road PR-53 was flooded and impassable due to Rio Fajardo out of its banks.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Puerto Rico in 2012Every state in 2012This day in weather historyWarnings in Puerto Rico, March 2012
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: 363350, 362952, 364585, 364586, 362926, 363354, 364587, 363356, 363357, 363394, 363398, 363400, 363401, 363402, 363409, 364575, 364577, 364588, 363410, 363411, 364578, 364579, 364581, 364739, 364583, 364745, 364740.