Flash Flooding and Heavy Rain in Puerto Rico, November 18, 2016

Name: Flash Flooding and Heavy Rain in Puerto Rico, November 18, 2016
Start: 2016-11-18T06:51
End: 2016-11-18T11:00
Location: Puerto Rico

November 18, 2016 · NWS SJU · 4 events in 4 counties and zones

Moist and unstable weather conditions affected Puerto Rico. Very heavy rainfall felt over the southeast sections of Puerto Rico.

Where it happened

Every event with a place to put it. Tap one for its entry below.

Tornadoes
Tropical storms and surge
Floods
Wind
Hail
Winter weather
Heat and drought
Cold
Fire, smoke and dust
Marine and coastal
Other

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The toll

Deaths: 0
Injuries: 0
Property damage: $1,000
Crop damage: None recorded
Events: 4

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.

What happened

The episode as NWS SJU wrote it up.

Moist and unstable weather conditions affected Puerto Rico. Very heavy rainfall felt over the southeast sections of Puerto Rico. Some flooding occurred with mudslides also reported as soils were very saturated due to previous heavy rainfall events.

What forecasters said that day

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 Nov 18, 5:55 AM AST, 56 minutes earlier.

Area forecast discussion, Nov 18, 5:55 AM AST, 56 minutes before

Area Forecast Discussion
National Weather Service San Juan PR
555 AM AST Fri Nov 18 2016

.SYNOPSIS...A frontal boundary will stall over the local islands
during the weekend maintaining a very moist and unstable environment
through at least Tuesday. The shearline/pre-frontal trough associated
with the frontal boundary will enhance the moisture convergence across
the local islands through early next week. Drier and more stable air
mass will encompass the region by midweek next week.

&&

.DISCUSSION...Active weather was observed across the coastal
waters and portions of the South and East Puerto Rico since
midnight. High moisture content combined with good low level
convergence to produce several rounds of heavy rainfall across
Southeast Puerto Rico. Rainfall accumulations in excess of 4
inches were estimated in Maunabo and Yabucoa. Other areas of the
Southeast Quadrant of Puerto Rico received between 1-3 inches.

The rest of today...the east-southeast flow will continue to favor
moisture transport over the forecast area today. As a result...showers
and isolated thunderstorms will continue to affect the south and
east portions of PR and the U.S. Virgin Islands during the morning
hours. Then...diurnal induced showers and thunderstorms will form
along the Interior, West and Northwest PR as well as portions of
the San Juan Metro Area.

Saturday through early next week...a frontal boundary will approach
the local islands from the north-northwest. Operational models
suggest that the moisture will peak late Sunday into Monday with
precipatable water values around 2.15 inches. The shearline/pre-
frontal trough will enhance the low level convergence and focus the
abudant moisture over Puerto Rico and the U.S. Virgin Islands. In
addition...the weak steering winds will favor higher rainfall
accumulations across the islands. Due to already saturated soils
across most of PR...the potential impacts include flooding along
rivers and streams as well as mudslides in areas of steep terrain.

Conditions will gradually improve by midweek next week as drier
and more stable air mass will move over the region.

&&

.AVIATION...SHRA/Isold TSRA over the Atlantic and Caribbean waters
will continue thru the fcst period. Mtn top obscd over eastern PR
due to SHRA/low cig/Scud clds expected for the rest of the morning
hours. SHRA/TSRA is expected to develop along the interior and
western sections of PR during the afternoon. Also, isold TSRA is
possible between el Yunque and TJSJ. MVFR conds expected with this
activity across the PR terminals. Mainly VFR at the leeward
terminals and VCSH at USVI terminals with possible VCTS at times
through the forecast period. Low level winds fm E-SE at 5-15 knots
with sea breezes aft 14z.

&&

.MARINE...A relatively tranquil marine conditions will prevail
across the local waters through the weekend. Then, a short-period
northerly swell of 4-6 feet will increase the seas next week.

&&

.PRELIMINARY POINT TEMPS/POPS...
SJU  86  77  86  76 /  60  40  40  50
STT  87  77  86  76 /  50  50  50  50

&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...None.
VI...None.
AM...None.
&&

13/11

Hazardous weather outlook, Nov 18, 5:24 AM AST, 1 hour 27 minutes before

PERSPECTIVAS SOBRE CONDICIONES PELIGROSAS DEL TIEMPO...CORRECCION
SERVICIO NACIONAL DE METEOROLOGIA SAN JUAN PR
511 AM AST VIERNES 18 DE NOVIEMBRE DE 2016

AMZ710>745-PRZ001>013-190915-
SAN JUAN Y VECINDAD-NORESTE-SURESTE-
ESTE INTERIOR-NORTE CENTRAL-CENTRAL INTERIOR-PONCE Y VECINDAD-
NOROESTE-OESTE INTERIOR-MAYAGUEZ Y VECINDAD-SUROESTE-CULEBRA-VIEQUES-
AGUAS COSTERAS Y MAR AFUERA DEL ATLANTICO Y DEL CARIBE-
511 AM AST VIERNES 18 DE NOVIEMBRE DE 2016

ESTA PERSPECTIVA SOBRE LAS CONDICIONES DEL TIEMPO PELIGROSAS ES PARA
PUERTO RICO Y LAS AGUAS COSTERAS ADYACENTES DEL ATLANTICO.

.DIA UNO...HOY Y ESTA NOCHE

.TRONADAS...EXISTE UN POTENCIAL DE TRONADAS CON LLUVIAS
FUERTES Y VIENTOS EN RAFAGAS BREVES ESTA TARDE A TRAVES DE PORCIONES
DEL INTERIOR ESTE, EL INTERIOR Y OESTE DE PUERTO RICO.

.INUNDACIONES...LLUVIAS FUERTES PODRIAN RESULTAR EN INUNDACIONES
URBANAS Y DE RIACHUELO.

.DIAS DOS HASTA SIETE...SABADO A JUEVES

LA HUMEDAD AUMENTARA A TRAVES DEL AREA DE PRONOSTICO HASTA EL FIN DE
SEMANA Y PRINCIPIOS DE LA SEMANA PROXIMA A MEDIDA QUE UN SISTEMA
FRONTAL SOBRE LAS AGUAS DEL ATLANTICO Y UNA VAGUADA EN LA SUPERFICIE
INDUCIDA SE EXTIENDA A TRAVES DEL ESTE DEL CARIBE. ESTO AYUDARA EN
EL DESARROLLO DE AGUACEROS Y TRONADAS A TRAVES DEL AREA DE
PRONOSTICO. DEBIDO A SUELOS YA SATURADOS...ESTA ACTIVIDAD RESULTARA
INUNDACIONES URBANAS Y DE RIACHUELOS AL IGUAL QUE INCREMENTOS
RAPIDOS A LO LARGO DE RIOS. DESLIZAMIENTOS EN AREAS DE TERRENO
EMPINADO SON POSIBLES.

.COMUNICADO SOBRE INFORMACION REPORTADA POR OBSERVADORES...

NO SE ANTICIPA ACTIVACION AMPLIA DE OBSERVADORES, SIN EMBARGO SE
INVITA A LOS OBSERVADORES A REPORTAR INUNDACIONES AL SERVICIO
NACIONAL DE METEOROLOGIA EN SAN JUAN.

AMZ715-725-VIZ001-002-190915-
SAN TOMAS SAN JOHN E ISLAS ADYACENTES-SANTA CRUZ-
AGUAS CERCA DE LA COSTA DEL ATLANTICO Y AGUAS COSTERAS ADYACENTES
DEL CARIBE-
511 AM AST VIERNES 18 DE NOVIEMBRE DE 2016

ESTA PERSPECTIVA SOBRE LAS CONDICIONES PELIGROSAS DEL TIEMPO ES PARA
LAS ISLAS VIRGENES AMERICANAS Y LAS AGUAS COSTERAS ADYACENTES.

.DIA UNO...HOY Y ESTA NOCHE

.TRONADAS...EXISTE UN POTENCIAL DE TRONADAS CON LLUVIAS FUERTES Y
VIENTOS EN RAFAGAS BREVES ESTA MANANA A TRAVES DE LAS AGUAS
CIRCUNDANTES DE LAS ISLAS. ALGUNA DE ESTA ACTIVIDAD PODRIA
APROXIMARSE A PORCIONES DE LAS ISLAS VIRGENES DURANTE EL DIA.

.DIAS DOS HASTA SIETE...SABADO A JUEVES

LA HUMEDAD AUMENTARA A TRAVES DEL AREA DE PRONOSTICO HASTA EL FIN DE
SEMANA Y TEMPRANO LA SEMANA PROXIMA A MEDIDA QUE UNA ZONA FRONTAL
SOBRE LAS AGUAS DEL ATLANTICO Y UNA VAGUADA EN LA SUPERFICIE
INDUCIDA SE EXTIENDA A TRAVES DEL ESTE DEL CARIBE.

.COMUNICADO SOBRE INFORMACION REPORTADA POR OBSERVADORES...

NO SE ANTICIPA ACTIVACION AMPLIA DE OBSERVADORES.

The radar

The San Juan radar (TJUA), 22 km away, was scanning. The volume nearest the first event began at 10:49 UTC.

Open the radar archive at this moment

Event by event

2 heavy rain, 2 flash flood. Local standard time, as filed.

Heavy Rain, Maunabo

When: November 18, 6:51 AM AST
Where: Maunabo County, 4.89 mi NE of Maunabo to 6.13 mi NNE of Maunabo
Property damage: $500
Reported by: 911 Call Center
Coordinates: 18.056, -65.875

A mudslide was reported at Highway PR-3, KM 111.2.

Flash Flood, Yabucoa

When: November 18, 6:51 AM AST to 10:00 AM AST
Where: Yabucoa County, 2.86 mi E of Yabucoa to 2.66 mi E of Yabucoa
Cause: Heavy Rain
Reported by: Emergency Manager
Coordinates: 18.064, -65.827

Highway PR-906 was closed due to flooding on the Guayanes river.

Flash Flood, Naguabo

When: November 18, 6:53 AM AST to 10:30 AM AST
Where: Naguabo County, 3 mi W of Naguabo to 3.13 mi W of Naguabo
Cause: Heavy Rain
Reported by: Emergency Manager
Coordinates: 18.215, -65.775

Highway PR-31 was closed due to flooding on the Blanco river.

Heavy Rain, Salinas

When: November 18, 11:00 AM AST
Where: Salinas County, Salinas to 4.18 mi N of Salinas
Property damage: $500
Reported by: Emergency Manager
Coordinates: 18.000, -66.250

Minor mudslide over Highway PR-1 in Parcel Vazquez sector.

What these are

Heavy Rain: Rainfall totals unusual for the place and season that did not produce a flood.
Flash Flood: Flooding that begins within six hours of the rain that causes it, or of a dam or levee failure or ice jam release, often with deadly speed.

After NWS Directive 10-1605, the rules offices file Storm Data by.

The same day elsewhere

Every storm in Puerto Rico in 2016 Every state in 2016 This day in weather history Warnings in Puerto Rico, November 2016

Sources

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: 665883, 665884, 666186, 666187.