A cold front on Thanksgiving Day caused scattered to locally numerous showers across Puerto Rico. 00 inches, with locally higher amounts, especially across the El Yunque area, where some rivers and streams went into action stage with Rio Blanco in Naguabo going into minor flood stage.
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 cold front on Thanksgiving Day caused scattered to locally numerous showers across Puerto Rico. Total rainfall amounts were between 0.50-2.00 inches, with locally higher amounts, especially across the El Yunque area, where some rivers and streams went into action stage with Rio Blanco in Naguabo going into minor flood stage.
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 25, 12:57 PM AST, 13 minutes earlier.
Area Forecast Discussion...UPDATED
National Weather Service San Juan PR
1257 PM AST Thu Nov 25 2021
.UPDATE...Lighting strikes have begun to occur from Manati to the
south coast including Ponce and Salinas. Showers are becoming more
intense, although coverage has been lagging behind somewhat, Still
expect some good amounts since although showers are moving rapidly
to the south, there are many bands that form as they approach the
islands and there have been short periods of sunshine as well.
The sounding from San Juan at 25/12Z came in as moist as expected
with 2.0 inches of precipitable water. Winds were northerly up to
around 12 kft. One notable item is the increase in the upper winds
such that winds greater than 50 knots are now found between 30
and 50 kft. Conditions become considerably more stable on Friday,
so have reduced, but not eliminated the coverage of thunderstorms.
Thunderstorms are unlikely after Friday afternoon.
&&
.AVIATION...Areas of MVFR/IFR conds, but mainly over interior
portions of the islands and briefly over TAF sites. Mtn
obscurations. CIGS 030-050. Northerly sfc winds 10-15 kt with
gusts to 25 kt to cont and shift to NE during the evening aft
25/21Z. Max winds W 50-65 kt btwn FL305-500.
&&
.MARINE...Seas have been tracking with the forecast so far. Buoy
41043 is seeing rapid rises in sea heights and the last reading
was 9.3 feet at 11 seconds; the inner buoy is now pushing through
5.3 feet. Not at all sure why the NWPS run for the 06Z model
lowered expectations by as much as 2 feet in the local outer
Atlantic waters, but this input was ignored for the morning
issuance of the Coastal Waters forecast. Continue to expect the
spread of 7 to 8 foot seas into the forecast area. Will also
reconsider how the model is leaving the Anegada passage below
small craft advisory criteria and may adjust that in the afternoon
release.
&&
.PREV DISCUSSION... /issued 434 AM AST Thu Nov 25 2021/
SYNOPSIS...Unsettled conditions are expected today during
Thanksgiving Holiday as a cold front approaches the area,
bringing widespread shower activity. The front will remain over
the area into the upcoming weekend, resulting in additional
chances of showers, although of lesser coverage. Hazardous marine
and coastal conditions are expected into the upcoming weekend due
to a northerly swell.
SHORT TERM...Today through Saturday...
Recent satellite imagery as well as the NWS doppler radar, both
suggest increasing cloudiness and shower activity along with
isolated thunderstorms over the Atlantic waters, as the frontal
boundary and associated shear-line continued to sink southwards
towards the forecast area. This along with a deepening upper level
trough shifting across the region will bring unstable and active
weather conditions. So far mostly showers of light to moderate
intensity have reached portions of the north coastal areas of Puerto
Rico and just offshore of the northern U.S Virgin Islands. Expect
the frontal boundary and associated band of moisture to continue to
sag southwards then linger across the region through Friday and into
early Saturday.
Based on recent model guidance and present conditions which both
initialized well, the forecast for increasing moisture and
instability remains on track for the short term. All suggest a
fairly active weather pattern starting later today and continuing
through Friday and early Saturday. The frontal boundary will
approach and linger across the area, thus providing good moisture
pooling and low level convergence along with the instability aloft.
Moisture will rapidly increase with precipitable water values
expected to near 2.00 inches later this afternoon and during the
evening. In addition the deepening upper-level trough will sweep
across the region with a 60-70 knots jet max to cross the area
placing the region in the right rear quadrant, consequently favoring
strong divergence aloft. The combination of all of these factors
along with the 500 millibar temperatures between -8 to -10 degrees,
will result good potential for widespread showers with enhanced
thunderstorm activity across the area later today through Friday.
Activity will continue to reach northern Puerto Rico and the coastal
waters of the northern U.S. Virgin Islands during the rest of the
morning hours, then later spread and develop over land areas while
affecting interior and southern portions of Puerto Rico and the
adjacent islands including the U.S. Virgin Islands, later in the
afternoon and evening hours. As a result the potential for urban and
small stream flooding will increase especially with the heaviest and
most persistent rainfall activity.
Late Friday through Saturday, moisture along the frontal shear-line
is expected to drift southwards, but will meander over eastern
Puerto Rico and the U.S Virgin islands. However, upper level
conditions are forecast to become hostile for organized convection
as the upper trough is expected to lift north and east of the region
as a ridge builds overhead from the west. This will result in a
gradual diminishing of overall moisture content, as well as more
stable conditions aloft. Nevertheless, given that frontal moisture
remnants will persist, expect some low to mid level moisture to
return from the east. This will maintain the potential for isolated
to scattered shower activity across the area. The activity should be
focused across portions of the the U.S. Virgin Islands and parts of
the northeastern and eastern Puerto Rico especially during the
overnight and morning hours. By then afternoon convection is
expected mainly across western and southwestern Puerto Rico, as the
steering flow should be from the northeast. This will be in response
to the surface high pressure ridge building north of the area. That
said, expect the worst conditions and best chance for urban and
small stream flooding across the region later today through Friday,
with less favorable conditions for organized convection and
significant rainfall accumulations on Saturday.
LONG TERM...Sunday through Friday...
Both GFS and ECMWF models suggest the lingering presence of the
frontal boundary over Puerto Rico and USVI by Sunday. The frontal
boundary is expected to initially stall throughout the day.
Meanwhile, another polar trough and associated strong surface low
exiting the eastern United States will settle over north central
Atlantic through Tuesday. The surface low will induce a wind shift
across the area from northeast on Sunday to southeast by late
Monday, and settles back to more east southeast by Tuesday. This
will cause the remnants of the frontal boundary to be pulled
northwestward throughout the first half of the long-term period.
Since the forecast area will be located just within the moisture
boundary as this happens, low-level moisture will gradually increase
on Sunday with precipitable water values close to 1.36 inches, peak
on Monday with 1.68 inches and later decrease to 1.26 inches by
Wednesday as the remnants of the frontal boundary retrogress
across the area.
A mid to upper ridge will maintain dry air and stable conditions
aloft hindering deep convection across the area and favoring a
more shallow convective activity. Therefore, expect a
continuation of a cloudy weather pattern with isolated to
scattered showers mainly over the eastern portions of Puerto Rico
and USVI during night and morning hours. Afternoon shallow
convection will depend on locally induced forcings such as surface
heating and sea breeze convergence. During this time, activity
will move to interior and, depending on the day and wind
direction, southwestern and northwestern sections of Puerto Rico
for Sunday and Monday/Tuesday, respectively. For Wednesday
onwards, a more seasonal weather pattern is expected with moisture
content becoming patchy and gradually increasing through the end
of the workweek. With this pattern, expect mainly fair weather
conditions with shallow areas of moisture embedded in the easterly
wind flow reaching the islands from time to time. This will cause
light passing showers across PR and the USVI on Wednesday and
becoming more frequent with increasing cloudy skies by Friday.
AVIATION...VFR conds til 25/14Z. An approaching frontal boundary
will bring increasing clouds and SHRA/Isold TSRA ovr the Atlantic
waters north of the islands thereafter. This will cause prds of
SCT- BKN lyrs nr FL022...FL050..FL090 with SHRA/Isold TSRA. Sfc
Wnds will be calm to light/vrb, bcmg fm N-NE around 10 kt with sea
breeze variations after 25/14z. VCSH/VCTS will be psbl at the
northern TAF sites of PR/USVI then ovr the interior and srn
portions of PR aft 25/16z. The frontal boundary is expected to
deteriorate local flying conditions en route and across PR/USVI
throughout the day w/prds of MVFR conds and brief Mtn Top obscr
psbl especially aft 25/16z.
MARINE...Marine and coastal conditions, due to a northerly swell,
are starting to deteriorate becoming hazardous and will continue
through the upcoming weekend. Seas are expected to range between 5
and 10 feet with occasional seas of up to 11 feet across the
Atlantic waters and local passages with the peak wave height
expected between this afternoon through Friday. Therefore, Small
Craft Advisories are in effect. Across coastal locations, there is
a high risk of rip currents across the beaches from Rincon
through Northeast Puerto Rico as well as the beaches of Culebra,
Vieques, and the USVI. There is also a High Surf Advisory in
effect for the beaches from Rincon through northeast Puerto Rico
as well as the beaches of Culebra from this afternoon into
Saturday due to breaking waves of up to 12 feet.
&&
.PRELIMINARY POINT TEMPS/POPS...
SJU 84 75 83 75 / 90 90 70 30
STT 82 76 85 77 / 80 80 70 40
&&
.SJU WATCHES/WARNINGS/ADVISORIES...
PR...High Rip Current Risk through Sunday afternoon for Culebra-North
Central-Northeast-Northwest-San Juan and Vicinity-Southeast.
High Surf Advisory from 4 PM this afternoon to 6 AM AST Saturday
for North Central-Northeast-Northwest-San Juan and Vicinity-
Southeast.
High Rip Current Risk from 4 PM AST this afternoon through
Sunday afternoon for Mayaguez and Vicinity-Vieques.
High Surf Advisory from 4 PM this afternoon to 6 PM AST Friday
for Culebra-Mayaguez and Vicinity.
VI...High Rip Current Risk through Sunday afternoon for St Croix-
St.Thomas...St. John...and Adjacent Islands.
AM...Small Craft Advisory from 4 PM this afternoon to 8 AM AST
Saturday for Coastal Waters of Northern Puerto Rico out 10
NM.
Small Craft Advisory until 8 AM AST Saturday for Atlantic Waters
of Puerto Rico and USVI from 10 NM to 19.5N.
Small Craft Advisory from 2 AM Friday to 8 AM AST Saturday for
Coastal Waters of Northern USVI and Culebra out 10 NM.
Small Craft Advisory from 4 PM this afternoon to 2 PM AST Friday
for Mona Passage Southward to 17N.
Small Craft Advisory from 2 AM to 2 PM AST Friday for Coastal
Waters of Northwestern Puerto Rico out 10 NM.
&&
SHORT TERM...WS
LONG TERM....GL
PUBLIC DESK...RVTPerspectivas sobre las Condiciones Peligrosas del Tiempo. Servicio Nacional de Meteorologia en San Juan PR 456 AM AST jueves 25 de noviembre de 2021 AMZ710>745-PRZ001>013-260900- San Juan y Vecindad-Noreste-Sureste- Este Interior-Norte Central-Interior Central-Ponce y Vecindad- Noroeste-Oeste Interior-Mayaguez y Vecindad-Suroeste-Culebra- Vieques-Las aguas costeras cercanas y lejanas a la costa del Atlantico y Caribe- 456 AM AST jueves 25 de noviembre de 2021 Esta Perspectiva sobre las Condiciones Peligrosas del Tiempo es para Puerto Rico y las aguas costeras adyacentes del Atlantico. .Dia Uno...Hoy y esta noche .Tronadas...Existe un aumento en la probabilidad de tronadas con lluvia fuerte y rafagas de vientos esta tarde y esta noche especialmente a traves de sectores de la mitad norte, este y alrededor de las islas adyacentes. Esta actividad pudiera producir vientos fuertes en rafagas. .Inundaciones...Las lluvias fuertes pudieran resultar en inundaciones urbanas y en crecidas subitas de los rios y riachuelos. .Olas...Oleaje aumentando entre 7 y 10 pies sobre las aguas mar afuera del Atlantico y de 6 a 8 pies para las aguas cercanas a la costa y mayormente el Pasaje de Mona mas tarde hoy y esta noche. .Corrientes Marinas...Existe un riesgo alto de corrientes marinas para la mayoria de las playas del norte de Puerto Rico, la mayor parte de las playas de Culebra; y un riesgo moderado de corrientes marinas para algunas de las plyas del norte de Vieques. Una advertencia de resacas fuertes estara en efecto mas avanzada la tarde y hasta esta noche. .Dias dos hasta el siete...viernes a miercoles Una zona frontal y condiciones atmosfericas inestables mantendran un patron de tiempo humedo y activo hasta el viernes. Esto mantendra un potencial de moderado a alto de inundaciones urbanas y de riachuelos, al igual que acumulacion de agua en carreteras y en areas de pobre drenaje. El riesgo moderado de corrientes marinas continuara por los proximos dias. Se espera que las condiciones maritimas continuen picadas y peligrosas hasta el viernes y posiblemente hasta el fin de semana. Condiciones de resacas peligrosas tambien continuaran hasta por lo menos el viernes. .Comunicado sobre informacion reportada por observadores... No se espera activacion amplia de observadores. Favor de reportar cualquier informacion sobre vientos, oleaje y corrientes marinas al Servicio Nacional de Meteorologia en San Juan mientras siguen las indicaciones de las autoridades locales y estatales. AMZ715-725-VIZ001-002-260900- San Tomas, San John e Islas Adyacentes-Santa Cruz- Aguas cercanas del Atlantico y aguas costeras adyacentes del Caribe- 456 AM AST jueves 25 de noviembre de 2021 Esta perspectiva sobre las condiciones peligrosas del tiempo es para Islas Virgenes Estadounidenses y las aguas costeras adyacentes. .Dia Uno...Hoy y esta noche. .Tronadas...Existe un aumento en la probabilidad de tronadas con lluvia fuerte y rafagas de vientos esta tarde y esta noche especialmente a traves de sectores de sectores del norte de las Islas Virgenes Estadounidenses. Esta actividad pudiera producir vientos fuertes en rafagas. .Inundaciones...Las lluvias fuertes pudieran resultar en inundaciones urbanas y en crecidas subitas de los rios y riachuelos, especialmente para el norte de las Islas Virgenes Estadounidenses avanzada la tarde y esta noche. .Olas...Oleaje aumentando entre 7 y 10 pies sobre las aguas mar afuera del Atlantico y de 6 a 8 pies para las aguas cercanas a la costa y mayormente el Pasaje de Mona mas tarde hoy y esta noche. .Corrientes Marinas...Existe un riesgo alto de corrientes marinas para la mayoria de las playas del norte de Puerto Rico, la mayor parte de las playas de Culebra; y un riesgo moderado de corrientes marinas para algunas de las playas del norte y este de Santa Cruz. Existe un riesgo moderado de corrientes marinas para el resto de las playas del norte. .Dias dos hasta el siete...viernes a miercoles Una zona frontal y condiciones atmosfericas inestables mantendran un patron de tiempo humedo y activo hasta el viernes. Esto mantendra un potencial de moderado a alto de inundaciones urbanas y de riachuelos, al igual que acumulacion de agua en carreteras y en areas de pobre drenaje. El riesgo moderado de corrientes marinas continuara por los proximos dias. Se espera que las condiciones maritimas continuen picadas y peligrosas hasta el viernes y posiblemente hasta el fin de semana. Condiciones de resacas peligrosas tambien continuaran hasta por lo menos el viernes. .Comunicado sobre informacion reportada por observadores... No se espera activacion amplia de observadores. Favor de reportar cualquier informacion sobre vientos, oleaje y corrientes marinas al Servicio Nacional de Meteorologia en San Juan mientras siguen las indicaciones de las autoridades locales y estatales.
The national radar mosaic for the moment the first event began.
1 flood. Local standard time, as filed.
Rio Blanco river went out of its banks, flooding road PR-31 near Exit 22 of Highway 53.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Puerto Rico in 2021Every state in 2021This day in weather historyWarnings in Puerto Rico, November 2021
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: 993066.