Flash Flood Warning 13, NWS JSJ

395 
WGCA72 TJSJ 282018
FFSSJU

Flash Flood Statement
National Weather Service San Juan PR
418 PM AST Mon Apr 28 2025

PRC009-019-107-282028-
/O.CAN.TJSJ.FF.W.0013.000000T0000Z-250428T2045Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Aibonito PR-Barranquitas PR-Orocovis PR-
418 PM AST Mon Apr 28 2025

...FLASH FLOOD WARNING FOR OROCOVIS COUNTY HAS BEEN REPLACED WITH A 
FLOOD ADVISORY...
...FLASH FLOOD WARNING IS CANCELLED FOR BARRANQUITAS AND AIBONITO 
COUNTIES...

&&

LAT...LON 1823 6652 1823 6651 1824 6651 1826 6650
      1825 6646 1826 6645 1826 6641 1827 6639
      1829 6638 1827 6638 1824 6635 1822 6635
      1819 6635 1820 6636 1819 6637 1818 6637
      1817 6638 1818 6646 1817 6651

$$

ERG

Area Forecast Discussion
National Weather Service San Juan PR
509 AM AST Mon Apr 28 2025

.SYNOPSIS...

An unsettled weather pattern is expected to continue through at
least Thursday due to a series of troughs and abundant moisture.
The likelihood of urban and small stream flooding due to strong
showers and thunderstorms, as well as mudslides and rapid river
rises, will remain high along with a chance of isolated flash
flooding as well. A high rip current risk remains in effect for
the northern exposed beaches of Puerto Rico, from Aguadilla to
Fajardo and Culebra through this afternoon.

&&

.SHORT TERM...Today through Wednesday...

Shower and thunderstorm activity that had been impacting the
municipalities of Arecibo and Barceloneta ended close to midnight,
leaving nearly 8 inches of rain in the northeasternmost tip of the
Arecibo municipality, with other areas receiving 4 to 6 inches. The
rest of the night was much calmer compared to the afternoon and
evening hours, with moderate showers occasionally moving over St.
Thomas. Minimum temperatures were mostly in the low to mid-70s
across coastal areas of the islands and in the mid to upper 60s in
the highest mountains and valleys of Puerto Rico.

Current satellite imagery and GLM data show that the most active
part of a deep-layered trough is located north of Puerto Rico, over
the offshore Atlantic waters, where the trough is exhibiting the
strongest low-level convergence and upper-level divergence. GOES-19
Precipitable Water satellite data continues to show well above
normal moisture over the region, particularly upstream of the local
islands. Therefore, during the rest of the morning hours, showers
and isolated thunderstorms are expected over the regional waters,
with some showers occasionally moving over windward coastal areas.

Winds will begin shifting today from southeasterly to easterly, and
then to a more northeasterly direction by Wednesday, as a surface
high pressure over the western Atlantic gradually pushes a frontal
boundary associated with the upper-level trough closer to the CWA.
The combination of above-normal moisture, instability aloft, diurnal
heating, and orographically driven convection will lead to another
active afternoon, with thunderstorms first developing over interior
Puerto Rico. The steering wind flow is expected to remain light
throughout most of the short-term forecast period. As a result, slow-
moving thunderstorms will initially cluster over the Cordillera
Central and may later move toward coastal areas as outflow
boundaries generate new convective cells. A similar weather pattern
is expected on Tuesday.

However, Wednesday appears to be the wettest and most active day, as
the aforementioned trough deepens and develops into a cutoff low,
closing off by the end of the forecast period, particularly by
Wednesday night. Widespread thunderstorm activity may develop, and
if it occurs during the evening and night hours, another round of
heavy showers and thunderstorms could impact the eastern third of
Puerto Rico, including Vieques, Culebra, and the U.S. Virgin
Islands. As a reminder, soils are already saturated, and streamflows
are running well above normal due to heavy rains over the past
several days. Therefore, urban and river flooding is likely to
continue, along with the potential for flash flooding and landslides
in flood-prone areas and steep terrain, respectively. Continue to
monitor the forecast as this unstable weather pattern persists
across the region.

&&

.LONG TERM...Thursday through Monday...

The long-term forecast continues on track, with a variable and
unsettled pattern ahead. The interaction between a high surface
pressure in the Western Atlantic and a surface low induced by an
upper-level trough will promote light NE-E winds through the period.
Global model ensembles agree that Thursday will be the wettest
day of the forecast period, suggesting above normal Precipitable
Water (PWAT) values (around 1.75 inches). Colder 500 mb
temperatures (-8 to -9 Celsius) and jet dynamics around 250 mb
with speed near 70 knots will bring ventilation and instability
aloft, supporting deep convection activity. As the mid to upper
level trough migrates eastward, drier air will filter into the
region, inhibiting deep convection activity. Additionally,
temperatures in the 500 mb layer should increase to seasonal
values (around -7 Celsius). Although global model ensembles tend
to a "drier" pattern this weekend, there's still enough low to mid
level moisture available for afternoon convection. With the
expected weather conditions, soils saturated, local effects, and
diurnal heating, the potential of flooding will remain limited to
elevated through this period, with showers during the morning
along windward sections and afternoon convection over interior and
western/southwestern Puerto Rico each day. Rainfall accumulations
will most likely promote ponding of water in roadways and poorly
drained areas, as well as urban and small stream flooding.

With the NE-E wind flow dominating the period, 925 mb temperatures
should remain near below normals.

&&

.AVIATION...

(06Z TAFs)

Expect -RA/VCTS posbl at TJSJ/TISX/TIST through 13z. Areas of SHRA
and SCT TSRA this aftn could produce tempo
MVFR/IFR conds and mtn obsc, particularly ovr TJBQ/TJSJ aft 28/17z.
VCTS/SHRA at TJPS for the most part. Despite this pattern, expect
mostly VFR conditions across all terminals through the forecast
period. E winds reaching speeds of up to 8-12 knots, accompanied by
higher gusts and sea breeze variations aft 28/13z.

&&

.MARINE...

Light to moderate east to southeast winds will prevail today and
tomorrow, turning from the northeast by Tuesday night. A deep layer
trough will continue to promote an unstable weather pattern across
the local waters. Showers and thunderstorms are expected to persist,
producing localized hazardous marine conditions, small craft should
exercise caution.

&&

.BEACH FORECAST...

Latest buoy observations show wave periods between 13 - 14
seconds, suggesting that pulses of the northeasterly swell
continue spreading across the local waters. Therefore, the high
risk of rip currents was extended through this afternoon for the
beaches of northern Puerto Rico, from Aguadilla to Fajardo, and
Culebra. As the swell dissipates across the local waters tonight,
a moderate risk of rip currents will prevail for the next few days
for the beaches in northern Puerto Rico, Culebra, and possibly
St. Thomas and St. John in the U.S. Virgin Islands.

&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...High Rip Current Risk through this afternoon for PRZ001-002-005-
     008-012.

VI...None.
AM...None.
&&

SHORT TERM/AVIATION...CVB
LONG TERM/MARINE....MNG

Hazardous Weather Outlook
National Weather Service San Juan PR
920 AM AST Mon Apr 28 2025

AMZ711>745-PRZ001>013-291330-
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-
920 AM AST Mon Apr 28 2025

This Hazardous Weather Outlook is for portions of Puerto Rico.

.DAY ONE...Today and Tonight

.Lightning...Isolated thunderstorms, particularly across
the regional waters and interior Puerto Rico. Stay alert and be
prepared to take shelter if storms develop.

.Excessive Rainfall...Flooding in urban areas, roads, small
streams, and washes. There is a low chance of isolated flash
floods. Elsewhere, plan for water ponding on roads and in poorly
drained areas.

.Excessive Heat...This level of heat affects primarily those
individuals extremely sensitive to heat, especially when outdoors
without effective cooling and/or adequate hydration. These
conditions are most likely across urban and coastal areas.

.Rip Currents...Life-threatening rip currents are possible in the
surf zone, particularly across the north-facing beaches. Isolated
stronger rip currents may occur elsewhere, especially near piers,
jetties, and channels.

.DAYS TWO THROUGH SEVEN...Tuesday through Sunday

Moderate rip current risk return tonight through the workweek.
Unstable and wet weather pattern will result in shower and
thunderstorm development through midweek, increasing the risk of
flooding and the potential for lightning activity and gusty wind
conditions.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is encouraged. Please relay any information
about flooding, winds, waves, and rip currents to the National
Weather Service in San Juan.

AMZ716-726-VIZ001-002-291330-
St. Thomas St. John adjacent Islands-St Croix-
Nearshore Atlantic and adjacent Caribbean Coastal Waters-
920 AM AST Mon Apr 28 2025

This Hazardous Weather Outlook is for portions of USVI.

.DAY ONE...Today and Tonight

.Lightning...Isolated thunderstorms. Stay alert and be prepared
to take shelter if storms develop.

.Rip Currents...Life-threatening rip currents are possible in the
surf zone. Isolated stronger rip currents may occur elsewhere,
especially near piers, jetties, and channels.

.DAYS TWO THROUGH SEVEN...Tuesday through Sunday

Moderate rip current risk is expected to prevail most of the
week. Shower and thunderstorm development is expected to continue
through midweek, increasing the risk of flooding and the potential
for lightning activity and gusty wind conditions.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is encouraged. Please relay any information
about flooding, winds, waves, and rip currents to the National
Weather Service in San Juan.

Preliminary Local Storm Report
National Weather Service San Juan PR
100 PM AST Mon Apr 28 2025

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

1225 PM     Landslide        4 N Bairoa              18.32N 66.07W
04/28/2025                   San Juan           PR   Emergency Mngr

            The Municipal Office of Emergency Management
            (OMME) in San Juan has reported a landslide
            affecting Road PR-853 near kilometer 5.0.
            The road is currently impassable and has
            been closed by emergency management
            authorities.

&&

ICP/CAM

Preliminary Local Storm Report
National Weather Service San Juan PR
110 PM AST Mon Apr 28 2025

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

1245 PM     Flash Flood      4 WSW Trujillo Alto     18.33N 66.07W
04/28/2025                   San Juan           PR   Emergency Mngr

            A flooded residence was reported in
            Boulevard de los Arboles, near the
            intersection with Guama St., in San Juan.
            Emergency Managers reported that no people
            were trapped. This house and neighboring
            houses are next to Rio Piedras (River).

&&

MRR

Preliminary Local Storm Report
National Weather Service San Juan PR
117 PM AST Mon Apr 28 2025

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

1234 PM     Flash Flood      2 SSW Trujillo Alto     18.33N 66.03W
04/28/2025                   Trujillo Alto      PR   911 Call Center

            The 911 Call Center has reported that two
            people and two dogs are trapped in a
            residence from rising floodwaters along Road
            PR-853 in Barrio Carraizo, near Camino
            Saldana.

&&

ICP/CAM

Preliminary Local Storm Report
National Weather Service San Juan PR
122 PM AST Mon Apr 28 2025

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

1209 PM     Flash Flood      3 N Bairoa              18.30N 66.07W
04/28/2025                   San Juan           PR   911 Call Center

            The 911 Call Center has reported individuals
            trapped in a Kia vehicle due to flash
            flooding from nearby streams along Camino
            Los Navarro in Barrio Quebrada Arenas, near
            Road PR-1.

&&

ICP

Preliminary Local Storm Report
National Weather Service San Juan PR
126 PM AST Mon Apr 28 2025

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

1213 PM     Landslide        4 SW Trujillo Alto      18.32N 66.07W
04/28/2025                   San Juan           PR   911 Call Center

            The 911 Call Center has reported a landslide
            affecting a portion of Camino Los Garcia in
            Barrio Caimito, Sector Los Cotto, near Road
            PR-842. The road is partially impassable.

&&

ICP

Preliminary Local Storm Report
National Weather Service San Juan PR
134 PM AST Mon Apr 28 2025

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0115 PM     Flash Flood      4 NNW Bairoa            18.31N 66.08W
04/28/2025                   San Juan           PR   Public

            The public has reported through social media
            that a vehicle is fully submerged in
            floodwaters in Sector Paracochero of Barrio
            Quebrada Arenas.

&&

ICP