Flash Flood Warning 30, NWS JSJ

302 
WGCA72 TJSJ 022037
FFSSJU

Flash Flood Statement
National Weather Service San Juan PR
437 PM AST Fri May 2 2025

PRC021-061-127-022047-
/O.CAN.TJSJ.FF.W.0030.000000T0000Z-250502T2045Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Bayamon PR-Guaynabo PR-San Juan PR-
437 PM AST Fri May 2 2025

...FLASH FLOOD WARNING FOR BAYAMON, GUAYNABO AND SAN JUAN HAS BEEN 
REPLACED WITH A FLOOD ADVISORY...

Flooding caused by excessive rainfall is expected.

Turn around, don't drown when encountering flooded roads. Most flood 
deaths occur in vehicles.

Be aware of your surroundings and do not drive on flooded roads.

Please report observed flooding to local emergency services or law 
enforcement and request they pass this information to the National 
Weather Service when you can do so safely.

&&

LAT...LON 1843 6608 1843 6606 1846 6611 1847 6612
      1846 6608 1845 6604 1840 6599 1838 6600
      1837 6603 1830 6605 1828 6616 1826 6619
      1831 6621 1842 6620 1844 6611

$$

CVB

Area Forecast Discussion
National Weather Service San Juan PR
501 AM AST Fri May 2 2025

.SYNOPSIS...

Once again, unsettled weather is expected over the next several
days due to a combination of abundant tropical moisture and a
series of upper- level troughs. The Flood Watch was extended
until Saturday morning due to the expected weather today.
Conditions will slightly improve on Sunday, but the wet and
unsettled weather conditions are likely return the next workweek.

&&

.SHORT TERM...Today through Sunday...

...A Flash Flood Watch remains in effect for Puerto Rico through
at least Saturday...

Shower and thunderstorm activity will continue to increase across
the U.S. Virgin Islands and the eastern sections Puerto Rico through
the rest of the morning hours. Ponding of water on roads and in poor
drainage areas is expected with this activity. Then, just before
noon and similar to previous days, thunderstorms are expected to
develop along portions of the Cordillera Central and last through
the evening hours. Due to already saturated soils and above normal
streamflows from previous days excessive rainfall and runoff, quick
river rises, landslides, and flash flooding is likely with these
thunderstorms once again. Winds will remain from the ENE but with a
prevailing easterly component in the steering flow, therefore,
portions of western PR that have not received as much rainfall in
the past days will see an increase in accumulations today.

The wet weather pattern will continue through at least Saturday,
with precipitable water content peaking around 2.15 inches from this
afternoon through Saturday, and decreasing to near 1.80 inches by
Sunday evening. This higher than normal moisture content will
combine with favorable atmospheric condtions at the mid-and upper-
levels from a developing trough/low to our northwest and produce
isolated to scattered thunderstorms with periods of heavy rainfall
for the next 24-36 hours. Residents and visitors are urge to monitor
the weather conditions and remain vigilant to take necessary action
to protect life and property from the expected flooding impacts
through the weekend. On Sunday, although the overall moisture
content is expected to decrease, diurnally induced afternoon
thunderstorms will develop once again over the mountain ranges of
PR, producing periods of locally heavy rainfall and triggering once
again flood concerns over extremely saturated soils.

For more information please refer to the latest updates from the
Flash Flood Watch (FFASJU).

https://forecast.weather.gov/wwamap/wwatxtget.php?cwa=SJU&wwa=flood%2
0watch

&&

.LONG TERM...Monday through Friday...

No significant changes were made to the long-term forecast. The
synoptic pattern continues as expected, with a surface high pressure
building in the Western Atlantic that should move eastward and an
induced low lingering over the Central Atlantic. The mid to
upper- level trough highlighted by the global models for the past
few days is still expected to approach the CWA by Wednesday,
increasing instability aloft. The wind pattern will be variable,
as ENE winds will reduce by Tuesday and remain light for the rest
of the forecast period. Regarding the shower activity, the latest
global model ensembles showed an increase in uncertainty, with
some members going for a less aggressive solution compared to the
past few days. However, they still expect PWAT values to remain
near to above climatological normals (1.7 - 1.9 inches) throughout
the entire period. The temperatures in the 500 mb should increase
to seasonal values (around -7 Celsius) by Monday and Tuesday, but
will get colder by midweek (around -8 Celsius). Additionally,
stronger upper level winds should bring ventilation aloft,
increasing instability. Therefore, there's confidence of
development of thunderstorms during the afternoons each day.

Windward sections can expect light to moderate showers
moving occasionally during the night and the morning hours, while
the deep afternoon convection will concentrate on the interior
portions of Puerto Rico. With the recent heavy rainfall, above-
normal streamflows, saturated soils, and the expected conditions,
the flood threat remains elevated mainly over the aforementioned
areas. There should be an improvement in the weather conditions by
Friday, as a drier air mass filters into the region, promoting
stable conditions across the local islands.

Seasonal temperatures should prevail for the rest of the forecast
period, with the heat risk remaining low across the CWA.

&&

.AVIATION...

(06Z TAFs)

SHRA and iso TSTMs increasing from the Atlantic and eastern waters
of the islands could move across the USVI/Eastern PR terminals thru
the rest of the morning hours. This can lead to brief MVFR cigs. Mtn
tops obscd and BKN/OVC lyrs btw FL030-250 expected aft 02/16z, when
SHRA/TSRA develops till at least 02/23z over the mountains and
western PR. Steering winds will have a more easterly component
today, but in general ENE winds expected at the sfc and increasing
btw 12-16 kt with stronger gusts aft 02/14. Stronger sustained winds
btw 16-21 kt are expected fm 02/22z-03/06z across the Atlantic and
eastern waters btw PR and the USVI.

&&

.MARINE...

A surface high pressure building across the western Atlantic and a
deep layered trough northeast of the region will continue promoting
light to moderate east-northeast to northeast winds for the next few
days. Showers and thunderstorms are expected to develop across the
local waters, producing locally higher winds and seas. Small craft
should exercise caution and stay weather alert.

&&

.BEACH FORECAST...

The moderate risk of rip currents will continue for the beaches in
northern Puerto Rico, Culebra, and St. Thomas and St. John in the
U.S. Virgin Islands. Beachgoers must exercise caution due to
possible life- threatening rip currents along the surf zone and
stay weather alert.

The rip current risk is still expected to gradually decrease this
weekend into early next week.

&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...Flood Watch through Saturday morning for PRZ001>013.

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

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

Hazardous Weather Outlook
National Weather Service San Juan PR
412 AM AST Fri May 2 2025

AMZ711>745-PRZ001>013-030815-
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-
412 AM AST Fri May 2 2025

This Hazardous Weather Outlook is for portions of Puerto Rico.

.DAY ONE...Today and Tonight

.Lightning...Isolated to scattered thunderstorms, particularly
across central Puerto Rico. Be prepared to stop all outdoor
activities and seek shelter if storms develop.

.Excessive Rainfall...Life-threatening flash flooding, which may
enter structures and cut off neighborhoods, especially in flood-
prone areas across mountainous areas. Isolated landslides in
areas of steep terrain. Elsewhere, prepare for ponding of water on
roads and in poorly drained areas, and flooding in urban areas,
roads, small streams, and washes. Stay alert for rising water.

.Wind...Breezy conditions (18-22 kts | 21-25 mph), particularly
across the Atlantic waters and the eastern waters of Puerto Rico.
Unsecured items could blow around.

.Marine Conditions...Small craft should exercise caution,
particularly across the Atlantic waters.

.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...Saturday through Thursday

An unstable and wet weather pattern will result in shower and
thunderstorm development through at least Saturday, increasing
the risk of flash flooding and the potential for frequent
lightning and gusty winds with the expected thunderstorms.
However, additional thunderstorm development is expected each
afternoon for the rest of the period, mainly over the central
portions of Puerto Rico. A moderate rip current risk will prevail
across the north facing beaches of the islands through Tuesday.

.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-VIZ001-002-030815-
St. Thomas St. John adjacent Islands-St Croix-
Nearshore Atlantic and adjacent Caribbean Coastal Waters-
412 AM AST Fri May 2 2025

This Hazardous Weather Outlook is for portions of USVI.

.DAY ONE...Today and Tonight

.Lightning...Isolated thunderstorms expected. 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.

.Wind...Breezy conditions (18-22 kts | 21-25 mph), particularly
across St. Thomas and the waters between the islands. Unsecured
items could blow around.

.Marine Conditions...Small craft should exercise caution,
particularly across the Atlantic waters.

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

.DAYS TWO THROUGH SEVEN...Saturday through Thursday

Shower and thunderstorm development is expected to continue
on Saturday, increasing the risk of urban flooding and the
potential for lightning activity and gusty winds. A moderate rip
current risk is expected on Saturday across the northern islands.

.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.

Special Weather Statement
National Weather Service San Juan PR
107 PM AST Fri May 2 2025

PRZ005-008>010-021830-
Northwest PR-North Central PR-Mayaguez and Vicinity PR-
Western Interior PR-
107 PM AST Fri May 2 2025

...A STRONG THUNDERSTORM WILL IMPACT NORTHEASTERN LAS MARIAS...
LARES...SAN SEBASTIAN...WESTERN ARECIBO...NORTHWESTERN ADJUNTAS...
ISABELA...MOCA...QUEBRADILLAS...NORTHEASTERN ANASCO...SOUTHERN
CAMUY...EAST CENTRAL RINCON...SOUTHERN HATILLO...NORTHWESTERN
UTUADO...AGUADA AND AGUADILLA MUNICIPALITIES THROUGH 230 PM AST...

At 106 PM AST, Doppler radar was tracking a strong thunderstorm near
Hato Arriba,San Sebastian, moving northwest at 10 mph.

HAZARD...Wind gusts up to 30 mph and pea size hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor hail damage to vegetation is
         possible.

This strong thunderstorm will be near...
  Moca, Aguadilla, Caban, and Aceitunas around 110 PM AST.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

&&

LAT...LON 1851 6702 1836 6673 1819 6681 1836 6727
      1837 6726 1839 6720 1842 6716 1849 6717
      1851 6714 1852 6704
TIME...MOT...LOC 1706Z 117DEG 42KT 1839 6706

MAX HAIL SIZE...0.25 IN
MAX WIND GUST...40 MPH

LIS

Special Weather Statement
National Weather Service San Juan PR
124 PM AST Fri May 2 2025

PRZ001-003>007-009-021900-
San Juan and Vicinity PR-North Central PR-Central Interior PR-
Western Interior PR-Ponce and Vicinity PR-Eastern Interior PR-
Southeast PR-
124 PM AST Fri May 2 2025

...STRONG THUNDERSTORMS WILL IMPACT CENTRAL INTERIOR MUNICIPALITIES
THROUGH 300 PM AST...

At 123 PM AST, Doppler radar was tracking strong thunderstorms along
a line extending from near Adjuntas to Cidra. Movement was northeast
at 10 mph.

HAZARD...Wind gusts up to 40 mph and pea size hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor hail damage to vegetation is
         possible.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Torrential rainfall is also occurring with these storms and may lead
to localized flooding. Do not drive your vehicle through flooded
roadways.

Frequent cloud to ground lightning is occurring with these storms.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

These storms may intensify, so be certain to monitor local radio
stations and available television stations for additional information
and possible warnings from the National Weather Service.

To report severe weather, contact your nearest law enforcement
agency. They will relay your report to the National Weather Service
office in San Juan.

&&

LAT...LON 1839 6672 1828 6608 1804 6617 1814 6684
TIME...MOT...LOC 1723Z 209DEG 8KT 1821 6676 1816 6616

MAX HAIL SIZE...0.25 IN
MAX WIND GUST...40 MPH

CVB