Special Weather Statement, NWS JSJ

Area Forecast Discussion
National Weather Service San Juan PR
204 PM AST Wed Sep 9 2026

...New SHORT TERM, LONG TERM, AVIATION, MARINE, BEACH FORECAST...

.KEY MESSAGES...
Issued at 204 PM AST Wed Sep 9 2026

- The tropical waves moving across the region today and tomorrow
  will increase the potential for rainfall and thunderstorm
  activity. Flood risk remains limited.

- Moderate to high Saharan Dust concentrations will gradually
  filter across the US Virgin Islands and Puerto Rico from tonight
  onwards.

- Heat risk remains limited for today and Thursday due to higher
  cloud cover, with a warmer pattern returning by Friday along
  with the dry air mass and Saharan Air Layer (SAL).

- Breezy to locally windy conditions will continue to deteriorate
  marine and coastal conditions. Therefore, Small Craft Operators
  should continue to exercise caution, and beach goers should
  continue to monitor beach conditions as the evolve.

&&

.Short Term(This evening through Friday)...
Issued at 204 PM AST Wed Sep 9 2026

The passage of a weak tropical wave over the US Virgin Islands and
Puerto Rico has brought TPW values to 2 inches and has favored
the development of isolated showers over the US Virgin Islands,
the windward waters and offshore Puerto Rico. Nonetheless, the
rain activity over the islands has remained limited with low
concentrations of Saharan dust particles. Passing showers and
thunderstorms are forecast to develop across the interior and
northwestern regions of Puerto Rico aided by the elevated humidity
levels, daytime heating and local effects. Breezy to locally
windy conditions prevailed today due to a low-level high pressure
over the Atlantic waters which is strengthening the pressure
gradient and leading to a ESE wind flow. Heat risk remains limited
due to the increasing cloudiness over the forecast region with
heat indices ranging from 90 - 105 degrees Fahrenheit along urban
and coastal sections of the US Virgin Islands and Puerto Rico and
around mid 80s to mid 90s degrees Fahrenheit across the interior
of Puerto Rico. While heat risk remains limited, individuals
should be cautious when outside and should remain well hydrated.

Another tropical wave is expected to arrive to the windward waters
between tonight and Thursday morning along with moderate to high
concentrations of Saharan Dust. This will lead to variable
conditions on Thursday over the US Virgin Islands and Puerto Rico.
We can expect similar conditions to those seen today, with some
passing showers and thunderstorms over the US Virgin Islands and
eastern Puerto Rico in the morning hours, with the main activity
gradually shifting to the interior and western Puerto Rico in the
afternoon. A low-level high pressure over the Atlantic waters
coupled with the wave activity over the region will continue to
favor breezy to locally windy ESE conditions across the forecast
region, particularly across coastal and exposed areas, limiting
the potential for significant rainfall accumulations. The 500
millibar temperatures will remain around -6 to -8 degrees Celsius
providing favorable conditions for convective activity. By late
Thursday into Friday, we expect the wave to move outside of the
forecast region and be displaced by a drier air-mass accompanied
by a Saharan Air Layer (SAL) that will drop TPW values from 2
inches to 1.5 inches. We suggest citizens and visitors to continue
to monitor conditions as the evolve and follow the
recommendations of health officials.

Warmer conditions may be expected by Friday aided by the limited
shower activity over the islands. Even if conditions are
unfavorable for the development of convection on Friday, the ESE
wind flow accompanied by daytime heating and local effects might
lead to isolated showers and thunderstorms during the morning
hours over the US Virgin Islands and eastern Puerto Rico and in
the afternoon for the interior and northwestern regions of Puerto
Rico.

&&

.Long Term(Saturday through next Tuesday)...
Issued at 204 PM AST Wed Sep 9 2026

A surface high-pressure is expected to promote easterly breezy winds
across the islands for most of the forecast period. The Saharan
dust layer will persist during the weekend, with concentration
values reaching high levels on Saturday. This will promote hazy
skies, reduced visibility, and poor air quality. Residents and
visitors are encouraged to follow medical recommendations and
closely monitor weather forecasts for updates. Precipitable water
values are expected to drop to around 1.25 to 1.5 inches over the
weekend, which is considered below-normal to seasonal values.
Nonetheless, passing showers during the morning cannot be ruled
out in portions of eastern Puerto Rico and the U.S. Virgin
Islands. Later on, afternoon showers and isolated thunderstorms
triggered by daytime heating and local effects are possible each
day, with a limited flood threat expected on Sunday afternoon
across western Puerto Rico.

A transition to a wetter pattern from Monday through the rest of
the long term, associated with a series of upper-level lows.
Current model guidance shows a drier air slot moving across the
area Tuesday morning. The persistent breezy easterly flow will
likely bring a few passing showers across windward areas of the
islands during the morning, followed by afternoon convection
across the western interior and western sectors of Puerto Rico.
Due to the aforementioned lingering upper-level lows, 500-mb
temperatures are expected to remain at or below -6 degrees
Celsius, which will likely trigger isolated thunderstorms during
the afternoon hours in combination with diurnal heating and local
effects.

A change in the pattern is anticipated by Tuesday night into midweek
as a tropical wave brings above-normal moisture, with PWAT values
exceeding 2 inches. This will bring an increasing chance of showers
and thunderstorms, along with a potentially elevated flood risk
across portions of the islands. Continue to monitor the forecast as
adjustments and updates become available.

Overall, hazy, drier, and warmer conditions are expected on
Saturday, followed by variable conditions Sunday into Tuesday, with
seasonal moisture and instability fueled by lingering upper-level
lows. By Tuesday night into Wednesday, moisture associated with a
tropical wave will increase the chance of showers and thunderstorms,
along with an increasing flood threat.

&&

.AVIATION...
(18Z TAFS)
Issued at 204 PM AST Wed Sep 9 2026

VFR conditions will persist across all TAF sites during the period
with surface winds from the E-Se at 15 to 20 knots and gusty winds.
Some VCSH to SHRA will move near the area mostly across eastern TAF
sites. Saharan dust particles will remain in place reducing VIS.
CIGS and VIS will also be reduced due to an increase in showers and
thunderstorms at around 10/03Z 10/12Z near TISX, TIST & TJPS.

&&

.MARINE...
Issued at 204 PM AST Wed Sep 9 2026

A surface high pressure strengthening across the central Atlantic
will promote moderate to fresh winds, with stronger gusts for the
rest of the week. This will result in choppy to locally rough
marine conditions. Seas will build up to 6 feet across the
offshore waters and local passages, with occasional seas up to 8
feet. A passing tropical wave will increase showers and
thunderstorms across the regional waters through this afternoon.
However, a second tropical wave will arrive tonight through
Thursday afternoon promoting similar weather conditions. Gusty
winds, brief periods of torrential rainfall, and locally higher
seas are expected with these tropical waves.

&&

.BEACH FORECAST...
Issued at 204 PM AST Wed Sep 9 2026

A moderate risk of rip currents will persist across most east,
south, and north-facing beaches of the islands through the end of
the week due to increasing winds and building seas across the
local coastal waters. Life-threatening rip currents are possible
in the surf zone, and beachgoers are urged to exercise caution.

A passing tropical wave will continue to enhance the development
of showers and thunderstorms across the region, promoting gusty
winds and lightning strikes during the afternoon hours. Beachgoers
should remain hydrated and limit prolonged sun exposure, and seek
shelter whenever they hear thunder.Expect another tropical wave to
reach the islands from tonight into Thursday.

&&

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

SHORT TERM...MMC/RVM
LONG TERM...YZR
MARINE/BEACH FORECAST...MMC
AVIATION...LIS

Special Weather Statement
National Weather Service San Juan PR
1114 PM AST Wed Sep 9 2026

PRZ002>004-006-007-100415-
Central Interior PR-Southeast PR-Northeast PR-Ponce and Vicinity
PR-Eastern Interior PR-
1114 PM AST Wed Sep 9 2026

...A STRONG THUNDERSTORM WILL IMPACT SOUTHEASTERN TO SOUTH-CENTRAL
PUERTO RICO UNTIL 1215 AM AST...

At 1114 PM AST, Doppler radar was tracking a strong thunderstorm over
southeastern Puerto Rico, moving west at 20 mph.

HAZARD...Wind gusts up to 40 mph and frequent lightning.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects.

Locations impacted include...
  Guayama, Coamo, Santa Isabel, Cayey, Cidra, Aibonito, Arroyo,
  Patillas, Salinas, Barranquitas, San Lorenzo, Maunabo, Orocovis,
  Yabucoa, Las Piedras, Humacao, Emajagua, Vazquez and Olimpo.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

&&

LAT...LON 1799 6647 1823 6646 1816 6575 1806 6580
      1805 6584 1801 6583 1798 6592 1798 6602
      1793 6616 1794 6615 1793 6621 1794 6621
      1794 6617 1796 6621 1794 6626 1793 6625
      1798 6632 1794 6639
TIME...MOT...LOC 0311Z 93DEG 23KT 1809 6615

MAX HAIL SIZE...0.00 IN
MAX WIND GUST...40 MPH

MRR/KML

Special Weather Statement
National Weather Service San Juan PR
1157 PM AST Wed Sep 9 2026

PRZ001-005-006-008-100500-
Central Interior PR-San Juan and Vicinity PR-North Central PR-
Northwest PR-
1157 PM AST Wed Sep 9 2026

...A STRONG THUNDERSTORM WILL IMPACT NORTH-CENTRAL PUERTO RICO UNTIL
UNTIL 1 AM AST...

At 1157 PM AST, Doppler radar was tracking a strong thunderstorm over
north-central Puerto Rico, moving west at 20 mph.

HAZARD...Wind gusts up to 30 to 40 mph, frequent lightning and heavy
         rain.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects.

Locations impacted include...
  Arecibo, Barceloneta, Florida, Manati, Vega Baja, Vega Alta, Ceiba,
  Pajonal, Imbery, La Luisa, La Alianza, San Antonio, Coto Norte,
  Barahona, Bajadero, Miranda and Monserrate.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

&&

LAT...LON 1833 6679 1849 6680 1847 6673 1849 6663
      1849 6655 1847 6647 1847 6645 1849 6644
      1849 6640 1847 6636 1848 6636 1849 6638
      1847 6629 1835 6628 1833 6672 1835 6673
      1833 6677
TIME...MOT...LOC 0355Z 94DEG 28KT 1846 6659

MAX HAIL SIZE...0.00 IN
MAX WIND GUST...40 MPH

MRR

Special Weather Statement
National Weather Service San Juan PR
207 AM AST Thu Sep 10 2026

PRZ003-004-006-007-009-100730-
Central Interior PR-Southeast PR-Ponce and Vicinity PR-Eastern
Interior PR-Western Interior PR-
207 AM AST Thu Sep 10 2026

...STRONG THUNDERSTORMS WILL IMPACT SOUTHERN PUERTO RICO UNTIL 315
AMAST UNTIL 330 AM AST...

At 207 AM AST, Doppler radar was tracking strong thunderstorms over
the Southern Coastal Waters, moving northwest at 20 mph towards
mainly south-central to southeastern Puerto Rico.

HAZARD...Wind gusts up to 30 to 40 mph, frequent lightning and heavy
         rain.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects.

Locations impacted include...
  Ponce, Yauco, Guayama, Coamo, Santa Isabel, Salinas, Aibonito,
  Villalba, Juana Diaz, Cayey, Arroyo, Patillas, Penuelas,
  Guayanilla, Maunabo, Yabucoa, Emajagua, Los Llanos, Las Ollas and
  Jauca.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Monitor the weather situation closely and be alert for threatening
weather conditions.

If outdoors, consider seeking shelter inside a building.

&&

LAT...LON 1815 6588 1802 6583 1798 6592 1798 6602
      1795 6605 1794 6626 1793 6625 1798 6632
      1794 6639 1799 6646 1796 6662 1797 6661
      1800 6663 1797 6667 1800 6677 1801 6677
      1796 6686 1815 6691
TIME...MOT...LOC 0606Z 146DEG 16KT 1797 6613

MAX HAIL SIZE...0.00 IN
MAX WIND GUST...40 MPH

MRR/KML