Special Weather Statement, NWS JSJ

Area Forecast Discussion
National Weather Service San Juan PR
113 PM AST Mon Jun 29 2026

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

.KEY MESSAGES...
Issued at 108 PM AST Mon Jun 29 2026

* Shower and thunderstorm activity for the rest of today,
  resulting in ponding of water over roadways and poorly drained
  areas, including urban and small stream flooding, across the
  islands.

* Warmer to hot conditions are expected for the next few days, with
  heat indices exceeding 100 degrees Fahrenheit across urban and low-
  lying areas of Puerto Rico and the U.S. Virgin Islands. Stay
  hydrated.

* Moderate to high concentrations of Saharan Dust will filter into
  the region tonight into Tuesday, resulting in hazy skies,
  reduced visibility, and poor air quality. Sensitive groups must
  follow medical recommendations.

&&

.Short Term(This evening through Wednesday)...
Issued at 108 PM AST Mon Jun 29 2026

Today was generally calm across Puerto Rico and the U.S. Virgin
Islands with a few passing showers that moved across the islands
from time to time. Afternoon temperatures reached the upper 80s to
mid 90s across coastal and urban areas, while higher elevations
remained in the upper 70s to lower 80s. By the early afternoon,
daytime heating, local effects, and exiting tropical wave allowed
showers to become stronger and produce lightning across the north-
central to northwestern sections of Puerto Rico. This activity is
currently ongoing.

Tonight, a much drier and more stable air mass will gradually spread
across the region. At the same time, moderate to high concentrations
of Saharan dust will gradually filter inland.

On Tuesday, expect the highest concentrations of Saharan Dust. As a
result, skies will become hazier, rainfall coverage will decrease,
and shower activity will be limited mainly to brief, fast-moving
trade wind showers. Sensitive groups, including individuals with
respiratory conditions, are urged to limit prolonged outdoor
exposure and take necessary precautions.

Tuesday through Wednesday, a broad Atlantic high-pressure system and
a strengthening mid-level ridge will maintain stable weather
conditions across the northeastern Caribbean. While a few passing
showers cannot be ruled out, especially during the overnight and
morning hours, widespread or significant rainfall is not expected.
The combination of increased sunshine and drier conditions will
allow temperatures to rise into the 90s across coastal and urban
areas, with heat index values reaching or exceeding 100°F during the
afternoon. Residents and visitors are encouraged to stay hydrated,
limit prolonged outdoor activities during the hottest part of the
day, and take frequent breaks in shaded or air-conditioned areas.

&&

.Long Term(Thursday through next Sunday)...
Issued at 257 AM AST Mon Jun 29 2026

For the long-term forecast period, the region will experience a
transition from a marginally unstable environment to a drier, hazier
pattern before moisture returns early next week on Monday. At the
surface, a dominant high-pressure system will maintain a generally
easterly low-level wind flow, which is expected to veer to the
southeast by Thursday morning. Aloft, a 250 mb cut-off low will
linger near the local area from Thursday into Friday, providing
modest upper-level support and atmospheric instability, with 500 mb
temperatures forecast to hover between -8 °C and -7 °C during this
time. On the other hand, precipitable water values are expected to
range between 1.4 and 1.6 inches.  Given the expected conditions,
passing showers are anticipated across eastern sections of Puerto
Rico during the morning hours, followed by the development of
afternoon showers over the western interior and northwestern
quadrants of the island, fueled by local effects and daytime heating.

From Friday through Sunday, a slightly drier weather pattern will
establish across the forecast area. Available moisture will become
relatively shallow, generally trapped between the 1000 and 850 mb
levels. Furthermore, recent NASA Goddard aerosol model guidance
indicates the arrival of another mass of Saharan particulates. This
dust will result in hazy skies, leading to mostly dry and variable
conditions with very limited rainfall accumulations throughout the
weekend. By Monday, a more uniform area of low-level moisture is
forecast to filter into the region. This will aid in diminishing the
hazy conditions as dust concentrations decrease, promoting a return
to a more typical, scattered shower pattern across the islands.

Regardless of the fluctuations in moisture and Saharan dust,
persistently warm to hot conditions will dominate the entirety of
the long-term period. An elevated heat threat is expected each day,
particularly across urban and coastal areas. Maximum heat index
values will consistently peak between 100 and 108 °F across portions
of the north-central coastal plain and southern sectors of Puerto
Rico during the peak daytime heating hours.

&&

.AVIATION...
(18Z TAFS)
Issued at 108 PM AST Mon Jun 29 2026

VFR conds are expected to prevail across all TAF sites. However, a
tropical wave will enhance the development of SHRA and iso TS over
TJBQ & TJSJ throu 29/22Z. SE winds between 12-16 kt are expected
with higher gusts near TS and sea breeze variations. Winds will
become light and variable at 5-10 kt aft 29/23Z, increasing back to
around 15kts by 30/12Z across more TAF sites.

&&

.MARINE...
Issued at 108 PM AST Mon Jun 29 2026

A tropical wave near the Mona Passage will continue to bring showers
and isolated thunderstorms across the regional waters and Caribbean
Passages, with gusty winds and lightning, creating localized
hazardous conditions for small craft. Following the tropical wave, a
dense Saharan Air Layer will filter into the region tonight through
Wednesday, bringing hazy skies and reduced visibility. The surface
high pressure across the Central Atlantic will promote the return of
moderate to locally fresh east-to-east-southeasterly winds,
resulting in choppy seas across regional waters.

&&

.BEACH FORECAST...
Issued at 108 PM AST Mon Jun 29 2026

No changes were introduced to the beach forecast, as the risk of rip
currents should remain low across most beaches of Puerto Rico and
the U.S. Virgin Islands for the next few days. Nevertheless,
beachgoers should pay attention to the beach conditions, as life-
threatening rip currents can often occur near groins, jetties,
reefs, and piers. The risk should gradually increase by the upcoming
weekend, as the local pressure gradient increases and winds
strengthen, with a moderate risk of rip currents across most beaches
of the islands. Besides rip currents, showers and isolated
thunderstorms can be expected for the rest of today due to the
influence of a tropical wave near the Dominican Republic, which
could move near coastal areas of the islands. As the tropical wave
continues to move across the Caribbean Basin, moderate to high
concentrations of Saharan Dust will gradually filter into the region
tonight, persisting through Wednesday. These concentrations will
result in hazy skies, reduced visibility, and poor air quality.

&&

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

SHORT TERM/AVIATION...MMC
LONG TERM...LIS
MARINE/BEACH FORECAST...MNG

Special Weather Statement
National Weather Service San Juan PR
139 PM AST Mon Jun 29 2026

PRZ008>010-291815-
Northwest PR-Mayaguez and Vicinity PR-Western Interior PR-
139 PM AST Mon Jun 29 2026

...A STRONG THUNDERSTORM WILL IMPACT NORTHWESTERN SAN SEBASTIAN...
ISABELA...MOCA...NORTHEASTERN AGUADA AND AGUADILLA MUNICIPALITIES
THROUGH 215 PM AST...

At 138 PM AST, Doppler radar was tracking a strong thunderstorm near
Hato Arriba, or near Moca, moving northwest at 10 mph.

HAZARD...Wind gusts up to 30 mph.

SOURCE...Radar indicated.

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

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

&&

LAT...LON 1851 6701 1851 6700 1833 6698 1831 6705
      1838 6722 1842 6716 1849 6717 1850 6715
      1852 6708
TIME...MOT...LOC 1738Z 149DEG 11KT 1837 6707

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

LIS

Special Weather Statement
National Weather Service San Juan PR
221 PM AST Mon Jun 29 2026

PRZ005-006-291915-
North Central PR-Central Interior PR-
221 PM AST Mon Jun 29 2026

...A STRONG THUNDERSTORM WILL IMPACT MANATI & BARCELONETA
MUNICIPALITIES THROUGH 315 PM AST...

At 221 PM AST, Doppler radar was tracking a strong thunderstorm over
Coto Norte, or over Manati. This thunderstorm was nearly stationary.

HAZARD...Wind gusts up to 40 mph.

SOURCE...Radar indicated.

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

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

&&

LAT...LON 1849 6641 1834 6636 1833 6649 1848 6656
      1849 6655 1847 6650 1847 6645 1849 6643
TIME...MOT...LOC 1821Z 167DEG 4KT 1841 6645

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

LIS