National Weather Service Today's Weather Impact Levels

112
FXCA62 TJSJ 150745
AFDSJU

Area Forecast Discussion
National Weather Service San Juan PR
345 AM AST Sat Aug 15 2026

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

.KEY MESSAGES...
Issued at 249 AM AST Sat Aug 15 2026

- An approaching tropical wave (Invest 92L) will move across the
  Caribbean Sea, increasing moisture across the area from early
  this evening into Sunday morning. Therefore, residents can
  expect an increase in fast-moving showers.

- Heat Risk is elevated today, with a Heat Advisory in effect.
  Risk may decrease over the weekend, particularly on Sunday,
  increasing again by early next week.

- Marine and coastal hazards are ongoing and will remain through
  Sunday. For more detailed information, please refer to the
  Marine and Beach Forecast sections.

&&

.Short Term(Today through Monday)...
Issued at 249 AM AST Sat Aug 15 2026

Calm conditions prevailed overnight with a few passing showers
moving through the local Atlantic and Caribbean waters. A few
reached the northern coast of Puerto Rico without leaving
significant rainfall accumulations. Overnight temperatures remained
warm, staying in the upper 70s to low 80s in coastal and urban
areas, while dropping into the low-to-mid 70s at higher elevations.
Breezy conditions continued overnight under a northeasterly wind
flow of 10 to 15 mph.

A strong high-pressure system to the north will maintain a tight
pressure gradient today, generating breezy to locally windy easterly
flow and pushing drier air into the region. Precipitable water
(PWAT) values will fall below seasonal normals to around 1.30
inches, keeping rainfall very limited today.

Today, above-normal warm temperatures and abundant sunshine will
elevate heat risks, triggering a Heat Advisory today from 10 AM to
5 PM AST across all coastal and urban areas of Puerto Rico,
Culebra, Vieques, and the U.S. Virgin Islands. The combination of
low humidity, dry soils and vegetation, and strong easterly winds
will also create conditions favorable for rapid wildfire spread,
especially along Puerto Rico`s southern and southwestern coastal
plains and adjacent slopes, where a Fire Danger Statement is in
effect.

Moisture will begin to increase from this evening into Sunday as
Invest 92L moves across the Caribbean Sea, passing south of the
local islands. Current model guidance suggests the bulk of this
tropical wave will stay well to the south, though PWAT values are
expected to surge up to 2.10 inches. This surge will bring overnight
and early morning showers to the U.S. Virgin Islands and eastern
Puerto Rico, followed by scattered afternoon showers and
thunderstorms across Puerto Rico driven by daytime heating and local
effects. While the strongest storms could produce heavy downpours,
lightning, and gusty winds, widespread significant rainfall is not
anticipated. Following the wave`s passage, drier air and stable
conditions will return Sunday afternoon and persist through at least
midweek.

&&

.Long Term(Tuesday through Saturday)...
Issued at 249 AM AST Sat Aug 15 2026

A relatively dry and stable weather pattern is expected Tuesday,
followed by increasing moisture and instability Wednesday into
Thursday as Invest 94L (AL94) approaches the northeastern Caribbean.
On Tuesday, PWAT values should remain around 1.3 to 1.5 inches, with
relatively dry mid-levels limiting shower and thunderstorm coverage.
Moisture will gradually increase Wednesday, with the most
significant surge expected Wednesday night into Thursday, when PWAT
could rise to around 2 inches or greater. Increasing low- to mid-
level moisture, cooler 500 mb temperatures, and steeper mid-level
lapse rates should favor increasing showers and thunderstorms, with
locally heavy rainfall and urban and small-stream flooding possible.

Considerable uncertainty remains Thursday into Saturday regarding
the evolution, track, timing, and moisture distribution associated
with AL94. Regardless of development, the disturbance could bring a
substantial tropical moisture envelope across or near the local
islands. Small changes in its track or evolution could significantly
influence rainfall coverage and amounts. Although moisture may
fluctuate Friday into Saturday, cooler temperatures aloft and
favorable mid-level lapse rates should maintain an unstable
environment, supporting periods of showers and thunderstorms where
deeper moisture persists. Therefore, the flooding threat will depend
largely on the duration and location of the deepest moisture.

The expected rainfall could provide beneficial moisture to areas
experiencing dry conditions; however, significant drought relief is
not anticipated, as rainfall amounts and coverage will likely vary
considerably. Heat will also remain a concern, particularly Tuesday
and during periods of sufficient sunshine later in the week.
Increasing humidity may maintain elevated heat indices, while
greater cloud and shower coverage Thursday onward could provide some
relief. Continue to monitor the latest forecasts and updates
regarding the evolution of AL94.

&&

.AVIATION...
(06Z TAFS)
Issued at 249 AM AST Sat Aug 15 2026

Mainly VFR conds expected across all TAF sites. HZ from Saharan
dust will continue affecting the local islands, resulting in VIS
reductions through 15/22Z. An approaching tropical wave will
increase the frequency of SHRA/TSRA later this evening, resulting
in VCSH at all terminals aft 15/22-23Z. E winds at 10-15 kt
through 15/14Z, increasing to 20-25 kt with gusts 30-35 kt through
15/22-23Z.

&&

.MARINE...
Issued at 249 AM AST Sat Aug 15 2026

A tight pressure gradient will maintain fresh to locally strong
easterly winds and choppy to rough seas around 5 to 7 feet, with
occasional seas of 8 to 9 feet across the offshore waters and local
passages. Small Craft Advisories remain in effect through at least
Sunday. Showers and thunderstorms will increase by Saturday
afternoon into Sunday as the tropical wave AL92 moves south of the
region, affecting Caribbean waters and local passages.

&&

.BEACH FORECAST...
Issued at 249 AM AST Sat Aug 15 2026

Dangerous conditions for beachgoers are expected to continue this
weekend. The latest nearshore buoys continue to report seas between
3 and 5 feet, while scatterometer data shows winds between 15 - 20
kt, isolated areas between 20 - 25 kt. Based on the latest model
guidance, building seas between 5 and 7 feet, occasionally higher,
may lead to breaking waves between 6 and 7 feet across exposed
beaches of the islands. Therefore, the high risk of rip currents
continues across most exposed beaches of Puerto Rico, including
Vieques and Culebra, and the U.S. Virgin Islands. Beachgoers must
pay attentions to the beach conditions prior entering the waters,
as life-threatening rip currents are likely along the surf zone.
They should heed the advice of lifeguards, local beach patrol and
the flag warning systems. Conditions should gradually improved by
Monday, as weakening winds and subsiding seas should lead to a
moderate risk of rip currents.

Besides rip currents, beachgoers should stay weather alert
particularly this weekend as tropical wave AL92 approaches the
Caribbean Basin. Although the system is forecast to move south of
the CWA, showers and thunderstorms associated with it may move near
the coastal areas of the islands, bringing gusty winds and
lightning. They must seek shelter whenever they hear thunder.

&&

.FIRE WEATHER...
Issued at 249 AM AST Sat Aug 15 2026

Elevated fire danger is expected today as a very dry airmass
remains across the region and strong easterly winds continue
today with winds between 15 to 20 mph with gusts around 35 mph.
Similar to previous days, these conditions combined with little
to no wetting rainfall, ongoing rainfall deficits, stressed
vegetation, and dry fuels will maintain conditions favorable for
rapid fire spread. Therefore, a Fire Danger Statement will be in
effect across all Puerto Rico, Culebra, Vieques, and the U.S.
Virgin Islands from 10 AM AST this morning through 5 PM AST this
afternoon.

The northern periphery of an approaching tropical wave (Invest
92L) will approach the U.S. Virgin Islands and the southern coast
of Puerto Rico later this afternoon, slightly increasing the
moisture content across the area. Nonetheless, the dry conditions
will persist until then.

&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...High Rip Current Risk through late Sunday night for PRZ001>003-
     005-007-008-011>013.

     Heat Advisory from 10 AM this morning to 5 PM AST this afternoon
     for PRZ001>005-007-008-010>013.

VI...High Rip Current Risk through late Sunday night for VIZ001-002.

     Heat Advisory from 10 AM this morning to 5 PM AST this afternoon
     for VIZ001-002.

AM...Small Craft Advisory until 5 PM AST Sunday for AMZ711-723-733-
     741.

     Small Craft Advisory until 1 PM AST this afternoon for AMZ712-
     716-726-735.

&&

$$

EVENING SHIFT...CVB/MNG
MIDNIGHT SHIFT...GRS

NWS SJU Office Area Forecast Discussion