National Weather Service Today's Weather Impact Levels

739
FXCA62 TJSJ 011856
AFDSJU

Area Forecast Discussion
National Weather Service San Juan PR
256 PM AST Wed Apr 1 2026

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

.KEY MESSAGES...
Issued at 240 PM AST Wed Apr 1 2026

* Large breaking waves and life-threatening rip currents will
  continue along north and east-facing beaches tonight and
  tomorrow. Stay out of the water.

* Choppy to rough seas will result in hazardous conditions for
  small craft, persisting over the weekend. Small Craft Advisories
  remains in effect.

* Showers and isolated thunderstorm will continue in the afternoon
  over interior and southern Puerto Rico, leading to ponding of
  water over roadways and poorly drained areas.

* Breezy to locally windy conditions expected across coastal areas
  of the islands through early next week.

&&

.Short Term(This evening through Friday)...
Issued at 240 PM AST Wed Apr 1 2026

A surface high over the Atlantic will continue to promote up to
breezy ENE flow during the period as well as steer patches of
moisture towards the region. Current satellite-derived precipitable
water (PWAT) values indicate a patch of moisture of around 1.6
inches over the Atlantic waters and approaching the islands. Diurnal
heating, along with the ENE flow have will continue to result in the
development of showers and isolated t-storms over the Cordillera
towards south-central, southwestern and western PR, as well as
showers over the northern USVI towards Culebra and eastern Puerto
Rico and mainly downwind of Vieques. This will result in a limited
flooding risk over mainly the southwestern quadrant of Puerto Rico.
Although these afternoon showers will gradually dissipate and/or
move offshore, the above mentioned patch of moisture over the
Atlantic will result in an increase in passing shower activity over
windward sectors late tonight as this air mass moves over the
region. Afternoon convection is once again forecast tomorrow,
Thursday, for similar areas as today due to diurnal heating and
local effects but with more E to ENE steering flow possibly steering
showers towards western PR as well. A limited flooding risk
continues. Moisture is expected to deepen and become more
established from tomorrow, Thursday, night into Friday. This setup
will lead to more frequent passing showers across the eastern and
northern parts of Puerto Rico and the U.S. Virgin Islands under ENE
flow. The highest rainfall totals will be a result of afternoon
convection each day over mainly interior to W, SW and S-Central PR
depending on the steering flow. Shower and isolated t-storm
development will be favored due to the combination of a nearby upper-
level trough and the lack of a well-defined trade wind cap. A
limited flooding risk will continue each day (especially late
tomorrow onwards) resulting in ponding of water in roads and poorly
drained areas and possible urban and small streams flooding. PWAT
values are forecast at normal to high-end normal values while 925 mb
wind speeds will be at 15-20 kts throughout the shower term period,
promoting quicker moving showers. 925 temperatures will be below
normal throughout the short term period. Highs will be in the 80s
across coastal areas of the islands with isolated sectors at around
90, lows will be in the upper 60s to low 70s across coastal areas of
the islands and in the upper 50s to lower 60s at higher elevations
of Puerto Rico.

&&

.Long Term(Saturday through next Tuesday)...
Issued at 200 AM AST Wed Apr 1 2026

For the beginning of the long-term period, a weather pattern
influenced by an induced surface trough and an upper-level shortwave
trough is expected. This combination will lead to increasingly
unstable conditions across the islands. As the disturbance moves
west of the region, its interaction with a high-pressure system over
the Central Atlantic will promote an east-southeasterly wind flow.

The upper-level trough will enhance instability and support
thunderstorm development, resulting in a high probability of
showers. However, a deep upper-level cloud layer may limit daytime
heating, potentially reducing widespread activity. Even so,
localized, well-developed showers are expected, especially across
northwestern areas and the San Juan metro region. By Sunday,
precipitable water values are forecast to reach around 1.7 inches,
near the 75th percentile for this time of year. A limited to
elevated flood risk will persist each afternoon. As a result,
similar conditions are expected on Sunday, as the upper-level trough
continues to influence the region along with periods of enhanced
cloud cover. During this time, a limited to elevated flood risk will
persist each afternoon.

From Monday through Wednesday, the surface pattern will become
dominated by a broad high-pressure system over the Central Atlantic,
resulting in southeasterly winds. During this period, increasing low-
level moisture from the Caribbean will spread across the islands,
with precipitable water values rising to around 1.9 inches and
remaining near the 75th percentile, based on climatological data for
this time of the year. With weaker upper-level dynamics, cloud cover
aloft will be less extensive, allowing for more effective daytime
heating. As a result, afternoon convection is expected to become
more widespread and better organized, particularly across western
and interior Puerto Rico, where local effects will enhance shower
and thunderstorm development. This pattern, combined with warm and
humid conditions, will increase the risk of urban and small stream
flooding.

&&

.AVIATION...
(18Z TAFS)
Issued at 240 PM AST Wed Apr 1 2026

Mainly VFR conditions through the period. Brief MVFR conditions are
possible mainly at TJPS and TIST as -SHRA and ,for TJPS, VCTS
develops through around 01/22z.  VCSH/-SHRA reaching mainly northern
sites from the Atlantic under ENE flow. ENE winds at 12 to 18 kts
with higher gusts through this evening, with 8 to 14 kts overnight,
and increasing again after 02/13Z. VCSH/-SHRA reaching mainly
northern sites from the Atlantic under ENE flow.

&&

.MARINE...
Issued at 240 PM AST Wed Apr 1 2026

Hazardous marine conditions will persist through the week under a
strong Atlantic high-pressure system. Fresh to strong northeasterly
winds and a persistent north-northeasterly swell will maintain
choppy to rough seas across regional waters, with conditions
continuing even as winds shift easterly by the end of the week.
Frequent trade wind showers will move across the Atlantic waters and
local passages, with isolated afternoon thunderstorms possible over
the Caribbean waters that may produce lightning. Small Craft
Advisories remain in effect for northern and exposed waters through
at least Saturday.

&&

.BEACH FORECAST...
Issued at 240 PM AST Wed Apr 1 2026

Some changes were introduced to the beach forecast. Current
nearshore buoys are reporting seas between 6 and 8 feet and a period
of around 11 seconds, resulting in breaking waves between 12 and 14
feet. NDBC buoy 41043 continues to report seas between 11 and 14
feet, with a dominant period around 11 - 13 seconds. This energy,
expected to arrive tonight, will very likely lead to large breaking
waves (between 10 and 13 feet, occasionally higher) over exposed
beaches in the northern areas of the islands. Additionally, the
swell direction is gradually shifting, becoming from the north-
northeast, and based on the latest guidance, winds will gradually
strengthen starting this afternoon. Given the current conditions and
the expected forecast, the High Surf Advisory has been extended for
the northern and eastern beaches of Puerto Rico, including Vieques
and Culebra, and the U.S. Virgin Islands through 6 PM AST Thursday.
Beachgoers and inexperienced surfers are urged to avoid going into
the water, walking over rocks or jetties, as large breaking waves
pose a life-threatening risk. Heed the advice of lifeguards, beach
patrol flags, and signs. Additionally, these conditions could result
in localized beach erosion over vulnerable areas. The Rip Current
remains in effect through late Friday night, though it will likely
be extended as life-threatening rip currents may persist in the
upcoming weekend.

Besides rip currents and high surf conditions,  beachgoers should
stay weather alert due to showers and isolated thunderstorms in the
afternoon that may produce lightning over the western coastal areas
of Puerto  Rico. Seek shelter inside a building whenever you hear
lightning.

&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...High Rip Current Risk through late Friday night for PRZ001-002-
     005-008-010-012-013.

     High Surf Advisory until 6 PM AST Thursday for PRZ001-002-005-
     008-010-012-013.

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

     High Surf Advisory until 6 PM AST Thursday for VIZ001-002.

AM...Small Craft Advisory until 6 AM AST Saturday for AMZ711-712-716-
     723-741-742.

     Small Craft Advisory until 6 AM AST Friday for AMZ726.

&&

$$

SHORT TERM/AVIATION...MRR
LONG TERM....YZR
MARINE/BEACH FORECAST...MNG

NWS SJU Office Area Forecast Discussion