Your Number One Source for Real-Time Puerto Rico Weather & Hurricane Tracking Updates

281
FXCA62 TJSJ 210643
AFDSJU

Area Forecast Discussion
National Weather Service San Juan PR
243 AM AST Tue Apr 21 2026

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

.KEY MESSAGES...
Updated at 233 AM AST Tue Apr 21 2026

* Mostly sunny skies will prevail across the islands. Fair
  weather, with a few passing showers possible, are expected to
  persist through the next couple of days.

* Drier weather is expected for much of Puerto Rico, but afternoon
  showers will continue to develop along the interior and west each
  afternoon.

* A moderate rip current risk is expected through midweek, mostly
  for north and east Puerto Rico and for the Virgin Islands.

&&

.Short Term(Today through Thursday)...
Issued at 233 AM AST Tue Apr 21 2026

Overnight, calm and mostly clear skies prevailed across Puerto Rico
and the U.S. Virgin Islands under a dry and stable air mass.
Winds remained light and variable, similar to previous nights.
Minimum temperatures stayed into the upper 60s to low 70s across
coastal areas, with cooler observations across higher terrains. No
significant weather impacts were observed overnight.

For today (Tuesday), a relatively drier and more stable pattern
will continue as a surface high pressure system over the North Atlantic.
Winds will gradually shift from easterly to east-southeasterly
during the morning, then trend northeasterly by the afternoon as
cold front over western Atlantic moves closer to the region.
Available moisture will remain shallow, mostly confined below
700800 mb, limiting widespread rainfall potential. However, local
effects and daytime heating will still support scattered
afternoon showers, mainly across southwestern and southern Puerto
Rico. Isolated thunderstorms cannot be ruled out. While rainfall
coverage will be limited compared to recent days, ponding of water
in poorly drained areas and minor urban or small stream flooding
remain possible, especially where soils are already saturated.
Temperatures will remain near seasonal normals, with highs in the
mid-80s along the coast and cooler conditions in the mountains.

Looking ahead to Wednesday and Thursday, trade winds will continue
to bring occasional patches of low-level moisture, leading to
isolated to scattered passing showers, particularly during the
overnight and early morning hours. Each afternoon, diurnal heating
and local effects may still trigger limited convection across the
interior and western sections of Puerto Rico. Winds will generally
remain light to moderate with a northeasterly component, and
temperatures will stay near normal through the period.

&&

.Long Term(Friday through Tuesday)...
Issued at 233 AM AST Tue Apr 21 2026

A wetter and more unstable weather pattern is expected to prevail at
the start of the long-term period as remnants of a frontal boundary
linger near the region under southeasterly low-level flow. This
pattern will promote precipitable water values near or above
climatological normals. Afternoon convective development will remain
possible across interior and western/northwestern Puerto Rico, aided
by daytime heating, local effects, and sea breeze convergence. While
widespread rainfall is not anticipated on Friday, moderate rainfall
may still cause localized ponding of water in urban and poorly
drained areas, especially where showers persist or repeatedly affect
the same locations.

Through the weekend, low-level winds are forecast to veer more
southerly, allowing a deeper tropical moisture plume to spread
across the area while also advecting warmer temperatures into the
region. This evolving pattern will likely result in above-normal
daytime temperatures, particularly across coastal and urban areas of
Puerto Rico and the U.S. Virgin Islands. As a result, increased heat
risk is possible during the peak hours of the day, with heat indices
near or slightly above 100 degrees possible in some locations.
Residents and visitors should anticipate warmer and more humid
conditions through the weekend period.

Shower and thunderstorm coverage during the weekend will depend in
part on the availability of mid-level moisture, as the latest
guidance suggests some pockets of drier air aloft may intermittently
limit the overall extent of convection. Nevertheless, sea breeze
convergence, local effects, and stronger daytime heating may still
support isolated to scattered afternoon showers and thunderstorms
each day, with the greatest activity focused over interior and
northern portions of Puerto Rico. Localized urban and small stream
flooding will remain possible where stronger showers develop, along
with brief gusty winds and frequent lightning.

By early next week, a gradual increase in columnar moisture in
combination with some troughiness aloft is expected to support
greater areal coverage of showers and thunderstorms across the
forecast area. This should result in more numerous showers from
Monday into Tuesday, with the greatest afternoon activity once again
focused over interior and western/northwestern portions of Puerto
Rico, while passing showers remain possible elsewhere. In this
pattern, periods of locally heavy rainfall and isolated
thunderstorms will be possible, increasing the potential for urban
flooding, quick river rises, and localized flooding in flood-prone
areas through the latter part of the forecast period.

&&

.AVIATION...
(06Z TAFS)
Issued at 233 AM AST Tue Apr 21 2026

VFR conditions across all TAF sites, as fair weather condt
prevails.Prevailing winds should remain from E-NE around 10 to 15
kts gusts around 25 knots after 21/11Z or near VCTS/SHRA and with
sea breeze variations. After 21/17Z winds will become E-NE.

&&

.MARINE...
Issued at 233 AM AST Tue Apr 21 2026

A high-pressure system over the north-central Atlantic will promote
gentle to moderate easterly winds, with seas in the 3 to 5 foot
range today. Winds and seas will slightly diminish tonight. A weak
frontal boundary north of the region, and a brief pulse of northerly
swell spreading across the Atlantic waters, will cause winds to back
from the northeast. As a result, seas will increase to 5 to 6 feet
from Wednesday night into Thursday. Small craft should exercise
caution in the offshore Atlantic waters and local passages during
this time. Winds will then veer to an east to southeast direction by
the end of the workweek, then becoming more southerly to end the
weekend.

&&

.BEACH FORECAST...
Issued at 233 AM AST Tue Apr 21 2026

A moderate risk of rip currents (life-threatening rip currents are
possible in the surf zone) will be present at northwestern,
northern, northeastern, eastern and southeastern beaches of Puerto
Rico today, as well as at beaches of Vieques and St. Croix. As winds
become lighter this evening into Wednesday, the risk is expected to
generally decrease. However a moderate risk of rip currents will
likely persist at northern PR. Even if the risk of rip currents
is low in other areas, life-threatening rip currents often occur
in the vicinity of groins, jetties, reefs, and piers. Late
Wednesday night into Thursday, a brief pulse of northerly swell is
expected to spread across the Atlantic waters, and the risk is
anticipated to increase to moderate or high (life-threatening rip
currents are likely in the surf zone) along the northern coastline
of Puerto Rico, and to moderate along Culebra, St. Thomas, and
St. John. Up to a moderate risk is then expected to persist Friday
through the weekend. For more information, please visit:
weather.gov/beach/sju.

&&

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

$$

SHORT TERM...ERG
LONG TERM....CVB
AVIATION...99

NWS SJU Office Area Forecast Discussion