812
FXCA62 TJSJ 220623
AFDSJU

Area Forecast Discussion
National Weather Service San Juan PR
223 AM AST Wed Apr 22 2026

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

.KEY MESSAGES...
Updated at 212 AM AST Wed Apr 22 2026

* Today, expect fair weather with a few showers during the
  afternoon across the interior and southwestern PR. Meanwhile,
  the USVI can expect calm weather with a few showers embedded in
  the winds.

* Beachgoers can expect a moderate risk of rip currents along
  north- and east-facing beaches throughout the forecast period in
  PR and the USVI. However, a long period northerly swell will
  promote a moderate/high risk on Thursday as this swell moves
  across the local Atlantic Waters.

* A wetter and more unstable weather pattern will set up over the
  region as early as Thursday afternoon and more likely from
  Friday into early next week.

&&

.Short Term(Today through Friday)...
Issued at 212 AM AST Wed Apr 22 2026

Compared to previous nights, overnight conditions were among the
calmest across Puerto Rico and the U.S. Virgin Islands. Mostly clear
skies allowed for slightly cooler minimum temperatures. Coastal
areas experienced lows in the lower to mid 70s, with some
unofficial stations dipping into the upper 60s. Interior and
mountainous areas experienced localized drops into the upper 50s,
though most remained in the 60s. Winds were light and variable,
with no significant hazards and minimal impacts under stable,
tranquil conditions.

For today (Wednesday), guidance supports and the forecast leans towards
a relatively dry and stable pattern. A weak surface high over the
central Atlantic will continue to maintain an east-northeasterly
wind flow across the islands. Overall, mostly fair weather is
expected, with isolated convection over interior and southwestern
Puerto Rico and downwind of the US Virgin Islands. Rainfall risk
will remain limited overall. Temperatures will reach the upper 80s
in lower elevations and urban areas, and in the 70s in higher
terrains.

A transition in weather conditions begins Thursday into Friday as a
frontal boundary approaches from the western Atlantic. At the
same time, a mid- to upper-level trough will amplify over the
western Caribbean, weakening the mid-level ridge and increases
instability. This pattern will bring more showers and
thunderstorms from late Thursday into Friday, with locally heavy
rainfall possible, especially in the afternoon and evening. Main
hazards include ponding on roads and reduced visibility at time
with the heaviest thunderstorms.

Overall, conditions will shift from stable and relatively dry to
more unsettled and moisture-rich by the end of the workweek, with
increasing impacts expected Thursday night into Friday. Therefore,
we urge visitors and citizens to monitor the forecast for changes
in the forecast regarding the increase of the flooding threats and
more.

&&

.Long Term(Saturday through Wednesday)...
Issued at 212 AM AST Wed Apr 22 2026

A surface high-pressure system positioned over the central Atlantic,
east of the Lesser Antilles, is expected to continue migrating
further eastward through early next week. As this system moves away,
winds will shift toward a more southerly flow, drawing tropical
moisture from the warm Caribbean waters into the region. At the same
time, lingering moisture from the remnants of a frontal boundary
will persist across the area through the upcoming weekend. This
atmospheric setup will drive daytime temperatures above normal,
particularly across coastal and urban areas of Puerto Rico and the
U.S. Virgin Islands. The combination of intense heat and abundant
moisture is expected to rise heat indices to 100F or higher.

While the weekend may see variable conditions, as pockets of drier
mid-level air arriving intermittently could limit widespread rain,
the combination of daytime heating and sea breeze convergence will
still likely trigger isolated to scattered afternoon thunderstorms.
This activity will be most concentrated over the interior and
northern regions, bringing the risk of frequent lightning, gusty
winds, and localized urban flooding.

By Monday afternoon into Tuesday, a deeper plume of moisture is
expected to arrive. The environment will become increasingly
unstable due to the arrival of this moisture alongside an upper-
level trough, likely leading to more widespread shower and
thunderstorm activity than over the weekend. While passing showers
remain a threat for all the islands, the most active rainfall is
expected over the interior and the western to northwestern portions
of Puerto Rico during the afternoon hours. Residents and visitors,
particularly those in flood-prone areas, are encouraged to monitor
weather conditions closely and remain aware of potential rapid river
rises and localized flooding through the midweek.

&&

.AVIATION...
(06Z TAFS)
Issued at 212 AM AST Wed Apr 22 2026

Mostly VFR cond across all TAF sites. As fair weather cond with
clear skies will prevail. Prevailing winds should remain from
E-NE around 5 to 13 kts gusts around 20 knots after 22/12Z or
near VCsh and with sea breeze variations after 22/17Z.

&&

.MARINE...
Issued at 212 AM AST Wed Apr 22 2026

A high-pressure system extending from the central to the eastern
Atlantic is interacting with a frontal boundary approaching from the
western Atlantic. Additionally, long-period swells will move
across the local Atlantic and Caribbean Passages. The first swell,
arriving from the northwest, is expected to arrive around this
evening, followed by a second, larger swell coming from the north
to northeast around Saturday.

&&

.BEACH FORECAST...
Issued at 212 AM AST Wed Apr 22 2026

A moderate risk of rip currents is expected to persist for most of
the period, except on Thursday, as a weak northerly swell reaches
the Atlantic waters. This will result in life-threatening rip
currents. Heed the advice of lifeguards, beach patrol flags, and
posted signs.

A moderate risk of rip currents is expected to continue into the
weekend along northern exposed beaches. Although the risk is
moderate, rip currents can still become life-threatening. Always
follow the guidance of lifeguards, beach patrol flags, and posted
warning signs.

Visitors should also stay alert to changing weather conditions in
addition to surf hazards.

For additional information and location-specific rip current
details, please visit weather.gov/beach/sju.

&&

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

$$

SHORT TERM/AVIATION...MMC
LONG TERM...GRS
MARINE/BEACH FORECAST...CVB

NWS SJU Office Area Forecast Discussion