121
FXCA62 TJSJ 181831
AFDSJU

Area Forecast Discussion
National Weather Service San Juan PR
231 PM AST Sun Jan 18 2026

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

.KEY MESSAGES...
Issued at 226 PM AST Sun Jan 18 2026

* Marine and coastal conditions remain hazardous, though they are
  gradually subsiding. Seas are still rough with an ongoing risk of
  rip currents. Small Craft operators and beachgoers should continue
  to exercise caution and follow any posted warnings and advisories.

* Trade wind-driven showers will persist, moving from time to time
  and producing slippery road conditions and ponding of water in low-
  lying and poor drainage areas.

* Breezy to windy conditions will continue, and although winds are
  slowly easing, unsecured items may still be blown around,
  especially in more exposed locations.

&&

.Short Term(This evening through Tuesday)...
Issued at 226 PM AST Sun Jan 18 2026

Mostly fair conditions prevailed during the morning hours. Passing
showers moved mainly across the waters, a few moving over portions
of St. Croix in the U.S. Virgin Islands and eastern portions of
Puerto Rico. Breezy to windy conditions continue across the islands,
as CWOP/ASOS stations reported maximum wind gusts between 30 and 33
mph over coastal areas (31 mph at the Henry E. Rohlsen International
Airport in St. Croix, VI, and 33 mph at Camp Santiago in Salinas,
PR) and higher elevations. Todays 12z RAOB showed slightly lower
PWAT values compared to the 00z (from 1.36 to 1.18 inches), due to a
drier airmass that filtered into the region early today. Considering
that HIRES models do not suggest significant rainfall accumulation
for this afternoon, shallow convection is the most likely scenario,
with passing showers moving through the western portions of Puerto
Rico.


No major changes were introduced to the short-term forecast, as
variable and breezy to windy (winds between 15 - 25 mph) conditions
are expected to continue across the CWA. The wind pattern will
continue from the east to east-southeast due to a broad surface high
pressure over the Central Atlantic. Based on the latest model
guidance, the moisture content is expected to increase late tonight
due to a patch of moisture.  According to the deterministic guidance
of the GFS and ECMWF, PWAT values are expected to increase (between
1.2 and 1.4 inches), typical for the season. An increase in
frequency of showers can be expected, particularly affecting
portions of the U.S. Virgin Islands and windward sections of Puerto
Rico. Due to strengthening winds,  short-lived showers should not
leave significant rainfall accumulations. The presence of a mid-
level ridge will dominate most of the weather pattern across the
local area, as warmer-than-normal 500 mb temperatures (around -4
degrees Celsius), low 700 - 500 mb lapse rates (between 5 and 5
degrees Celsius per kilometer), and lower RH content in the 700 -
500 mb levels indicate unfavorable conditions for deep convection.
Hence, from Monday onwards, the variable conditions will continue
due to abundant low level moisture content across the CWA, with
passing showers across windward sections during the morning hours
and shallow afternoon convection over western Puerto Rico, along
with the U.S. Virgin Islands streamers. The highest accumulations
may be expected over western PR, with mainly localized ponding of
water over roadways, urban, and poorly drained areas.

&&

.Long Term(Wednesday through next Saturday)...
Issued at 413 AM AST Sun Jan 18 2026

As noted in previous discussions, model guidance continues to
indicate a humid and unsettled pattern throughout the long-term
period across Puerto Rico and the U.S. Virgin Islands. The most
unstable conditions are expected on Thursday, with unsettled weather
persisting through Saturday. Precipitable water values rising
above 1.75 inches after Wednesday reflect above-normal moisture
associated with a deep tropical plume, enhancing overall shower
coverage.

This pattern will support thunderstorms and periods of moderate to
locally heavy rainfall, increasing the potential for localized
flooding, particularly in urban, poor drainage, and low-lying
areas. Repeated showers over the same locations could worsen
runoff issues, while frequent lightning may pose hazards to
outdoor activities. Although east to northeast winds of 17 to 20
mph should help limit widespread flooding, locally enhanced
rainfall will remain possible, especially in terrain-favored
areas.

Temperatures are expected to trend back toward seasonal norms by
Thursday, but persistent high moisture and cloud cover will
maintain humid conditions through the remainder of the period.

&&

.AVIATION...
(18Z TAFS)
Issued at 226 PM AST Sun Jan 18 2026

Mainly VFR conds are expcd across all terminals, with VCSH due
passing SHRA throughout the TAF prd.  VCSH will continue aft 18/23z,
reducing CIGs/VIS at exposed terminals (ISX, IST, and JSJ). Winds
from the E-ESE will slgtly weaken tonight, around 18/23z, btwn 8 -
10 kt at PR TAF sites, while IST and ISX can expc around 12 kt.
Strengthening wind will return by 19/13z, btwn 15 - 17 kt and gusts
up to 24 - 25 kt.

&&

.MARINE...
Issued at 226 PM AST Sun Jan 18 2026

Broad surface high pressure over the central Atlantic will continue
to influence the regional waters through at least tonight. Fresh to
locally strong east winds will persist, maintaining choppy to rough
seas, although conditions are expected to gradually subside later
today. Small Craft Advisories remain in effect at least through this
afternoon, as hazardous marine conditions will continue, especially
across the offshore Atlantic waters and passages. Mariners should
continue to exercise caution until seas and winds further
diminish.

&&

.BEACH FORECAST...
Issued at 226 PM AST Sun Jan 18 2026

A High Rip Current Statement remains in effect for the north and
east-facing beaches of Puerto Rico, including Culebra, and the U.S.
Virgin Islands through 6 AM AST on Monday. While marine and surf
conditions are slowly subsiding, hazardous rip current conditions
persist, and the risk remains high along exposed beaches. Residents
and visitors are urged to continue following the warning flag system
and to favor beaches with lower rip current risk, such as those
along the western and southern coasts of Puerto Rico.

In addition, breezy to locally windy conditions continue along
coastal areas, which may still result in unsecured objects being
blown around, particularly in the most exposed locations. Beachgoers
should remain cautious both in and near the water until conditions
improve further.

For localized and updated risk levels, visit weather.gov/beach/sju.

&&

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

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

AM...Small Craft Advisory until midnight AST Monday night for AMZ711-
     723.

     Small Craft Advisory until 6 PM AST this evening for AMZ712-716-
     726-733-741.

&&

$$

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

NWS SJU Office Area Forecast Discussion