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

025
FXCA62 TJSJ 181756
AFDSJU

Area Forecast Discussion
National Weather Service San Juan PR
156 PM AST Thu Dec 18 2025

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

.KEY MESSAGES...
Issued at 1028 AM AST Thu Dec 18 2025

* High Surf Advisory conditions will continue along the northern
  beaches of Puerto Rico and Culebra until this afternoon. Life-
  threatening rip currents will prevail across the northern
  exposed beaches of the islands through early Friday due to a
  lingering northerly swell.

* Another northerly swell and increasing trade winds will cause
  hazardous seas and life-threatening rip currents again from late
  Saturday through Sunday.

* A weak surface trough will increase shower activity across the
  USVI and eastern half of PR from late this afternoon through
  tonight.

* Cooler temperatures and better rain chances are anticipated
  around mid-week next week due to an approaching frontal
  boundary.

&&

.Short Term(This afternoon through Saturday)...
Issued at 1028 AM AST Thu Dec 18 2025

Mostly sunny to partly cloudy skies prevailed during the morning
hours across the islands. Maximum temperatures were in the mid 80s
in general across the lower elevations. The wind was from the east
to northeast between 12 and 16 mph with gusts between 22 and 26
mph. Streamers were developing around noon over the USVI, and
passing showers were increasing from the Anegada Passage and
Caribbean waters.

For the rest of this afternoon into tonight, a weak surface trough
will cross the region, increasing cloudiness and quick passing
showers over the USVI and the eastern half of PR, as well as
across the northern and southern coastal areas of the island.
Ponding of water in roads and other poor drainage areas can be
expected. For Friday and Saturday, more stable conditions and a
drier air mass is expected to prevail over the islands under the
influence of a building upper level ridge across the central
Caribbean. Moderate to fresh trade winds with a northeasterly
component will bring quick passing showers with minor rainfall
accumulations across the islands at times, particularly across
the windward areas. Shallow afternoon convection is possible each
afternoon over the SW quadrant of PR, however, rainfall amounts
are not expected to cause flood concerns.

&&

.Long Term(Sunday through next Thursday)...
Issued at 500 AM AST Thu Dec 18 2025

Late in the weekend and into early next week, a weak mid- to
upper-level ridge will prevail across the region, supporting
generally stable atmospheric conditions. During this period,
precipitable water (PWAT) values are expected to remain below to
near seasonal climatological levels, ranging from 1.2 to 1.6
inches. At the surface, patches of low-level moisture will
continue to move through the area, producing brief passing showers
over windward sections of the islands. Rainfall accumulations
should remain limited, although isolated afternoon showers may
develop across western Puerto Rico. From midweek onward, the mid-
level ridge will gradually weaken as a polar trough departing the
eastern United States advances from the northwest. This pattern
change will increase atmospheric instability, with 500 mb
temperatures cooling to below-normal values between -7 and -10
degrees Celsius. A transition toward higher rain chances is
anticipated, with moderate probabilities (50 to 60%) for scattered
to numerous showers. At the surface, an associated frontal
boundary is forecast to approach the region around Wednesday into
Thursday (Christmas Eve and Christmas Day) and potentially move
across the area. As the front nears, moisture will increase, with
PWAT values rising to between 1.5 and 1.8 inches, within the
seasonal to above-normal range. The combination of cooler
temperatures aloft and increased moisture supports a more
unsettled pattern during the holiday period, including scattered
showers and isolated thunderstorms. Guidance, including the
Galvez-Davison Index, suggests the potential for shallow
convection with isolated thunderstorm development. Periods of
locally heavy rainfall may occur, which could elevate the risk of
localized flooding in flood-prone and poorly drained areas,
including ponding on roadways. At this time, the extended forecast
indicates a limited flood risk. Also, cooler temperatures are
expected in the wake of the possible frontal passage.

&&

.AVIATION...
(18Z TAFS)
Issued at 1028 AM AST Thu Dec 18 2025

VFR early in the fcst period. However, a surface trough over the
Anegada Passage will cross the local area later this afternoon
through tonight. This will increase SHRA over the USVI terminals
fm 18/20z-19/03z, at TJSJ fm 19/00z-07z, and fm 19/03-09z at
TJBQ/TJPS. Tempo MVFR conds are possible with these showers. For
most of the fcst period winds will continue ENE at 10-15 kt with
higher gusts at times and sea breeze variations at TJPS til
18/21z.

&&

.MARINE...
Issued at 1028 AM AST Thu Dec 18 2025

A surface trough moving from the east will increase showers across
the regional waters today. A weak surface low northeast of the
region near 28N and a surface high pressure over the western
Atlantic will promote moderate to locally fresh east to northeast
winds during the next few days. These winds, combined with
additional pulses of northerly swells, will maintain hazardous
seas for small craft, particularly across the Atlantic waters and
local passages.

Small Craft Advisories(SCA) are in effect through at least midday
Friday. SCA conditions will return late in the weekend across the
Atlantic waters and local passages.

&&

.BEACH FORECAST...
Issued at 1028 AM AST Thu Dec 18 2025

Lingering northerly swell will continue to cause life-threatening
rip currents along the north facing beaches of the islands through
early Friday. Please follow the guidance of lifeguards, beach
patrol flags, and signs.

Another northerly swell and increasing winds will bring large
breaking waves during the weekend along the north and eastern
beaches of PR and the USVI. Rough surf conditions and life-
threatening rip currents are expected once again.

&&

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

     High Surf Advisory until 6 PM AST this evening for PRZ001-002-
     005-008-012.

     High Rip Current Risk until 6 PM AST this evening for PRZ010.

VI...High Rip Current Risk until 6 PM AST this evening for VIZ001.

AM...Small Craft Advisory until noon AST Friday for AMZ711.

     Small Craft Advisory until midnight AST tonight for AMZ712-741.

&&

$$

SHORT TERM...DSR
LONG TERM....YZR
AVIATION...DSR
BEACH/MARINE...DSR

NWS SJU Office Area Forecast Discussion