National Weather Service Today's Weather Impact Levels

539
FXCA62 TJSJ 250757
AFDSJU

Area Forecast Discussion
National Weather Service San Juan PR
357 AM AST Thu Dec 25 2025

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

.KEY MESSAGES...
Issued at 338 AM AST Thu Dec 25 2025

 * Hazardous marine and coastal conditions will persist until the
   end of the workweek across all the offshore Atlantic waters
   and north- exposed beaches of the islands.

 * Frequent passing showers will continue to filter over the
   Puerto Rico and the US Virgin Islands through the morning hours
   or at least through the first half of the day.

 * Weather conditions will begin to improve as the dry air just
   behind the frontal boundary moves across the islands.

&&

.Short Term(Today through Saturday)...
Issued at 338 AM AST Thu Dec 25 2025

Moderate to heavy showers, along with isolated thunderstorms were
observed during the night hours across most of the region. The
heaviest activity was observed in San Juan, with radar estimates of
2 to 3 inches of rainfall. Two flood advisories and one Flash Flood
Warning were issued. Most of eastern Puerto Rico collected 1 to 2
inches as well. Rainfall in the Virgin Islands was not as strong,
but passing showers moved inland all night long.

Moisture associated with the frontal boundary is observed in the
satellite derived precipitable water products, with the bulk of the
moisture now between Vieques and Saint Croix. Showers will persist
mostly in the morning hours, impacting portions of Puerto Rico and
the Virgin Islands. Wet roads and ponding of water in low-lying
areas are the main impacts associated with these rains. Water surges
has been observed along the rivers of the northeast, with at least
four streams reacting last night. On the other hand, the drier air
mass is already reaching northwestern Puerto Rico, and moisture will
gradually decrease, so a lot less rain is anticipated later today
and tonight. Showers may persist all day long in the vicinity of St.
Croix, however.

The front is being pushed toward the Caribbean waters by a high
pressure over the western Caribbean. This feature will bring a
breeze from the northeast at 14 to 20 knots, gusting up to 25 knots.
It will also be cooler, with 925 mb temperatures cooling down nearly
one standard deviation for the rest of the short term period. This
will translate in cool nights, with lows in the 50s in the highest
mountains, and in the 60s and low 70s in the lower elevations. It
will warm up during the day, but highs should be mostly in the 70s
in the mountain and the low 80s in coastal areas.

For the rest of the period, mainly fair weather will persist, but it
will not be completely dry. Some showers will continue to stream at
times over portions of northern Puerto Rico and the Virgin Islands,
but no significant impacts are anticipated with these rains. Also, a
long wave trough will weaken the pressure gradient, with speeds
falling below 10 knots on Friday, and 5-8 kts on Saturday.

&&

.Long Term(Sunday through Thursday)...
Issued at 338 AM AST Thu Dec 25 2025

The long-term forecast remains unchanged. Drier air behind a frontal
boundary will dominate the region through Monday, with
precipitable water (PWAT) values falling well below 1.0 inch.
However, isolated patches of moisture may occasionally move across
the area, promoting brief passing showers. Despite the prevailing
dry pattern early in the period, a building surface high over the
western Atlantic and a frontal low over the north-central
Atlantic will promote a northeasterly steering flow through
Monday. 925 mb temperatures are expected to remain below two
standard deviations for this time of year, supporting cooler-than-
usual conditions. Later in the workweek, temperatures are forecast
to moderate back to near-normal values.

Latest model guidance suggests that winds will gradually veer by
Tuesday, becoming southeasterly, allowing Caribbean moisture to
filter across Puerto Rico and the U.S. Virgin Islands. Along with
this wind shift, a trough moving across the area will result in a
wetter pattern, with increasing chances for showers and isolated
thunderstorms by midweek. Confidence regarding the specific timing
and impacts remains medium. Therefore, residents and visitors are
encouraged to continue monitoring the forecast, as more active
weather conditions could develop.

&&

.AVIATION...
(06Z TAFS)
Issued at 338 AM AST Thu Dec 25 2025

SHRA will impact TJSJ and USVI terminals early today, with
intermittent periods of reduced VIS and low ceilings. Conditions
should improve after 15Z. Winds will be from the NNE at 9-13 kts at
FL050, gusting up to 20-25 kts from 14-22Z. Winds will slow down
after 22Z.

&&

.MARINE...
Issued at 338 AM AST Thu Dec 25 2025

A series of surface highs and frontal lows will continue moving
into the Atlantic during the period, resulting in moderate northeast
winds today. A long-period northerly swell, from the above mentioned
frontal low, will continue to spread across the offshore Atlantic
waters. This will result in choppy to rough seas, becoming hazardous
for small craft. These conditions will continue throughout the week
as seas build to 6 to 10 feet, spreading to the nearshore Atlantic
Waters and local Passages. Another pulse of long period northerly
swell will arrive by late Friday night into early Saturday morning,
supporting dangerous conditions throughout the weekend.

&&

.BEACH FORECAST...
Issued at 338 AM AST Thu Dec 25 2025

Deteriorating coastal conditions are still expected through at
least the end of the workweek, as a persistent long-period swell
from the north will continue to affect the regional waters. This
swell will continue to result in extremely dangerous conditions
for swimmers, high rip current risk, and localized beach erosion.
Therefore, a high surf advisory is in effect until 6 AM AST on
Thursday, and a high risk of rip current through Friday. For more
details, please consult the Coastal Hazard Message (CFWSJU).

&&

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

     High Surf Advisory until 6 AM AST early this morning for PRZ001-
     002-005-008-010.

     High Rip Current Risk through late tonight for PRZ012.

     High Rip Current Risk through this afternoon for PRZ013.

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

     High Rip Current Risk through this afternoon for VIZ002.

AM...Small Craft Advisory until midnight AST tonight for AMZ711-712-
     716-723-726-741-742.

&&

$$

SHORT TERM/AVIATION...ERG
LONG TERM/MARINE/BEACH FORECAST...MMC

NWS SJU Office Area Forecast Discussion