National Weather Service Today's Weather Impact Levels

965
FXCA62 TJSJ 281800
AFDSJU

Area Forecast Discussion
National Weather Service San Juan PR
200 PM AST Wed Jan 28 2026

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

.KEY MESSAGES...
Issued at 200 PM AST Wed Jan 28 2026

* Relatively stable weather conditions are expected through
  Friday, with brief morning showers across eastern areas of
  Puerto Rico and the USVI and afternoon showers developing over
  western Puerto Rico; minor ponding on roads is possible.

* There is an increasing risk of urban and small stream flooding
  from the weekend into early next week as a frontal boundary
  approaches from the west of the region.

* Dangerous swimming conditions and hazardous seas are expected
  along the Atlantic coastlines and coastal waters by early next
  week as swell action spreads across the region.

* For the U.S. Virgin Islands, the primary hazard will remain
  dangerous swimming conditions and hazardous seas early next
  week. While moisture is expected to increase during the weekend,
  most of the weather is currently forecast to stay west of the
  islands.

&&

.Short Term(This evening through Friday)...
Issued at 200 PM AST Wed Jan 28 2026

Mostly sunny skies prevailed across Puerto Rico and the U.S.
Virgin Islands during the morning hours, becoming variably cloudy
during the afternoon. Temperatures reached the mid-80s under
light to moderate easterly winds.

Continue to expect passing showers across eastern sections of
Puerto Rico and the U.S. Virgin Islands this afternoon and tonight
as an area of cloudiness and associated low-level moisture moves
across the forecast area. As this moisture progresses, locally
induced showers cannot be ruled out across western Puerto Rico
this afternoon. Nevertheless, due to limited upper-level forcing
and precipitable water values remaining near or below
climatological normals, the primary threat will remain ponding of
water on roadways and in low-lying areas.

On Thursday, a similar weather pattern is expected to persist
under a weakening mid- to upper-level trough and light to
moderate east-southeasterly winds. However, ensemble guidance
suggests Friday night into Saturday as a transition period, with
moisture gradually increasing under a more southeasterly flow. As
a result, shower frequency is expected to increase across eastern
Puerto Rico and the U.S. Virgin Islands, and the risk of flooding
is anticipated to rise toward the end of the forecast period.

No changes in terms of Tmax and Tmin with temperatures at the 925
mb level remaining slightly above climatological normals. Maximum
temperatures are forecast to reach the mid-80s in lower elevations
and the mid-to-upper 70s across the higher terrain.

&&

.LONG TERM...(Saturday through Wednesday)...
Issued at 422 AM AST Wed Jan 28 2026

The synoptic pattern is forecast to remain generally unchanged
through the long-term period, with a frontal boundary lingering near
the local area. A southerly to southeasterly low-level flow ahead of
this boundary will persist, continuing to advect warm and moist air
across Puerto Rico and the U.S. Virgin Islands. As a result, above-
normal temperatures are expected to persist through the period.

Global model guidance continues to indicate an increase in available
moisture beginning Saturday, with precipitable water values rising
to near 2.0 inches or higher and remaining above climatological
normals through early next week. Low- to mid-level moisture,
particularly below 700 mb, is forecast to remain elevated. Although
some drying at mid levels (around 700-500 mb) is suggested at times,
the overall moisture profile should remain sufficient to support
periods of enhanced shower and thunderstorm activity.

At upper levels, the region is expected to remain between an upper-
level trough over the western Atlantic and a ridge to the southeast,
providing periods of favorable upper-level dynamics depending on the
exact placement and evolution of these features. This pattern,
combined with persistent low-level moisture convergence along the
nearby frontal boundary, will support increasing rainfall coverage,
particularly from Sunday through Tuesday.

Recent guidance continues to suggest a signal for above-normal
rainfall across portions of the forecast area early next week. Of
note, ECMWF Extreme Forecast Index output consistently highlights a
rainfall signal several days in advance, which is somewhat
surprising given the lead time and suggests increasing ensemble
agreement toward a wetter-than-normal pattern. While confidence in
the exact timing, magnitude, and spatial distribution of rainfall
remains limited at this range, the persistence of the signal
supports a continued potential for locally heavy rainfall,
especially where showers and thunderstorms repeatedly affect the
same areas. Some uncertainty remains with respect to the exact
placement of the frontal boundary, as a westward position closer to
Hispaniola would result in reduced low-level convergence and
consequently less widespread shower and thunderstorm coverage across
the local forecast area.

Diurnal heating, local effects, and sea breeze convergence will
continue to play a role in convective development each afternoon,
depending on the persistence of cloud cover, mainly across interior
and western to northwestern Puerto Rico. Potential impacts include
ponding of water on roadways, urban and small stream flooding, and
localized flooding, particularly in areas that receive repeated
rounds of rainfall. Gusty winds may accompany heavier showers or
isolated thunderstorms.

Overall, the long-term period is expected to remain unsettled, with
the primary concerns being above-normal rainfall and localized
flooding potential through at least Tuesday.

&&

.AVIATION...
(18Z TAFS)
Issued at 200 PM AST Wed Jan 28 2026

Mainly VFR conditions expected to prevail across all TAF sites
during the next 24 hrs. VCSH or -SHRA are more likely across TJBQ
and TJSJ thru 28/22Z. Brief periods of reduced vis and low cigs
can be anticipated. Aft 28/23Z, passing showers are expected
across TISX. Aft 29/15-17Z, VCSH are possible across TJPS and
TJBQ again. E to SE winds around 13 kts or below generally
becoming lighter after 29/00Z, then picking up again around
29/14-15Z.

&&

.MARINE...
Issued at 200 PM AST Wed Jan 28 2026

Light to moderate easterly winds will persist through the end of
the week as surface high pressure shifts eastward, with seas
generally subsiding across the local waters. By early next week, a
long-period northwesterly to northerly swell is expected to reach
the regional waters by Monday. This swell, combined with
strengthening winds, will likely result in choppy to rough seas
and potentially hazardous marine conditions, including Small Craft
Advisory criteria, especially across the offshore Atlantic waters
and local passages.

An increase in shower and thunderstorm activity is also anticipated
from this weekend into early next week, particularly over the
northwestern Atlantic waters and the Mona Passage, with an
increasing potential to observe lightning and gusty winds.

&&

.BEACH FORECAST...
Issued at 200 PM AST Wed Jan 28 2026

Pulses of weak northerly swells will continue to affect the
Atlantic waters through the remainder of the week, with the
strongest pulse expected tomorrow, Thursday afternoon. A generally
moderate risk of rip currents is expected along most north-facing
beaches of the islands, however, a high rip current risk cannot
be ruled out on Thursday, when life-threatening rip currents may
develop. Beachgoers are encouraged to monitor the forecast for
updates and changing conditions.

Residents and visitors should also note that beach conditions may
further deteriorate early next week due to increasing winds and
the arrival of a stronger northwesterly to northerly long-period
swell, potentially leading to hazardous beach conditions.
Additionally, a change in the weather pattern may bring showers
and thunderstorms from this weekend into early next week,
increasing risks for beachgoers.

&&

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

$$

SHORT TERM/KEY MESSAGES...OMS
LONG TERM...CVB
AVIATION/MARINE/BEACH...YZR

NWS SJU Office Area Forecast Discussion