National Weather Service Today's Weather Impact Levels

359
FXCA62 TJSJ 130738
AFDSJU

Area Forecast Discussion
National Weather Service San Juan PR
338 AM AST Thu Nov 13 2025

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

.KEY MESSAGES...
Issued at 335 AM AST Thu Nov 13 2025

* Dangerous beach conditions along northern Puerto Rico, Culebra,
  St. Thomas and St. Croix. Avoid approaching or swimming in these
  beaches.

* Showers and thunderstorms are expected to develop this afternoon
  along western Puerto Rico. There is a low risk of urban and small
  stream flooding.

* For the Virgin Islands, seasonably warm temperatures and passing
  showers are expected. No significant threat are expected over
  land areas.

&&

.Short Term(Today through Saturday)...
Issued at 335 AM AST Thu Nov 13 2025

A variable weather pattern prevailed overnight, with frequent
passing showers along the local waters and some reaching the
northeast coast of Puerto Rico and the U.S. Virgin Islands. Shower
activity remained limited across the interior and western portions
of Puerto Rico. Minimum temperatures stayed in the mid-to-upper 70s
across the mountain areas, with slightly warmer readings across the
coastal zones in the upper 70s to low 80s, including the U.S. Virgin
Islands. Winds were from the east at 10 mph or less with land breeze
variations.

For today, a variable weather pattern is forecast, mainly influenced
by surface high pressure over the Central Atlantic, resulting in
easterly winds. This surface flow will keep the islands under a
moist pattern due to patches of moisture from an induced surface
trough just north of the area, with precipitable water values around
1.6 inches, near climatological normals. With sufficient low-level
moisture, local effects, and colder temperatures at 500 MB
decreasing from -5 to -6 C, a convective pattern will develop,
especially across the western interior. Although widespread activity
is not expected, isolated thunderstorms cannot be ruled out. A
drying trend is anticipated on Friday as precipitable water values
decrease to the 25th percentile, allowing for a calmer weather
pattern with isolated showers, particularly during the night hours.

Surface conditions are expected to change rapidly late Saturday as
an approaching frontal boundary sinks southward north of the
islands, while the pre-frontal trough weakens the pressure gradient.
This evolving pattern will result in light and variable winds, as
suggested by the 925 MB winds, which are forecast to weaken to near
5 knots. At upper levels, a decrease in 250 MB heights will enhance
divergence aloft, supporting upward motion, while the 850700 MB
layer will show a spike in moisture values above the normal
climatological range. As a result, an increase in shower activity is
expected across the offshore Atlantic waters, extending into the
northern coastal areas by Saturday afternoon.

&&

.Long Term(Sunday through Thursday)...
Issued at 335 AM AST Thu Nov 13 2025

A polar trough will escort a cold front near the area on Sunday,
increasing moisture across the region. Ahead of the front, high
pressure centered over the eastern Atlantic will drive the trade
winds from the south at speeds of only 3 to 4 kts. So far, the
global models only indicate precipitable water values near normal
levels, and also quite a large dew point depression in the mid
levels. This means that a widespread rainfall event is not expected.
However, some showers will reach the islands at times. Also, the
heaviest activity is expected to develop along the interior of
Puerto Rico due to local effects.

As the front dissipated north of the region, a short wave trough in
the upper levels will move into the region. This will cause mid-
levels temperatures to cool down, increasing instability aloft.
Moisture levels will not be impressive though, but should be enough
to see a few thunderstorms developing each afternoon along the
interior and western Puerto Rico. The risk of flooding is low at
this time, although isolated urban and small stream flooding cannot
be ruled out.

By the end of the week, another trough digs from the northeast. A
surface reflection of this trough will change the winds from the
northeast, at speeds of 10 to 15 mph. The islands are not expected
to be in the most favorable area for deep convection to develop, but
the frequency of passing showers could increase for portions of
northeast Puerto Rico, as well as for the Virgin Islands.

&&

.AVIATION...
(06Z TAFS)
Issued at 335 AM AST Thu Nov 13 2025

VFR conditions will prevail across all TAF sites during the period.
After 13/15Z, winds will increase again from the east at around 15
knots with sea breeze variations. Afternoon showers may lead to
lower ceilings and reduced visibility, resulting in brief MVFR
conditions at TJBQ and TJPS between 13/17Z and 13/22Z.

&&

.MARINE...
Issued at 335 AM AST Thu Nov 13 2025

A north-northwesterly swell will continue to arrive today,
deteriorating marine conditions. Conditions are expected to gradually
improve tomorrow. A broad surface high pressure over the north-central
Atlantic will continue to promote moderate to locally fresh easterly
winds across the regional waters during the next few days, keeping
choppy to occasionally rough seas.

&&

.BEACH FORECAST...
Issued at 335 AM AST Thu Nov 13 2025

An approaching north-northwesterly swell will spread across the
local Atlantic Waters and Caribbean Passages today, deteriorating
the coastal conditions into tonight. Thus, life-threatening rip
currents are expected to form from Rincon to Fajardo and Culebra
late tonight or early Thursday morning, creating a High Risk of
rip currents. Meanwhile, the risk will moderate for the north-
facing beaches along St. Thomas, St. John, and the Adjacent
Islands. Conditions will improve gradually tomorrow.

&&

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

     High Surf Advisory until 6 PM AST this evening for PRZ001-002-
     005-008-010.

     High Rip Current Risk through late tonight for PRZ012.

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

AM...Small Craft Advisory until 6 AM AST Friday for AMZ711.

     Small Craft Advisory until 6 AM AST Friday for AMZ712-741-742.

&&

$$

SHORT TERM/AVIATION...LIS
LONG TERM/MARINE...ERG

NWS SJU Office Area Forecast Discussion