National Weather Service Today's Weather Impact Levels

492
FXCA62 TJSJ 190916
AFDSJU

Area Forecast Discussion
National Weather Service San Juan PR
516 AM AST Mon Jan 19 2026

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

.KEY MESSAGES...
Issued at 511 AM AST Mon Jan 19 2026

 * Hazardous coastal and marine conditions persist today, with a
   high risk of rip currents across all north-exposed beaches in
   Puerto Rico, including Culebra, Vieques, and the U.S. Virgin
   Islands.

 * Breezy to windy conditions are forecast during the workweek.

 * Variable weather conditions will persist for today and
   Tuesday, with some brief showers moving in and out of the
   islands, with no flooding threat.

 * Conditions will deteriorate from Wednesday into Friday as a
   surface disturbance moves into the region, increasing the potential
   for showers and isolated thunderstorms. The peak of the
   showers is expected across eastern sections in the morning and
   evening hours.

&&

.Short Term(Today through Wednesday)...
Issued at 511 AM AST Mon Jan 19 2026

Since midnight, radar detected rainfall accumulations over eastern
and eastern interior PR (up to 0.17 in and locally higher), Vieques
(0.08 in), Culebra (0.04 in) and southern St. Thomas (0.01 in).
Coastal windward and some high elevation stations continue to report
breezy conditions with gusts in the low to mid 20s. Stations over
the interior have reported overnight lows in the low to mid 60s, and
stations over western PR have reported overnight lows in the upper
60s. Other lower elevation and coastal stations of the islands have
reported lows up to the upper 70s. GOES-19 satellite imagery also
detects patchy fog over areas of the interior.

A broad surface high over the central to eastern Atlantic,
interacting with a frontal boundary over the western Atlantic, will
promote breezy to windy (up to 15 to 25 mph) easterly flow for most
of the period, with more ENE winds by Wednesday. Current satellite
derived precipitable water values indicate below normal to normal
values for this time of the year. The highest PWAT values (1.40-1.50
in), however, were detected over the waters. Model guidance indicate
generally normal PWAT values today (Martin Luther King Jr Day), and
then gradually increasing as the first half of the workweek
continues. A mid to upper level trough is also over the central
tropical Atlantic well east of the region, while ridging persists
over the islands. This ridging will help maintain available moisture
generally below 800 mb through at least late Wednesday night, warmer
than normal 500 mb temperatures, below normal lapse rates and, as a
result, low Galvez-Davidson Index values. This will all serve to
inhibit deep convection. However breezy to windy trades will
continue to bring quick moving showers over the region throughout
most of the period, with shallow convection also forecast for
western PR and downwind of the local islands during the afternoon
hours each day. Although the fast moving nature of these showers
will limit the flooding risk, these showers can promote localized
ponding of water over roadways, urban, and poorly drained areas. A
plume of moisture related to a surface perturbation associated with
the mid to upper level trough east of the region will increase PWAT
values to around 1.5 in on Tuesday and possibly at around 1.8 in
over western Puerto Rico on Tuesday afternoon. This can increase in
shower frequency under the breezy to windy flow and also result.
Current model guidance indicate, more seasonal PWAT values on
Wednesday, with Wednesday afternoon convection over W-SW PR under
more ENE winds, before sharply increasing to above normal values
late Wednesday (as a surface disturbance approaches) and into the
long term period, once again increasing shower frequency. Patchy fog
possible each night over sectors of the interior. 925 mb
temperatures will be normal to above normal values to start the
period, becoming more normal by midweek under the ENE flow.

&&

.Long Term(Thursday through Monday)...
Issued at 511 AM AST Mon Jan 19 2026

Weather conditions from Thursday into Friday will remain variable
due to a surface disturbance moving across the islands. According
to the global model guidance, abundant surface moisture trapped in
the low and mid levels will enhance conditions for frequent,
isolated to moderate showers across eastern sections of Puerto
Rico and the U.S. Virgin Islands, followed by afternoon showers
across the western interior. So far today, the model suggests
precipitable water values from Thursday into Friday fluctuating
between 1.6 and 1.9 inches, which is slightly above climatological
normals. Combine with the moisture, colder temperatures at 500 MB,
allowing the development of one or two isolated thunderstorms with
the strongest shower activity. Rainfall accumulations for each
day are forecast to result mostly in poor driving conditions and
some minor flooding in isolated low-lying areas.

Weather conditions will improve by Saturday into Sunday, when the
disturbance moves out of the region and a drier airmass filters
into the local islands. At the surface, a broad surface high
pressure extending across the Atlantic basin will promote mostly
easterly wind flow across the area. At the mid to upper levels,
subsidence will inhibit well development of showers; however, the
local effect would enhance some brief, isolated to moderate
showers, with no flooding threat each day. On Monday, the surface
conditions will change as veering winds start in response to the
pre-frontal trough moving southward near the north of the
Hispaniola. Therefore, winds will turn more northeasterly,
resulting in a more advective pattern across the area. The
northward component of winds will also result in colder
temperatures during the morning and night hours.

&&

.AVIATION...
(06Z TAFS)
Issued at 511 AM AST Mon Jan 19 2026

Mainly VFR conditions will prevail. Winds at the terminals will
continue variable to up to 10 knots through 19/13Z. After 19/13Z E
winds at up to 15 to 17 knots with gusts up to around 23 to 25 kts,
as well as sea breeze variations and local effects. Winds at
terminals decreasing again to up to around 10 kts after 19/23Z.
SHRA/VCSH will continue at the terminals which can briefly reduce
VIS as fast moving SHRA move over the region.

&&

.MARINE...
Issued at 511 AM AST Mon Jan 19 2026

Hazardous marine conditions remain in place across most local
waters for the rest of the day. These conditions are due to pulses
of northerly swell and wind-driven seas associated with moderate
to locally fresh easterly winds across the region. As a result,
hazardous seas will continue through the day, with seas up to 8
feet across the offshore Atlantic waters and winds of 20 to 25
knots across most waters, including the local passages. Therefore,
several Small Craft Advisories remain in effect through the rest
of the day into Tuesday.

Wind condtions will continue for most of the workweek inducing
choppy marine conditions hazardous for small craft operators. Improving
marine conditions are forecast for the upcoming weekend.

&&

.BEACH FORECAST...
Issued at 511 AM AST Mon Jan 19 2026

Recent buoy data continues to show hazardous coastal conditions
across the northern exposed coastal areas of Puerto Rico,
including Culebra, Vieques, and the U.S> Virgin Islands.
Therefore, 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 late tonight. 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 Puerto Rico`s western and southern coasts.

For the western and southern coastal areas, where the risk remains
moderate, beachgoers can expect breezy to locally windy
conditions to continue, 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, up-to-date
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 Tuesday night for AMZ711-
     723.

     Small Craft Advisory until 6 AM AST early this morning for
     AMZ712-716-726-733-741.

&&

$$

SHORT TERM & AVIATION...MRR
LONG TERM, MARINE & BEACH FORECAST...LIS

NWS SJU Office Area Forecast Discussion