771
FXCA62 TJSJ 050815
AFDSJU

Area Forecast Discussion
National Weather Service San Juan PR
415 AM AST Wed Nov 5 2025

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

.KEY MESSAGES...
Issued at 415 AM AST Wed Nov 5 2025

* There is a high chance of urban and small stream flooding today
  across the interior into western Puerto Rico and again on Sunday
  across eastern and southern areas, as moisture levels are
  forecast to increase.

* Mostly fair weather is expected across the U.S. Virgin Islands
  today, with a few brief passing showers.

* The risk of rip currents along the north-facing beaches of
  Puerto Rico and the U.S. Virgin Islands is expected to increase
  late Thursday night into Friday as a northerly swell spreads
  across the local waters.

* Heat indices are forecast to range from 100 to 105 degrees F,
  posing potential health risks for individuals who are highly
  sensitive to heat.

&&

.Short Term (Today through Friday)...
Issued at 415 AM AST Wed Nov 5 2025

Skies were mostly clear to partly cloudy across the local islands
during the overnight hours. Passing showers were observed over the
northern slopes of Puerto Rico, as well as Vieques, Culebra, and the
northern U.S. Virgin Islands. However, rainfall amounts were minimal.
Temperatures ranged from the mid-70s to around 80 degrees F at lower
elevations, and from the mid- to upper-60s in higher terrain.

A mid-level ridge pattern will continue to dominate the region,
though a gradual weakening is expected as an upper-level trough
prevails south of the area. At the surface, a front north of the
area will dissipate while a high-pressure system moves into the
central Atlantic. This high will maintain an east-southeast wind
flow, advecting patches of moisture across the islands from time to
time. Nonetheless, precipitable water values should remain below 2.0
inches and largely confined below 850 mb.

Under this evolving pattern, a typical seasonal weather pattern will
prevail. Expect locally induced afternoon showers across western
Puerto Rico each day, while mainly fair weather conditions persist
elsewhere. Based on the latest guidance, today is likely to be the
wettest day of the period as a moisture patch moves across the area.
Therefore, the flooding risk is elevated today. Shower activity is
then expected to decrease significantly on Thursday and Friday under
a drier air mass.

In addition to the elevated flooding risk today across western
Puerto Rico, there will be a limited heat risk across the islands,
with heat indices ranging from 100 to 105 degrees F. The prevailing
east-southeast wind flow will support slightly above-normal
temperatures at the 925 mb level, particularly on Thursday and
Friday. These conditions mainly affect individuals who are highly
sensitive to heat, especially those spending extended periods
outdoors without proper cooling or hydration.

&&

.Long Term (Saturday through Wednesday)...
Issued at 415 AM AST Wed Nov 5 2025

During the long term period, a surface high-pressure system over
the northern Atlantic is expected to gradually shift eastward. By
the end of the period, this high will generally be positioned over
the central to eastern Atlantic. This pattern will support winds
with an easterly component, becoming breezy from the weekend into
early next week as the pressure gradient tightens. A weak mid-
level ridge will persist north to northeast of the region.

The latest precipitable water (PWAT) guidance indicates values
fluctuating from below-normal to near-normal levels on Saturday,
ranging from around 1.5 to 1.7 inches. This setup will support a
typical weather pattern of quick-moving passing showers across the
windward areas of Puerto Rico and the U.S. Virgin Islands during
the night and morning hours, followed by afternoon showers and
isolated thunderstorms mainly across western and northwestern
Puerto Rico. These will be driven by diurnal heating, sea-breeze
convergence, and local terrain effects, resulting in a limited
flooding potential. Rain chances are expected to increase on
Sunday, along with a limited to elevated flooding risk, as a
tropical wave moves across the Caribbean waters. This feature will
raise the moisture content to around 2.00 to 2.25 inches of PWAT
(above normal based on climatological data) and enhance moisture
in the mid and upper levels of the atmosphere. The U.S. Virgin
Islands, as well as the eastern and southern areas of Puerto Rico,
are expected to experience the greatest likelihood of showers,
with winds shifting from northeast to southeast as the wave
passes.

Early next week, in the wake of the tropical wave, alternating
patches of moisture and drier air will continue to move across the
region under a southeasterly flow. A strengthening mid level
ridge will promote stability and drier air aloft. As a result, the
return of a typical weather pattern is expected: passing showers
across the windward areas of Puerto Rico and the U.S. Virgin
Islands during the night and morning hours, followed by afternoon
showers and isolated thunderstorms mainly across western Puerto
Rico. No significant impacts are anticipated.

Regarding temperatures, a none to limited heat risk is expected to
persist throughout the forecast period.

&&

.AVIATION...
(06Z TAFS)
Issued at 415 AM AST Wed Nov 5 2025

VFR conditions are expected at all TAF sites with -SHRA at JSJ/JBQ
early this morning. SHRA/TSRA may develop across W PR after 05/17Z,
possibly affecting JBQ and JPS through about 05/22z. ESE winds at 10-
15 kts and typical sea breeze variations.

&&

.MARINE...
Issued at 400 AM AST Wed Nov 5 2025

A weak surface high pressure system over the central to eastern
Atlantic will maintain light to moderate easterly winds over the next
few days. Meanwhile, a surface low moving across the northwestern
Atlantic will generate a northerly swell, increasing seas to around 6
feet or higher across the Atlantic waters and local Caribbean passages
by late Thursday into Friday. Additionally, moderate to fresh easterly
winds are anticipated by next weekend, along with a better chance of
showers as a tropical wave moves across the Caribbean waters. Small
craft operators will likely need to exercise caution.

&&

.BEACH FORECAST...
Issued at 415 AM AST Wed Nov 5 2025

Today, there is a moderate risk of rip currents for the northern
and eastern beaches of Puerto Rico and Culebra. Beachgoers should
exercise caution, as life-threatening rip currents are possible
along the surf zones. A low risk prevails elsewhere.

By Thursday night into Friday, a weak northerly swell will begin
to affect the local Atlantic waters and northern coastlines. This
will lead to breaking waves around 5 to 6 feet, and the moderate
rip current risk will expand to include western Puerto Rico,
Vieques, and the U.S. Virgin Islands. By Friday, a high risk of
rip currents is anticipated for north and east-facing beaches of
Puerto Rico, Culebra, and northern U.S. Virgin Islands.

Additional hazards include the development of isolated thunderstorms
near the coasts during the afternoon hours. If you hear thunder,
seek shelter inside a building immediately. Residents and visitors
should continue monitoring the beach forecast for updates or changes.
For detailed information about your area of interest, please visit
weather.gov/beach/sju.

&&

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

$$

MIDNIGHT SHIFT...OMS/YZR

NWS SJU Office Area Forecast Discussion