714
FXCA62 TJSJ 071823
AFDSJU

Area Forecast Discussion
National Weather Service San Juan PR
223 PM AST Tue Oct 7 2025

.KEY MESSAGES...

* Shower and thunderstorms will continue to affect the local
  islands through tonight. There is moderate flood risk, meaning
  flooding in urban areas, roads, small streams, and washes,
  particularly across the central, western, and northeastern PR.

* Frequent lightning and gusty wind conditions are still possible
  across the central, western, and northeastern PR. Stay alert and
  be prepared to take shelter if storms develops near or in you
  area.

* For the US Virgin Islands, minor flooding and lightning possible
  through tonight.

* Coastal conditions remain hazardous for the US Virgin Islands,
  as well as along the western, northern, eastern coast of Puerto
  Rico, Culebra, and Vieques. The rip current risk remains high.
  Remember that rip currents can sweep even the best swimmers
  away from shore into deeper water, where it becomes difficult to
  return to safety.

&&

.SHORT TERM...Rest of the Afternoon through Thursday...

During the morning hours, a tropical wave with its axis located just
east of the local area resulted in numerous showers and isolated
thunderstorms across the regional waters, with some of this activity
moving over the U.S. Virgin Islands. By midday, convection began to
develop over interior Puerto Rico, aided by daytime heating and the
approaching wave. This activity is expected to continue through the
afternoon, with increased areal coverage and variable wind
conditions as surface winds gradually shift from east-northeast to
east-southeast behind the wave axis.

As the wave continues to move west-northwestward, southerly flow
will persist, maintaining the advection of deep tropical moisture
across the region. Precipitable water values (PWAT) will remain near
or above 2.0 inches through the short-term period. Meanwhile,
troughiness aloft will enhance instability, promoting additional
convective development across the islands.

With this setup, scattered to numerous showers and thunderstorms are
expected, particularly across interior, western, and northwestern
Puerto Rico, as well as near El Yunque and portions of the San Juan
metro area. Over the U.S. Virgin Islands and surrounding waters,
periods of showers with isolated thunderstorms are possible. Hazards
include frequent lightning, gusty winds, and localized flooding
associated with the stronger thunderstorms each afternoon. Ponding
of water on roadways and minor to isolated flash flooding will be
possible, especially in areas with poor drainage or where heavier
downpours persist.

The prevailing southerly flow combined with ample low-level moisture
will maintain above-normal temperatures and elevated heat indices,
especially across coastal and urban areas. Periods of reduced cloud
cover could further enhance daytime heating, resulting in
potentially hazardous heat conditions.

By Thursday, the weather pattern will begin to be influenced by
recently developed Tropical Storm Jerry, which is currently being
monitored by the National Hurricane Center. The latest forecast
places Jerry as a hurricane located about 200 to 250 miles northeast
of the U.S. Virgin Islands, Vieques, Culebra, and northeastern
Puerto Rico by late Thursday into early Friday. However, uncertainty
remains regarding its track and intensity forecast. Residents and
visitors should remain informed and monitor official updates from
the National Hurricane Center and our local office as Jerry
approaches the Caribbean basin.


.LONG TERM...Friday through Tuesday...
//from previous discussion//

The forecast remains on track with the arrival of increased moisture
associated with a tropical wave (Invest 95L) into the region. The
National Hurricane Center (NHC) is currently monitoring an area of
low pressure over the central Atlantic with a high formation chance
of becoming a tropical cyclone within the next 48 hours (80%) and in
the next seven days (90%). This system is expected to gradually
become better organized over the next day and is likely to form into
a Tropical Depression or Tropical Storm soon. The latest model
guidance continues to suggest this system will be near or north of
the Lesser Antilles by Friday.

On Friday, moisture associated with the system, in combination with
daytime heating and local orographic effects, will enhance the
potential for convective activity (showers and thunderstorms) across
Puerto Rico and the U.S. Virgin Islands. By Sunday, as the system
moves north of the region, winds will veer from the south. This wind
shift, along with the arrival of trailing moisture from the system`s
tail, will promote scattered showers and thunderstorms across
portions of central and northern Puerto Rico and the U.S. Virgin
Islands. Unstable conditions are expected to persist across the area
through at least Monday.

Conditions are expected to improve quickly by Tuesday as a high-
pressure system at all levels settles over the central Atlantic.
This pattern will promote drier and more stable atmospheric
conditions aloft through the end of the workweek.

Across the local area, uncertainty remains high in terms of precise
rainfall amounts and any potential local threats related to the
Invest 95L. Residents and visitors are therefore urged to monitor
the progress of this system closely over the coming days and stay
updated with the latest forecasts.

&&

.AVIATION...
(18Z TAFS)

A tropical wave will continue to bring SHRA/TSRA across all TAF
sites through the period. TSRA activity will persist mostly over
interior PR this aftn, potentially affecting mostly TJPS with TEMPO
MVFR/IFR conds possible at times due to low CIGS/VIS. USVI TAF sites
could also observe SHRA/TSRA at times. Sfc winds ESE 07-12 kt, bcmg
more ESE aft 07/22Z. Gusts up to 20 kt psbl in/near SHRA/TSRA.

&&

.MARINE...

A long-period northeasterly swell will gradually continue to fade
across the local Atlantic waters and passages today. A tropical wave
will influence the region through Wednesday, increasing the frequency
of showers and thunderstorms over the regional waters, especially
during the afternoon hours, with activity further enhanced near
coastal areas by diurnally driven convection. Tropical Storm Jerry is
expected to move northeast of the region by Friday. Tropical storm or
hurricane conditions are possible, mostly across the eastern half of
the regional waters including Atlantic and Caribbean waters and
Anegada Passage.

&&

.BEACH FORECAST...

The dissipating long-period northeasterly swell will continue to
produce life-threatening beach conditions through 6 PM this
evening, mainly along Atlantic exposed beaches. A moderate risk of
rip currents is expected to return by tomorrow (Wednesday)
through at least Friday for Puerto Rico and potentially becoming
high for Saint Croix by the end of the workweek as Tropical Storm
Jerry approaches the region. We encourage people to stay updated
for any changes in the forecast from the National Hurricane
Center.

&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...High Rip Current Risk until 6 PM AST this evening for PRZ001-002-
     005-008-010-012-013.

VI...High Rip Current Risk until 6 PM AST this evening for VIZ001-002.

AM...None.
&&

$$

SHORT TERM/AVIATION...CVB
LONG TERM...GRS
MARINE/BEACH FORECAST...MMC