056
FXCA62 TJSJ 100937
AFDSJU

Area Forecast Discussion
National Weather Service San Juan PR
537 AM AST Fri Oct 10 2025

.KEY MESSAGES...

* Tropical Storm Jerry will pass well to our northeast this
  morning before continuing its track towards the open Atlantic.
  Its closest approach to St. John was at around 5 AM at
  approximately 152 miles, and its closest approach to San Juan
  will be at around 8 AM at about 231 miles.

* Deep tropical moisture from Jerry will help support rounds of
  showers and thunderstorms through the weekend, maintaining a
  moderate risk of flooding, mostly for eastern Puerto Rico and
  the U.S. Virgin Islands.

* Hazardous marine conditions for small crafts and hazardous beach
  conditions are forecast as swells from Jerry continue affecting
  the regional waters through Saturday.

* For the U.S. Virgin Islands, particularly St. Thomas and St.
  John, conditions could deteriorate further as periods of gusty
  winds and locally heavy rainfall are possible today into the
  weekend.


&&

.SHORT TERM...Today through Sunday...

During the overnight period, some showers and a few thunderstorms
moved across the local waters, with some reaching the northeast
corner of Puerto Rico. Radar estimates indicated rainfall
accumulations of one inch or less across eastern municipalities.
Surface weather stations across the islands recorded low
temperatures in the mid 70s to low 80s in coastal and urban areas,
and in the mid to upper 60s across interior Puerto Rico. Winds have
been mainly light and variable.

Today, Tropical Storm Jerry will pass to the northeast of Puerto
Rico and the U.S. Virgin Islands. Its closest approach to St.
John was at around 5 AM at approximately 152 miles, and its
closest approach to San Juan will be at around 8 AM at about 231
miles. It is expected to move away from the islands later today.
According to the latest 5 AM bulletin from the National Hurricane
Center (NHC), the center of Tropical Storm Jerry was located near
latitude 19.2 North, longitude 62.5 West. Jerry is moving toward
the northwest near 17 mph.

This storm will bring indirect impacts to our forecast area through
at least Saturday. Weak northerly steering winds will dominate
during the morning hours, then gradually shift to acquire a
southerly component due to Jerrys influence. The latest satellite
derived precipitable water (PWAT) values range in the from normal to
above normal, approximately 2.00 to 2.20 inches across the region.
The combination of these variables and local effects will promote
slow-moving convection capable of producing heavy rainfall, frequent
lightning, and localized gusty winds. Therefore, an elevated flood
risk is expected, particularly across interior and eastern Puerto
Rico and the U.S. Virgin Islands today and Saturday. The rainfall
forecast have 2 to 4 inches of rain expected for the USVI. For
eastern Puerto Rico, moisture associated with Jerry combined with
local orographic effects may result in up to 2 to 4 inches of rain,
with isolated 6 inches possible. This rainfall could result in flash
flooding, particularly in urban areas and in steep terrain. In terms
of heat for today, there is a limited heat risk across urban and
coastal areas of Puerto Rico and the USVI, however some areas may
experience locally higher heat indices, especially in areas with
less rain or cloud coverage. We will continue to monitor the heat
threat during the morning in case any advisory is needed.

By Sunday, lingering tropical moisture combined with southeasterly
winds will continue to bring warm, humid, and unstable weather
conditions. Afternoon thunderstorms are likely to redevelop across
interior and northwestern Puerto Rico due to sea breeze
interactions. Residents and visitors are encouraged to stay informed
and follow official updates from the National Hurricane Center and
the National Weather Service office in San Juan.


.LONG TERM...Monday through Friday...

Drier air will filter in to start the workweek under easterly flow,
displacing the moisture plume related to Jerry. Patches of below
normal to above normal moisture will filter over the islands Tuesday
through Wednesday and then gradually increasing during the second
half of the workweek. Mid to upper level ridging will be present to
start the period, however model guidance has an upper level low
approaching the Caribbean by midweek. Latest runs have backed off on
the deep level trough digging down towards the Caribbean during the
second half of the period. However, as its surface low moves towards
the northwestern Atlantic and a high positions itself over the
eastern tropical Atlantic, steering flow will become southeasterly
on Tuesday, southeasterly to southerly on Wednesday and southerly
through most of the rest of the period. PWAT values are forecast to
gradually increase Thursday and Friday as both moisture from a
frontal boundary approaches from the north and southerly flow steers
tropical moisture over the region, these features can bring above 2
inches of PWAT to end the forecast period. Flooding risk remains,
particularly during afternoon convection steered by the above
mentioned dominant winds, due to diurnal heating, sea breeze
convergence and local effects, and due to the plumes of moisture at
the beginning and end of the forecast period. Surface winds will be
generally light to moderate through Tuesday, becoming light
Wednesday onwards as the southerly component establishes itself.
This southerly component will also aid in sustaining a heat risk
during the period. Low concentrations of Saharan Dust will also be
present to start the workweek.

&&

.AVIATION...
(06Z TAFs)

VFR conditions should prevail this morning across most TAF sites.
Tropical Storm Jerry will pass to the northeast of Puerto Rico and
the U.S. Virgin Islands today, cloudiness increasing. VCSH are
likely across TJSJ and USVI TAF sites during the morning period,
After 16Z18Z, SHRA/TSRA developing over the Cordillera will reach
TAF sites, potentially causing intermittent periods of MVFR
conditions, locally gusty winds and reduced VIS. The general flow
will remain variable today with sea breeze variations. Tonight, USVI
sites have a moderate to high chance to observe periods of heavy
rain and t-storms.

&&

.MARINE...

Tropical Storm Jerry is now about 155 miles northeast of St. John
and about 235 miles northeast of San Juan. This system will
continue moving northwestward at a safe distance from Puerto Rico
and the USVI. Although no direct tropical storm impacts are
expected, indirect marine impacts will continue spreading across
the regional waters through late tonight and early Saturday.
Swells generated by Jerry will lead to hazardous seas up to 8 to 9
feet, particularly across the offshore Atlantic waters and the
Anegada Passage, where a Small Craft Advisory is in effect through
late tonight. Conditions are forecast to gradually improve late
Saturday onwards.


&&

.BEACH FORECAST...

A high risk of rip currents will be in effect this morning for
the beaches of the USVI as swells from Tropical Storm Jerry begin
to affect the local waters. The high risk of rip currents will
then spread to Vieques, Culebra and Puerto Rico (north and east
facing beaches), this evening. These swells can lead to hazardous
surf conditions with breaking waves up to 6 to 7 feet along
exposed beaches. Conditions are expected to gradually improve to a
moderate risk of rip currents by tomorrow evening.

Heed the advice of lifeguards, beach patrol flags and signs. If you
become caught in a rip current, yell for help. Remain calm, do not
exhaust yourself and stay afloat while waiting for help. If you have
to swim out of a rip current, swim parallel to shore and back toward
the beach when possible. Do not attempt to swim directly against a
rip current as you will tire quickly.


&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...High Rip Current Risk from this evening through Saturday
     afternoon for PRZ001-002-005-008-012-013.

VI...High Rip Current Risk through Saturday afternoon for VIZ001-002.

AM...Small Craft Advisory until 6 AM AST Saturday for AMZ711-723.

&&

$$

SHORT TERM...MRR
LONG TERM....YZR
AVIATION...99