Your Number One Source for Real-Time Puerto Rico Weather & Hurricane Tracking Updates

770
FXCA62 TJSJ 121710
AFDSJU

Area Forecast Discussion
National Weather Service San Juan PR
110 PM AST Sun Apr 12 2026

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

.KEY MESSAGES...
Updated at 101 PM AST Sun Apr 12 2026

* Locally induced showers and thunderstorms will continue to develop
  once again over the interior portions of Puerto Rico this
  afternoon, where the flood threat remains elevated. Heavy rainfall
  may lead to ponding of water on roads, rapid rises on streams, and
  flooding in low-lying and poor drainage areas.

* Across the U.S. Virgin Islands, showers are expected to increase
  from late tonight into Monday morning. Periods of moderate to
  heavy rain may cause localized flooding and hazardous travel
  conditions.

* There is a Flood Watch for Puerto Rico and the U.S. Virgin Islands
  from 10 AM Monday through 8 AM Wednesday. Repeated rounds of
  rainfall may result in flash flooding, river rises, and landslides
  in areas of steep terrain.

* A High Risk of Rip Currents remains in effect for the western,
  northern, and eastern coasts of Puerto Rico and Culebra through
  Monday afternoon.

&&

.Short Term(This evening through Tuesday)...
Issued at 101 PM AST Sun Apr 12 2026

Overall, calm conditions and partly cloudy skies prevailed through
the morning hours, with brief showers moving across the eastern
municipalities and producing light accumulations. Mostly clear
conditions were observed across western Puerto Rico, where no
official weather stations reported temperatures reaching the 90s.
Across the rest of the coastal and urban areas, temperatures
remained in the 80s, while mountainous regions ranged from the upper
70s to low 80s. Heat indices along the coastal/urban areas reported
values in the low 100s. By early afternoon, shower activity
developed across the interior and western portions of Puerto Rico,
driven by available moisture and local effects. Winds remained from
the southeast at around 10 mph, with occasional higher gusts.

Tonight, moisture will gradually increase as a pre-frontal trough
and an upper-level trough approach from the northwest. Model
guidance indicates the upper-level trough will deepen by Monday,
supporting a moist and unstable pattern through the remainder of the
short-term period. Satellite-derived products show an elongated
convective area over the Dominican Republic and the western Atlantic
that is expected to move into Puerto Rico and the U.S. Virgin
Islands by Monday.

Rainfall will increase from Monday into Tuesday, with daily
accumulations of 1 to 3 inches and locally higher amounts possible.
Colder-than-normal 500 mb temperatures, ranging from -10C to -11C,
will enhance instability and support vertical development of
convection. Winds will shift to a northerly component from Monday
afternoon into early Tuesday as a frontal boundary moves southward
across the region, with the most active period expected during this
time.

Given saturated soils, this pattern will maintain an elevated to
significant risk of urban and river flooding, as well as potential
mudslides in areas of steep terrain. A Flood Watch is in effect from
10 AM Monday through 8 AM Wednesday for all of Puerto Rico and the
U.S. Virgin Islands. Residents and visitors should continue to
monitor the latest forecasts.

&&

.Long Term(Wednesday through next Saturday)...
Issued at 240 AM AST Sun Apr 12 2026

The wet and unsettled weather pattern may extend into the long-term
forecast. A surface high pressure is expected to build over the
Western Atlantic, gradually increasing the pressure gradient,
resulting in strengthening southeasterly to easterly winds. These
conditions will bring back breezy to locally windy conditions across
the coastal areas of the islands. Nevertheless, the influence of the
deep-layered trough and abundant moisture content across the CWA
will maintain a limited to elevated risk of flooding.  From the
latest model guidance, at least through Saturday, PWAT values should
increase and remain above normal for this time of the year (between
1.6 and 1.8 inches, low chance for 2.0 inches). Additionally,
moisture content in the low and mid levels should remain high
through most of the period, with relative humidity above 60 - 70 %,
and steep lapse rates in the 850 - 700 mb levels. Due to the
proximity of the trough, mid level temperatures will likely remain
cooler than normal (around - 8 degrees Celsius), while a jet streak
in the high levels will maintain strong winds (70 - 80 kt) through
Saturday, allowing ventilation and cloud growth. Additionally,  the
Galvez-Davison Index (GDI) suggests deep convection activity across
the CWA, with isolated to scattered thunderstorms in the afternoons
and the night hours. The most likely scenario, from Wednesday
through Saturday, is moderate to locally heavy showers and isolated
thunderstorms moving over windward sections of Puerto Rico and the
U.S. Virgin Islands throughout the day, with afternoon convection
over the interior into northwestern/western sections of Puerto Rico.
Due to the expected weather event in the short term, saturated soils
and above-normal river levels are very likely and may enhance
flooding potential. Hence, the limited to elevated flooding threat
remains, with a limited lightning potential. Impacts may include
urban and small stream flooding, with localized flash flood,
landslides, and rapid river rises. By Sunday into Monday, weather
conditions should gradually improve, but there are discrepancies
between global solutions for early next week as members of the GEFS
are trending to wetter conditions, while ENS members are trending
to a seasonal pattern.

&&

.AVIATION...
(18Z TAFS)
Issued at 101 PM AST Sun Apr 12 2026

VFR conds across most TAF sites with brief MVFR conds
TJBQ/TJPS/TJSJ from 18z-23z, +SHRA/TSRA are expected to develop
over the interior of PR, causing mostly VCTS. ESE winds between
8-14 kt and occasional higher gust. An approaching front from the
NW Atlantic waters could lead to +TSRA across the offshore
Atlantic waters and Mona Passage from late tonight into Monday
morning.

&&

.MARINE...
Issued at 101 PM AST Sun Apr 12 2026

A broad surface high pressure across the central Atlantic and a
front over the western Atlantic will promote light to moderate
trades through at least tonight. Pulses of northerly swell will
continue to move through the Atlantic waters and passages, where
small craft should continue to exercise caution for the next several
days. Between Monday through Wednesday, the combination of the front
and associated pre-frontal trough will increase showers and
thunderstorms across the local waters, creating locally hazardous
marine conditions. Small Craft Advisory conditions are expected
across the Atlantic waters due to seas building up to 7 feet through
midweek.

&&

.BEACH FORECAST...
Issued at 101 PM AST Sun Apr 12 2026

A high risk of rip currents (life-threatening rip currents are
likely in the surf zone) continues for the northwestern and eastern
coastlines of Puerto Rico and Culebra, though conditions will
gradually subside through Monday as the northerly swell weakens.
Breaking waves can still reach 6 to 7 feet, particularly along the
northern coastline of Puerto Rico.

A moderate risk of rip currents is expected to develop across
northern exposed beaches by Tuesday, with conditions becoming more
hazardous again by the end of the workweek.

Beachgoers and inexperienced surfers should avoid entering the
water, especially near jetties, as life-threatening rip currents
remain possible. Heed the advice of lifeguards, beach patrol flags,
and posted signs. Access to hazardous beaches may be limited, and
individuals should follow all posted warnings and safety guidance.

Visitors should also remain mindful of the weather in addition to
surf hazards. A very unsettled weather pattern is developing, with
the potential for heavy showers and thunderstorms producing locally
gusty winds and brief heavy rainfall. If thunder is heard, seek
shelter indoors immediately.

For additional information and location-specific rip current
details, please visit: weather.gov/beach/sju.

&&

.HYDROLOGY...
Issued at 240 AM AST Sun Apr 12 2026

As a mid-to upper-level trough approaches from the northwest, the
likelihood of flooding is increasing from late tonight until at
least midweek. An elevated flooding risk is forecast through this
period. Showers and thunderstorms will increase in frequency on
Monday, but the heaviest activity is anticipated for Monday night
into Tuesday. Although a level of uncertainty is still present,
the days with the highest potential for flooding are Monday and
Tuesday. However, above normal moisture will persist through late
in the week. The likelihood of urban and small stream flooding,
isolated flash flooding, landslides and rapid river rises continues
to increase. Residents and visitors are urged to remain alert to
changing weather conditions and to avoid flooded roadways. A Flood
Watch (FFASJU) and an Hydrologic Outlook (ESFSJU) are currently
in effect to highlight this flooding potential.

&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...High Rip Current Risk through Monday afternoon for PRZ001-002-
     005-008-010-012.

     Flood Watch from Monday morning through Wednesday morning for
     PRZ001>013.

VI...Flood Watch from Monday morning through Wednesday morning for
     VIZ001-002.

AM...None.
&&

$$

SHORT TERM/AVIATION...MMC
HYDROLOGY...DSR
LONG TERM...MNG
MARINE/BEACH...CVB

NWS SJU Office Area Forecast Discussion