723
FXCA62 TJSJ 140632
AFDSJU

Area Forecast Discussion
National Weather Service San Juan PR
232 AM AST Tue Apr 14 2026

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

.KEY MESSAGES...
Updated at 232 AM AST Tue Apr 14 2026

 * Deteriorating weather conditions are expected to continue
   through the rest of the week as an unsettled pattern promotes periods
   of showers and thunderstorms across the region. Therefore, a
   Flash Flood Watch remains in effect until Wednesday afternoon
   for all of Puerto Rico.

 * A moderate risk of rip currents will persist across local
   beaches over the next several days.

 * Seas are forecast to
   gradually increase during the latter part of the week,
   resulting in building wave heights and more hazardous marine
   conditions for small craft, particularly across the offshore
   Atlantic waters and passages.

 * Variable and unstable weather conditions will prevail across
   the U.S. Virgin Islands, driven by increasing atmospheric
   instability and shifting wind patterns, which will support the
   development of scattered to numerous showers and isolated
   thunderstorms.

&&

.Short Term(Today through Thursday)...
Issued at 232 AM AST Tue Apr 14 2026

Overnight conditions were mostly cloudy to overcast across the
entire forecast area, with skies remaining largely covered through
the night. Shower activity over land was limited, with only a few
brief and isolated showers observed; however, more persistent
shower activity prevailed across the Caribbean and Atlantic
waters, occasionally moving near the coastal areas. These cloudier
conditions helped keep temperatures relatively mild along the
coasts, generally in the mid-70s, while cooler temperatures were
observed across the higher elevations due to elevation and cloud
cover. Overall, it was a calm but cloudy night with most of the
rainfall remaining offshore.

A mid-level cut-off low will remain positioned north of the
region today, promoting a strong upper-level jet streak of over 90
knots across the local area and supporting enhanced divergence
aloft, which will favor convective development. At 500 mb, a low
will induce a southwesterly flow around 25 knots, while at the
surface, an induced trough will promote variable to east-
southeasterly winds across eastern Puerto Rico and surrounding
waters, introducing some uncertainty in the focus of showers
throughout the day. Moisture will remain abundant, with
precipitable water values around the 75th percentile, well above
climatological normals, while mid-level relative humidity values
between 750500 mb will exceed two standard deviations above
normal early in the day before gradually decreasing. Cold
temperatures aloft, ranging between -9 to -10C at 500 mb, will
enhance instability and support the development of isolated to
scattered thunderstorms embedded within the broader shower
activity. Based on the latest analysis and model guidance, shower
activity is expected to start around mid to late morning and then
become more widespread across the interior and western sections of
Puerto Rico during the afternoon hours, with some showers
becoming locally heavy and resulting in urban and small stream
flooding. Therefore, a Flood Watch remains in effect for today,
with an elevated to significant flooding risk across portions of
the islands, although some uncertainty persists regarding the
exact placement and movement of the heaviest rainfall due to the
variable low-level wind flow associated with the surface trough.

For Wednesday, surface conditions will evolve as winds within the
03 km layer remain from the southeast while a surface
perturbation moves across the forecast area. According to model
guidance, the induced surface trough is expected to move east of
the CWA earlier in the day; however, the GFS places a more
defined low center just northwest of the area, and these
discrepancies may introduce some uncertainty in the overall
conditions. Nonetheless, sufficient deep moisture, with
precipitable water values near 1.8 inches, above-normal relative
humidity between 850700 mb, and slightly colder temperatures at
500 mb will support a convective pattern with better-organized
convection, especially during the afternoon as cloudiness
interacts with local effects. Given these conditions, an elevated
flooding risk is expected, particularly across northwestern
sections of the islands, including the San Juan metro area, due to
the prevailing wind direction as the induced surface trough moves
across the region.

For Thursday, conditions become slightly more interesting at 250
mb as the previous cut-off low shifts eastward out of the area,
while a deep-layered trough continues to deepen with its axis
positioned over Hispaniola, leaving Puerto Rico and the U.S.
Virgin Islands under its influence. As a result, a more unstable
and dynamic weather pattern is expected, with abundant moisture
and increasing instability combining with favorable upper-level
support to promote the development of scattered to numerous
showers and thunderstorms across the region. Activity will likely
begin by late morning and become more widespread through the
afternoon, especially across interior and western Puerto Rico,
where locally heavy rainfall is expected, supporting efficient
rainfall processes and some storm organization, which will
increase the risk of urban and small stream flooding along with
isolated gusty winds.

&&

.Long Term(Friday through Tuesday)...
Issued at 232 AM AST Tue Apr 14 2026

An unsettled weather pattern is expected Friday through the weekend
into early next week as a short wave trough sinks into the
Caribbean. At the surface, high pressure over the western to central
Atlantic will promote moderate to fresh ESE to easterly winds Friday
and Saturday, becoming easterly Sunday and slightly ENE by Monday.
The pressure gradient will remain uneven, with stronger winds across
eastern areas and weaker flow farther west, supporting faster moving
showers in the east and slower storm motion in the west. Moisture
will increase Friday into the weekend, with PWAT values above normal
and at times exceeding climatological maxima, before slightly drier
air filters in late Sunday into Monday. Aloft, a jet streak will
lift over the area by Monday, while mid level temperatures remain
modestly cool. This pattern will support periods of convection and
isolated to locally scattered thunderstorm development across the
region. Confidence is medium, as details depend on the timing and
placement of the trough and deeper moisture.

Flooding will be the primary hazard, followed by lightning and
breezy conditions. Showers and isolated to locally scattered
thunderstorms are expected daily, generally favoring eastern Puerto
Rico and the U.S. Virgin Islands overnight into the morning, then
shifting westward each afternoon based on the latest model guidance.
The greatest risk will focus over northwestern Puerto Rico Friday
and Saturday, western Puerto Rico on Sunday, and southwestern Puerto
Rico by Monday. Faster storm motion over eastern areas may limit
rainfall totals, but slower moving convection in western sectors
could enhance flooding impacts. Breezy conditions will persist due
to the general wind flow and may be locally enhanced by thunderstorm
downdrafts. Soils may remain saturated, which could further increase
the risk of flooding, landslides, and rapid river rises. This
pattern will likely disrupt outdoor plans at times. Conditions
should gradually improve late Sunday into Monday, though some
uncertainty remains.

&&

.AVIATION...
(06Z TAFS)
Issued at 232 AM AST Tue Apr 14 2026

Mainly VFR conditions are expected across the local terminals
early in the period, deteriorating to MVFR at times due to
increasing SHRA and isolated TSRA, particularly across TJSJ, TJBQ,
and TJPS between 14/17Z and 14/23Z. Periods of lower ceilings and
reduced visibility are likely with the heaviest activity. Winds
will remain light and variable through around 14/15Z, then
increase from the E-SE at around 10 knots, with higher gusts
possible near showers and thunderstorms.

&&

.MARINE...
Issued at 232 AM AST Tue Apr 14 2026

A broad surface high pressure across the central Atlantic and a
frontal boundary over the western Atlantic will promote light to
moderate trades through the rest of the weekend. Pulses of northerly
swell will continue to move through the Atlantic waters and
passages, where small craft should continue to exercise caution over
the next several days. The combination of the front and associated
pre-frontal trough will increase showers and thunderstorms across
the local waters, creating locally hazardous marine conditions
through at least mid-week.

&&

.BEACH FORECAST...
Issued at 232 AM AST Tue Apr 14 2026

A moderate risk of rip currents will continue for most north-and
east-facing beaches of Puerto Rico, including Vieques and Culebra,
and the U.S. Virgin Islands, where rip currents are possible and can
be life-threatening. A low risk will likely persist across western
and southern Puerto Rico. Increasing winds early to midweek could
lead to a return of more hazardous marine and coastal conditions.
Residents and visitors are encourage to exercise caution at the
beach, especially along the exposed coasts.

&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...Flood Watch through Wednesday morning for PRZ001>013.

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

AM...None.
&&

$$

SHORT TERM, KEY MESSAGES & AVIATION...LIS
LONG TERM, BEACH FORECAST & MARINE....ICP/GRS

NWS SJU Office Area Forecast Discussion