831
FXCA62 TJSJ 161843
AFDSJU

Area Forecast Discussion
National Weather Service San Juan PR
243 PM AST Sat May 16 2026

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

.KEY MESSAGES...
Issued at 243 PM AST Sat May 16 2026

* Showers and isolated t-storms will continue across interior to
  W-NW PR and downwind of El Yunque and the local islands this
  afternoon.

* Above-normal temperatures will persist across the region, with
  heat indices reaching the upper 90s to low 100s during peak
  afternoon hours, especially across urban and coastal areas.

* An upper-level trough will approach the islands tomorrow. This
  can increase the frequency of showers and isolated t-storms.

* A moderate risk of rip currents will persist along most beaches
  of Puerto Rico, Vieques, Culebra, and the USVI through much of
  the forecast period.

* Low concentrations of Saharan dust particles are over the
  region, gradually decreasing Sunday afternoon.

&&

.Short Term(This evening through Monday)...
Issued at 243 PM AST Sat May 16 2026

Variable weather conditions prevailed today as abundant moisture
continued to move over the region. Showers affected portions of
eastern Puerto Rico and the San Juan metropolitan area through
late morning, though Doppler radar estimated minimal rainfall
accumulations. By early afternoon, showers developed and expanded
across the interior, spreading toward the north-central and
northwestern portions of Puerto Rico. Radar and satellite imagery
also detected a few thunderstorms across these areas, with
rainfall accumulations reaching up to 3 inches in northern San
Sebastian and southern Quebradillas and Isabela. Warm temperatures
were observed across the region, particularly throughout the
islands urban and coastal areas. Maximum temperatures reached the
upper 80s to low 90s in these sectors, and ranged from the low to
mid-80s in the interior. Winds prevailed from the east at 15 to 20
mph, with higher gusts and sea breeze variations.

For the rest of the day, showers and isolated thunderstorms will
persist across northwestern and north-central Puerto Rico.
Additional rainfall accumulations could lead to minor urban and
small stream flooding, as well as quick river rises. Similar
conditions are expected on Sunday as a mid-level ridge continues to
weaken and an upper-level trough approaches from the west. This
trough will amplify and increase instability across the region,
especially tomorrow through late Tuesday.

As instability rises, moisture levels will also increase. Combined
with daytime heating and local effects, this will help to enhance
active afternoons, leading to showers and isolated thunderstorms
across the interior and western to northwestern Puerto Rico.
Convection is also expected downwind of El Yunque, and from the U.S.
Virgin Islands toward eastern Puerto Rico. The approaching upper-
level trough will continue to fuel this afternoon convection daily.
Meanwhile, low concentrations of Saharan dust particles will peak
today and late tonightprompting occasionally hazy skiesbefore
gradually decreasing tomorrow morning. Despite the expected shower
activity, warm to hot temperatures will persist through early next
week, potentially leading to elevated heat indices across urban and
coastal areas. Residents and visitors are urged to stay hydrated,
seek shade, and monitor local conditions to ensure safety during
peak heating hours.

&&

.Long Term(Tuesday through Saturday)...
Issued at 452 AM AST Sat May 16 2026

A gradual transition toward a wetter and somewhat more unstable
weather pattern is expected across Puerto Rico and the U.S. Virgin
Islands through the latter half of the upcoming workweek. Surface
high pressure over the western Atlantic will maintain moderate to
locally fresh easterly to east-southeasterly winds, with occasional
stronger and gusty periods. Early in the week, conditions should
remain relatively quiet overall, with intermittent patches of
moisture promoting passing showers across eastern Puerto Rico and
the U.S. Virgin Islands, followed by isolated afternoon convection
across western Puerto Rico. Rainfall coverage should generally
remain more dry than wet, especially across southern and eastern
Puerto Rico, which may continue to favor ongoing drought concerns.

At upper levels, a deep trough lingering over the western Atlantic
is forecast to gradually sink farther south late in the workweek,
supporting enhanced divergence aloft, cooling mid-level
temperatures, and a less dry environment across the region.
However, moisture continuity through the vertical column still
appears somewhat inconsistent, meaning moisture depth and
persistence will largely determine daily shower and thunderstorm
coverage. By late week, increasing moisture and stronger diurnal
heating should support more frequent afternoon showers and
thunderstorms across interior and western Puerto Rico, with flooding
concerns gradually increasing. Heat concerns will continue through
the period, although slightly cooler conditions may develop at times
due to increased cloud cover and rainfall activity.

&&

.AVIATION...
(18Z TAFS)
Issued at 243 PM AST Sat May 16 2026

Mainly VFR conds expected to continue across all TAF sites during
the next 24 hrs. SHRA/TSRA will continue to develop in the
afternoon causing brief MVFR/IFR conds particularly at TJBQ thru
16/22Z. E winds btw 12-16 kt will continue thru 16/22-23Z, with
sea breeze variations and higher gusts. Winds are expected to
decrease to 5 kt or less thru 17/14Z.

&&

.MARINE...
Issued at 243 PM AST Sat May 16 2026

A series of broad surface high pressures over the Atlantic will
continue to promote moderate to fresh east to southeast winds
across the regional waters, becoming more easterly early next
week. These breezy conditions will maintain choppy seas,
particularly across the offshore and exposed Atlantic and
Caribbean waters. Seas are forecast to remain between 4 and 6
feet. Afternoon and early evening isolated thunderstorms can be
expected each day across the western waters of Puerto Rico.

&&

.BEACH FORECAST...
Issued at 243 PM AST Sat May 16 2026

Tonight, there is a moderate risk of rip currents across the
northern, eastern, and southern beaches of Puerto Rico, as well as
across Vieques, Culebra, and the U.S. Virgin Islands. This means
life-threatening rip currents are possible in the surf zones, and
beachgoers should exercise caution when entering these beaches.
Through the rest of the weekend and into early next week, breezy
winds will result in similar conditions continuing. Check the
forecast before entering the water. For additional information
and location-specific rip current details, visit
weather.gov/beach/sju.

&&

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

$$

SHORT TERM/AVIATION...GRS
LONG TERM...ICP
MARINE/BEACH...YZR

NWS SJU Office Area Forecast Discussion