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120
FXCA62 TJSJ 030540
AFDSJU

Area Forecast Discussion
National Weather Service San Juan PR
140 AM AST Fri Jul 3 2026

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

.KEY MESSAGES...
Issued at 127 AM AST Fri Jul 3 2026

* Expect moderate to high concentrations of Saharan dust through
  the holiday weekend. Dust concentrations will gradually increase
  by late Friday, peaking around Saturday. Expect hazy skies,
  reduced visibility, and potential health impacts, especially for
  people with respiratory conditions.

* Elevated heat risk is expected through Saturday. Hot, humid
  conditions will increase the risk of heat-related illness,
  particularly for those spending extended periods outdoors.

* A moderate risk of rip currents is expected beginning Saturday.
  Life-threatening rip currents will be possible at several local
  beaches.

&&

.Short Term(Today through Sunday)...
Issued at 127 AM AST Fri Jul 3 2026

Overnight, weather conditions across Puerto Rico and the U.S.
Virgin Islands remained generally tranquil, with only a few groups
of trade-wind showers moving across the local waters. Despite
mostly clear skies, overnight temperatures remained typical for
early July, ranging from the upper 70s to lower 80s across coastal
and urban areas and from the upper 60s to lower 70s across the
interior and higher terrains. Similar to previous nights, winds
were light and variable, becoming nearly calm at times.

The advective weather pattern will prevail through Saturday, with
east to east-southeast winds transporting patches of shallow
moisture across the region from time to time. As a result, periods
of passing showers will affect the U.S. Virgin Islands and
windward sections of Puerto Rico, particularly during the
overnight and morning hours, while afternoon convection will
remain limited to portions of the interior, north central to
northwestern sections of Puerto Rico. Precipitable water values
are forecast to remain near to slightly below normal, supporting
generally light and localized rainfall.

A Saharan Air Layer (SAL) will gradually filter over the U.S.
Virgin Islands by late Friday, bringing moderate to high
concentrations of suspended dust before strengthening to high on
Saturday. By Saturday morning, the highest dust concentrations are
expected across Puerto Rico and lingering into Sunday. The
intrusion of this drier air mass will gradually suppress shower
activity despite occasional patches of trade-wind moisture.
Consequently, rainfall coverage should decrease through the
holiday weekend, with mainly brief passing showers affecting
windward areas. These high concentrations of Saharan Dust will
also promote hazy skies, periods of reduced visibility, and
deteriorating air quality, especially for sensitive groups.
Therefore, we urge residents and visitor to follow health
recommendations during this dust events.

Meanwhile, warm conditions will persist through the short-term
period, especially from late morning through the afternoon. While
heat index values are forecast to remain below Heat Advisory
criteria over the next couple of days, heat-related impacts remain
possible. Residents and visitors are encouraged to stay hydrated,
wear lightweight, light-colored clothing, and limit prolonged
outdoor activities during the peak heating hours.

&&

.Long Term(Monday through Friday)...
Issued at 127 AM AST Fri Jul 3 2026

No major changes to the long term forecast. A Saharan Air Layer
(SAL) with moderate to high concentrations of Saharan Dust will
continue to filter over the islands to start the next workweek,
these concentrations are forecast to persist through Wednesday.
However, model guidance suggests that another plume of moderate to
possibly high concentrations of Saharan Dust will reach the islands
once again on Friday. Even with Saharan Dust filtering in and
promoting hazy conditions, a humid and unstable pattern is still
forecast as a tropical wave and its related moisture field arrive by
midweek. A surface high over the Atlantic will continue during the
workweek, promoting up to breezy E to SE winds (becoming breezy to
windy later in the period). An upper-level low will continue
lingering north of the islands throughout much of the workweek with
model guidance suggesting another upper-low reaching the area from
the east to end the workweek, providing modest instability through
the period. As patches of moisture continue to filter over the
islands on Monday and Tuesday, precipitable water (PWAT) values will
increase to high-end normal and above normal values. This will
promote passing overnight and morning showers over eastern the
eastern region and convective afternoon showers and t-storms across
the western interior and northwestern Puerto Rico, as well as
downwind of the local islands and El Yunque, due to local effects
and diurnal heating. Most available moisture will be below 800 mb,
with the exception of Wednesday where available moisture reaches the
mid to upper levels. By late Tuesday and Wednesday, a tropical wave
is expected to bring a surge of tropical moisture (with above normal
PWAT), which, along with favorable upper-level dynamics, will
increase widespread showers and isolated thunderstorms, as well as
increase flooding and lightning risks. However, concentrations of
Saharan Dust will continue to filter over the region. Conditions
will once again dry out on Thursday as PWAT values decrease to below
normal to low-end normal values, however a brief window with less
concentrations of Saharan Dust is forecast, giving way to a more
typical summer pattern (under breezy to windy flow) with overnight
and morning passing showers as well as afternoon showers and
isolated t-storms over W Puerto Rico. Even drier air with another
plume moderate to possibly high concentrations of Saharan Dust will
reach the islands on Friday, prompting a drier and hazy pattern.
Warm to hot conditions will continue during the workweek as heat
index values are expected to reach and/or surpass the 100s over
coastal and lower elevation areas of the islands.

&&

.AVIATION...
(06Z TAFS)
Issued at 127 AM AST Fri Jul 3 2026

VFR conds across all terminals. Once again, afternoon TSRA may
result in VCSH/VCTS at TJBQ aft 03/17 thr 03/23Z. VCSH over TJSJ
aft 03/16Z. E-SE winds between 12-16 kt are expected with higher
gusts and sea breeze variations. Winds will become light and
variable at 5-10 kt aft 03/23Z.

&&

.MARINE...
Issued at 127 AM AST Fri Jul 3 2026

Surface high pressure over the central Atlantic will maintain
moderate to locally fresh east to east-southeasterly winds across
the regional waters through the next several days. Seas will remain
generally moderate, ranging between 3 and 5 feet across most waters,
with locally choppy conditions, particularly across the offshore
Atlantic and Caribbean waters where small craft should exercise
caution at times. A Saharan Air Layer will gradually build through
the weekend, with moderate concentrations expected by late weekend.
Isolated afternoon thunderstorms may develop over the northwestern
coastal waters of Puerto Rico, resulting in locally higher winds and
seas.

&&

.BEACH FORECAST...
Issued at 127 AM AST Fri Jul 3 2026

The risk of rip currents will remain low through Friday before
gradually increasing to moderate across many east- and north-facing
beaches this weekend as easterly winds strengthen and seas slowly
build. Despite the low risk, life-threatening rip currents remain
possible near jetties, reefs, and piers. Saharan dust will gradually
increase through the weekend, with moderate concentrations expected
by late weekend, resulting in hazy skies and reduced air quality.
Hot daytime conditions will persist, while isolated afternoon
showers and thunderstorms remain possible near the northwestern
beaches of Puerto Rico.

&&

.FIRE WEATHER...
Issued at 127 AM AST Fri Jul 3 2026

LOW fire weather threat for today.

&&

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

$$

SHORT TERM/AVIATION/FIRE WEATHER...MMC
LONG TERM...MRR
MARINE/BEACH FORECAST...ICP

NWS SJU Office Area Forecast Discussion