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180
FXCA62 TJSJ 100610
AFDSJU

Area Forecast Discussion
National Weather Service San Juan PR
210 AM AST Mon Aug 10 2026

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

.KEY MESSAGES...
Issued at 210 AM AST Mon Aug 10 2026

* Heat remains the main hazard, with elevated to significant heat
  risks through much of the week.

* Elevated fire danger is expected today as dry, warm, dusty
  conditions combine with stressed fuels and gusty afternoon
  winds.

* Tuesday will be the most active weather day, with the
  highest lightning and localized flooding risk.

* Marine and coastal conditions deteriorate late week as stronger
  trades build seas and increase the rip current risk.

* NHC is monitoring multiple Atlantic disturbances; it remains
  too early to determine any impacts to Puerto Rico or the U.S.
  Virgin Islands.


&&

.Short Term(Today through Wednesday)...
Issued at 210 AM AST Mon Aug 10 2026

A departing tropical wave will be followed by a drier air mass and
increasing Saharan dust today. Lingering moisture and local
effects may still support a few afternoon showers and an isolated
thunderstorm across interior and western Puerto Rico, but warming
temperatures aloft, weak lapse rates, subsidence, and increasing
mid-level dryness should keep most of the region dry. An elevated
heat risk is expected, and a Heat Advisory has been issued for
coastal, lower-elevation, urban, and other heat-prone areas. Some
locations could reach significant heat risk levels later today.
Saharan dust concentrations will remain high before gradually
decreasing overnight.

A surge of tropical moisture will increase shower and thunderstorm
activity Tuesday, with the greatest coverage expected during the
afternoon. Tuesday carries the highest potential for lightning and
locally heavy rainfall, with localized urban and small-stream
flooding possible where stronger thunderstorms develop. Pockets of
drier Saharan air will gradually follow Tuesday night, before a
brief moisture pulse arrives early Wednesday. Cooler temperatures
aloft associated with an approaching upper-level trough will favor
some convection Wednesday, but increasing mid-level dryness should
gradually limit its coverage. Elevated to significant heat risks
will continue Tuesday and Wednesday, with the highest heat
potential expected Wednesday as warmer low-level temperatures,
sufficient humidity, and greater sunshine favor higher heat
indices. Winds will decrease today into Tuesday, then begin
increasing Wednesday night as the local pressure gradient tightens
behind the tropical wave.


&&

.Long Term(Thursday through Monday)...
Issued at 210 AM AST Mon Aug 10 2026

A tightening pressure gradient associated with the Atlantic ridge
will support breezy easterly to southeasterly winds Thursday into
the weekend. A drier air mass and Saharan dust will dominate, with
precipitable water values dropping to around 1.3 inches Thursday
and only brief patches of low-level moisture thereafter. Shower
activity should remain limited, with mainly passing showers and
very localized afternoon convection. Fewer clouds, warm low-level
temperatures, and sufficient low-level humidity will maintain an
elevated to significant heat risk, especially across coastal and
urban areas, where heat indices could approach 114 degrees.
Strengthening trades will also lead to deteriorating marine and
coastal conditions late in the week, with building seas and an
increasing rip current risk.

Forecast confidence decreases late in the period as NHC continues
to monitor multiple disturbances across the central and eastern
tropical Atlantic. Guidance suggests that one of these systems
could approach the northeastern Caribbean early next week, but
considerable uncertainty remains regarding its track, strength,
timing, and any potential local impacts. Therefore, the forecast
for Monday and beyond may change depending on how these systems
evolve.


&&

.AVIATION...
(06Z TAFS)
Issued at 210 AM AST Mon Aug 10 2026

Mainly VFR conditions expected across all terminals during the next
24 hours. HZ will persist, with VSBY occasionally around 6SM. SHRA
expected at TJSJ/TIST/TISX after 10/23Z. VCTS possible at TJBQ during
the afternoon. SFC winds 8-10 kt early, increasing to 15-20 kt after
10/13Z and continuing through around 10/23Z.


&&

.MARINE...
Issued at 210 AM AST Mon Aug 10 2026

The Atlantic ridge will maintain moderate to locally fresh
easterly winds today, with choppy seas occasionally reaching
around 6 feet. Winds and seas should ease somewhat Tuesday as the
pressure gradient relaxes. A tropical wave crossing the eastern
Caribbean Tuesday into Wednesday will increase the potential for
showers and thunderstorms over the local waters. Winds will begin
increasing again Wednesday night as the pressure gradient tightens
behind the wave, with increasingly hazardous conditions for small
craft expected Thursday into Friday. Easterly winds could reach 20
to 25 knots, with seas building to around 6 to 9 feet late in the
workweek.


&&

.BEACH FORECAST...
Issued at 210 AM AST Mon Aug 10 2026

A moderate risk of rip currents will continue today along the
northern, eastern, and southeastern beaches of Puerto Rico, as
well as Vieques, Culebra, and St. Croix. The risk should gradually
decrease, with low-risk conditions becoming more widespread
Tuesday night into Wednesday. Even under a low risk, life-
threatening rip currents remain possible near groins, jetties,
reefs, and piers.

The rip current risk is expected to increase again to moderate
across more beaches Thursday as easterly winds and seas increase,
with a high risk possible Friday into the weekend. Heat will
remain an important beach hazard through the period, while Tuesday
will have the greatest potential for dangerous cloud-to-water
lightning as shower and thunderstorm activity increases. Saharan
dust and haze will persist in pulses through the period.


&&

.FIRE WEATHER...
Issued at 210 AM AST Mon Aug 10 2026

Elevated fire danger is expected today as very dry and stressed
fuels combine with a warmer and drier air mass moving into Puerto
Rico behind the departing tropical wave. Saharan air, limited
cloud cover, and little to no rainfall will favor additional
drying of fine fuels, while afternoon sea-breeze enhancement will
support winds of 15 to 20 mph with locally higher gusts,
increasing the potential for rapid fire spread where ignitions
occur. Refer to the Fire Danger Statement for additional details.


&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...Heat Advisory from 10 AM this morning to 4 PM AST this afternoon
     for PRZ001>005-007-008-010>013.

     Fire Danger Statement from 10 AM this morning to 4 PM AST this afternoon
     for PRZ014>016-018-019-024-027.

VI...Heat Advisory from 10 AM this morning to 4 PM AST this afternoon
     for VIZ001-002.

AM...None.
&&

$$

EVE...LIS/MRR
MID...ICP

NWS SJU Office Area Forecast Discussion