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

838
FXCA62 TJSJ 081832
AFDSJU

Area Forecast Discussion
National Weather Service San Juan PR
232 PM AST Sat Aug 8 2026

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

.KEY MESSAGES...
Issued at 208 PM AST Sat Aug 8 2026

- A Heat Advisory remains in effect through 5 PM for the lower
  elevations of Puerto Rico and the US Virgin Islands.

- Elevated fire weather conditions may persist for the next few
  days across southern and southwestern Puerto Rico due to
  critically dry fuels, low relative humidity, and breezy
  conditions.

- Moderate to high concentrations of Saharan Dust will persist
  through Monday. Sensitive groups must follow medical
  recommendations.

- Limited rainfall is expected for the next several days,
  allowing drought conditions to continue worsening across Puerto
  Rico and the U.S. Virgin Islands.

&&

.Short Term(This evening through Monday)...
Issued at 208 PM AST Sat Aug 8 2026

A stable and overall dry/hazy air mass will remain in place
through Monday across the northeastern Caribbean. The 8/12z upper
air sounding indicated a significant drying trend, with
precipitable water values dropping well below normal seasonal
values to 1.20 inches. Dry air in the mid-levels accompanied by a
persistent trade wind cap will prevent deep vertical cloud
development across most of the area. While brief, isolated trade
wind showers cannot be completely ruled out across the waters
between the islands and localized in western Puerto Rico this
afternoon, overall rainfall accumulations will remain minimal
through the rest of the weekend. However, a weak tropical wave is
expected to move across the Caribbean waters through Sunday, which
could enhance the typical diurnal cycle of early morning passing
showers across windward areas, and shallow afternoon convection
over western PR.

Even though moisture is expected to increase briefly in the low
levels of the atmosphere, the primary feature dominating the
environment will be a dense intrusion of the Saharan Air Layer.
Aerosol tracking models and satellite aerosol observations show
dust concentrations peaking on Sunday and lingering through Monday
evening, bringing thick haze and reduced visibility across the
region. Light cloud cover combined with strong solar radiation and
warm low-level temperatures will drive daytime highs into the
upper 80s and lower 90s. When combined with coastal surface
humidity, afternoon heat indices will reach 102F to 108F or higher
along urban and coastal areas, increasing the heat threat once
again for prolonged outdoor activities. In addition, the dust
event will reduce air quality, making outdoor activities hazardous
for sensitive groups with respiratory conditions.

&&

.Long Term(Tuesday through next Friday)...
Issued at 208 PM AST Sat Aug 8 2026

Weather conditions during the long-term period will turn more
variable with the arrival of a wind surge and a tropical wave across
the CWA. On Tuesday, a surface high pressure anchored over the
Central Atlantic will maintain easterly winds, pushing a weak wind
surge in the 700 to 500 mb layer across the area. Precipitable water
values are forecast by the GFS and ECMWF to range between 1.6 and
1.8 inches, which will be enough moisture to enhance afternoon
convection along the western sections of the islands. From late
Tuesday into Wednesday, surface winds will shift more from the
southeast due to the interaction between the Atlantic surface high
and the approaching tropical wave. The peak of this moisture field
is forecast for Wednesday afternoon, favoring a variable weather
pattern with morning to early afternoon showers along northeastern
Puerto Rico, followed by deep afternoon convection along the western
coast driven by local effects. Although rainfall accumulations of 1
to 2 inches are possible with the heaviest showers, this will not be
enough to mitigate existing drought conditions across the island.

A rapid drying trend is forecast by Thursday as a drier air mass
moves back into the region, limiting overall shower development
across the area. By Friday, global model guidance suggests another
tropical wave tracking across the Caribbean region. As of today, the
GFS keeps the bulk of the moisture moving over the Caribbean waters
south of the local area. However, given the extended time frame
of the forecast, changes to the moisture track and intensity
remain possible by the end of the period.


&&

.AVIATION...
(18Z TAFS)
Issued at 208 PM AST Sat Aug 8 2026

Mainly VFR conditions are expected to prevail across all
terminals. Moderate to high concentrations of Saharan dust will
promote hazy conditions across all terminals through the rest of
the weekend, and VSBY could drop to 6SM. The 08/12z TJSJ sounding
indicated ESE winds up to 26kt blo FL050.

&&

.MARINE...
Issued at 208 PM AST Sat Aug 8 2026

A broad surface high over the Atlantic will maintain moderate to
fresh easterly winds throughout the weekend into early next week.
Marine conditions will become increasingly choppy, with the highest
risk for hazardous conditions Sunday into Monday, particularly
across the offshore waters and local passages. Afternoon isolated
thunderstorms may produce locally hazardous winds and seas, while
Saharan dust may reduce visibility through Monday.

&&

.BEACH FORECAST...
Issued at 208 PM AST Sat Aug 8 2026

A moderate risk of rip currents will continue along the northern and
eastern facing beaches of Puerto Rico, Culebra, Vieques and St.
Croix into early next week. A low risk will return on Wednesday
across most beaches, before increasing to moderate Thursday and
potentially high Friday into next weekend as easterly winds
strengthen significantly.

Heat will remain the primary beach hazard this weekend, while
isolated afternoon thunderstorms over western Puerto Rico may
produce dangerous cloud-to-water lightning. A dense Saharan Air
Layer with high concentrations of dust will continue to arrive
today, promoting hazy skies and reduced visibility through early next
week.

&&

.FIRE WEATHER...
Issued at 208 PM AST Sat Aug 8 2026

Elevated fire weather conditions continue this afternoon across
southern and southwestern plains of Puerto Rico, where critically
dry fuels, extreme drought conditions and low relative humidity
values are supporting an increased risk for wildfire ignition and
spread. Relative humidity values have fallen into the low to mid 50s
across portions of the southern coastal plains with sustained east
winds of 15 to 20 mph, with higher gusts. Although isolated showers
and thunderstorms remain possible across the interior and western
sections of Puerto Rico through late afternoon, rainfall coverage
and amounts are expected to be limited and insufficient to provide
meaningful relief over the southern coastal plains, where fuels
remain critically dry.

The northern periphery of a tropical wave located over the Caribbean
waters will bring a slight increase in moisture levels over the
southern coastal plains on Sunday. However, drier conditions will
persist and combined with the ongoing rainfall deficits and
critically dry fuels will support an elevated to locally critical
fire weather threat each day across the southern and southwestern
coastal plains of Puerto Rico. Residents and visitors should
continue to avoid outdoor burning and exercise caution with
activities capable of producing sparks or open flames, as favorable
conditions for wildfire ignition and rapid spread are expected to
persist through the weekend.

&&

.SJU WATCHES/WARNINGS/ADVISORIES...
PR...Heat Advisory until 5 PM AST this afternoon for PRZ001>005-007-
     008-010>013.

VI...Heat Advisory until 5 PM AST this afternoon for VIZ001-002.

AM...None.
&&

$$

AVIATION/SHORT TERM...DSR
LONG TERM...LIS
BEACH/MARINE/FIRE...GRS

NWS SJU Office Area Forecast Discussion