textproduct: San Juan

KEY MESSAGES

Issued at 241 AM AST Thu Jul 2 2026

* Warm to hot conditions will continue through the next several days, with heat indices reaching or exceeding 100F across urban and low-lying areas of the islands.

* Low concentrations of Saharan dust will persist through early Friday before increasing again for the 4th of July holiday.

* Expect limited to elevated flooding associated with the shower activity expected across western to northwestern PR.

* Winds are expected to increase over the weekend, accompanied by building seas. As a result, the risk of rip currents is expected to increase to moderate along most beaches across the islands.

Short Term(Today through Saturday)

Issued at 241 AM AST Thu Jul 2 2026

Overnight conditions remained generally quiet, with only a few passing showers over the local waters. Low temperatures ranged from the low 80s to upper 70s across the coastal areas and into the 70s across the mountains. Winds remained light, generally between 5 and 10 mph.

Today, expect light Saharan Dust concentrations maintaining slightly hazy skies. Meanwhile, moisture will remain near seasonal levels, with precipitable water values ranging between 1.40 and 1.80 inches. A lingering upper-level cut-off low just north of the region will continue to provide modest instability, while surface high pressure over the central Atlantic maintains east- southeasterly winds of 15 to 20 mph. The primary weather concerns today will be excessive heat and limited to elevated afternoon flooding. Mostly sunny skies and east-southeasterly winds will allow temperatures to climb into the upper 80s and lower 90s across coastal and urban areas, resulting in heat index values at or above 105F. Brief trade wind showers will move across the windward coasts during the morning, followed by scattered showers and isolated thunderstorms across the interior and western to northwestern municipalities of Puerto Rico during the afternoon. Daytime heating, sea-breeze convergence, and the nearby upper- level low will support this activity, with locally heavy rainfall leading to ponding of water on roads, urban flooding, and isolated small-stream flooding. In contrast, eastern Puerto Rico and the U.S. Virgin Islands are expected to receive little more than isolated passing showers.

On Friday, weather conditions will remain similar, although Saharan dust concentrations will gradually increase late in the day. By Saturday, a thicker dust plume will overspread the islands, producing hazier skies and a more stable environment that should limit shower coverage. Even so, isolated afternoon showers remain possible over western Puerto Rico due to local effects, while hot conditions continue across the coastal and urban areas.

Long Term(Sunday through Thursday)

Issued at 241 AM AST Thu Jul 2 2026

Moderate to possibly high concentrations of Saharan dust will continue to filter over the islands through at least late Wednesday. Nevertheless, a transition from relatively dry and hazy conditions to a more humid, unstable but still hazy tropical pattern is forecast. A surface high pressure over the central Atlantic will maintain generally southeasterly winds (becoming breezier as the period continues), while a lingering upper-level cut-off low will continue to linger through next mid-week providing modest instability through the period. To start the week, shallow moisture and a plume of Saharan dust will promote hazy skies, hot conditions, and limited rainfall. However, brief morning showers over eastern Puerto Rico and isolated afternoon showers and t-storms across the western interior and northwestern Puerto Rico remain possible due to local effects and daytime heating. Patches of moisture will continue to filter in over the area on Tuesday, increasing precipitable water (PWAT) values to high end normal and above normal values. This increasing moisture will support more active afternoon convection across western and northwestern Puerto Rico, however moderate to locally high concentrations of Saharan Dust continue to be forecast. By late Tuesday and Wednesday, a tropical wave is expected to bring another surge of tropical moisture (keeping PWAT above normal), which, along with favorable upper-level dynamics, will increase widespread showers and isolated thunderstorms. This can result in localized ponding of water on roads and in poor drainage areas. However, concentrations of Saharan Dust will continue to filter over the region. Conditions will once again dry out on Thursday, however a brief window with less concentrations of Saharan Dust is forecast, giving way to a more typical summer pattern. Warm to hot conditions will persist throughout the period 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 241 AM AST Thu Jul 2 2026

Mostly VFR conds across all TAF sites. Afternoon TSRA may result in VCSH/VCTS at TJBQ aft 02/17 thr 02/23Z. 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 02/23Z.

MARINE

Issued at 241 AM AST Thu Jul 2 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, with locally choppy conditions 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.

BEACH FORECAST

Issued at 241 AM AST Thu Jul 2 2026

The risk of rip currents will remain low through Friday before gradually increasing to moderate across many exposed local beaches this weekend as 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, leading to hazy skies and reduced air quality. Hot daytime conditions and isolated afternoon thunderstorms near the northwestern beaches of Puerto Rico will also be possible.

FIRE WEATHER

Issued at 241 AM AST Thu Jul 2 2026

Low fire weather threat for today.

SJU WATCHES/WARNINGS/ADVISORIES

PR...None. VI...None. AM...None.