textproduct: San Juan

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.