textproduct: San Juan

KEY MESSAGES

Issued at 227 PM AST Thu Jul 2 2026

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

* Elevated heat risk is expected each afternoon. 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(This evening through Saturday)

Issued at 227 PM AST Thu Jul 2 2026

Another warm, hot, and humid day prevailed today, with maximum temperatures in the upper 80s and low 90s, and heat indices around 105 degrees Fahrenheit along the coast and in urban areas. Winds were mainly from the east to east-southeast at 5 to 15 mph, with higher gusts and sea-breeze variations.

The main threat for the rest of the afternoon is the warm, hot conditions, with heat indices in the upper 90s to 105 degrees Fahrenheit at most coastal and urban sites. However, the amount of heat combined with the available moisture will result in another day of showers across the interior, the north and northwest quadrants of PR, and downwind of the USVI. Isolated strong thunderstorms cannot be ruled out due to these local effects. This activity will promote a limited-to-elevated risk of flooding rain this afternoon.

The islands will continue under an advective pattern Friday and Saturday, with showers embedded in east-to-east-southeast winds each day, especially along the windward sections, and limited afternoon convection across the interior and western sections of PR and downwind from the USVI.

The US Virgin Islands and Puerto Rico will continue under a warm-to- hot weather pattern through the short term, especially from mid- morning into the afternoon, when Heat Advisories may be necessary.

Additionally, a Saharan Air Layer (SAL) will spread across the region, with moderate concentrations by Friday, becoming high from Saturday morning across the USVI, spreading to the rest of PR by Saturday afternoon. This SAL will limit rainfall while contributing to hazy skies, reduced visibility, and degraded air quality.

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

(18Z TAFS) Issued at 227 PM AST Thu Jul 2 2026

Mainly VFR conditions are expected to prevail across all terminals during the next 24 hours. However, -SHRA and -TSRA are expected to develop in and near TJBQ btw 02/18-20z, causing intermittent MVFR conds. ESE winds around 14 to 18 kts with gusts near 20 to 25 kts, below 10 kts overnight, increasing again aft 03/13-14z. VCSH at times near San Juan &USVI sites overnight and early morning.

MARINE

Issued at 227 PM AST Thu Jul 2 2026

Surface high pressure over the central Atlantic will maintain moderate east-to-east-southeasterly winds through Friday, becoming moderate to locally fresh from Saturday onward. Therefore, we can expect moderate chop, with seas becoming more choppy over the weekend. A Saharan Air Layer will gradually build through the weekend, with moderate concentrations on Friday, and high concentrations on Saturday and early Sunday. Isolated afternoon thunderstorms may develop over the northwestern coastal waters of Puerto Rico through this evening.

BEACH FORECAST

Issued at 227 PM AST Thu Jul 2 2026

The local beaches in Puerto Rico and the US Virgin Islands will have a low risk of rip currents for the rest of tonight and tomorrow. It's important to note that even at low-risk beaches, isolated, life- threatening rip currents can still occur, particularly near jetties, groins, reefs, and piers. This will prevail through at least the middle of the week. Marine guidance indicates a moderate possibility of observing life-threatening rip currents across some portions of southeast and east PR, Vieques, Culebra, St Croix, St. John, and St. Thomas, spreading to the rest of the beaches on Sunday onward as the winds increase, as well as the breaking wave action.

In addition, afternoon convection may help form one or two isolated thunderstorms across Puerto Rico and the US Virgin Islands. If you are at the beach or participating in outdoor activities, remain alert for lightning. Remember: If you can hear thunder, you are close enough to be struck by lightning. Move to a substantial building or a hard-top vehicle immediately and remain there until 30 minutes after the last rumble of thunder.

Heat-related, expect hot, humid conditions that may produce dangerous heat levels at the beaches. Stay hydrated, seek shade frequently, wear lightweight clothing, and limit prolonged sun exposure during the hottest part of the day.

FIRE WEATHER

Issued at 227 PM AST Thu Jul 2 2026

Overall, weather surface stations registered winds near or above the critical values, around 15 to 18 mph with gusts up to 24 to 28 mph. Minimum relative humidity values remained above fire critical thresholds slightly helping to reduce the fire danger. The fire weather threat remains low.

SJU WATCHES/WARNINGS/ADVISORIES

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