textproduct: San Juan

KEY MESSAGES

Updated at 114 PM AST Wed Jun 3 2026

- Showers, will continue to affect the eastern half of Puerto Rico, as well as the northwestern areas of PR through this evening.

- Warm-to-hot conditions are expected to continue over the next few days across the islands, with an elevated heat risk persisting, particularly at the lower elevations and urban areas of western and northern PR.

- A small northerly swell and persistent SE winds will promote a moderate risk of rip currents across most beaches of the islands through Thursday.

- Moderate concentrations of Saharan dust will return Thursday, promoting hazy skies, reduced visibility, and poor air quality.

Short Term(This evening through Friday)

Issued at 114 PM AST Wed Jun 3 2026

Today, conditions remained generally calm during the morning hours, with a few passing showers filtering across eastern Puerto Rico, Culebra, and Saint Croix, although rainfall accumulations were minimal. During the afternoon hours, streamer activity developing from Culebra, Vieques, and the U.S. Virgin Islands affected portions of the San Juan metropolitan area. Temperatures remained in the upper 80s across most coastal and urban areas, while western Puerto Rico observed temperatures reaching into the low 90s under mostly clear skies through the early afternoon hours. Heat indices stayed in the upper 90s to around 100 degrees Fahrenheit across urban and coastal areas. Additional showers with lightning are expected to develop across the interior and northwestern sections of Puerto Rico as diurnal heating, local effects, and a moisture patch moving across the region supported convective development.

By Thursday into Friday, conditions are expected to become drier once again as another moderate Saharan Air Layer plume filters into the northeastern Caribbean. NASA dust aerosol guidance continues to indicate increasing concentrations of suspended dust particles across the local islands, resulting in hazy skies, reduced visibility, and deteriorating air quality conditions. At the same time, a notable drying trend is forecast and precipitable water values decreasing to around 1.30 inches, below normals for early June. Consequently, shower activity will become more limited and mainly confined to brief trade wind showers across eastern Puerto Rico and the U.S. Virgin Islands, along with isolated afternoon convection over western Puerto Rico.

Warm to hot conditions will persist through the forecast period as moderate east to east-southeasterly winds continue under the influence of surface high pressure near the Azores and frontal systems over the western Atlantic. With limited cloud coverage and reduced rainfall activity expected later this week, daytime heat indices are forecast to exceed 100 degrees Fahrenheit across urban and coastal areas, maintaining a limited to elevated heat risk. Residents, particularly those sensitive to poor air quality or heat-related impacts, should continue to take precautions as hazy skies and above-normal temperatures return by Thursday and Friday.

Long Term(Saturday through next Tuesday)

Issued at 114 PM AST Wed Jun 3 2026

During the long-term period, surface high pressure will continue to dominate across the Atlantic, promoting an east to east-southeast wind flow across the local region at 10 to 18 mph, with higher gusts, particularly near coastal areas. Latest model guidance suggests precipitable water (PWAT) values will gradually increase on Saturday, reaching near-seasonal levels of around 1.5 to 1.6 inches. Conditions aloft will become slightly more favorable for thunderstorm development as mid-level temperatures cool to near- seasonal values of -6 to -7 degrees Celsius, supported by an upper- level trough building northwest of the region. Combined with daytime heating and local effects, the near-seasonal moisture could support the development of afternoon showers across northwestern Puerto Rico.

By Sunday, model guidance indicates that moisture associated with a tropical wave will move into the region, with PWAT values increasing to between 1.75 and nearly 2.0 inches. This will enhance the potential for frequent showers across the area, particularly over windward areas during the morning hours, followed by scattered to numerous showers and isolated thunderstorms across western Puerto Rico during the afternoon. As a result, the potential for ponding of water on roadways and in poorly drained areas will increase, consistent with a limited flood risk highlighted in that area, continue to monitor the forecast for updates. Following the passage of the tropical wave, a drier air mass is expected to filter into the region by the beginning of the workweek, bringing PWAT values back to near-seasonal levels. This pattern will support generally fair weather conditions during the morning hours, followed by increased afternoon shower activity across western Puerto Rico. The U.S. Virgin Islands will remain under mostly fair weather conditions, with warm temperatures prevailing.

Additionally, moderate concentrations of Saharan dust are expected to persist through much of the period, resulting in hazy skies, reduced visibility, and deteriorated air quality. In terms of temperatures, warm to hot conditions will persist on most days, with limited to elevated heat risks continuing, particularly at lower elevations and in urban areas. Residents and visitors are encouraged to stay hydrated and limit prolonged sun exposure during the peak heating hours of the day.

AVIATION

(18Z TAFS) Issued at 114 PM AST Wed Jun 3 2026

VFR conditions across all TAF. However, brief MVFR contd possible over TJSJ and TJBQ. SHRA and VCTS possible thru 03/22z. Iso -TSRA cannot be ruled out near TJBQ during this period. Winds will continue ESE decreasing to around 10 kt overnight, increasing once again 04/12Z with stronger gusts and sea breeze variations.

MARINE

Issued at 114 PM AST Wed Jun 3 2026

A broad surface high pressure over the central Atlantic will continue to result in moderate to fresh east to southeast winds, which will then result in choppy seas across the regional waters throughout the week. The small northerly swell over the local waters will continue gradually subsiding, tonight and tomorrow, Thursday, however additional small pulses are forecast to arrive throughout the workweek. Seas near coastal areas should remain between 2 and 4 feet (occasionally higher), offshore Atlantic waters should remain between 5 and 6 feet (occasionally higher); small craft must exercise caution. A surge of moisture will continue to promote an increase in shower activity over the local waters today. This surge of moisture will gradually move away from the region later tonight and another pulse of moderate concentrations of Saharan Dust is expected to move over the region tomorrow.

BEACH FORECAST

Issued at 114 PM AST Wed Jun 3 2026

Up to a moderate risk of rip currents (life-threatening rip currents are possible in the surf zone) will persist across the majority of exposed beaches of the islands through this evening. The small northerly swell over the local waters will continue gradually subsiding, tonight and tomorrow, Thursday, however additional small pulses are forecast to arrive throughout the workweek. Up to breezy winds will continue during the next few days, prompting a persisting moderate risk of rip currents over the northern and eastern exposed beaches of Puerto Rico, as well as for the beaches of the local islands throughout the rest of the workweek and into the next weekend. Besides rip currents, beachgoers sensitive to Saharan Dust particles should follow medical recommendations, as moderate concentrations will return tomorrow, Thursday, through at least early next week.

FIRE WEATHER

Issued at 114 PM AST Wed Jun 3 2026

The fire weather threat for today remains low, meaning some isolated fire conditions remain possible, particularly over the southern coastal areas of PR.

SJU WATCHES/WARNINGS/ADVISORIES

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