textproduct: San Juan

KEY MESSAGES

Issued at 335 PM AST Tue Nov 10 2026

- A high risk for life-threatening rip currents will continue through late tonight, becoming moderate by tomorrow through the weekend.

- Moisture content at low-levels, diurnal heating and topographic effects will still support shower and thunderstorm development over the next few days, mainly over north to northwestern Puerto Rico each afternoon.

- Sensitive individuals should remain hydrated and seek indoors during peak daytime heating hours, as the excessive heat risk will increase to moderate levels later this week into the weekend.

Short Term(This evening through Thursday)

Issued at 335 PM AST Tue Nov 10 2026

Additional activity is expected this afternoon mainly over northern to northwestern portions of Puerto Rico. A mid- level ridge building aloft will promote more subsidence and drier air in the mid-levels through the short-term period. However, precipitable water values will remain seasonal with the highest concentration at the low-levels. This combined with increased diurnal heating due to clearer skies expected during the morning, and terrain effects will promote shower and isolated thunderstorm development each afternoon over the north to northwest region, driven by a predominant S-SE wind flow. Meanwhile, passing showers during the morning are still possible over the windward areas. Winds are expected to increase in speed on Wednesday onwards due to a local pressure gradient tightening caused by a surface high pressure system. This could limit high rainfall accumulations, as the wind flow will promote faster-moving showers. Nonetheless, there's an 80% chance of 24-hour precipitation exceeding 0.5 inches mainly over north/northwestern Puerto Rico on Thursday.

Given these conditions, the potential for excessive rainfall will be present each afternoon, mainly towards northwestern Puerto Rico. This will pose a threat of ponding of water over roadways and poorly drained areas, along with isolated urban and small stream flooding. In addition, landslides should not be ruled out due to saturated soils from previous days' activity. Additionally, above-normal 925 mb temperatures, seasonal moisture content at low-levels, and low cloud cover could trigger hot and humid conditions, which will increase heat indices over the next few days to levels that affect most individuals sensitive to heat. Thus, these individuals are encouraged to remain hydrated and seek cooler areas during peak daytime heating hours.

Long Term(Friday through next Monday)

Issued at 335 PM AST Tue Nov 10 2026

A mid-level ridge establishing over northeastern Caribbean late this weekend should promote more stable conditions over the weekend. As a result, warming temperatures at the mid-levels (500mb), with a 80% chance of exceeding -6 degrees Celsius each afternoon until early next weekend, could promote subsidence and stability aloft. In addition, a surface high pressure will increase the local pressure gradient, strengthening winds from the S-SE. This pattern will extend into early next week, and while more stable conditions are expected, low-level moisture and local effects should enhance shower and isolated thunderstorm activity each afternoon mainly towards the interior to northwest region, driven by a predominant S-SE wind flow. Deeper convection is expected on Friday, with more shallow convection expected for the rest of the period. However, the probability of rainfall accumulations exceeding at least 0.5 inches in 24 hours remain below 30% on Friday until Monday, suggesting that we could see less intense downpours during this period. By Tuesday, a disturbance will drag moisture into the islands, increasing the chance of exceeding 0.5 inches of rainfall to 40-50%.

The highest flooding potential is expected on Friday, mainly towards northwestern/northern Puerto Rico. This will pose a threat of flooding impacts. Additionally, with a S-SE wind flow, seasonal moisture content in the low-levels, and minimal cloud cover could trigger hot and humid conditions, especially during the weekend, likely to increase heat indices to levels that affect most individuals sensitive to heat. Therefore, they are encouraged to stay hydrated and cool during peak daytime heating hours.

AVIATION

(18Z TAFS) Issued at 335 PM AST Tue Nov 10 2026

Mainly VFR conditions to prevail through the period. -SHRA/SHRA developing across sectors of northern PR, with VCTS mainly affecting TJBQ. This pattern can persist through 10/22Z. Surface winds should range between 4 to around 12 kts with higher gusts, sea breeze variations, and an ESE background flow, through 10/22Z. Winds decreasing after 10/22Z, before picking up again after 11/13Z to up to around 8 to 13 kts from the ESE with sea breeze variations and local effects.

MARINE

Issued at 335 PM AST Tue Nov 10 2026

A northerly swell will maintain elevated seas up to 4 to 5 feet across the Atlantic waters and local passages through at least Wednesday. Elsewhere, seas across the Caribbean waters will generally remain at 1 to 3 feet. A surface high pressure moving through the Central Atlantic will tighten the local pressure gradient, promoting an increase from light to gentle winds today, becoming moderate to locally fresh by Wednesday onwards. This will cause choppy seas across most local waters through early weekend. Showers and isolated thunderstorms may produce locally higher winds and seas.

BEACH FORECAST

Issued at 335 PM AST Tue Nov 10 2026

The ongoing swell will continue to promote hazardous swimming conditions through tomorrow morning along the north-facing and exposed beaches of Puerto Rico and Culebra. This will continue to produce life-threatening rip currents in the surf zone. A moderate-to-limited risk for life-threatening rip currents will persist through the remainder of the forecast period. Beachgoers should exercise caution when swimming at the beach and remain updated with the latest forecasts as they become available.

Showers and thunderstorms will remain a concern each afternoon especially along the northern and northwestern beaches of Puerto Rico. If you hear thunder seek shelter immediately.

SJU WATCHES/WARNINGS/ADVISORIES

PR...High Rip Current Risk through late tonight for PRZ001-002-005- 008-010-012.

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