textproduct: San Juan

KEY MESSAGES

Issued at 343 AM AST Tue Nov 10 2026

- Locally induced afternoon showers and isolated thunderstorms are expected to develop each day over the interior and northern sections of Puerto Rico.

- Across the U.S. Virgin Islands, fair weather conditions will prevail for most of the week. Warm to hot temperatures are expected with daily highs ranging from the upper 80s to low 90s.

- Northeasterly swells will maintain a high rip current risk for the north-facing beaches of Puerto Rico through late tonight/early Wednesday morning. - Southerly winds will promote warm to hot conditions during the second part of the week.

Short Term(Today through Thursday)

Issued at 343 AM AST Tue Nov 10 2026

Recent surface analyses and the latest global model guidance indicate that surface high pressure will remain the dominant synoptic feature over the western and central Atlantic through Thursday. This positioning will maintain a moderate east to southeast trade wind flow across the northeastern Caribbean. In the lower levels, weak perturbations embedded within this southeasterly flow will traverse the region, providing subtle forcing. Recent satellite-derived moisture data and sounding climatology highlight a humid airmass entrenched over the islands, with precipitable water values generally hovering between 1.90 and 2.20 inches. Moisture levels will remain from normal to slightly above normal, providing sufficient fuel for showers today.

Although moisture content will fluctuate during the rest of the period, a building ridge aloft should promote overall stable conditions and drier air aloft. However, sufficient moisture at the lower levels of the atmosphere will set the stage for a fairly typical, diurnally driven precipitation pattern. During the overnight and early morning hours, patches of low-level moisture will be advected across coastal areas, bringing passing showers to the U.S. Virgin Islands and the eastern and southeastern coastal plains of Puerto Rico. By the afternoon hours, daytime heating combined with local topographical effects and sea breeze convergence will aid in more concentrated convective development focused over the interior and western to northwestern quadrants of Puerto Rico. While significant instability is not anticipated, this afternoon convection can support localized heavy rainfall. Consequently, isolated instances of urban and small stream flooding, as well as minor water accumulation on roadways, will remain the primary weather hazards each afternoon.

Long Term(Friday through Tuesday)

Issued at 343 AM 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 40-45%.

The highest flooding potential is expected on Friday, mainly towards northwestern/northern 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. 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

(06Z TAFS) Issued at 343 AM AST Tue Nov 10 2026

Mainly VFR conditions are expected to prevail across all terminals during the next 24 hours. However, locally induced SHRA/TSRA may develop in and around TJSJ/TJBQ btw 10/16-22z and cause tempo MVFR conditions. Weak SSE winds up to 10 knots with sea breeze variations expected aft 10/13z.

MARINE

Issued at 343 AM AST Tue Nov 10 2026

The northerly swell will continue to maintain seas of 4 to 5 feet across the offshore Atlantic waters today. Meanwhile, another northerly swell is expected to reach the Atlantic waters later today, maintaining elevated seas 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. Light to gentle winds will prevail today before increasing to moderate from Wednesday onward. Showers and isolated thunderstorms may produce locally higher winds and seas.

BEACH FORECAST

Issued at 343 AM AST Tue Nov 10 2026

Energy from the ongoing northerly swell will continue to produce hazardous swimming conditions along the northern exposed beaches of Puerto Rico and Culebra. Another pulse of northerly swell is expected to arrive later today, prolonging hazardous surf zone conditions. Therefore, the high risk of rip currents has been extended through at least early Wednesday morning for the affected beaches. A moderate risk of rip currents will continue along the beaches of Vieques and the U.S. Virgin Islands. Continue to monitor the forecast for additional updates.

Thunderstorms will remain an additional beach hazard, particularly during the afternoon hours. If thunder is heard, 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.