textproduct: San Juan

KEY MESSAGES

Issued at 249 PM AST Thu Nov 13 2025

* Dangerous coastal conditions through Friday due to hazardous breaking waves and life-threatening rip currents along the north-facing beaches of Puerto Rico and the northern US Virgin Islands.

* The US Virgin Islands can expect occasional showers each day, followed by afternoon activity downwind from the islands.

* Puerto Rico will experience afternoon showers and thunderstorms each day, increasing the potential for flooding rains during the weekend.

Short Term(This evening through Saturday)

Issued at 249 PM AST Thu Nov 13 2025

Tonight through Saturday

The mid-to-upper-level trough approaching the islands weakened the mid-to-upper-level ridge, resulting in scattered showers that initially affected the local waters, then moved inland, crossing the US Virgin Islands and impacting the windward locations of Puerto Rico. Then, showers developed along the interior and western PR around noon onward. Maximum temperatures ranged from the mid-80s to the low 90s along coastal areas and the low 80s in the mountains. Winds were predominantly from the east, with speeds ranging from 5 to 15 mph, and higher gusts and variations in the sea breeze.

The mid-to-upper-level ridge will slowly weaken as an upper- level trough approaches from the northwest to the Northeast Caribbean. This will increase the probability of afternoon convection (50 percent to 70 percent) of one or two thunderstorms. At the surface, a frontal boundary will linger north to northwest of the islands, extending from the western Caribbean to the Central Atlantic, weakening the steering winds, especially Friday into the weekend.

According to the weather pattern outlined above, we anticipate an increase in the potential for unstable weather patterns due to the approaching upper-level trough and the proximity of a frontal boundary, especially during the afternoon hours. However, a drier air mass moving across the islands will result in a mixture of sunshine and clouds on Friday, followed by a moderate to high chance (50-70 percent) of afternoon convection, with a slight to moderate chance of urban and small stream flooding. As the frontal boundary lingers north of the islands and the trough amplifies aloft, the potential for moderate to high showers and thunderstorms will continue, especially on Saturday afternoon and night.

Long Term(Sunday through next Wednesday)

Issued at 249 PM AST Thu Nov 13 2025

A polar trough will escort a cold front near the area on Sunday, increasing moisture across the region. Ahead of the front, high pressure centered over the eastern Atlantic will drive the trade winds from the south at speeds of only 3 to 4 kts. So far, the global models only indicate precipitable water values near normal levels, and also quite a large dew point depression in the mid levels. This means that a widespread rainfall event is not expected. However, some showers will reach the islands at times. Also, the heaviest activity is expected to develop along the interior of Puerto Rico due to local effects.

As the front dissipated north of the region, a short wave trough in the upper levels will move into the region. This will cause mid- levels temperatures to cool down, increasing instability aloft. Moisture levels will not be impressive though, but should be enough to see a few thunderstorms developing each afternoon along the interior and western Puerto Rico. The risk of flooding is low at this time, although isolated urban and small stream flooding cannot be ruled out.

By the end of the week, another trough digs from the northeast. A surface reflection of this trough will change the winds from the northeast, at speeds of 10 to 15 mph. The islands are not expected to be in the most favorable area for deep convection to develop, but the frequency of passing showers could increase for portions of northeast Puerto Rico, as well as for the Virgin Islands.

AVIATION

(18Z TAFS) Issued at 249 PM AST Thu Nov 13 2025

VFR conds should prevail across all TAF sites during the prd. San Juan Streamer and aftn conv will promote VCTS across JSJ, JPS, and JBQ from 13/18z, may reduce CIGs/VIS. Wind will become lighter from the E- ENE by 1323z, btwn 5 - 6 kt, calmer at JPS. Winds should increase once again btwn 8 - 11 kt by 14/13 - 14/14z.

MARINE

Issued at 249 PM AST Thu Nov 13 2025

Dangerous marine conditions will continue due to a north- northwesterly swell moving across the local Atlantic Waters and Caribbean Passages. Conditions are expected to gradually improve tomorrow. A frontal boundary will linger northwest of the islands, extending from the western Caribbean into the Central Atlantic through the workweek. Therefore, expect moderate to locally fresh winds through today, becoming light to gentle from Friday into the weekend, as a pre-frontal trough forms near the islands.

BEACH FORECAST

Issued at 249 PM AST Thu Nov 13 2025

A long-period northwesterly swell will result in hazardous breaking waves and life-threatening rip currents along the north- facing beaches in PR and St Thomas, St John, and the Adjacent Islands. Thus, a High Surf Advisory and the High Risk of Rip Currents will continue through late Thursday night. Conditions will slowly improve tomorrow as the wave energy dissipates, leaving a moderate risk of rip currents for Friday.

SJU WATCHES/WARNINGS/ADVISORIES

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

High Surf Advisory until midnight AST tonight for PRZ001-002-005- 008-010.

VI...High Rip Current Risk through late tonight for VIZ001.

AM...Small Craft Advisory until 6 AM AST Friday for AMZ711-712-716.

Small Craft Advisory until 6 PM AST this evening for AMZ741-742.