textproduct: San Juan

KEY MESSAGES

Issued at 208 AM AST Fri Oct 30 2026

* Another active afternoon expected for the interior and western Puerto Rico. There is a risk for urban and small stream flooding and frequent lightning.

* Showers activity is expected to increase late Saturday and Sunday, but the confidence in how strong or widespread the showers may be has decreased since yesterday.

* Hot conditions will persist across the islands, with a level of heat that mainly affects those individuals that are extremely sensitive, outdoors and without adequate hydration.

Short Term(Today through Sunday)

Issued at 208 AM AST Fri Oct 30 2026

The night was mostly tranquil for the area, with only a few showers reaching the Virgin Islands at times. Skies were clear across Puerto Rico. Temperatures dropped to the low 80s and upper 70s in coastal areas, and near 60 in the Cordillera Central.

The most recent satellite-derived precipitable water product shows that, while there is still plenty of moisture around, an area of slightly drier air is filtering in. At the surface, there is also a weak disturbance moving just south of the local islands. Aloft, the axis of a trough is centered just north of Venezuela. Also, a surface high pressure will maintain the surface winds from the southeast today and tomorrow, at 9-13 kts, and from the east on Sunday. For today, while conditions are not as favorable for convection as yesterday, local effects should still trigger showers and thunderstorms across the interior and west in the afternoon. There is a risk for urban and small stream flooding, as well as frequent lightning activity. Passing showers are expected elsewhere, including the Virgin Islands.

For the weekend, the trough centered just to the north of Venezuela will lift moisture from the Caribbean Sea, especially at the mid levels. While this set-up will usually result in significant shower activity, there is going to be dry air intrusion at the lower levels and plenty of clouds at the upper levels. Compared to yesterday, the confidence in the forecast has decreased. However, the probability of precipitation was left at 50-70%, since at least some showers are expected to reach the islands during this period. For now, the period with the higher chance of showers is from Saturday late afternoon into the early morning hours of Sunday. After that, another slot of dry air is expected to filter in, and rain should be mainly focused in the interior and west portions of Puerto Rico.

In terms of heat, 925 mb temperatures remain above normal, by nearly one standard deviation. Heat indices in general should range from 102 to 107 degrees, although isolated areas could observed higher indices. Regardless, the users are advised to take plenty of breaks from outdoor activities and to stay hydrated.

Long Term(Monday through Friday)

Issued at 208 AM AST Fri Oct 30 2026

The forecast remains on track with a wet and humid pattern expected through the long-term period. Abundant moisture will promote unsettled weather and the potential for shower activity. Precipitable water values will remain above normal for this time of year, sitting at the 75th percentile for November and ranging between 2.00 and 2.40 inches through much of the period.

At the surface, a high-pressure system migrating from the U.S. East Coast into the central Atlantic will maintain an easterly to southeasterly wind flow. By Wednesday, winds will gradually shift to the south-southeast. Late Wednesday into Thursday, an upper-level trough to the west of the islands will cause the local pressure gradient to relax, resulting in a weak, southerly wind flow.

From Tuesday onward, guidance indicates a gradual warming of mid- level temperatures at 500 mb, which should limit the development of thunderstorms across the region. However, as winds become light by midweek, any developing showers will be slow-moving. This will increase the risk of localized flooding, particularly across portions of central and northern Puerto Rico during the afternoon hours. Confidence in the overall rainfall coverage and intensity remains uncertain, as upper-level dynamics may become less favorable and afternoon convection will heavily depend on lingering cloud cover and the amount of daytime heating. Overall, a typical diurnal weather pattern is expected. Passing showers will move across the U.S. Virgin Islands and eastern to southeastern Puerto Rico during the overnight and morning hours. During the afternoons, convection will develop across the interior, western, and northern portions of Puerto Rico, with localized showers and streamers developing downwind of El Yunque and the local islands on most days. Periods of heavy rainfall could lead to urban and small stream flooding and quick river rises.

At the 925 mb level, temperatures will remain above normal through most of the period. The warmest days are expected by midweek, as the southeasterly to southerly winds brings in deeper moisture. This combination will result in warm conditions and elevated heat indices across the region. Residents and visitors are encouraged to stay hydrated and continue monitoring the forecast for updates as model guidance becomes more consistent.

AVIATION

(06Z TAFS) Issued at 208 AM AST Fri Oct 30 2026

Mainly VFR conditions expected to prevail through at least 17Z. Passing SHRA will persist across the local waters, but with little to no impacts to operations. SHRA and TSRA are expected again along the Cordillera Central and western Puerto Rico. Mountain obscuration is expected. For TJBQ, reduced VIS and low ceilings expected from 17-22Z. Winds are from the SE at 9-13 kts with stronger gusts and sea breeze variations from 14-22Z.

MARINE

Issued at 208 AM AST Fri Oct 30 2026

A surface high pressure over the central Atlantic will continue to promote moderate east to southeasterly winds across the regional waters over the next few days. Meanwhile, the long-period northerly swell affecting the local waters is expected to gradually subside today. Nevertheless, choppy conditions may persist across portions of the offshore waters and local passages.

Scattered showers and isolated thunderstorms are expected to develop during the afternoon hours, particularly over the waters north and west of Puerto Rico. These showers and thunderstorms may produce locally gusty winds and brief periods of reduced visibility.

BEACH FORECAST

Issued at 208 AM AST Fri Oct 30 2026

There is a moderate risk of rip currents along the northern beaches of Puerto Rico and Culebra, as well as the U.S. Virgin Islands, today and through the weekend. This means life-threatening rip currents are possible in the surf zone. Beachgoers should remain cautious.

Additionally, the ongoing period of exceptionally high tides will continue through at least today. Localized coastal flooding will remain possible around the time of high tide, particularly along susceptible, low-lying shorelines, with the highest tide expected late this morning.

Lastly, afternoon showers and thunderstorms remain in the forecast. If you hear thunder, seek shelter immediately inside a sturdy building.

SJU WATCHES/WARNINGS/ADVISORIES

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