textproduct: San Juan

KEY MESSAGES

Issued at 213 PM AST Fri Jun 12 2026

* Mostly fair weather conditions are expected this weekend. However, showers and thunderstorms are expected this afternoon across the interior and western portions of Puerto Rico, but activity will be more localized than the previous days.

* Hot heat index values will prevail throughout the weekend, especially across urban, coastal, and lower-elevation areas.

* Saharan dust particles will continue to produce hazy skies, particularly through the weekend, though effects should lessen after tonight as concentrations diminish.

* A low fire weather risk is expected today across southern Puerto Rico and Saint Croix. Breezy and dry conditions may increase fire danger on Saturday.

* A moderate risk of life-threatening rip currents will persist along the north- and east-facing beaches of Puerto Rico and the U.S. Virgin Islands, expanding to southern Puerto Rico from Sunday into early next week as winds strengthen.

Short Term(This evening through Sunday)

Issued at 213 PM AST Fri Jun 12 2026

Partly cloudy to cloudy skies prevailed across the local area today. The most unstable portion of the upper-level trough remained well north of the region, however, a few thunderstorms developed over the surrounding waters. One of these storms moved across portions of the south-central municipalities during the morning hours, producing approximately 0.25 to locally 0.50 inches of rainfall based on radar estimates. Daytime temperatures ranged from the upper 80s to lower 90s across coastal areas of Puerto Rico and the U.S. Virgin Islands, while mountain locations remained in the lower 80s. Heat indices generally ranged from the upper 90s to lower 100s, with localized values reaching between 105 and 109 degrees. Winds were mainly from the east at 10 to 15 mph, with higher gusts and sea-breeze variations.

This afternoon, some isolated to scattered showers and thunderstorms are expected across the interior and western portions of Puerto Rico, but activity will be more localized than the previous days. From tonight onward, a drier air mass will gradually dominate the local weather pattern. A strengthening surface high- pressure system over the Atlantic will promote breezy to windy conditions through the weekend, particularly on Sunday. Aloft, the trough is expected to weaken while 500 mb temperatures gradually warm. The latest model guidance indicates precipitable water (PWAT) values decreasing to below-normal levels for this time of year, supporting a transition toward more stable atmospheric conditions.

Under this pattern, brief passing showers will remain possible across windward areas during the overnight and morning hours, followed by isolated afternoon showers across portions of northwestern and western Puerto Rico. Overall shower activity should remain limited, with little to no flood risk anticipated. Warm to hot temperatures will persist through the weekend, and an elevated heat risk is likely to continue across urban and coastal areas of Puerto Rico and the U.S. Virgin Islands.

Long Term(Monday through Friday)

Issued at 148 AM AST Fri Jun 12 2026

Some changes were introduced to the long-term forecast. As discussed in previous discussions, a surface high pressure building and lingering through most of the period, promoting E-ESE winds that will lead to breezy to locally windy conditions across the islands. Through Wednesday, drier air masses, along with minor concentrations of SAL, and patches of moisture embedded in the trades will likely move across the region, with PWAT values fluctuating mainly between 1.3 and 1.6 inches. Taking a look at the latest cross-section, the highest moisture content concentrates in the 1000 - 850 mb layer, while RH values drop to 10 - 30 % in the 700 - 500 mb layer. A mid- level ridge should linger through Wednesday, maintaining typical and slightly warmer than normal 500 mb temperatures (between -6 and -7 degrees Celsius), allowing subsidence and stability aloft. From Monday through early Thursday, isolated showers may move from time to time over windward sections, with shallow afternoon convection over portions of western/northwestern Puerto Rico. Since rainfall accumulations should remain limited, no flooding threat is expected. By late Thursday, the latest global solutions suggest an increase in moisture content, associated with a tropical wave that may move south of the CWA and a TUTT that could amplify and move closer to the region. While PWAT values should increase between 1.5 and 1.75 inches, the TUTT may cool mid-level temperatures, suppress high- level heights, and enhance vertical motion. These conditions should increase instability across the CWA, enhancing the potential of deep convection and lightning threat. Therefore, isolated to scattered showers and isolated thunderstorms may move over the windward sections by Thursday evening. Nevertheless, the highest flooding potential can be expected late Thursday night into Friday.

Typical to warmer than normal conditions can be expected through the long-term, which may increase the chance of heat indices exceeding 100 degrees Fahrenheit. Hence, the heat threat will remain limited to elevated across urban and lower elevations of the islands. Heat Advisories will be issued if required.

AVIATION

(18Z TAFS) Issued at 213 PM AST Fri Jun 12 2026

Mainly VFR conditions are present across all TAF sites. VCTS and TSRA possible across TJBQ around from 12/18Z-20Z. Low to moderate concentrations of HZ will remain present over the forecast period and could result in slight VIS reductions. ESE winds around 10-15 kts with higher gusts and sea breeze variations thru 12/22-23Z, becoming 10 kts or less overnight. Main aviation concern tomorrow will be increasing winds aft 13/13Z, expect breezy to windy conds.

MARINE

Issued at 213 PM AST Fri Jun 12 2026

Moderate east to east-southeast winds and seas of 2 to 4 feet will prevail across the regional waters through tonight. However, a strengthening surface high pressure system over the Atlantic will promote fresh trade winds and choppy marine conditions from Saturday through at least the middle of next week. Seas are expected to build to 4 to 6 feet, occasionally higher, across the regional waters and local passages. Small craft operators will be advised to exercise caution across the regional waters and local passages as seas build and trade winds strengthen. Drier air and slightly hazy skies associated with Saharan dust will persist through the weekend.

BEACH FORECAST

Issued at 213 PM AST Fri Jun 12 2026

Tonight, a moderate risk of rip currents will return to the northern beaches of Puerto Rico and Culebra.

By Saturday, winds will gradually increase, becoming breezy to locally windy. As a result, a moderate risk of rip currents will expand to most beaches of Puerto Rico, as well as Culebra, Vieques, and the U.S. Virgin Islands. A moderate risk means that life-threatening rip currents are possible in the surf zone. Beachgoers should exercise caution, always swim near a lifeguard and remember to heed the advice of the local beach patrol and flag warning systems. These conditions are expected to persist through the weekend and into at least early next week.

A low risk of rip currents will remain along the western beaches of Puerto Rico. However, life- threatening rip currents can occur even when the risk is low, especially near groins, jetties, reefs, and piers. Remain cautious. For additional information and location-specific rip current forecasts, visit weather.gov/beach/sju.

FIRE WEATHER

Issued at 213 PM AST Fri Jun 12 2026

The rest of today, a low fire weather risk is expected across the southern sections of the islands. By tonight into Saturday (tomorrow), a dry air mass will move into the area, potentially lowering relative humidity values to near or below critical thresholds across the southern coastal plains and possibly adjacent areas.

Breezy conditions will gradually return over the weekend. Combined with above-critical KBDI values and increasingly dry fuels, these conditions may result in elevated fire danger. Conditions could become favorable for wildfire spread across the southern coastal plains of Puerto Rico on Saturday. A Fire Danger Statement (RFDSJU) may be needed if current trends continue.

SJU WATCHES/WARNINGS/ADVISORIES

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