textproduct: San Juan

KEY MESSAGES

Issued at 300 AM AST Mon Jun 15 2026

* Generally stable and fair weather will dominate, despite the possibility of a slight increase in moisture and shower activity toward the end of the week.

* Warm to hot conditions will continue, with elevated heat indices posing a risk to vulnerable populations and those spending prolonged time outdoors.

* Prolonged dryness, critically dry fuels, above-normal temperatures, and breezy conditions will continue to support an increased risk of rapid wildfire spread, especially across southern and western Puerto Rico.

* Breezy trade winds will maintain choppy marine conditions and a continued risk of rip currents along many exposed beaches.

Short Term(Today through Wednesday)

Issued at 300 AM AST Mon Jun 15 2026

Broad surface high pressure over the North Atlantic will maintain a prevailing east to east-southeast trade wind flow through the period, steering intermittent patches of shallow moisture interspersed with drier-than-normal air across the region. At the same time, a persistent mid-level ridge and dry air aloft will continue to suppress deep convection. As a result, expect mainly brief, fast-moving passing showers across windward areas and isolated to locally induced afternoon showers over western Puerto Rico, with no significant rainfall accumulations anticipated.

A tropical wave moving through the Caribbean tonight into Tuesday will remain well south of the local islands and have minimal influence on the local weather pattern. Although the mid-level ridge will gradually shift westward and an upper-level trough retrogrades across the Atlantic by midweek, only subtle changes in atmospheric conditions are expected. Precipitable water values should remain generally below normal, briefly approaching seasonal levels Tuesday night into early Wednesday, while persistent dry air aloft continues to limit vertical cloud development. Overall, limited shower activity is expected through Wednesday.

The primary hazards through the period will continue to be heat, non-thunderstorm winds, and fire weather. Afternoon heat indices will commonly exceed 100 degrees Fahrenheit, with isolated locations reaching or exceeding 108 degrees. Wind speeds will generally range between 15 and 20 mph, with gusts up to 30 mph, especially across exposed coastal areas and the local islands. Combined with dry fuels and limited rainfall, these conditions will support an elevated fire danger risk across portions of southern and western Puerto Rico. While the weather pattern may appear favorable for outdoor activities, residents and visitors should remain mindful of the heat, winds, and fire danger.

Long Term(Thursday through Monday)

Issued at 300 AM AST Mon Jun 15 2026

Model guidance suggests a modest increase in moisture late this week as a tropical wave passes south of Puerto Rico and the U.S. Virgin Islands. At the same time, the persistent mid-level ridge is forecast to shift west of the region while a lingering upper- level trough east-northeast of the area exerts greater influence, resulting in slight cooling aloft and a gradual weakening of the trade wind cap. However, dry mid-level air is expected to persist, and moderate Saharan dust concentrations forecast through Friday should temper the overall coverage and intensity of showers and thunderstorms.

As a result, only a modest increase in shower activity and the potential for isolated thunderstorms is anticipated from Thursday into Friday. While localized heavier downpours cannot be ruled out, the prolonged dry pattern and significant rainfall deficits should keep the overall flooding threat limited. Beyond Friday, forecast uncertainty increases, but a generally typical trade-wind pattern with passing showers and isolated afternoon convection is expected to continue. Overall confidence in the long-term forecast remains moderate, as the timing and interaction of these features continue to vary among model guidance.

AVIATION

(06Z TAFS) Issued at 300 AM AST Mon Jun 15 2026

Mainly VFR conds will prevail at all TAF sites thru the fcst pd. VCSH with brief -SHRA is psbl in the vcnty of TJSJ and TJBQ btwn 15/16Z-20Z due to iso aftn convection. Light concs of Saharan dust will persist acrs the local area, resulting in locally hazy skies with minimal VIS impacts. E-ESE sfc winds will incr to 15-20 kt with higher gusts and sea-breeze variations fm 15/14Z-23Z, bcmg 10 kt or less ovrngt.

MARINE

Issued at 300 AM AST Mon Jun 15 2026

A broad area of high pressure over the central Atlantic will maintain moderate to fresh trade winds and choppy marine conditions through much of the forecast period. Seas are expected to range between 4 and 6 feet, with occasional higher waves across the offshore waters and local passages, prompting Small Craft Exercise Caution conditions. Winds may ease slightly by Tuesday into Wednesday, allowing seas to gradually subside to 3 to 5 feet. Overall, fair weather and limited shower activity are expected to prevail, although a tropical wave approaching the northeastern Caribbean later this week could bring a modest increase in moisture and shower activity across the local waters.

BEACH FORECAST

Issued at 300 AM AST Mon Jun 15 2026

Breezy to windy conditions will maintain a moderate risk of rip currents for most beaches across Puerto Rico, including Culebra and Vieques, as well as the U.S. Virgin Islands through at least midweek. Life-threatening rip currents are possible, and beachgoers should remain vigilant, swim near lifeguards when available, and follow the guidance of local authorities and beach warning flags.

A low risk of rip currents will continue along the western coast of Puerto Rico. However, dangerous rip currents can still occur, particularly near jetties, groins, reefs, and piers. Additional rip current safety information is available at weather.gov/beach/sju.

FIRE WEATHER

Issued at 300 AM AST Mon Jun 15 2026

Persistent above-normal temperatures, breezy east to east- southeast winds, and limited rainfall will continue as broad surface high pressure maintains the trade wind flow and a persistent mid-level ridge suppresses widespread precipitation. Prolonged rainfall deficits, with some locations receiving less than 5 percent of normal rainfall in recent weeks, combined with abnormally dry to moderate drought conditions and KBDI values exceeding 600 across much of southern Puerto Rico, will keep fuels critically dry. Although a few passing showers are expected, no meaningful wetting rainfall is anticipated. Therefore, a Fire Danger Statement has been issued for today, and similar or even locally critical fire weather conditions capable of supporting rapid fire spread may continue over the next several days if the current pattern persists.

SJU WATCHES/WARNINGS/ADVISORIES

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