textproduct: San Juan

KEY MESSAGES

Issued at 148 AM AST Mon Jun 8 2026

* Hazy skies and warmer-than-normal temperatures will persist through at least Tuesday as Saharan dust remains over the region and east-southeast winds continue.

* Heat indices may reach hazardous levels this week, especially in coastal and urban areas. Additional Heat Advisories may be needed over the coming days.

* Passing showers will continue to affect windward areas of Puerto Rico and the U.S. Virgin Islands, particularly during the overnight and morning hours as patches of moisture move in with the trade winds.

* A moderate risk of life-threatening rip currents will continue through Tuesday on many exposed beaches due to breezy east- southeast winds. Conditions gradually improve Tuesday through Thursday, but beachgoers should still exercise caution near the surf zone.

Short Term(Today through Wednesday)

Issued at 148 AM AST Mon Jun 8 2026

Overnight conditions across the region remained relatively calm under mainly hazy skies. Temperatures stayed warm across the urban and coastal areas, with lows ranging from the upper 70s to lower 80s, while mountain locations observed temperatures in the upper 60s to lower 70s. Winds were generally light and variable overnight.

For today through Wednesday, hazy skies will continue across the local islands as lingering Saharan dust particles remain suspended in the atmosphere. An east to east-southeast wind flow will persist throughout the week, contributing to warmer-than-normal temperatures across the region. As a result, a Heat Advisory is in effect today from 10 AM through 5 PM, and additional heat advisories may be needed over the coming days.

The combination of Saharan dust and hot temperatures will continue to pose health concerns across the islands. People with respiratory conditions are urged to follow recommendations from health officials due to reduced air quality associated with the dust particles. In addition, residents and visitors are encouraged to avoid prolonged exposure to the sun, stay hydrated, and take frequent breaks in shaded or air-conditioned areas, as heat- related illnesses will remain possible during the warmest hours of the day.

Despite the generally dry and hazy pattern, patches of low-level moisture embedded in the trade winds will continue to move across the area, bringing a few passing showers to windward sections of Puerto Rico and the U.S. Virgin Islands. In addition, local effects, sea breeze convergence, and daytime heating will promote afternoon convection each day, mainly across the interior and western sections of Puerto Rico.

By late Wednesday onward, a slight increase in moisture is anticipated, which may result in a gradual increase in shower activity across portions of the region.

Long Term(Thursday through Monday)

Issued at 148 AM AST Mon Jun 8 2026

The long term period will start relatively wet with the arrival of an upper level trough from the northwest and a tropical wave approaching the Caribbean from the east. Precipitable water (PWAT) values can reach up to 1.9 inches (high-end normal values for this time of the year) according to latest model guidance. These systems will result in instability as 500mb temperatures cool to -7 to -9 C. This can aid in shower and t-storm formation. Isolated to scattered showers are forecast to move over windward sections of the islands throughout the day, while afternoon convection (including t-storms) should concentrate over interior and W-NW Puerto Rico. Lines of showers can also develop from El Yunque and the local islands. This activity can result in ponding of water over roadways and poorly drained areas, along with urban and small stream flooding, gusty winds and lightning. Generally drier air is forecast to filter over the islands on Friday and Saturday, with occasional patches of higher moisture also filtering in. However, limited flooding risk is forecast at least on Friday. In general PWAT values should remain below normal as available moisture is also limited to the lower levels with drier mid-levels. Troughiness however will also persist in the upper levels as troughs continue to linger north of the islands, however by the weekend subsidence will dominate. In general passing shower activity will continue to reach windward sectors at times with diurnal heating and local effects aiding in afternoon convection. This activity will be steered by up to breezy east to east-southeast steering flow, as another surface high builds over the Atlantic and tightens the local pressure gradient. More humid patches of moisture are then forecast to reach the area by Sunday and Monday, with PWAT values possibly reaching above normal values and ultimately enhancing in the above mentioned diurnal pattern. Saharan Dust will continue to filter over the local islands during the long term period, current model guidance suggests moderate concentrations continuing to reach the region on Thursday, persisting, albeit gradually decreasing in concentrations, throughout the end of the period. Current model guidance also suggests higher concentrations approaching the islands and eventually reaching beyond the long term period, stay tuned for more updates. 925 mb temperatures will continue at or above normal, prompting a possible limited to elevated heat risk each late morning to afternoon. Heat indices can reach and exceed 100 degrees F towards Heat Advisory Criteria at urban and lower elevations areas of the islands, particularly to start the long term period.

AVIATION

(06Z TAFS) Issued at 148 AM AST Mon Jun 8 2026

Mainly VFR conditions across all TAF sites. HZ associated with Saharan dust particles will reduce VIS. Expect the ESE winds around 15-20 kt with higher gusts and sea breeze after 08/13Z. VCSH possible across western Puerto Rico, affecting mainly TJPS and TJBQ between 08/18Z and 08/23Z.

MARINE

Issued at 148 AM AST Mon Jun 8 2026

A weak surface high pressure over the western Atlantic will merge with a broad surface high over the eastern Atlantic during the next few days. Moderate to locally fresh east to southeast trades are expected to continue across portions of the Caribbean and eastern waters of the islands through this evening. Locally higher winds due to the sea breeze are expected over the Atlantic waters just north of Puerto Rico this afternoon. Moderate trades are expected to prevail for most of the workweek as the surface high moves over the Azores and a weak frontal boundary lingers over the southwestern Atlantic. A tropical wave is expected to pass well south of the region on Thursday, however, scattered showers are expected across the local waters. Hazy skies due to moderate concentrations of Saharan dust will persist across the region through tomorrow Tuesday.

BEACH FORECAST

Issued at 148 AM AST Mon Jun 8 2026

A moderate risk of life-threatening rip currents will continue across the north and east/southeast facing beaches of PR and St. Croix today. Moderate concentrations of Saharan dust will persist over the region through tomorrow Tuesday. As winds and seas diminish through midweek, a low risk of rip currents is expected across all beaches of the islands from Tuesday through Thursday. However, life- threatening rip currents often occur in the vicinity of groins, jetties, reefs, and piers. Beach goers should always exercise caution regardless if the risk is low.

FIRE WEATHER

Issued at 148 AM AST Mon Jun 8 2026

Expect an elevated fire danger across the southern coastal plains of Puerto Rico. From late this morning through late this afternoon, relative humidity is expected to drop to near 50% or even lower, while wind speeds are expected to range between 13 and 20 mph, with stronger gusts. Fine fuels will continue to dry out and remain highly receptive to ignition.

Fire and emergency officials should be aware that weather conditions are becoming more conducive for the ignition and spread of wildfires.

Fire danger statements are issued when fire weather conditions are approaching, but not meeting or exceeding, Red Flag Warning criteria.

SJU WATCHES/WARNINGS/ADVISORIES

PR...Heat Advisory from 10 AM this morning to 5 PM AST this afternoon for PRZ001>003-005-007-008-010>013.

VI...Heat Advisory from 10 AM this morning to 5 PM AST this afternoon for VIZ001-002.

AM...None.