Puerto Rico, US Virgin Islands: High temperatures to persist forecast across the region through at least June 27

High temperatures are forecast to persist across Puerto Rico and the US Virgin Islands through at least June 27. A plume of Saharan dust over the region is trapping heat over the islands and causing hazy air quality. Power outages have been reported in parts of Puerto Rico in recent days due to the strain on the power grid amid the high temperatures. As of early June 26, the US National Weather Service (NWS) has issued excessive heat warnings for Culebra, Mayaguez and vicinity, North Central, Northwest, Ponce and vicinity, San Juan and vicinity, Southeast, and Southwest counties in Puerto Rico and St. Croix County in the US Virgin Islands. Heat advisories are in place for Northeast and Vieques counties in Puerto Rico and the rest of the US Virgin Islands. Authorities will likely issue new alerts or update/rescind existing advisories as weather conditions change over the coming days.

The high temperatures may result in increased energy and water demand and a heightened risk of heat-related illnesses, such as heat exhaustion and heat stroke. Authorities have advised the public, especially those with chronic diseases, the elderly, and children, to avoid being outdoors during the hottest parts of the day.

The extended period of oppressive heat and dry conditions may produce ideal circumstances for wildfire growth throughout the affected areas. Heatwaves also pose a threat to vulnerable groups - such as the elderly, children, pregnant women, and those with respiratory illnesses - due to the increased possibility of heat stroke or heat exhaustion during prolonged exposure to high temperatures. These health risks could also extend to relatively healthy individuals during significant heatwave events. In addition to significantly impacting athletes and those who work outdoors, high temperatures can cause problems for people using mass transit. The lack of air conditioning and cramped vehicles during rush hour may lead to some passengers being hospitalized for dehydration.

Very high temperatures may warp rail tracks and force passenger and freight trains to operate at reduced speeds. Road surface damage is also possible, and overheated vehicles may worsen traffic problems in urban areas where congestion is already a problem. Commercial trucking disruptions might occur, as very high temperatures put more stress on vehicles, making tire blowouts more common. Major flight disruptions are unlikely at regional airports, but general aviation disruptions are possible, and some airfreight carriers could reduce cargo loads. High temperatures could lead to an increased demand for electricity, which might trigger localized brownouts or blackouts, exacerbating hazardous conditions when air conditioning is no longer possible.