The National Weather Service has 52 active heat advisories in effect across 12 states Friday, stretching from California’s Central Valley to New Jersey, as a broad dome of high pressure pushes temperatures into the triple digits across much of the West and holds humid heat over parts of the East.
The hardest-hit region is California, where the Sacramento and San Joaquin Valleys, the Sierra foothills, the Coast Range and the Sierra north of Highway 50 face highs of 102 to 108 degrees and overnight lows of only 65 to 80, conditions the weather service says will produce Moderate to Major HeatRisk through 10 p.m. PDT Sunday. Dozens of California counties are under the advisory, including Shasta, Tehama, Butte, Glenn, Colusa, Sutter, Yuba, Yolo, Solano, Sacramento, El Dorado, Amador, San Joaquin and Stanislaus, along with interior Mendocino, Trinity, Humboldt and Lake counties. In southwestern interior Mendocino County, forecasters expect temperatures of 90 to 101 degrees and say Saturday will mark the peak day for HeatRisk in that area.
In New Mexico, the National Weather Service has posted a heat advisory for the Middle Rio Grande Valley, including the Albuquerque metro area, the Sandia and Manzano Mountains, the Northwest Plateau and the Espanola Valley, with highs of 99 to 103 degrees expected from noon today through 8 p.m. MDT.
Advisories also cover parts of Colorado, Idaho, Nevada, Oklahoma, Oregon, Texas, Utah and Puerto Rico, along with a cluster of counties in the Northeast — including Morris and Hunterdon in New Jersey and Bucks, Chester and Montgomery counties in the Philadelphia region. In the southern Plains, the advisory list includes Woods, Harmon and Greer counties in Oklahoma and Hardeman, Foard and Baylor counties in Texas.
The National Weather Service is warning that hot temperatures can cause heat illness, particularly for anyone without effective cooling or adequate hydration, and its guidance urges residents to check on vulnerable neighbors, limit outdoor exertion during peak afternoon hours and never leave children or pets in parked vehicles. With little overnight relief expected in California’s advisory zone — lows staying in the 60s and 70s in some areas — forecasters say the risk of heat-related illness will persist even after the sun goes down.
Residents in the affected corridor, including those checking conditions in Houston weather, should expect the advisories to remain in force into the weekend before any significant cooling arrives.