“Urgent Heat Advisory Issued as Temperatures Soar: What You Must Do Now to Stay Safe”

Subtropical high pressure parked over the West is sending the mercury soaring, and the National Weather Service has issued a Heat Advisory for large portions of Northern and Central California from 11 a.m. to 8 p.m. PDT Friday, with afternoon highs ranging from the mid-90s to 105 °F in interior valleys and foothills. What areas are included • Santa Clara Valley and surrounding eastern hills • Interior Central Coast communities such as Salinas Valley and Paso Robles • East Bay hills/valleys and North Bay interior mountains Similar advisories or watches extend south into coastal Southern California and east toward the lower Colorado River Valley, while Phoenix and Las Vegas flirt with the season’s first 110 °F readings. Why this event is dangerous Even healthy adults can experience heat exhaustion when high temperatures pair with low overnight cooling. A Heat Advisory is issued when dangerous heat is expected within 12 hours, posing significant risk to vulnerable populations and straining infrastructure. Hospitals typically see spikes in dehydration, heat-related illness, and cardiac emergencies during multi-day hot spells. Forecast highlights • Peak heat index: 95–108 °F Friday afternoon • Warm nights: lows only falling to the mid-70s in urban cores, limiting recovery time for the body • Minor cooling possible Sunday as a weak onshore flow returns, but another ridge could rebuild next week Potential ripple effects • Power demand: With air-conditioners running nonstop, California ISO may issue Flex Alerts asking residents to conserve electricity during late-afternoon peaks. • Wildfire risk: Single-digit humidity and dry vegetation mean any spark could spread rapidly, especially in the interior Coast Range. • Infrastructure: Asphalt can soften, rail lines can expand, and pets’ paws burn in seconds on sun-baked pavement. Heat safety checklist 1. Hydrate before feeling thirsty; water and electrolyte drinks are best. 2. Use air-conditioned spaces—public libraries, malls, or designated cooling centers—if home cooling is unavailable. 3. Limit outdoor labor to early morning or evening; schedule frequent breaks in shade. 4. Never leave children, the elderly, or pets in parked vehicles; interior temperatures can top 130 °F within minutes. 5. Check on neighbors who live alone, especially seniors or those with chronic illnesses. 6. Wear lightweight, light-colored clothing and broad-brimmed hats; apply SPF 30+ sunscreen every two hours. Signs of trouble • Heat exhaustion: heavy sweating, dizziness, nausea—move to a cooler place, sip cool fluids. • Heat stroke: body temp ≥103 °F, confusion, loss of consciousness—call 911 immediately and begin rapid cooling with ice or wet cloths. When will relief arrive? Computer models hint at a Pacific trough dipping south late Sunday, bringing stronger coastal breezes and shaving 5–10 °F off inland highs. Until then, plan for at least three consecutive days of triple-digit heat in the valleys and upper-80s along the bay shoreline. Bottom line This first significant West Coast heat wave of 2025 arrives ahead of the official start of summer, catching many residents off guard. Follow local forecasts, practice heat safety, and reduce energy use during the late-afternoon peak to help keep the grid stable—and yourself healthy—through the weekend.