The National Weather Service in San Diego issued an updated extreme heat warning covering the Orange County Coast and San Diego County coastal areas, citing dangerously hot conditions and warm overnight lows that will limit relief from the heat.
The NWS warned of high temperatures in the mid 80s at beaches rising into the 90s for higher coastal terrain, and it described the expected impact as Major to Extreme HeatRisk through Wednesday.
The office said emergency alerts will be sent to all enabled mobile phones for considerable or catastrophic hazards and urged residents to sign up for county alert systems for lesser risks.
The NWS release noted that heat related illnesses increase significantly during extreme heat events and advised people to monitor symptoms and seek medical attention if conditions worsen.
Local guidance from the Environmental Health and Safety office at UC Irvine emphasized frequent fluid replacement during heat exposure, advising roughly three to four cups of water every hour in high heat, and warned against alcohol and caffeine because they dehydrate the body.
Authorities also recommended frequent breaks in shaded or cooled areas, wearing breathable sun protective clothing, and knowing how to call for medical help if symptoms persist.
Regional Heat Risk Products Health Data And Guidance
The NWS Phoenix Heat page outlines the bureau's HeatRisk product, which assigns a 0 to 4 numeric and color scale to daily heat risk based on how much temperatures exceed normal, heat duration, and humidity.
HeatRisk levels run from Level 0 green for no elevated risk to Level 4 magenta for extreme risk that can affect everyone when overnight relief is minimal, the agency explained.
The Phoenix office said an Extreme Heat Watch indicates about 50 percent confidence that extreme heat will occur, and an Extreme Heat Warning follows when confidence rises above roughly 80 percent; Major or Extreme HeatRisk forecasts typically prompt those legacy products.
The NWS Phoenix analysis tied higher HeatRisk categories to measurable health outcomes. It reported that emergency room visits and Phoenix Fire Department heat-related calls rose steadily as HeatRisk increased, with spikes during Major and Extreme days.
The Phoenix guidance listed populations most vulnerable to heat, such as infants, older adults, people who are homeless, those who overexert, and people on certain medications. It recommended drinking water, wearing light clothing, avoiding alcohol, and seeking air conditioning when possible.
For heat emergencies, the Phoenix material advised rapid cooling, fluids for heat exhaustion, and calling emergency services for suspected heat stroke, stressing that quick action can prevent severe outcomes.
