A stubborn area of high pressure will strengthen across Southern California this weekend, sending temperatures soaring well above average and bringing dangerous heat to inland communities and deserts.
The National Weather Service in San Diego said high temperatures will run about 10 degrees above average through Saturday
, with the hottest conditions expected across the Inland Empire, mountain valleys and deserts.Desert communities could see temperatures climb as high as 114 to 118 degrees, while parts of the Inland Empire could reach the upper 90s to around 110 degrees.
Coastal areas will remain cooler, with temperatures generally in the upper 70s to 80s, but even those locations will run several degrees warmer than normal.
The heat will not disappear overnight. Forecasters warn nighttime temperatures will also remain unusually warm, especially in the deserts, where lows could stay in the 90s. Some locations may challenge daily records for warmest overnight temperatures from Friday through Sunday.
The highest heat impacts are expected Friday and Saturday, when the National Weather Service forecasts major to extreme HeatRisk across much of inland Southern California. The greatest concern is for the lower deserts, including the Coachella Valley, where prolonged heat can increase the risk of heat-related illness.
A gradual cooldown is expected early next week, but temperatures will remain above average. By Wednesday, inland areas could still see highs in the 90s to low 100s, with desert communities reaching the upper 100s.
Forecasters are also monitoring a possible increase in moisture Sunday that could bring more clouds and a slight chance of afternoon thunderstorms to mountain areas. However, the overall pattern remains dominated by strong high pressure and above-normal heat.
“High temperatures will range from around 80 near the coast to the upper 90s to 110 for the Inland Empire with 114 to 118 for the lower deserts," the National Weather Service in San Diego said.
Where will it be hottest?
- Lower deserts: 114-118 degrees
- Inland Empire: Upper 90s to around 110 degrees
- Central Valley: 100-110 degrees, with widespread triple-digit heat
- Apple and Lucerne valleys: Major to extreme heat risk
- Coastal areas: Upper 70s to mid-80s
“HeatRisk is expected to peak on Friday and Saturday with widespread extreme HeatRisk for the lower deserts.”
National heat index map: How hot is it in your city?
The map below identifies areas where the heat index is forecast to reach NWS-defined levels from "Caution" (80 degrees Fahrenheit) to "Extreme Danger" (above 125 degrees).
The heat index measures how hot it actually feels when factoring for humidity. Prolonged exposure to a heat index above 80 degrees can lead to fatigue, as previously reported by USA TODAY. As it gets hotter, the risk continues to increase − potentially resulting in heat stroke or even death. Older adults, children, and outdoor workers are generally at higher risk of heat-related incidents.
What’s the difference between temperature and heat index?
The temperature is the actual air reading — what a thermometer records in the shade. The heat index, on the other hand, represents what it feels like to the human body when both temperature and humidity are factored in, according to the National Weather Service.
When humidity is high, sweat doesn’t evaporate as easily, making it harder for your body to cool down. That’s why the heat index is often higher than the air temperature, and why it’s used to gauge the risk of heat-related illness.
What are the symptoms of heat-related illness?
Extreme heat is the deadliest weather-related hazard in the United States, claiming more lives each year than hurricanes, floods or tornadoes.
Experts urge Californians to take precautions: stay hydrated, avoid outdoor activity during peak afternoon hours, wear light clothing and check on vulnerable neighbors, including older people and those without air conditioning, throughout these next couple of weeks and into the summer.
According to the Centers for Disease Control, there are multiple types of heat-related illnesses. Heat cramps and heat rash can be treated by staying indoors and getting hydrated. But some others are more serious.
Heat exhaustion symptoms
Heat exhaustion is a mild heat-related illness that occurs in hot temperatures, especially when you’re not drinking enough water or other nonalcoholic fluids. People most at risk for heat exhaustion are the elderly, those with high blood pressure, and individuals working or exercising in the heat.
Symptoms of heat exhaustion include:
- Excessive thirst
- Profuse sweating
- Headache
- Dizziness or confusion
- Nausea
If you or anyone you’re with experiences these symptoms, move to a shaded or air-conditioned area, use a fan, or immerse in cool water. Also, drink cool, nonalcoholic beverages like water or sports drinks with electrolytes.
Heat stroke symptoms
Heat exhaustion can escalate into heat stroke, a serious, life-threatening condition. Heat stroke occurs when the body’s temperature rises rapidly, and it can no longer cool itself down.
Early symptoms of heat stroke are similar to heat exhaustion but progress to more severe signs, including:
- Lack of sweating
- Body temperature rising to 106°F or higher within 10-15 minutes (even without a thermometer, the skin will feel very hot)
- Loss of consciousness
Heat stroke is a medical emergency. If you suspect someone is experiencing it, seek immediate medical attention. Without emergency treatment, heat stroke can cause death or permanent disability.
Brandi D. Addison covers weather across the nation as the Weather Connect reporter for the USA TODAY Network and contributes to Texas Connect coverage across the state. She can be reached at baddison@usatodayco.com. Follow her on Facebook here.
This article originally appeared on Palm Springs Desert Sun: California to bake under extreme heat for next several days. See the maps
