National Weather Service United States Department of Commerce

Areas of Dangerous Heat and Severe Thunderstorms

Dangerous heat will build across the Southwest U.S. through the end of the week with daytime highs of 110-115°F. Heat across the southern Plains will briefly ease to near-normal by late week before returning over much of the Plains into next week. Severe thunderstorms are expected across parts of the central and southern High Plains, central Great Lakes, and Ozarks Wednesday. Read More >

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Last Map Update: Wed, Aug 26, 2026 at 1:04:36 am PDT

The Valley Air District has issued an Air Quality Alert for Merced County from Tuesday morning at 10:30AM through 11:00AM Thursday morning due to smoke from a local fire. Exposure to particle polluction can cause serious health problems; aggrevate lung disease, cause asthma attacks and acutre bronchitis and increase risk of respiratory infections. In people with heart disease, short-term exposure to particle pollution has been liked to heart attacks and arrhythmias accourding to the US Environmental Protection Agency. Children and elderly people are also more susceptible to consequences of high particulate levels. Stay indoors if possible. Avoid prolonged or strenuous outdoor physical activities to reduce the affect of unhealthy air. For current air quality conditions, go to fire.airnow.gov.
(Updated 8/23 4:30 PM) - Widespread Moderate Heat Risk is expected across the San Joaquin Valley and adjacent lower foothills (including Lake Isabella) as temperatures range from 100 to 104 degrees from Monday through at least Wednesday. Moderate Heat Risk affects those who are sensitive to heat, especially those without cooling/hydration, and some health systems and industries. A Heat Advisory has been issued for the southern San Joaquin Valley valid from Monday through late Wednesday evening.
Widespread Moderate to Major Heat Risk is expected across the Mojave Desert as temperatures reach up to 108 degrees from Monday through at least Wednesday. Morning low temperatures between 75 and 80 degrees will provide little overnight relief from the heat. This level of heat brings a Major Risk of heat-related illnesses for much of the population, especially those without effective cooling or hydration.
The high pressure ridge will once again sit itself over the West Coast this week. With that, max temperatures will range from 100 to 104 degrees across the San Joaquin Valley, Lower Foothills and the Mojave Desert. Best chances for the heat will be today through Wednesday with chances dropping off later in the week.

 

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