Severe Thunderstorms in the Midwest and Arizona; Heat Continues in the Southeast and Southwest

Thunderstorms, some severe, may lead to scattered instances of flash flooding across the Midwest and Ohio Valley and southern Arizona. The threat will shift to the Mid-Atlantic coast on Thursday. Dangerous heat persists in the South and Southeast while building into the Southwest. Overnight lows will be so warm that little-to-no relief from the scorching daytime highs will be available. Read More >

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Last Map Update: Thu, Aug 20, 2026 at 4:44:44 am EDT

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A Saharan Air Layer, or SAL, is still sitting comfortably across the region. While the concentration, or amount, of dust will gradually taper off, rain chances are expected in increase much until next week. This SAL has resulted in record "precipitable water" or PWAT values over the past few days---when looking at our soundings on the Storm Prediction Website (where most people view them), PWAT is calculated in the lowest 400 mb of the atmosphere. However, hot temperatures also linger since we don't even have much in the way of cloud cover. Heat index values in the afternoon through the end of this week will continue to reach the mid 100's with our hottest locations (Big Pine Key area, Upper Keys area) briefly hitting the upper 100's. Try to stay safe from heat illness, especially if you are not acclimated/vulnerable!

The low temperature at the Florida Keys - Marathon International Airport yesterday, August 19th, only dipped to 85F. This sets a new daily warm low record as the previous record was 84F, most recently set in 2024. Temperature records at Marathon date back to 1951.

Today...Mostly sunny with a slight chance of showers and thunderstorms. Highs near 90F. Variable winds near 5 mph, or near 4 knots. Chance of rain 10 percent. Heat index values may approach the mid to upper 100s at times during the late afternoon.

TODAY...Light to gentle and generally variable winds. Bay and nearshore waters smooth to a light chop. Seas in Bay and Gulfside waters one foot or less. Seas across Hawk Channel, the Florida Straits, and the Southeast Gulf around one foot. A slight chance of showers and thunderstorms with the best chance across Florida Bay and the Bayside waters.