An intensifying upper-level ridge is driving extreme heat across the Southwest, with temperatures expected to peak on Thursday. The National Weather Service warned on Aug. 24, 2026, that afternoon highs and morning lows could reach 5 to 10 degrees above normal, triggering widespread Major to Extreme Heat Risks through Friday.
Extreme Heat and Record Temperatures
Extreme Heat and Record Temperatures
The National Weather Service Las Vegas announced on Aug. 24, 2026, that a strengthening upper-level ridge centered over Arizona will drive extreme heat throughout the workweek. Highs are forecast to reach the upper 100s to mid 110s in valleys across the Mojave Desert, including Las Vegas, while lows could remain in the mid 80s to low 90s. This pattern has placed numerous daily high and warm minimum temperature records in jeopardy.
In Las Vegas, the forecast indicates that temperatures could hit 112 degrees, matching a record set in 2021, or reach 111 degrees, matching a record from 2011. For Wednesday, Aug. 26, 2026, the forecast suggests temperatures may hit 109 degrees, nearing the 2001 record. On Thursday, Aug. 27, 2026, highs could reach 110 degrees, matching a 2017 record. Minimum temperatures are also expected to stay high, with Wednesday's low potentially reaching 88 degrees, nearing the 2020 record of 88 degrees.
Saint George is also facing intense heat. According to a forecast from the National Weather Service on Aug. 24, 2026, temperatures in Saint George are expected to climb steadily, reaching 105 degrees on Tuesday, Aug. 25, 2026, 107 degrees on Wednesday, Aug. 26, 2026, 108 degrees on Thursday, Aug. 27, 2026, and 106 degrees on Friday, Aug. 28, 2026.
Thunderstorms and Flash Flood Risks
Thunderstorms and Flash Flood Risks
While heat dominates, localized weather activity remains a factor. The National Weather Service Grand Junction reported on Aug. 24, 2026, that afternoon thunderstorms will continue through the week, particularly in the higher terrain of eastern Utah and western Colorado. These storms may produce gusty outflow winds and downpours, which could lead to flash flooding, especially over susceptible terrain and recent burn scars.
In the Salt Lake Desert, the National Weather Service Salt Lake City reported on Aug. 22, 2026, that afternoon and evening showers and thunderstorms would become more isolated over time, largely impacting higher terrain through early next week. The agency noted that any weekend storms would carry a threat of strong, gusty microburst winds.
In the Wasatch Mountains, the National Weather Service Salt Lake City forecast on Aug. 22, 2026, that isolated showers and thunderstorms would persist through Monday, Aug. 24, 2026. Moisture levels, measured by precipitable water (PWAT), are expected to remain between 125% and 150% of normal through Wednesday, Aug. 26, 2026, before decreasing toward the end of the week.
Fire Weather and Drying Conditions
Fire Weather and Drying Conditions
As the week progresses, a shift in weather patterns may increase fire risks. The National Weather Service Grand Junction reported on Aug. 24, 2026, that drier conditions at the end of the workweek, combined with increased afternoon wind gusts from an approaching trough, could create localized critical fire weather conditions on Friday, Aug. 28, 2026, and Saturday, Aug. 29, 2026.
The Storm Prediction Center issued an Elevated Fire Weather Outlook for Aug. 24, 2026, and Aug. 25, 2026. While some guidance suggests stronger moisture advection could mitigate these risks, the combination of rising temperatures and decreasing humidity remains a primary concern for fire management officials.
In the Salt Lake Desert, the National Weather Service Salt Lake City reported on Aug. 22, 2026, that valley humidities would decrease slowly, reaching near-critical to critical levels as early as Monday, Aug. 24, 2026. The agency noted there is little sign of an additional monsoon surge until after the following weekend.
Weekend Forecast Outlook
Weekend Forecast Outlook
The current period of extreme heat and localized storms is expected to transition as a trough moves east into the ridge. The National Weather Service Las Vegas reported on Aug. 24, 2026, that temperatures should fall back to near-normal values by the weekend.
In Saint George, the forecast for the upcoming weekend shows a slight chance of showers and thunderstorms on Saturday, Aug. 29, 2026, and Sunday, Aug. 30, 2026, with temperatures remaining high at 103 degrees on Saturday and 100 degrees on Sunday.
Aviation and Regional Impacts
Aviation and Regional Impacts
For aviation, the National Weather Service Las Vegas reported on Aug. 24, 2026, that winds at Harry Reid International Airport would become less gusty and fall to less than 10 knots after sunset, while maintaining a southwesterly direction. In the surrounding region, including northwestern Arizona, outflow boundaries from decaying storms could cause sudden changes in wind direction and speed overnight.
