On August 25, the National Weather Service Grand Junction reported that daily afternoon thunderstorms are expected this week, primarily affecting the higher terrain of eastern Utah and western Colorado. These storms may bring frequent lightning, gusty winds, and localized heavy rainfall.
Localized heavy rainfall continues to pose a threat for flash flooding, particularly over susceptible terrain and burn scars. If storms form over sensitive areas or train over the same location, flash flooding and debris flows may occur.
Temperatures are expected to run 5 to 10 degrees above normal to start the week and will gradually increase through Friday. As high pressure moves into the Desert Southwest, daytime highs may increase a degree or two each day.
A pattern shift may occur late this week into the weekend as a deep trough approaches the West Coast. This could lead to stronger winds and potential localized Critical Fire Weather conditions, depending on whether the air becomes drier or wetter.
While some weather models favor wetter conditions, others suggest drier conditions. Current guidance indicates that as troughing spreads over the western United States through the weekend, a wetter and cooler pattern may emerge, with temperatures potentially falling near or a few degrees below normal heading into early September.
In aviation forecasts, isolated showers are tracking east across northwestern Colorado and northeastern Utah. Thunderstorms are expected to develop over higher terrain between 16Z and 00Z, potentially causing brief periods of MVFR conditions due to gusty outflows, lightning, and heavy rainfall.
