Helpful Links:

Favorites – Weather Forecasts

Current US Radar Map

Forecast US Radar Map

Lightning Risk & Strikes Map

Hail Size Map

Current Air Quality Map

Smoke (High-Res) Surface Map

Smoke (High-Res) Sky Map

5-Day Temperature Outlook:

Summer heat is returning in full force this week with above-normal temperatures expected throughout the West over the next 5 days.

Tuesday (Aug 19):

Monsoon moisture will primarily be confined to New Mexico, Eastern Arizona, and Southern Colorado, where scattered afternoon thunderstorms will develop. Stronger thunderstorms will be capable of producing heavy rain, including the potential for flash flooding, especially over fire burn scars. 

North of the Sangre de Cristo Range, a few stray afternoon thunderstorms could develop over the higher peaks of the Front Range in Colorado. 

Wednesday (Aug 20):

Monsoon moisture will shift southward and westerward with scattered thunderstorms favoring New Mexico and Arizona. Stronger storms will be capable of producing heavy rain, with flash flooding possible over burn scars, dry washes, and slot canyons.

To the north, a few stray thunderstorms could develop over the higher peaks of Colorado, especially near the Continental Divide. 

Thursday (Aug 21):

The monsoon circulation will remain relatively weak for now, but moisture will expand northward a bit with an uptick in thunderstorm coverage across Utah and Southwest Colorado, in addition to Arizona and New Mexico.

Thunderstorm coverage will mainly be isolated to scattered across the green-shaded region, with most storms producing light rain. However, stronger storms could produce moderate to heavy rain, and flash flooding could not be ruled out in Southern Utah slot canyons.

Friday (Aug 22):

This will be the start of a stronger monsoon moisture surge as significant moisture originating in the Gulf of California streams northward and circulates around a high pressure area near the Four Corners.

An uptick in thunderstorm coverage is expected across the Southwest, Utah and Colorado, and over the higher terrain of California and Nevada, including the Sierra Nevada Range.

Thanks to the arrival of deeper moisture, storms will be capable of producing heavy rain along with the potential for flash flooding in vulnerable terrain. 

Also, a backdoor cold front will slide into Northeast Colorado with increasing moisture behind the front, supporting an uptick in thunderstorms along the Front Range of Colorado, eastern-most ranges of Wyoming, and the adjacent plains. 

Saturday (Aug 23):

Monsoonal moisture will continue to increase across the West, with precipitable water levels (water vapor in the atmosphere) approaching 200% of normal over California and Nevada, and 150-170% of normal ovr Utah.

An active day of thunderstorms is likely from the Sierra to the Central Rockies, as well as the canyon regions of Southern Utah and Northern Arizona. Storms will be capable of producing heavy rain, and flash flooding will also be possible. 

A nearly stationary cold front over Eastern Colorado will result in continued upslope winds along the eastern slopes of the Rockies in Colorado and Wyoming, where another active thunderstorm day is anticipated.

August 24-28:

An active monsoon is expected during this period with moisture expanding northward into Wyoming, Idaho, and Montana. A relatively weak but persistent trough over Southern California will likely aid in this northward flow of monsoonal moisture. 

Frequent thunderstorms with heavy rain can be expected across the Southwest, Central Rockies, and the Sierra, though the day-to-day details in terms of coverage are uncertain this far out.

Temperatures are expected to be below normal across the Southwest and portions of the Rockies and Sierra thanks to the uptick in moisture and cloud cover. However, the Northwest is likely going to see a late-season heatwave with a ridge of high pressure in place along with drier conditions. 

August 29 - September 2:

Heading into Labor Day, a busy pattern is expected to continue across much of the West, with an active late-season monsoon keeping rain and thunderstorm chances going across the Southwest and the Rockies. Also, there are some signs of Pacific disturbances reaching the Northwest with showers possibly returning to the picture. 

Temperatures are expected to remain on the cooler side of normal from California to the Central Rockies, while the Northwest should hang onto slightly above-normal temperatures, but with a cooling trend possible later in the period. 

Keep in mind, we are still 10-15 days out from Labor Day weekend, but there are some early hints that it could be a wetter-than-normal Labor Day weekend for some areas, so we'll need to keep an eye on this. 

Thanks so much for reading! Next update on Thursday (August 21).

Alan Smith