Big Picture Weather Pattern:

Monsoonal moisture will rotate around a high pressure center near the NM/CO border early this week with Arizona, Southern Utah, and Colorado favored.

A shortwave disturbance moving across the Northern Rockies with jet stream support will help trigger storms across Montana, while eastern ranges from the Canadian Rockies to Central Montana will see stronger storms in the wake of a backdoor cold front (arriving from the northeast). 

5-Day Temperature Outlook:

Temperatures will be below-average near and east of the Divide in the Northern Rockies this week thanks to cooler air spilling in from the north. Temperatures will be above-average west of the Divide but most locations here will not be as hot compared to recent times.

Wildfire and Smoke Outlook:

There are still numerous fires burning across the West, but at a larger scale, smoke production and transport are not as intense compared to the past couple of weeks.

On Monday, heavy smoke will largely be confined to areas near and just downwind of large and active fires, with general haziness for most other parts of the West away from large fires. Winds across the Northwest where most fires are located will be blowing from SSW to NNE.

Smoke (High-Res) Sky Forecast for 5pm Monday:

On Tuesday, a trough moving into the Pacific Northwest will lead to a wind shift (winds will blow from the NW to W) over BC and Washington, resulting in heavier smoke across Central and Eastern Washington. Elsewhere, conditions look similar to Monday.

Smoke (High-Res) Sky Forecast for 5pm Tuesday:

A similar pattern is expected mid to late week with heavier smoke across Washington and Northern Idaho, while elsewhere, heavy smoke will mainly be confined to areas near and just downwind of large and active fires.

There are a couple of exceptions to keep in mind, though. 1) There are some hints of heavier smoke from Northern Canada wildfires spilling southward into Monday by Wednesday. 2) If any new significant wildfires develop, or if there are any significant upticks in current fire behavior, that could change the smoke outlook.

Rain and Thunderstorm Forecast for Mon (Aug 5) to Tue (Aug 6):

Thunderstorm coverage and rainfall amounts will be greatest across Colorado, the Southwest, North Central Montana, and the Canadian Rockies of Alberta.

Colorado:

Scattered thunderstorms can be expected across mountain ranges statewide on both Monday and Tuesday with heavy rain possible under stronger storms.

Here is our 5-day forecast for Mt. Elbert with an hourly precipitation and lightning forecast for Monday:

Utah:

Scattered thunderstorms can be expected across Northern and Southern Utah on Monday, while most of the action will be confined to Southern Utah on Tuesday.

While this pattern is nothing out of the ordinary for early August, flash flooding will be a possibility across portions of Southern Utah with the exception of Zion and Glen Canyon where drier conditions are expected.

Arizona:

Scattered thunderstorms can be expected across both Northern and Southern Arizona with locally heavy rain possible, along with the potential for flash flooding in slot canyons, dry washes, and small streams.

Thunderstorm coverage looks greater on Tuesday compared to Monday, especially for southern areas near and just west of Tucson.

New Mexico:

This will be a drier setup for New Mexico with thunderstorm activity primarily confined to northern parts of the state, where heavy downpours will be possible. Thunderstorm activity looks minimal over southern parts of the state, other than some very isolated storms. 

Northern Rockies:

Isolated to widely scattered thunderstorms across Idaho, Wyoming, and Western Montana on Monday will give way to scattered and more numerous storms in Montana and Wyoming on Tuesday. There will be a mix of wet and dry thunderstorms, with dry lightning potential leading to an elevated fire risk.

Rainfall potential will be greater along the easternmost ranges on Tuesday from Glacier to Red Lodge to the Bighorns. 

Forecast for Wed (Aug 7) to Thu (Aug 8):

More of the same can be expected across the Southwest with daily thunderstorms producing locally heavy downpours. The flash flood risk is expected to increase across Southern Colorado and Northern New Mexico on Thursday.

Models are in poor agreement on Utah, with this particular model keeping thunderstorm activity isolated, while other models have more significant moisture across Southern Utah which would lead to elevated flash flood potential.

A further increase in moisture is expected near and east of the Continental Divide in the Northern Rockies, with heavy downpours possible for Glacier, the Bob Marshall Wilderness, the Beartooth Range, and the Bighorn Range. 

Forecast for Fri (Aug 9) to Sat (Aug 10):

The end of the week looks active as a northward surge of monsoonal moisture is expected into Utah and Colorado, resulting in an uptick in thunderstorm coverage along with greater potential for heavy rain and flash flooding. The Front Range foothills in Colorado could also pick up some much-needed moisture.

The Northern Rockies look to stay active as well, especially near and east of the Continental Divide where more numerous storms and locally heavy rain is expected. 

A trough moving into the Pacific Northwest could also bring some showers to the Washington Cascades.

Outlook for Sun (Aug 11) to Thu (Aug 15):

Temperatures will be near average across the Central and Eastern Rockies and along the West Coast, with above-average temperatures for the Southwest and Northwest.

The pattern also looks active throughout the Rockies with near-daily thunderstorms thanks to monsoonal moisture stretching from the Southwest into the Northern Rockies. The pattern looks wettest across Colorado and Utah, where more numerous storms can be expected along with the potential for heavy rain.

Thanks so much for reading! Next update on Wednesday (August 7).

Alan Smith