The first of two Pacific storm systems is moving across the Northern Rockies on Friday afternoon, after producing widespread showers and thunderstorms along with wetting rains across Idaho, Montana, and Western Wyoming on Thursday night and Friday morning.

The second system is approaching from the Gulf of Alaska and will result in cool temperatures and welcome rainfall over the weekend.

As of early Friday afternoon, showers and thunderstorms associated with the first system were numerous across Wyoming, Eastern Idaho, and Northern Colorado.

Current Radar

Lightning Density

Forecast Radar

Temperatures over the next 5 days will generally be below average across the Northwest and Northern Rockies and above average across the Southwest and Southern Rockies. The exception to the latter will be across Southern Arizona, where some monsoonal moisture will return. 

Fire activity has increased significantly over Northern California during the past week, and heavy smoke is resulting in poor air quality from California east toward Utah. The smoke will eventually push east into Colorado late Friday as well.

Farther north, fire activity is more spotty and less intense until you get into the the Northern Washington Cascades and British Columbia where fires are more numerous.

Forecast Smoke (surface)

Forecast Smoke (sky)

Current Air Quality

Over the coming days, prevailing winds will favor heavy smoke transport and poor air quality across California, Nevada, Utah, and Colorado, while areas farther north in Idaho and Wyoming will see more variable levels of smoke.

Wetting rains and cooler temperatures across the Northwest this weekend should help to reduce fire activity, at least to some extent, across Washington and British Columbia.

Forecast for Friday, August 6th

Showers and thunderstorms along with wetting rains can be expected across Idaho, Wyoming, and Southwest Montana through Friday, while Northern/Central Colorado will see scattered thunderstorms with lighter rain amounts. Southern Arizona and New Mexico will see some isolated thunderstorm activity as a little bit of monsoonal moisture arrives from the south.

The Northwest Coast, Olympics, and Cascades will see rain showers arrive during the overnight hours on Friday night.

Forecast for Saturday, August 7th

Showers and wetting rains can be expected across Western Washington on Saturday, with lighter/more isolated showers extending south into Oregon and east into the Idaho Panhandle and Northwest Montana. North of the border, wetting rains in British Columbia should start to help with ongoing wildfires in the area.

Elsewhere across the Rockies, dry conditions will prevail aside from some isolated thunderstorms east of the Divide in Wyoming, and across southern portions of Arizona and New Mexico.

Forecast for Sunday, August 8th

Widespread wetting rains along with thunderstorms will extend eastward into Northern Idaho and Montana, with heavy rain totals possible in the Glacier National Park vicinity. Lighter showers will linger across the Cascades early Sunday before drying out later in the day.

Conditions are looking dry for the remainder of the West with monsoonal moisture further retreating south of the Mexico border.

Forecast for Monday, August 9th

In terms of precipitation, Monday is looking quiet across the West with just some lingering showers/thunderstorms along and east of the Divide in Montana and Wyoming. Farther south, moisture and thunderstorm chances will sneak back into Southern Arizona and a few storms couldn't be ruled out over the higher terrain in Colorado.

Forecast for Tuesday, August 10th

Northern areas will begin to dry out, while monsoonal moisture will surge northward into Arizona with more increasing thunderstorm coverage and the potential for heavy rains. Isolated thunderstorms could develop across the higher terrain of New Mexico, Colorado, Utah, and Southern California as well.

Outlook for Wed, Aug 11th - Sun, Aug 15th

Late next week, a strong ridge of high pressure will set up over the West Coast, and a heatwave is likely across California, Oregon, Washington, Idaho, and Nevada. This, of course, is not ideal for fire conditions.

Farther south, the monsoon will make a comeback across the Four Corners states – most noticeably across Arizona and New Mexico, but Southern Utah and the San Juans/southern ranges of Colorado should see an uptick in thunderstorm activity as well.

Thanks so much for reading! Next update on Monday (8/9).

ALAN SMITH

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