Most of the West will see beautiful "Indian summer" conditions on Friday and Saturday with sunny skies and above-average temperatures. Not to mention the fall colors, which are getting close to peak across parts of the Rockies right now.

Temperatures over the next 5 days will be above-average across the Rockies and Great Basin and near average over the West Coast and Southwest, where more unsettled weather looms over the coming days.

Recent warm and dry conditions have resulted in an increase in fire behavior across California, and smoke will be an issue across much of the state this weekend as a result. Strengthening southwest flow will also start to transport some of this smoke downstream into the Great Basin and areas farther east/northeast as the weekend progresses.

Forecast Smoke (surface)

Forecast Smoke (sky)

Current Air Quality

Over the next couple of days, the most active weather will actually occur over Southern California and Arizona, thanks to a weak area of low-pressure meandering near the CA/Mexico border.

There will be plenty of instability in this pattern to trigger thunderstorms over the SoCal Mountains and foothills. Check out the forecast radar for Friday afternoon.

Current Radar

Lightning Density

Forecast Radar

By late in the weekend, the next storm system will begin to impact the Pacific Northwest, while the weaker area of low pressure over the Southwest will slowly move eastward.

Early next week, the stronger storm will begin to progress inland while the Four Corners region will see some impacts from the lingering weak area of low pressure.

Late Tuesday and into Wednesday, the stronger storm will "split" with weaker energy/less moisture lifting northeast into Canada and the stronger southern piece of energy impacting Southern/Eastern Utah, Colorado, Arizona, and New Mexico. 

Forecast for Friday, September 24th

Showers and thunderstorms will favor SoCal, Arizona, and Southern New Mexico on Friday afternoon with dry conditions for the remainder of the West.

Forecast for Saturday, September 25th

Saturday's pattern will be similar to Friday's with showers and thunderstorms across the Southwest and dry conditions elsewhere.

Forecast for Sunday, September 26th

Rain will reach the Pacific Northwest on Sunday with the heaviest amounts expected across the Olympics and Northern Cascades. The area of low pressure over the Southwest will start to move east/northeast with shower and thunderstorm activity becoming more widespread over Arizona and New Mexico. The San Juans in Colorado will get in on the action as well.

Forecast for Monday, September 27th

The Pacific Northwest will see another wet day on Monday with heavier rains extending southward into the Oregon Cascades and lighter showers into Northern California. The system will gradually progress eastward with shower activity picking up over Northern Idaho and far Northwest Montana. The Four Corners region will also see another active day of showers and thunderstorms.

Forecast for Tuesday, September 28th

Showers will continue over the West Coast and Cascades while Central/Northern Idaho and Northwest Montana will see heavier and more widespread rain as the storm system moves inland.

This is also when we'll start to see the storm system "split" with stronger energy diving southward into the Four Corners region, where more widespread showers will develop on Tuesday afternoon/Tuesday night.

A cold front will also move across the Pacific Northwest on Monday night and then track across the Interior West on Tuesday and Tuesday night. This will not be a particularly strong cold front like what we saw last week, but it will be enough to expect high elevation snow across the Cascades, Idaho mountain ranges, and Southwest Colorado.

Outlook for Wed, Sept 29th - Sun, Oct 3rd

Colorado, New Mexico, and possibly Arizona/Southern Utah will continue to see storm impacts with rain showers and high elevation snow mid to late next week. Additional storms will likely impact the Cascades and PNW Coast as well through the first weekend of October.

The Pacific Northwest and Four Corners regions will see the most active weather during this period with drier conditions across the Northern Rockies and California. 

Thanks so much for reading! Next update on Monday (9/27).

ALAN SMITH

We will continue to post the Western U.S. Daily Summit 3x/week through Friday, October 1st.

Starting on Monday, October 4th, we will transition to the US & Canada Daily Snow, at which point we will still talk about impactful weather in the West as needed, but with more of a focus toward snow across North America as a whole as we change seasons.