Smoke issues aside (more on that later), Labor Day weekend is shaping up to be outstanding for many areas of the West with dry conditions expected. A ridge of high pressure will build across the West over the next 5 days, resulting in warm days and cool/crisp nights for most mountain areas.

 

Temperatures will be warmer than average and summer-like throughout the West over Labor Day weekend, so high elevation areas and coastal areas will be the most comfortable.

While an overall drying trend is expected this weekend, parts of the Central and Eastern Rockies are experiencing active weather Friday on the backside of a disturbance moving through.

This disturbance has some late-season monsoonal moisture to work with, and scattered thunderstorms will develop across Colorado and surrounding states on Friday afternoon. Although storms will be moving at a pretty good clip, brief heavy rains will be possible under stronger storms.

Current Radar

Lightning Density

Forecast Radar

On Saturday, moisture will retreat farther south with the best thunderstorm chances expected over New Mexico, while Southern/Central Colorado will only see isolated activity.

Smoke and Wildfire Update

First of all, the good news since my last post is that the Caldor Fire (which has threatened South Lake Tahoe along with multiple ski resorts) has slowed thanks in part to decreasing winds. Wind speeds look to remain below critical levels through the holiday weekend but could increase again toward the middle of next week.

High pressure centered over California is helping to keep most of the smoke confined to Northern California, Nevada, and Oregon with lessening impacts farther east. However, a few fires have flared up over the past week in Oregon, Idaho, and Montana, which will continue to result in periods of smoke and haze across the Northern Rockies.

The overall pattern on Saturday looks similar to Friday, though smoke will increase across Oregon and decrease to some extent across Utah.

Forecast Smoke (surface)

Forecast Smoke (sky)

Current Air Quality

From Sunday through Tuesday, only slight day-to-day variations are expected in the overall pattern with the heaviest smoke remaining concentrated over Northern California, Nevada, and Oregon and also extending east into Idaho.

Forecast for Friday, September 3rd

Some of the rainfall across western portions of this map already occurred early on Friday morning with a drying trend ensuing from west to east. However, afternoon thunderstorms will develop across Eastern Wyoming, Colorado, Eastern Utah, and Arizona and New Mexico. 

Forecast for Saturday, September 4th

The focus of rainfall will shift southward into New Mexico and Eastern Arizona, with locally heavy rains and flash flooding possible. Colorado will see a noticeable downtick in thunderstorm activity, but some isolated storms could develop over the Sangre de Christo Range and Southern Front Range/Continental Divide Region.

A powerful storm system will impact Vancouver Island and the Coast Range of British Columbia on Saturday, with light to moderate rain showers extending south of the border into the Northern Washington Cascades and Olympic Peninsula. 

Forecast for Sunday, September 5th

Lingering showers over the Cascades and Olympics early in the day should taper off by the afternoon. A drying trend is also expected across the southwest will little to no thunderstorm activity in Colorado while the best chances of storms will be confined to Southern New Mexico and Arizona.

Forecast for Monday, September 6th

Labor Day is looking nearly precipitation-free across the West, with the only exception being some possible terrain-driven isolated thunderstorms activity over the Southwest and perhaps into Southern Colorado.

Forecast for Tuesday, September 7th

An approaching weak disturbance will result in showers across the Cascades. Elsewhere, a quiet pattern will continue with only some isolated thunderstorms across the Southwest as you get closer to the Mexico border.

Outlook for Wed, Sept 8th - Sun, Sept 12th

High pressure will continue to dominate the pattern across the Rockies around the middle of next week, while a weak disturbance could potentially bring some showers to the far northern Rockies on Wednesday.

As we head into the weekend of September 11th-12th, high pressure is projected to weaken with some energy and moisture arriving from the Pacific via southwesterly winds aloft. This will result in shower chances and cooler temperatures across the Olympics, Cascades and Northern Rockies.

Late-season monsoonal moisture is also projected to surge northward into the Central Rockies, which will result in chances for showers and thunderstorms along with a gradual cooling trend.

Thanks so much for reading and have a great holiday weekend! Next update on Wednesday (9/8).

ALAN SMITH

P.S. Could you take a moment to rate the OpenSummit app with a 5-star review? These reviews help us to be seen by more people, and a larger audience provides the support needed for us to build more features and value for you.

Review iPhone app

Review Android app

Simply click either link above and scroll down to the section titled 'Ratings & Reviews'.