A Weak Week

Posted Wednesday, January 13th, 2021 by Jackson Sponaugle

TL;DR: A weak system is expected to impact the area today with no major accumulations, and high winds. A ridge will build into the weekend, but a pattern shift will follow next week.

Nowcast: The valley inversion has weakened overnight due to high clouds warming the inverted layer. This has cleared some of the pollution in the valley air, but moderate air persists this morning. High stratus clouds are over the ski resorts, and are expected to hang around. Gusty conditions in the mountains are expected this afternoon. Alta could have gusts as high as 50 mph. Below is a current look of Superior:


Notice the valley is somewhat clear and skies are overcast with small patches of blue sky.

Short-Term Forecast: A brief passing trough is expected to have little impact to Utah as it stays to our north. Central Idaho and Jackson Hole are getting the bulk of this storm. There are high precipitable water values in the atmosphere today, but this current trough is not expected to bring any major precipitation to the ski resorts. Alta could get 2 inches at most, but some precipitation could fall as rain. Expect dust on crust and hope for the best. Here is a look at the GFS 500mb Geopotential Height Anomaly for later today:


You can see that the Wasatch is barely missed, and the ridge continues to build to our west.

Long-Range Forecast: As we look forward, we have good news for our air quality. The ridge will build into the weekend, but there will be small frequent trough passages to mix out the valley inversion. The bad news is that these troughs do not look to bring major accumulations. There is also a pattern shift that will hopefully move the ridge to our west. This could bring cold temperatures and more snow late next week. Something to keep an eye on as we approach the beginning of next week.

Jackson Sponaugle

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