Another Pattern Shift Brings More Spring Warmth

May 12th, 2021
A dip in the jet stream over the Pacific Northwest Friday evening will bring several...
A dip in the jet stream over the Pacific Northwest Friday evening will bring several thunderstorms to Wyoming, some of which could be strong to severe.(KGWN)
Updated: May. 12, 2021 at 12:15 PM CDT
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The winter weather is now behind us (for those of us that dealt with it) and warmer temperatures are coming back around as the jet stream begins to lift over the western half of the country and a bit of a ridging pattern builds in. Temperatures are expected to climb through Thursday and into Friday before leveling off around the region. Most locations will be hovering in the mid 60s-mid 70s, with Cheyenne on the lower end of that range, Casper in the middle, and Scottsbluff Nebraska the upper. This is important to note with storm chances that ramp up as we finish off the week and head into the weekend.

There is the possibility for some scattered showers and storms today, but they will mainly be reserved for the eastern third of the state. Showers and storms are expected to form off of the eastern side of the Big Horn and Laramie Mountain Ranges later this afternoon. There is a possibility for somewhere like Casper towards Central Wyoming that sees an isolated shower, however that chance does remain quite low. It is more likely that Casper will just see scattered clouds during the afternoon, with somewhere further east like Douglas having the chance for showers. The highest possibility for showers and thunderstorms this afternoon will be northeast Wyoming in places like Gillette and Newcastle and the Panhandle of Nebraska.

Tomorrow looks to be the day of the week with the lowest precipitation chance thanks to the ridge reaching its peak. A few isolated showers will remain possible, though at this time they look to be reserved to the northeastern corner of Wyoming and into South Dakota. A good bit of cloud cover is expected however, especially in the afternoon hours. Pockets of sunshine should still hang around as temperatures continue to climb, with Cheyenne reaching the upper 60s and Casper into the lower 70s. Scottsbluff Nebraska looks to reach the mid 70s, along with some areas in northern Wyoming like Thermopolis and Worland.

Friday is when the next “pattern shift” takes place. Temperatures will drop by only a few degrees, however a shortwave trough from the west in the jet stream will drive up instability and generate widespread thunderstorm activity in the afternoon. Heavy downpours are likely with these storms, as well as some strong wind gusts and small hail. The SPC will likely issue some form of severe weather risk with these storms as well, though for Wyoming it is unlikely this goes above the Slight (Level 2) risk. Wyoming will likely remain in the Marginal (Level 1) risk due to temperatures topping off in the upper 60s and lower 70s. The Panhandle of Nebraska will be the place to watch, as storms coming from Southeast Wyoming like to merge and intensify in the region. Temperatures for the Panhandle are expected to be in the mid 70s as well.

This pattern will continue through the weekend as some energy breaks off the jet stream and hangs around the Western US. The highest risk for severe weather will likely be Friday and Saturday, however the possibility for more strong storms Sunday and Monday remains before the risk drops off a bit come Tuesday. Temperatures will continue to hover in that mid-60s to mid-70s range, even with the passing of the trough.

CHEYENNE, Wyo. (Wyoming News Now) -

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