textproduct: Western and Central Wyoming

KEY MESSAGES

- Scattered snow showers will be possible across much of the state this afternoon and evening.

- Clearing skies should allow for a hard freeze tonight into Saturday morning as temperatures drop into the teens and low 20s across nearly all low elevation locations.

- Dry and tranquil weather expected from Saturday through early next week, with above normal temperatures returning Sunday and especially from Monday through Wednesday.

UPDATE

Issued at 103 PM MDT Fri Apr 17 2026

The jackpot from this recent system was across portions of Natrona and Johnson Counties. Snow reports from this morning show amounts ranging from 3 to 7 inches around Casper and 1 to 3 inches across Johnson County. While for the Wind River Basin it was another reminder of the disappointment that was this winter. Little to no snow fell across the basin, which is how things were trending over the past day or so. As for the forecast much of the previous discussion remains on track with scattered snow showers developing this afternoon and evening. Otherwise, the main focus will be cold overnight temperatures Friday night into Saturday morning. Freeze warnings remain in place across the Bighorn Basin and lower Wind River Basin as well as the Lander Foothills. Temperatures tonight look to get even colder than this morning. Clouds cleared out briefly this morning but are gradually building back in as a result of developing showers. Clouds should clear out after sunset tonight leading to mostly clear skies overnight. This should further aid in the cooling, allowing for a prolonged hard freeze tonight into Saturday morning across nearly all low elevation locations. Lows are expected to drop down into the low 20s to upper teens east of the Divide and low to mid teens west of the Divide. Locations such as YNP may see temperatures drop to near or even possibly below zero due to new snowcover. As a result, of these temperatures Freeze Warnings are going to be issued for portions of Johnson and Natrona County for tonight through Saturday morning. Sensitive plant life will be in danger along with any outdoor plumbing such as sprinkler systems.

The remainder of the weekend into the first half of next week sees a return of dry and mild conditions. Early summer-like weather arrives by Monday with temperatures returning to the mid to upper 70s east of the Divide and upper 60s to low 70s west of the Divide. By the second half of the week there is the possibility for another disturbance to enter the region. However, any hopes for precipitation should be checked as this most recent system is a great example of how quickly the forecast can change. Overall, next week bears monitoring but at this time, its still way too far out and uncertainty is too high to have any idea of what to expect.

DISCUSSION

Issued at 135 AM MDT Fri Apr 17 2026

Score one for the GFS yesterday. It had the area of snow from the Fremont / Natrona County line to Casper nailed down fairly well. Some snow is continuing this morning as I write this around 1 am and will continue in eastern portions of the area through the night but it appears the heaviest snow has come to an end. We will likely expire most of the advisories at 6 am and likely cancel the Wind River Range as most guidance shows the heavy snow just about over. We will leave Natrona County up for now, given it has been the center of the heaviest snow and roads should remain slick until the strong mid April sun can melt them off through the morning.

The main story today will be the much colder temperatures when compared the previous several days. With areas that saw snow, like Casper, struggling to get out of the 30s. And, with moist northwest flow remaining as well as cyclonic curvature over the area, there will be some convective snow showers around the area and possibly a few snow bands. These are almost impossible to pinpoint but most areas will have at least a 1 in 5 chance of one. Accumulations should remain light, with a less than 1 in 10 chance of 3 inches or more even in the mountains, with most locations receiving less than an inch. At this time, travel concerns from them should be minimal, as the strong sun angle should keep roads mainly wet unless the snow persists.

These snow showers should decrease as we lose the heating of the day, with most ending by midnight. The concern then turns to the cold temperatures. We still look to have a widespread freeze across many locations East of the Divide. We will continue the freeze warnings in the zones that already have them. We will likely need them in other zones but will let the day shift do that after the Winter Weather Advisories are over. Expected low temperatures have come up a bit in the area with little snow, but most locations still have a greater than 4 out of 5 chance of low temperatures below 25 degrees. Exactly how cold it does get will have to do with how quickly the sky can clear, and there is still some uncertainty with this.

More tranquil weather should then be the rule for at least the next 4 days as ridging builds across the northern Rockies. Temperatures will begin to rebound. Saturday looks near to below normal, but then much warmer temperatures move in for Sunday and through at least Wednesday. Monday and Tuesday look especially warm, with some of the warmer spots making a run at 80 degree high temperatures. The only concern would be possible elevated fire weather, especially in areas favored to southwesterly breezes, like Casper. Saturday likely won't be a problem with the snow bringing some needed moisture, but possible Sunday and early into next week, especially Wednesday. The next potential weather maker is an upper level low that will move into the Pacific Northwest on Tuesday and move toward the area for the middle of the week. There has been poor model consistency in regarding the low, so details are impossible to predict at this time. However, this looks to be our next chance of precipitation for the middle or end of next week.

AVIATION /00Z TAFS THROUGH 00Z SUNDAY/

Issued at 345 PM MDT Fri Apr 17 2026

VFR conditions expected at all locations throughout the entirety of the period. Winds will diminish by 02Z with radiational cooling and improving skies overnight. With that, expect a light fog possible (20-30%) around CPR with the recent snowfall. Otherwise, a low scattered stratus deck around JAC off the lake but otherwise VFR expected. Winds will increase once again towards 16-17Z with daytime heating and mixing to the surface, highest at CPR/RKS up to 25kts and up to 18kts at COD/RIW. This will last through the end of the period with no other weather elements expected at this time.

Please see the Aviation Weather Center and/or CWSU ZDV and ZLC for the latest information on icing and turbulence forecasts.

RIW WATCHES/WARNINGS/ADVISORIES

Freeze Warning until 9 AM MDT Saturday for WYZ003>006-017-018.

Freeze Warning until 9 AM MDT Saturday for WYZ010-011-019-020.