textproduct: Western and Central Wyoming

KEY MESSAGES

- Today will be a mainly dry and cool day across the area.

- The coldest temperatures of the year for many arrive Friday and linger through Saturday night.

- There will be a couple of chances of light snow, one tonight and Friday and another Saturday. However, no major storms are expected for through the middle of next week at this time.

DISCUSSION

Issued at 237 AM MST Thu Jan 22 2026

For the most part things are quiet at the humble Riverton weather abode as high pressure is bringing dry, quiet and for the most part seasonably cold weather tonight. We have two questions tonight that we are pondering tonight for the forecast as we listen to classic rock tonight (two Gen Xers working tonight). The first is how much snow we will get over the next three days, and the second, more important question, is how cold will it get as we have the coldest air of the season moving in for the weekend and will people be Stone Cold, Cold As Ice or So Cold (I threw in Breaking Benjamin for the Millennials). We will do something different and address these individually.

We will start with snow. Dry conditions are expected today, but the next cold front (the third we have seen this week) will across the area tonight and into Friday. And, I'm going to sound like a broken record, with the Arctic origins of the air, has little moisture to work with. As a result, snowfall amounts are expected to be light. In the deterministic model realm, the European brings a fairly broad area of light QPF (less than a tenth of an inch) across most areas East of the Divide. The GFS is much drier with only some light snow showers across areas East of the Divide. Then we transition into the probabilistic realm of ensemble guidance. The snow is still expected to be of the anafrontal variety, falling behind the front. And with the northerly flow behind the front, the heaviest snow (a relative term with this system) would fall in the favored northerly upslope locations. This looks to be further east as well, generally around Casper and from Thermopolis and eastward into the southeastern Bighorn Basin. Even here, the chance of over an inch of snow in the lower elevations is only 1 out of 2. When we bump the totals to advisory level (3 inches), the only possible area is around Casper, where there will be a bit of right rear quadrant jet energy to enhance lift a bit. Even here, the chance is only 1 out of 5 at the most. This, plus the fact the cold air will ooze in rather then move in quickly, wind should not be too strong. So, no advisories here. Elsewhere, the chance of an inch of snow is less than 1 out of 10. This round of snow should end Friday night. After a dry Saturday, the fourth and last front will move into the area Saturday night. This system is even drier and will bring even less snow, with only some showers expected and any accumulation expected to be light.

The main story looks to be the cold air, the coldest of the season. One disclaimer here, this will not be a record breaking cold outbreak. temperatures will generally be 10 to 15 degrees below normal as the core of the cold air will remain well to the east, over the northern plains and Great Lakes, with Wyoming seeing more of a glancing blow. The 700 millibar temperatures will be generally down to around minus 21, as opposed the minus 30s further east. Friday will be the coldest day in a long time for areas East of the Divide, with highs remaining in the teens and single digits. As of now, it is looking more likely that many areas will see lows in below zero East of the Divide, with most areas having at least 4 out of 5 chance. There are still a couple of wild cards though. One is if the clouds don't clear quickly enough, keeping temperatures up just a bit. The other is snow cover. Areas further west may not have any snow cover, keeping temperatures a bit warmer. The coldest temperatures may end up being in Natrona County, where snow cover should be the deepest, aiding in cooling. Here, there is a 2 out of 5 chance of lows lower than minus 10. As for cold highlights, don't think they are needed now since minus 20 is not expected and the wind should be fairly calm. Saturday looks cold as well.

The cold should not last though, as the cold air moves to the east as flow turns more northwesterly and westerly. A slow moderation begins on Sunday, but should really be felt on Monday as a weak shortwave approaches and mixes out the atmosphere. Temperatures should return to above normal levels again on Monday. The forecast gets more muddy after that, but no Arctic air is expected as we had toward the end of January.

AVIATION /18Z TAFS THROUGH 18Z FRIDAY/

Issued at 1000 AM MST Thu Jan 22 2026

VFR conditions expected through the period at all locations. Light winds 10kts or less not expecting more throughout the period. Increasing clouds in the upper level this afternoon lowering to the mid levels after 02-03Z with a disturbance skirting to the northeast. This will bring some low confidence snow at CPR after 12Z with a prob30 group at this time. COD/WRL even lower confidence snow chances (<10%) with VCSH after 12Z. Otherwise, low but VFR ceilings for these locations and all other in the mid levels around 8-10kft. Expect mountain obscuration for the remainder of the period after 06Z for much of Friday.

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

None.