textproduct: Western and Central Wyoming

KEY MESSAGES

- Strong wind likely in Johnson County this morning, otherwise mainly dry with temperatures close to normal for most.

- A cold front will bring some of the coldest temperatures in quite a while for many locations Friday into the weekend.

- There will be a few chances for mainly light snow, but no major storms are expected through the weekend.

DISCUSSION

Issued at 158 AM MST Wed Jan 21 2026

It has been a very mild winter across most of the area so far this year. It has turned more seasonable lately, but we have been lacking some really cold temperatures. Many locations continue to average more than 10 degrees above normal through meteorological winter (December through February). And locally, here at the humble Riverton weather abode and in nearby Lander, I was looking at below zero lows, or the lack of this year. At the airport, we have not done it once so far this winter. This currently the second latest (2000 was January 29th) and Lander, which has records that date back to 1891, it is the third latest (February 25 in 1934 is the latest). We may finally have a chance to reach that mark, but in a few days.

Today looks to be a seasonable and mainly dry day. We can't completely rule out a stray snow shower over the Bighorns, but the chance is so low (less than 1 out of 10) we have left it out of the forecast. This will be courtesy of another cold front dropping southward through the area, and has even less moisture then the one yesterday. The main impact will be more gusty wind, mainly over Johnson County, as is usual with cold advection / northwest flow situations. I have a small concern for a few high wind gusts, as the NBA ensemble guidance has a 1 in 2 chance of wind gusts of 50 mph and there is some right front jet dynamics for a bit of downward forcing. The strongest wind would only last around 6 hours. This is a bit similar to yesterday except no snow, when the high wind gusts were isolated. So, no wind highlights although we may issue a Special Weather Statement. Gusty breezes may be found elsewhere but no high wind.

Thursday looks to be a day of near to below normal temperatures, with breezes that will make it the coolest day in a while. It looks mainly dry during the day, but the question is what will happen when the third cold front this week approaches and moves through the area. This one has Arctic air behind it and as a result little moisture. However, it does have some right rear quadrant energy that may enhance upward motion somewhat. The problem is there is little moisture to lift. There is a model spread with the deterministic models, with the European the wettest, but even it only gives barely over a tenth of an inch of QPF. As for probabilistic guidance, the best chance of over an inch of snow is around Casper, where some anafrontal northerly flow may bring a brief period of upslope, but even here it is only around 1 out of 3 through Friday night. Snow showers would could fall in areas similar to Tuesday. The snow will not be the main concern though.

The main concern will be the cold temperatures, the coldest of the year for many locations. Models have trended colder than yesterday. And although the core of the cold air will remain well east of Wyoming, some areas will see 700 millibar temperatures as low as minus 20. This is the best chance of areas like Riverton and Lander to finally fall to below zero. Probabilistic guidance gives at least a 1 in 2 chance of lows below zero across most areas East of the Divide. The one concern I have is that the cold advection may have to overcome cloud cover. However, Friday night looks to be the coldest night in a while for many locations.

Saturday looks drier and a bit warmer before another cold front moves through Saturday night and Sunday with a reinforcing shot of colder air. This is similar to the last few, with more wind impacts than snow as it, say it with me, moisture starved. Following that, flow turns more zonal again and will bring a return to near to somewhat above normal temperatures by early next week.

AVIATION /12Z TAFS THROUGH 12Z THURSDAY/

Issued at 416 AM MST Wed Jan 21 2026

VFR conditions expected through the next 24 hours, starting with clear skies before some high cirrus sweeps in this evening. Gusty northwest winds continue to sweep across central WY, and will continue to bring gusts of 25 to 30kts for KCPR and KBYG, with remaining sites stay below 10kts.

RIW WATCHES/WARNINGS/ADVISORIES

None.