textproduct: Western and Central Wyoming

KEY MESSAGES

- A weather system brings light to moderate snow to much of the area from today through Thursday morning.

- The coldest temperatures in some time begin Thursday and continue into Saturday.

- Mainly dry weather returns Friday and lasts through at least Monday, with a gradually warming trend through the period.

DISCUSSION

Issued at 210 AM MST Wed Feb 18 2026

Much of the area East of the Continental Divide is about to get slapped back into reality of winter is really like in reality. It won't be a huge punch, like a Mike Tyson uppercut. It will be more like a good jab, like on from Larry Holmes or Floyd Mayweather Jr. In other words, it will turn much colder, but not bitterly cold. And there will be accumulating snow, but not a real big storm.

Back to the forecast now. Radar is showing a good band of snow at this time extending from Idaho into northwestern Wyoming, largely north of Jackson. This is in association with the right rear quadrant of a jet stream moving across the area. The main culprit for this system is an upper level low that is opening up across the Pacific northwest and will become a negatively tilted trough as it moves across Wyoming. We have some things guidance that are in fairly good agreement and a few things that don't line up very well even now.

There is good agreement on timing of the system. Most precipitation should remain west of the Divide through this afternoon, the spread to the east after sunset as the trough moves through the area. There is decent agreement in having the heaviest snow in the afternoon across western Wyoming and then progressing eastward, with the heaviest snow East of the Divide falling this evening from 6 pm until around 2 am or so. Amounts look fairly consistent West of the Divide as well. There could some locations on the peaks that get greater than 12 inches, but these are places with little impact or places that want to snow, like the ski resorts. Most of the western mountains still have a greater than 5 in 6 chance of 6 inches or more, but only around 1 in 4 chance over 12 inches. So, we will let the advisory ride here for now. In the valleys, the chance of 6 inches is less than 1 out 4 for the most part. One area of concern here is Alpine, where a period of favorable northwest flow with the trough axis may bring somewhat higher amounts, with around a 2 in 5 chance of 6 inches or more. We will let things go for now though. Snow will continue in the west, but should gradually taper off through the night.

Now we move to where things are a bit more uncertain, mainly East of the Divide with snowfall amounts. The main concern is the same as yesterday, the position of the 700 millibar low and it's impacts on things like easterly flow to bring in moisture and flow turning upslope to enhance areas of snow. So, we went with a blend of models with a good area of advisory level snow. For the advisory, we decided to go close to the 1 out of 2 chance of 3 inches or more on the National Blend of Model ensemble. This is generally east of a Shell to Thermopolis to Riverton line. All these areas have had Winter Weather Advisories starting at 00z Thursday and running through 18Z Thursday. The heaviest snow would likely fall in period from around 6 pm to 2 am though. As far as an area of 6 inches or more, the NBM ensemble is giving around a 2 in 5 chance form roughly the Fremont-Natrona County line to Casper as well as from east to Thermopolis to the south of Worland, probably indicating that more ensemble members are picking up on an enhanced period of northerly upslope in this location. Our in-house model also shows less than 1 in 4 chance of 6 inches or more in all locations. So, we kept things with advisories. The day shift can see if any locations need an upgrade to a warning. Most of the snow should end Thursday morning with dry conditions by sunset.

Our attention then turns to temperatures. Thursday will be a much colder day, 20 to 25 degrees cooler than today East of the Divide. Many locations have around a 1 in 2 chance of seeing below zero lows on Thursday night. The X factor will be how much clearing occurs. If it stays cloudy, temperatures could remain a bit warmer. For now, we went with low temperatures around zero. Not bitterly cold for Wyoming, but it will feel cold given the recent mild weather we have had.

Quieter weather should then dominate for the most of the remainder of the period. On Friday, a weak shortwave may bring a few showers to northwestern Wyoming but nothing heavy. Another system passing over Colorado may spread a few showers to southern Wyoming, but nothing heavy is expected. Temperatures should moderate a bit but remain below normal. Ridging then builds into the area Saturday into Monday and brings dry conditions along with moderating temperatures. Basins may be a bit longer to warm as there may be inversions, but these should gradually shrink as the stronger late February sun melts to the snow off and decreases the albedo. The next system should approach early next week and bring some showers to western Wyoming, but details this far out are difficult to hash out.

AVIATION /06Z TAFS THROUGH 06Z THURSDAY/

Issued at 930 PM MST Tue Feb 17 2026

West of the Divide...KBPI/KJAC/KPNA/KRKS Terminals.

VFR and dry to start the period with incoming snow pushing in from Idaho. This should be on station for JAC/BPI/PNA after 08Z bringing in MVFR conditions with light snow. Winds remain light less than 10kts. This will becoming predominant after 14Z with possible IFR conditions for JAC after 23Z as winds increase with the FROPA. RKS looks to be more than likely dry with best chance for any snow after 00Z (10-15%) with VCSH. Winds will be strongest for RKS after 15Z up to 30kts increasing to 35kts after 00Z with FROPA with a more westerly flow at that point in time. Snow and winds will diminish into the next TAF cycle into Thursday morning.

East of the Divide...KCOD/KCPR/KLND/KRIW/KWRL Terminals.

VFR conditions with diminished winds to start the period. Winds increase for COD/CPR after 10-13Z with the incoming system from the southwest. Snow looks to begin first at LND/CPR after 01Z, then to RIW/COD/WRL by 02Z as winds increase to the north to northeast behind FROPA. Light snow and MVFR conditions more likely (60-70%) through the end of the period and for much of the next TAF cycle. Improvements do not look to occur until later Thursday morning and possibly early afternoon for CPR into the 12Z period.

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

Winter Weather Advisory until 11 PM MST this evening for WYZ001-012-014-015-024.

Winter Weather Advisory from 5 PM this afternoon to 11 AM MST Thursday for WYZ005>011-017>020-022.

Winter Weather Advisory until 5 PM MST this afternoon for WYZ013-023.