textproduct: Western and Central Wyoming

KEY MESSAGES

- Light snow shower chances (20%) exist through 6PM MDT across the western mountains, the Bighorns, and Casper Mountain.

- A potent winter storm system is forecast to bring widespread precipitation, wind, and freezing temperatures to the entire area beginning late Wednesday until Friday evening. Confidence in measurable snowfall continues to increase for low elevations.

- There is high (90% +) confidence in a hard freeze (28 degrees or below) across low elevations Friday morning and Saturday morning, with the potential for widespread lows in the teens on Saturday morning.

UPDATE

Issued at 100 PM MDT Tue Apr 14 2026

Today's weather is on track to be the last tranquil day across the area before the upcoming weather system. Weak flow with relatively dry mid-level air will be present behind the departing trough and allow for mostly sunny skies this afternoon. Expect highs to be in the 60s east of the Divide and in the 40s to 50s west of the Divide. As mentioned in the morning discussion, isolated light snow shower chances (20%) exist this afternoon across higher elevations as a weak disturbance traverses the state. Breezy conditions are expected west of the Divide as this disturbance passes over this afternoon.

All attention continues to be focused on the upcoming winter weather system that is forecast to impact the region Wednesday night through Friday. This system, a strong cold front, is expected to bring widespread wind, precipitation, and cold. As the trough and associated cold front makes its way into the northern Rockies on Wednesday, expect strong southwest winds Wednesday afternoon as the pressure gradient tightens ahead of the cold front. Frequent wind gusts of 25 mph to 40 mph can be expected across most of the area and result in elevated fire weather conditions. Relative humidity values are expected (70-90%) to remain above 20 percent.

The first push of the winter weather arrives across western Wyoming Wednesday afternoon. Across the western mountains, the most likely period of heavy snow will occur early Wednesday evening through midday Thursday as the cold front makes its push east. Snow totals have also trended up across the Wind River Mountains beginning Wednesday evening, so this area has been added to the Winter Storm Watch. Precipitation will then spread east across the rest of Wyoming Thursday afternoon, most likely as rain. The cold push currently looks to not arrive until after sunset on Thursday for most low elevations. Thanks to strong cold air advection, this will feel like a good punch of cold behind the front with 700mb temperatures rapidly dropping from positive 2 celsius to near negative 10 celsius in a matter of hours. This strong northerly push will also result in gusty winds, especially near Buffalo where there is an 85% chance of 45+ mph gusts. Given the moisture content with this system and the cold temperatures, there is fairly high confidence (80%+) in most low elevation areas seeing measurable snowfall by Friday morning. However, no highlights will be issued at this time for locations east of the Divide due to the greatest impacts occurring in 2+ days (Thursday night into Friday midday).

DISCUSSION

Issued at 145 AM MDT Tue Apr 14 2026

Finally a more active pattern across Wyoming trying to bring precipitation! The latest system is a trough ejecting into the central Plains from the Four Corners region. This system is set a little too far south to bring a significant amount of precip, but still enough energy to produce precip for areas of Casper Mountain, the Bighorns, and higher elevations of the Tetons.

But this does set the table for a potent late winter storm diving out of the PacNW into the northern Rockies. This system starts to spread precip into the NW mountains during the day Wednesday before slowly moving east Thursday and Friday. The system will be accompanied by ample moisture, so the potential for meaningful accumulations is improving. The system will also be accompanied by a strong push of colder air, so most precip will be snowfall, especially Thursday night into Friday. This includes most of the lower elevations as well, with the current forecast totals of 2 to 5 inches. Winter Storm Watches have been posted for the northwestern Mountains and YNP for this system, and may need to be expanded is the snow forecast increases with later updates.

The other concern with this next system is the significant cold air push coming with and behind the next system. Cold temperatures will arrive during the day Thursday, with lows Thursday night in the low to mid 20s east of the Divide and in the teens west of the Divide. The main core of the cold air then settles in on Friday, with the core of the cold air setting in Friday night. Probabilities of temperatures falling below 28 degrees are high (>90%), with current forecast lows reaching the teens. The complicating factor will be how quickly cloud cover clears out behind the weather system, allowing for radiational cooling. If clouds hold longer, these teens would likely not be achieved.

AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/

Issued at 1057 AM MDT Tue Apr 14 2026

VFR conditions are expected to prevail across nearly all terminals through much of the TAF period. The one exception to this currently is KJAC where some linger low level clouds persist. Conditions should continue to improve shortly after the start of the period with VFR conditions likely to return. A shower or two cannot be ruled out around 21Z Tuesday nearby KJAC. Due to low confidence in direct impacts at the terminal only a VCSH group has been added. Winds gradually increase this afternoon with nearly all terminals seeing winds of 15 to 25 knots. These winds should dissipate shortly after sunset with light winds around 5 to 10 knots persisting through the overnight. A nearing disturbance will start to usher in more cloud coverage for Wednesday. Winds will begin to increase near the end of the TAF period mainly across northern and western terminals. Mountain obscuration will linger mainly across western mountain ranges as low clouds continue to burn through the early afternoon with improvement expected by the mid afternoon.

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 Storm Watch from Wednesday evening through late Thursday night for WYZ001-002-012.

Winter Storm Watch from Wednesday evening through Friday afternoon for WYZ014-015.