textproduct: Western and Central Wyoming

KEY MESSAGES

- A cold front will cross the area tonight and Tuesday and bring much cooler temperatures and a chance of showers (30-40% coverage).

- Cooler and unsettled much of the week starting on Tuesday with chances of showers each day. The heaviest precipitation is expected Thursday into Friday.

UPDATE

Issued at 1230 PM MDT Mon Mar 30 2026

Forecast is still on track with FROPA later this Monday afternoon and into the evening/overnight hours. Shower activity behind the front looks to be less in coverage with the latest model trends, with many lower elevation areas remaining dry. The snow overnight into Tuesday will remain in the higher elevations, with not much of an impact to mountain passes. As such, will forego any winter headlines with this initial FROPA with much more to come for Wednesday and Thursday that will have a much greater impact to higher terrain and passes. Latest guidance has output of a foot or two of snow for western mountains, even extending to the Bighorns Thursday. This is likely a bit overdone as per usual with the NBM/WPC guidance, but will still likely (80-90%) exceed advisory level amounts if not warning level by the end of the system as it exits Friday.

Otherwise, winds and critical fire weather conditions continue this afternoon and into the evening hours. Winds will drop quickly towards sunset as the gradient relaxes in wake of the FROPA overnight. Well above average temperatures a couple degrees warmer today due to diurnal suppression ahead of the aforementioned frontal boundary. Record high temperatures should remain safe, though, as has been the case the past couple of afternoons. Enjoy the warmth while it lasts, as the cooler air pushes in tomorrow for the remainder of the week but still seasonable for this time of year. It still is early spring in WYoming...

DISCUSSION

Issued at 337 AM MDT Mon Mar 30 2026

I apologize for the lateness of this discussion. I had it 90 percent done. And for the reason why, I will direct you to the classic 90s movie Men In Black. It is when Tommy Lee Jones' character (Agent K) tells Will Smith's character (Agent J), "The red button there, kid. Don't ever touch the red button." Well, I touched the red button, and almost an hour of work went down the tubes. So, we have to start again. The general trend of the weather will will be more of the same today, then a change to a cooler and wetter pattern for much of the remainder of the work week.

We will have one more warm day today, with many locations 20 degrees above normal once again. And, like previous days, will be combined with relative humidity falling below 15 percent. And, again, we will have to deal with the wind. The difference is it will be stronger today, the reason being a tightening pressure gradient ahead of an advancing cold front moving out of Montana. Just about the entire area has at least a 1 in 2 chance of wind gusts over 30 mph. So, with critical fire weather likely we continued the Red Flag Warning as is. The second question today would be, do we need high wind highlights? For now, we decided against it. The only area with a greater than a 1 in 2 chance of wind gusts past 55 mph for a sustained time in the lower elevations would be the far western Cody foothills. And these areas have few roads or people so impacts would be minimal. In addition, fire weather looks like the greater threat so we wanted to emphasize that. There could be an isolated gust to 60 mph in the Upper Wind River Basin, south of Casper or near Buffalo, but it would be brief.

The aforementioned front will drop southward across the state tonight, and bring in cooler temperatures, around 20 to 30 degrees cooler for many locations. It will also bring some needed moisture. However, with its continental origin, not a lot of it. The best chance will be across northern Wyoming through tonight, with a second piece of energy possibly bring some showers to southern Wyoming Tuesday and maybe even a thunderstorm. As was stated earlier, amounts through Tuesday will be small, with less than 1 in 4 chance of a tenth of an inch across most of the lower elevations. We may also see some of the white stuff as well. But again, not a lot is anticipated. The only areas with a greater than 1 in 2 chance of 3 inches or more are the northern mountain ranges, mainly the Bighorns, Absarokas and the northern Tetons. The only place with a greater than 2 in 5 chance of 6 inches or more is the far northern Absarokas so no winter highlights will be issued this morning. In the lower elevations, a small accumulation will be possible in northern Wyoming as 700 millibar temperatures fall to around minus 6, putting snow levels between 5000 and 5500 feet. The only areas with greater than a 2 in 5 chance of an inch or more are the Cody Foothills and northern Johnson County, with less than a 1 in 10 chance of 3 inches or more. Most of this accumulation would be on non-paved surfaces. There could be a few slick roads later tonight but the high almost April sun angle should melt any snow on roads Tuesday morning.

The period of from Wednesday through Friday looks rather unsettled and damp for many, bringing some well needed moisture. The driver for this will be an upper level low that will move onshore in the Pacific Northwest Wednesday and cross Wyoming late Thursday into Friday. Showers will be ongoing Wednesday into Thursday morning, but this will be largely West of the Divide. There are a lot of small scale features through this initial period, so pinpointing heavier areas of showers is still difficult. The main impacts look to be later Thursday through Friday as the low moves across Wyoming. Models do have decent agreement with the placement of the low, bringing the center across central Wyoming. This would keep the heaviest precipitation across northern Wyoming, with tapering amounts further south. Much of the area has at least a 1 out of 2 chance of a quarter of an inch of precipitation over these three days, with many of the mountain ranges having a similar chance of over an inch of precipitation. And this also means some well needed snow for the mountains. The most will be in the favored northwest flow areas, like the Tetons and Bighorn range where there is greater than a 3 out of 5 chance of over a foot of new snow from Tuesday night through Friday. As for the lower elevations, mainly rain would fall through most of the Thursday. Colder air will then the pulled in as the low passes Thursday night and Friday, dropping snow levels to the valley and basin floors. Much of the area has at least a 1 in 2 chance of an inch or new snow. Chances of 3 inches remain limited though, with a 1 out of 2 chance largely in favored northwest flow areas like Ten Sleep and Thermopolis, some of the higher elevations areas like between Shoshoni and Casper as well as the western valleys. As for highlights, we will likely need some, especially for the mountains. However, we have held off for now to emphasize the fire Weather and wind concerns for today.

The low should clear the area by Saturday morning, followed by largely zonal to flat ridging over the area, bringing a return to above normal temperatures and breezy conditions for next weekend.

AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/

Issued at 1033 PM MDT Mon Mar 30 2026

The cold front is pushing southward across northern WY currently, with lower clouds and light precip already spreading into KCOD. Low clouds will reach KWRL and KCPR overnight, continuing into the day Tuesday. Cigs at KJAC will fill in and remain low VFR/MVFR through the night into the day as well. Precip chances have increased with newer model runs, so have updated most PROB30 groupings to predominant precip into the day Monday. Models have been differing on cigs at KLND/KRIW, but chances for lower cigs look better, so have brought down cigs, and added increased precip forecast for those sites.

Some brief improvements of cigs may develop late Monday afternoon, but any improvements would be brief, as a return of MVFR or lower cigs at all sites expected overnight Monday night.

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

FIRE WEATHER

Issued at 337 AM MDT Mon Mar 30 2026

Another day of well above normal temperatures, gusty to strong wind and humidity falling under 15 percent will bring one more day of elevated to critical fire weather to much of central Wyoming this afternoon and evening. Wind will be stronger than previous days, with some wind gusts past 50 mph possible. A passing cold front tonight will bring cooler temperatures and higher humidity starting on Tuesday. Much of the rest of the week will be unsettled with a chance of a wetting rain for some locations, especially Thursday and Friday.

RIW WATCHES/WARNINGS/ADVISORIES

None.