textproduct: Western and Central Wyoming

KEY MESSAGES

- A cold front will bring a 30 to 50 percent chance of light rain and snow to northern Wyoming through the overnight, mainly across the mountains. Dry but cooler conditions will be seen elsewhere on Sunday.

- Temperatures trend back up early next week, with little chance of precipitation through at least midweek.

UPDATE

Issued at 1225 PM MDT Sat Mar 21 2026

The forecast remains on track today. Wind is expected to ramp up over the next couple of hours as the upper jet dips into the area and a surface low develops over eastern Wyoming. This will exacerbate fire weather conditions today compared to the past few days given the stronger wind and still very dry mixed layer. The cold front mentioned below will push into far northern Wyoming between 4 PM and 6 PM bringing a transition to northerly wind as it pushes into central Wyoming this evening. Wind will generally decrease after sunset, though the initial arrival of the front is expected to bring brief northerly gusts of 25 to 35 mph to the Bighorn Basin, Johnson County, and Natrona County. Brief mountain rain or snow may accompany the front this evening across northern Wyoming, with the best chance for any lower elevation rain across northern Johnson County (20 to 40 percent chance of at least a trace).

DISCUSSION

Issued at 1252 AM MDT Sat Mar 21 2026

It has certainly been an usually warm stretch of weather we have had over the past few days, with numerous all time March record high temperatures being broken. And it will be more of the same today before somewhat cooler air moves in for Sunday. However, this pattern of above normal temperatures and below normal precipitation looks to continue through much of next week as well, much to the chagrin of many, as we need rain badly.

Today will be another warm day, with temperatures close to or even a bit warmer than yesterday. This should be the last day of widespread record high temperatures though as a cold front will be moving through tonight to bring some cooler weather. However, it will also bring something else, wind. And this wind should be rather strong. The NBM ensemble gives around a 2 out of 5 chance for wind gusts past 60 mph in the Cody Foothills for example. As for high wind, things look borderline at this time. We do have a few 50 knot wind barbs at 700 millibars, but these are largely near the Absarokas in places where impacts are small. Clark could have some wind gusts over 60 mph, but warning criteria is higher here as are a few mesonet sites near the Absarokas. So, we will hold off on any high wind highlights. Elsewhere, the chance is generally less than 1 out of 3. Almost all areas have at least a 4 out of 5 chance of wind gusts past 40 mph through, so it will a toupee and trash can alert day for all areas. However, there is a greater concern today.

That is fire weather. We have had a Red Flag Warning for the past three days and that will continue today. However, today looks especially concerning. Guidance has been a bit too high with relative humidity the past few days, so we have had to lower values again today. Some areas will see single digit humidity this afternoon. This, combined with the very day fuels, high temperatures 30 degrees above normal and wind gusting past 40 mph, will bring an especially impactful fire weather day. With this, we have added Big Horn County to the Red Flag Warning. Although humidity may be borderline, the increasing wind and hot temperatures more than warrant it. Please do not do any burning today, especially in the afternoon.

The aforementioned cold front will move toward northern Wyoming later this afternoon, dropping southward across the area through the night. It will be accompanied by wind, especially in the northwest flow areas like the Bighorn Basin and Johnson County. Unfortunately, it will not be accompanied by something we need very badly, a decent amount of precipitation. Any precipitation would likely be restricted to northern Wyoming, there there may be just enough jet forcing to squeeze some rain and mountain snow out of the meager moisture with the front. The only are with a 1 out of 2 chance of a tenth of an inch of QPF is the western Bighorn Range. At most, the lower elevations would receive 0.05 inches with most locations seeing nothing. The chance of any rain should end by around noon on Sunday.

Temperatures will be cooler on Sunday behind the front, but still above normal for most locations. The largest contrast will be across northern Wyoming where temperatures will be 20 to 25 degrees cooler than on Saturday. The difference then tapers off further south, with about a 10 degrees difference in southern Wyoming. There could still be some fire weather concerns though. Relative humidity will remain very low across southern Wyoming, possibly falling into the single digits again. Wind looks borderline at this time though. So, for now we will not issue any extension of the Red Flag Warning and will let future shifts take a closer look.

Temperatures will then begin to rise again as flow turns back to west to southwest with flat ridging over the area. Monday will be warmer, but the real warmer temperatures move back in for Tuesday and Wednesday, with some of the warmer locations taking a run at 80 degrees once again. The greater concern will be fire weather though. A subtle short wave will approach on Tuesday. It could bring a few showers to northwestern Wyoming but the bigger impact will be increasing wind. Relative humidity looks borderline on this day though. Of much more concern is Wednesday, when a stronger cold front may approach, tightening the pressure gradient even more. THe dew points also look to be around 5 to 10 degrees less, bringing a fairly large area of relative humidity under 15 percent. This is another day to watch for critical fire weather. Temperatures may cool again behind the front for the end of next week, but still some uncertainty. So, the theme of the next seven days continues to be above normal temperatures, below normal precipitation and periods of elevated to critical fire weather.

AVIATION /06Z TAFS THROUGH 06Z MONDAY/

Issued at 1030 PM MDT Sat Mar 21 2026

VFR conditions expected throughout the period at all TAF sites. Some low clouds at COD/CPR/WRL overnight with the passing system to the northeast but remaining VFR. Any shower activity will be limited to the higher elevations of the Absarokas and Bighorns. Otherwise, winds have diminished post FROPA to 10kts or less for the overnight hours remaining so through much of Sunday. However, a slight gust up to 18kts at COD/RKS with daytime heating of the afternoon with drainage for COD and the LLJ for RKS. These will diminish towards sunset after 00-01Z with all TAF sites 10kts or less at this point towards the end of the period and overnight into Monday.

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

FIRE WEATHER

Issued at 1252 AM MDT Sat Mar 21 2026

A combination of humidity falling to around 10 percent, record warm temperatures and a strong wind with gusts to around 50 mph will bring elevated to critical fire weather to much of western and central Wyoming. At this time, this looks like the most concerning day of the last four. Conditions should improve somewhat on Sunday as the passage of a cold front brings cooler temperatures and somewhat less wind behind the front.

RIW WATCHES/WARNINGS/ADVISORIES

None.