textproduct: Western and Central Wyoming

KEY MESSAGES

- Another day of record warmth and elevated to critical fire weather today.

- Warmth should peak on Saturday with more record high temperatures. Strong wind develops ahead of a cold front bring more serious fire concerns.

- A cold front will bring cooler weather for Sunday, but temperatures remain well above normal. Abnormal warmth returns early next week with the potential for more critical fire weather, especially on Wednesday.

DISCUSSION

Issued at 100 AM MDT Fri Mar 20 2026

It is now March 20th, it is now the first day of Summer! Wait, that was a mistake. It is actually the first day of astronomical spring (it arrives at 8:36 am this morning). However, it will feel more like the first day of summer as our expected highs are more June like than March like. It was an historic day yesterday for record high temperatures, please see the climate section of the discussion for more details but as a preview a LOT of records fell yesterday for most of our main climate sites.

It looks like more of the same for today, with more record high temperatures today. There is one fly in the ointment though. That is some lee enhanced clouds that have developed over the area. It will still be warm and in many locations another day of record heat. It could knock a few degrees off high temperatures East of the Divide though. So, we lowered temperatures a couple of degrees. It will still be 20 to 30 degrees above normal though. In areas west of the Divide, more sunshine will likely bring another day of all time March high temperatures. And, quoting the great 70s TV detective Columbo, "Just One More Thing". Wind will be a bit lighter than yesterday. This may mean some of the areas under Red Flag Warnings won't technically met Red Flag criteria. However, we feel this is a similar situation to last month, when humidity didn't quite meet criteria. However, we had dry fuels, record warmth and strong winds. This is situation has dry fuels, record warmth and very low humidity (single digits in some locations). Wind is borderline, but for impact purposes we will keep the Red Flag as is. This, in addition to poor humidity recovery, even at 1 am our humidity has only risen to 23 percent at our office; expect similar tonight.

There will be one more day of record breaking warmth on Saturday. This may end up being the warmest day of the period. The NBM ensemble gives around a 1 in 2 chance for temperatures 85 degrees or warmer in areas East of of the Divide below 5000 feet, like Worland, Thermopolis and even Riverton. And a few members are even giving a 1 in 8 chance of a place like Worland reaching 90! I don't buy this solution yet though. And the main reason for this will be increased west to southwest downsloping wind ahead of an approaching cold front that will move into far northern Wyoming later in the afternoon and cross the area at night. With the tightening pressure gradient, much of the area has at least a 3 out of 4 chance of wind gusts past 40 mph. As for the chance of wind gusts past 60 mph, aka High Wind criteria, the main location is in the favored lee of the Absarokas and the Cody Foothills with around a 1 out of 2 chance where there will be some addition downward forcing from the jet stream. The 700 millibar winds are borderline, generally topping out at around 45 knots. In addition, most of the high wind gusts would be close to the Absarokas at our observation sites where people and impacts are few. We will hold off on any high wind highlights for now and let the day shift take another look. The main impact looks to be for fire weather. Relative humidity will be a bit higher, but most lower elevations still have a greater than 4 out of 5 chance of relative humidity below 15 percent. With the strong wind expected, we are way more concerned about fire impacts on this day.

Since I brought up a 70s TV detective earlier in the discussion, let's now bring up a 70s Song for the next period of the forecast. The song is the Top 10 hit by the men from Melbourne, Australia, The Little River Band. And the song I speak of is "Cool Change". I will tweak the title though and call it "Cooler Change." The front will knock temperatures down anywhere from 15 to 25 degrees compared to Saturday. However, these temperatures will still be well above average. Even in Buffalo, where the coolest temperatures are expected, it will still be a few degrees above average. Central and southern Wyoming will still be 10 to 15 degrees above normal. And fire weather may still be a concern, as dew points may fall into the single digits in some locations. At this time, wind looks lighter, so likely not critical but elevated fire weather still appears possible. As for precipitation with the front, it does not look like much. The only location with a greater than 1 out of 2 chance of over a tenth of an inch is the western slopes of the Bighorns with none in the lower elevations. The main chance will be across the north, where the best jet energy will reside. The southern half of the state will likely remain dry.

Mainly dry and warmer weather then moves in for much of next week, with temperatures climbing once again to well above normal levels. New guidance now shows another strong ridge building across the western half of the area, possibly bringing more record warmth. A few model runs have a weak shortwave on Monday night, but moisture is very limited. Wednesday could be interesting with strong wind as an 160 knot jet will be very close to the area. With low humidity , this is a day to watch for potential critical fire weather once again. A few ensemble members show a front possibly bringing another cool down late next week, but again only back to near normal levels. But like the Saturday night front, it has little moisture to work with. We need rain and snow badly, but unfortunately there are no major storms on the horizon for the next 10 days.

AVIATION /18Z TAFS THROUGH 18Z SATURDAY/

Issued at 1030 AM MDT Fri Mar 20 2026

An anomalously strong area of high pressure in the southwest US will continue to dictate weather across WY for the next 24 hours. This will keep temperatures warm, skies mostly clear, and wind gusty from the west in the afternoon. Wind will be quite similar to yesterday, with most terminals 15-20 knots and gusts of 20-30 knots through the afternoon hours. Some thin high clouds (FL200-300) will pass overhead at times, otherwise skies will remain clear. Just beyond the forecast period, Saturday afternoon into Saturday night, a dry weather system will bring a cold front down from the north.

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 100 AM MDT Fri Mar 20 2026

Elevated to critical fire weather will continue today. Wind will be more borderline in some locations this afternoon, but a combination of record warm temperatures, dry fuels and humidity falling into the single digits at times will keep fire danger high. At this time, Saturday looks like a more impactful day with much stronger wind, with most areas having at least a 1 out of 2 chance of wind gusts past 40 mph along with continued low humidity and record warm temperatures. Conditions should improve as cooler temperatures move in behind a cold front on Sunday.

CLIMATE

Issued at 100 AM MDT Fri Mar 20 2026

It was a record setting day for warmth across the area on Thursday. Eight of our nine official climate sites set all time record high temperatures for March, with the other (Buffalo) tying the all time record high. Three locations (Casper, Riverton and Lander) had their first ever 80 degree high in the month of March. Big Piney had their first ever 70 degree high in the month of March, and the earliest by 16 days (April 4, 2021). Lake Yellowstone had their first 60 degree day in March, and the earliest by over a month (April 22, 2016). At Lander, Casper and Riverton (airport and downtown), the 80 degree high was the earliest by more than three weeks at each site. Records at Casper date back to 1939, at downtown Riverton to 1907 and Lander to 1891.

RIW WATCHES/WARNINGS/ADVISORIES

Red Flag Warning until 9 PM MDT Saturday for WYZ276>283-287- 289.