textproduct: Western and Central Wyoming

KEY MESSAGES

- Many locations are expected to break daily high temperature records and potentially all time March high temperatures with the ongoing record warmth. This record breaking warmth persists until Saturday.

- There is high confidence in critical fire weather conditions across low elevations of central and southern Wyoming through Saturday due to low humidity, gusty winds, and abnormal warmth. The most widespread fire weather conditions are expected to occur Saturday.

- A cold front brings a 30% chance for light snow showers across the northern mountains late Saturday/early Sunday. A brief cool down to closer to normal temperatures expected Sunday for the entire area.

UPDATE

Issued at 1200 PM MDT Thu Mar 19 2026

18Z water vapor imagery shows the strong upper level high centered over the southwestern CONUS that is responsible for the ongoing widespread record heat and fire weather conditions. Abundant sunshine today will allow for deep mixing to occur, and with 700mb temperatures ranging from 5 C to 9 C, surface temperatures will have no trouble reaching the upper 70s F and low 80s F today. Deep mixing will also allow for winds to mix down to the surface and keep humidity very low. As mentioned in the morning discussion, winds are not expected to be as strong as they were the past two days due to the strongest winds aloft being located over Montana. Regardless, frequent wind gusts of 20 to 35 mph can be expected this afternoon. Friday expect much of the same with slightly warmer temperatures with 20 to 30 mph gusts as the upper high slowly begins to shift east. More daily temperature records, and potentially all time March records, are expected to be broken through Saturday.

The combination of much above normal temperatures, gusty winds, low relative humidity, and dry fuels provides high confidence in critical fire weather conditions through Saturday. Thus, the Red Flag Warning remain in effect. It is important to note that Red Flag Conditions are greatest each day roughly from 10AM through 7PM MDT with some improvement overnight. Overnight relative humidity recovery is forecast to be poor to fair, but winds will generally follow the diurnal trend of weakening overnight. As the morning discussion mentioned, a cold front will approach the region on Saturday and tighten the pressure gradient and result in stronger winds. So, there is greater concern for more widespread fire weather conditions Saturday. The Saturday night/early Sunday cold front is currently forecast to only bring snow chances (30%) to the northern mountains and "cooler", closer to normal temperatures for Sunday. Winds on Sunday are forecast to be relatively tame compared to what we have been experiencing, but conditions will remain dry given the lack of widespread moisture associated with the cold front. Thus, elevated fire weather conditions are expected Sunday and Monday for most low elevations.

DISCUSSION

Issued at 120 AM MDT Thu Mar 19 2026

For those of us who do not like winter, today is a one of the most looked forward to days (although some say we haven't had a winter this year, they do have a very good point). Today is the last full day of astronomical winter, as the sun will move to the north of the equator for the first time on Friday 8:46am Mountain Time (the Vernal Equinox), ushering us into Astronomical Spring (Meteorological Spring began March 1st).

However, as most people know around here, this time of year is usually still rather cool. In addition, a majority of our huge snowfalls climatologically occur from now through April. As you may have noticed, this will not be the case over the next week or probably the next 10 days or so. An abnormally strong ridge will continue to bring temperatures over 30 degrees above normal in some locations through Saturday. It will feel more like the first day of summer, as in most locations most of the high temperatures we see for the next three days, will be our normal highs that we see in the middle or latter part of June, not late March. Like the past two days, we will tackle each concern individually, and we continue to have four of them.

RECORD HIGH TEMPERATURES: This portion of the forecast still looks to be on track. Looking at the temperatures from yesterday, we had 8 daily record highs, with 5 sites tying or breaking the all time March high temperature. I will include this data in the climate section of the discussion. We were a bit too cool on most of the highs yesterday, so we raised temperatures a bit. The NBM ensemble gives at least a 1 in 2 chance of high temperatures over 80 degrees to most of the elevations under 6000 feet east of the Divide. In areas west of the Divide, with the exception of the western valleys, have at least a 1 in 2 chance of highs over 70 degrees. Most locations have at least a 4 out 5 chance of breaking daily record highs (some locations it's almost a certainty), with a greater than 1 in 2 chance of breaking all time March records. Conditions look similar on Friday as well. Saturday may end up being the warmest day, as downsloping increases ahead of an approaching cold front, except for maybe the far north. Areas like Worland have a 1 in 2 chance of reaching 85 degrees, with even a 1 in 5 chance in places like Riverton, Thermopolis and even Casper. Temperatures should cool from 10 to 20 degrees by Sunday, as the ridge weakens and moves to the east and the aforementioned cold front sweeps across the area.

FIRE: The forecast remains on track here as well. Relative humidity was a bit lower yesterday than forecast, so we lowered by a few percent. Reasoning remains the same. Wind will be a bit lighter today as the jet gets pushed further north. Most of the areas in the Red Flag Warning have at least a 2 out of 3 chance of wind gusts reaching critical conditions (>25 mph). The only question is tomorrow, when some zones may not reach the wind criteria. However, since it continues to be unseasonably warm and humidity well below 15 percent, we will likely keep the Warnings going even if wind does not make it. Saturday still looks like the most impactful day though, as wind increases ahead of an approaching cold front, with some wind gusts over 40 mph possible and humidity remaining in the lower teens. Fire weather concerns should at least drop below critical for most locations as cooler temperatures move in for Sunday.

WIND: With the jet moving further north, strong wind looks less likely today. However, most areas should still have at least a 1 in 2 chance of gusts past 30 mph, mainly in the afternoon during peak heating and mixing. Wind reaches a nadir on Friday, with chances of wind gusts past 30 mph falling anywhere from 10 to 15 percent. Saturday continues like the windiest day ahead of the cold front with many areas, especially those prone to west to northwest flow, having at least a 1 in 2 chance of gusts past 45 mph. This is the day some locations may need some high wind highlights. At this time, northern Wyoming has the best chance of this with the cold advection / northwest flow pattern with the frontal passage, along with some jet stream enhancement. We will cross that bridge in future shifts.

RISING RIVERS AND STREAMS...Some streams and rivers are already seeing some rises with snow melt beginning. However, concerns for flooding remain low at this time for the same reasons as yesterday. For one, with the recent dry weather, the soil will soak up some of the water. Also, almost all of the snow is of the high elevation variety, and temperatures will still fall in to the 30s at night, slowing the melt somewhat at night. Reasoning remains the same as yesterday, with rises likely but flooding remaining unlikely.

As for the rest of the forecast, Sunday will be a cooler day but temperatures will remain above normal for all locations except for possibly northern Johnson County. The front has little moisture to work with so any precipitation amounts would be on the light side, with the southern thirds of the area likely seeing none. Even in northern Wyoming, almost now areas have a greater than 1 in 2 chance of a tenth of an inch or more of liquid precipitation through Sunday except the western slopes of the northern Bighorns. And with most guidance keeping the best forcing to the north, this may trend downward. Temperatures then trend well above normal again, but not to the levels we will see this week. A few members of the ensemble have another front moving through for midweek next week, but uncertainty is high. With the zonal flow, the western mountains would have the best chance of any meaningful precipitation. Looking further out, most guidance shows a generally zonal to flat ridging pattern across the area through the end of next week. So, unfortunately, the prospect of a widespread precipitation event is looking highly unlikely for the next 10 days.

AVIATION /00Z TAFS THROUGH 00Z SATURDAY/

Issued at 403 PM MDT Thu Mar 19 2026

VFR conditions will continue through the period as high pressure dominates the region. The main aviation concern continues to be wind, with most terminals seeing gusts of 20 to 30 knots through the afternoon hours. Wind will decrease after sunset. Other than a high, broken cloud deck moving in east of the Divide this evening, skies will remain mostly clear. Wind will again increase around 18Z Friday with gusts over 20 knots at several terminals through the end of the period.

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 120 AM MDT Thu Mar 19 2026

A combination of relative humidity falling in the teens and in some locations the single digits, dry fuels, record high temperatures and a gusty breeze will continue to bring elevated to critical fire weather to much of the area, especially east of the Continental Divide and in southern Wyoming. Wind may decrease somewhat tomorrow, but conditions should remain similar. Saturday continues to look like the most concerning day with continued warm temperatures and increasing wind ahead of a cold front moving in from the north. Conditions should improve somewhat on Sunday as slightly cooler temperatures move in behind the cold front.

CLIMATE

Issued at 120 AM MDT Thu Mar 19 2026

Eight more daily records were tied or broken yesterday, all of our main climate sites with the exception of Buffalo, bringing the total in the warm spell to 11. In addition, three sites (Casper, Lake Yellowstone, and the Riverton airport) set their all time March high temperatures and two other sites (Big Piney and Rock Springs) tied the all time March high temperature. Worland had it's earliest 80 degree high temperature, breaking the old record by 10 days (March 28, 1986). It is likely (greater than a 4 out of 5 chance) that 35 or more daily high records will be broken from Wednesday to Saturday and that all major climate sites, except for possibly Buffalo, set their all time March high temperature. Some locations may set the all time March record high three times or even four.

RIW WATCHES/WARNINGS/ADVISORIES

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