textproduct: Western and Central Wyoming

KEY MESSAGES

- Warm and mostly dry conditions are forecast for low elevations through at least Thursday, with highs in the 60s and 70s.

- Elevated to near critical fire weather conditions are expected on Tuesday and Wednesday with gusty 30 to 45 mph winds. More widespread fire weather concerns are expected Tuesday.

- Multiple weather systems are forecast Tuesday through the weekend, with precipitation chances (25% to 50%) largely confined to the higher elevations of western and northern Wyoming.

UPDATE

Issued at 1257 PM MDT Mon Apr 6 2026

The forecast for this afternoon largely remains on track across the state. With a weak passing disturbance aloft and expected deep mixing this afternoon, anticipate some breezy winds (15 to 20 mph gusts) through sunset. Additionally, with 700mb temperatures in the +2 C to -2C, temperatures this afternoon will have no issue warming into the upper 50s to upper 60s for most low elevations. As the aforementioned disturbance passes over the state, there is a low (15- 25%) chance of a light rain shower across the northern Absarokas into the northern Bighorn Basin roughly from 2PM to 8PM MDT. Mostly clear skies will allow for temperatures to quickly fall into the upper 20s to mid 30s tonight.

On Tuesday, an upper level low and associated cold front, currently (19Z) over the Alaskan Panhandle, will shift to the southeast towards far northeastern Montana. As it does so, the pressure gradient will tighten over Wyoming and result in widespread gusty 30 to 45 mph west winds. These gusty winds combined with relative humidity values in the 15 to 20 percent range will create elevated to near critical fire weather conditions across much of central and southern Wyoming Tuesday afternoon. There is less than a 15% chance of widespread relative humidity values dropping below 15 percent, so felt comfortable not issuing any highlights at this time. However, if a fire does start, erratic fire behavior is possible.

In addition to Tuesday's fire weather concerns, there are also precipitation chances across high elevations of western and northern Wyoming. Moisture ahead of the cold front is limited, with precipitation amounts forecast to be up to 0.03". This basically means that any light snow showers across the western and northern Wyoming mountains will have only light accumulations. A stray shower cannot be ruled out across Jackson Valley, the northern Bighorn Basin, and northern Johnson County but chances are low (up to 30%) at this time. There is also a non-zero chance in some rumbles of thunder with any light showers in the aforementioned areas with unstable mid level lapse rates and nearly 300 J/kg of most unstable CAPE. Otherwise, the cold front is on track to traverse the state early Wednesday and bring additional light snow chances to the northern Bighorn Mountains.

DISCUSSION

Issued at 100 AM MDT Mon Apr 6 2026

Northwest flow aloft continues to weaken over the CWA heading into the new work week with the main finger of the PFJ well to the north and northeast into Canada and through the Dakotas. Upper level ridging remains to the west but weakening with decreased convergence aloft ahead of an upper level system currently off the Alaskan Panhandle coast. This will deepen with its eastward progression with increased divergence aloft north of Montana. The PFJ will sag south but only clip the northwestern portions of the CWA and state heading into Tuesday. Above average temperatures will continue despite it passing to the north but winds will increase Tuesday afternoon and evening. Gusts up to 35 to 45 mph likely for many wind prone areas (especially northern Johnson and the Bighorn Basin) but not expecting high winds at this time. Humidity values are not quite as low as previously forecasts, and as such, elevated to near critical fire weather concerns expected with no highlights to be issued of any sort. Some accumulations of snow expected for the northern Bighorns with some spotty showers across the Bighorn Basin and Johnson County but nothing of note is expected.

Beyond Tuesday, the main upper level low will push east across southern Canada leaving the PFJ near the northern WY/MT state line bringing a sering of minor shortwaves Wednesday and Thursday. This will bring some limited chances for precipitation across similar areas, but nothing of significance is expected at this time with no outliers of the deterministic models showing otherwise. Temperatures will not be as warm Wednesday through Friday but back on the rise for the weekend as upper level ridging builds in with a negative tilt due to a cut off low to the southwest over southern California. This could be interesting to see how it interacts with the next bigger chance for more significant weather will come early the following week as the EC depicts a GOA low deepen with its progression to the Pacific northwest nearing the western CWA by early Monday morning. Stay tuned for updates in the coming days as this system could bring a more favorable southwest flow aloft across the CWA for some possible much needed precipitation.

AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/

Issued at 225 PM MDT Mon Apr 6 2026

VFR conditions continue through the next 24 hours. High cirrus will continue to sweep by, and are expected to thicken up during the day Tuesday. Main forecast issue is gusty winds on Tuesday. West to southwest winds will be stronger at all sites, picking up around 18Z. Most sites will see gusts around 30kts during the afternoon, with KRKS and KCPR possibly reaching 40kts occasionally.

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

None.