textproduct: Western and Central Wyoming

KEY MESSAGES

- Warm, dry, and breezy conditions will continue through the week. Chances for rain will be low (5 to 10 percent), mainly limited to the mountains.

- Wind gusts of 30 to 40 mph and humidity of 10 to 20 percent will lead to widespread elevated to critical fire weather conditions on Tuesday and Wednesday.

- A weak cold front slips into far northern Wyoming, especially Johnson County, Wednesday and Thursday dropping daytime highs to readings slightly below seasonal normals.

UPDATE

Issued at 134 PM MDT Mon Jun 15 2026

The forecast remains on track today, with fire weather the primary weather driver this week. Tuesday and Wednesday will by far be the windiest days, with fairly widespread gusts of 30 to 40 mph. The Fire Weather Watch for areas with critical fuels will be upgraded this afternoon. As noted below, very little chance of precipitation through the week as a dry northwest flow persists over the area.

DISCUSSION

Issued at 216 AM MDT Mon Jun 15 2026

A warming trend begins today with a northwest flow pattern aloft in place, as the result of a broad upper trough encompassing much of Canada and the central half of the CONUS. Conditions will be dry again today, with highs near 80 degrees returning across the CWA. Wind gusts up to 35 mph will develop over northern Johnson County by 18Z, with gusts up to 25 mph possible after 21Z across the Green River Basin and portions of Natrona County. Fire weather conditions will be elevated to critical today, with RH values of 12 to 18% occurring for most lower elevations areas this afternoon. Wind, or the lack thereof, will be the mitigating factor.

Heights will rise Tuesday within this northwest flow pattern as a subtle ridge builds in from the west. This will lead to high temperatures in the upper 80s to lower 90s in the Wind River and Bighorn Basins and portions of Natrona County. Northwest winds will increase late in the morning, with gusts of 30 to 45 mph expected across much of the CWA between 21Z and 03Z. These winds, combined with RH values below 15% and above normal temperatures, will lead to widespread critical fire weather conditions. A Fire Weather Watch will be issued for portions of Natrona County, due to the critical fuels in this zone for now. Conditions will remain dry, although a couple higher resolution models are progging virga showers/dry thunderstorms over eastern portions of the Bighorn Basin up against the west slopes of the Bighorns and crossing over Johnson County late in the afternoon into the early evening. Confidence remains low for this to occur at this time.

A dry cold front will quickly move through areas east of the Divide late Tuesday night/early Wednesday morning, reaching the Divide a few hours after sunrise. This will keep winds north-northeasterly in this area through the day, as well as dropping high temperatures 5 to 15 degrees cooler from Tuesday. Wind gusts of 35 to 45 mph will be in place over northern portions in the wake of the front, and southern portions as the front looks to remain stationary along the Divide through the rest of the day.

More seasonal conditions return for Thursday, with winds not being so strong. Gusts up to 25 mph look to be confined over southern portions of the CWA in the afternoon. A ridge looks to build over the region from the west, marking a return for temperatures in the upper 80s and lower 90s. Fire weather conditions will be elevated to critical on these days as well, with RH values dropping into the single digits across the south and possibly into central portions.

AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/

Issued at 955 PM MDT Mon Jun 15 2026

VFR conditions prevail at all terminals through the forecast period. The pressure gradient within northwest flow aloft tightens as a system moves into the Northern Rockies late Tuesday. This results in gusty west to northwest surface wind at all terminals, which develops from late Tuesday morning into the early afternoon hours. Wind gusts 25-35kts will be common by mid-afternoon and these speeds continue through around 03Z/Wednesday before diminishing by 10-15kts. Shortwave energy moving across Montana Tuesday evening nudges a cold front into northern Wyoming late in the period. This leads to 10-14kt winds at KCOD and KWRL just prior to 06Z/Wednesday.

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

FIRE WEATHER

Issued at 216 AM MDT Mon Jun 15 2026

Elevated to critical fire weather conditions expected through the week this week. Tuesday will be the most critical, with wind gusts of 30 to 45 mph expected across much of the forecast area. Above normal temperatures and widespread critical RH values will coincide with the winds. Thus, a Fire Weather Watch has been issued for zone 280 where fuels are critical at this time.

A dry cold front will quickly move over areas east of the Divide late Tuesday night/early Wednesday morning, turning winds more northerly in this area. Gusts of 30 to 45 mph will return for northern portions of the forecast area in the wake of the front, while southern portions (zones 277/278/279) also have northwest winds gusting 30 to 45 mph. RH values will be critical across the south, as the front is expected to be stationary along the Divide through the day Wednesday.

RIW WATCHES/WARNINGS/ADVISORIES

Red Flag Warning from noon to 9 PM MDT Tuesday for WYZ280.