textproduct: Western and Central Wyoming

KEY MESSAGES

- Mostly clear and cool today, with highs only in the 40s and 50s. Light rain will linger through midmorning for Natrona County, before clearing by noon.

- Clear and cold tonight, with lows in the 20s for all areas. Freeze Warnings have been issued for those are that have not already had a morning freeze.

- Dry and milder through the upcoming weekend with highs mainly in the 50s and 60s.

DISCUSSION

Issued at 152 AM MDT Thu Oct 15 2026

The H5 trough continues to exit to the southeast, and is gradually taking the clouds and precip with it. As of current writing time, the only remaining light rain is confined to Natrona County, and continues to draw to the southeast as well. Most light rain should be complete by 6AM, but light sprinkles may continue on Casper Mountain for a couple more hours. Skies will clear through the rest of the day, and with good cold air advection still in place, highs will struggle to reach the 50s. This will be accompanied by a modest northerly breeze, making for a brisk autumn day. Areas across Johnson County will hold some more of the influence of the sfc low gradient, so winds will be higher through the day, gusting 30 to 40 mph through the afternoon. Watch for cross winds along the I-90 corridor. Winds will die off quickly after sunset as high pressure sweeps in. This sets the stage for the first freeze of the season for most of the state. Most areas will fall into the 20s for several hours tonight. The only inhibiting factor may be enough of a breeze in the Wind River Basin to mix things enough to limit the overall timing of the freeze, but this airmass is cold enough to overcome most of this. Freeze Warnings are in effect tonight across central Wyoming, where freezing temperatures have not yet been reached.

The main pattern this weekend is a broad H5 ridge across the Rockies, bringing moderating temperatures and deflecting the storm track back into southern Canada. The main impact will be which way the winds are from. Winds Saturday will be from the southwest, bringing the warmer air back into the region. Sunday a weather system passes across southern Canada, switching winds back from the north. While no cold air will return with these winds, it will be enough to bring temperatures back to near normal around 60 degrees. The next weather impact across western Wyoming still looking to be sometime Tuesday, when the ridge is broken down by a trough along the Rockies, bringing more moisture back from the southwest.

AVIATION /12Z TAFS THROUGH 12Z FRIDAY/

Issued at 520 AM MDT Thu Oct 15 2026

Skies are quickly thinning and lifting this morning, with only cloud cover left over around KCPR and some high clouds over KRKS. Skies should be nearly clear by 18Z, and remain clear through the night tonight. Fog signal this morning is very weak and has not been forming so far, so have removed any notes in TAF for today. Winds will be from the north through the day at all sites, with gusts of 20 to 25kts at KWRL/KRIW/KCPR/KRKS this afternoon. Higher wind gusts will be noted at KBYG, reaching near 40kts this afternoon. All sites go nearly calm overnight, with KCPR/KRKS shifting back from the southwest late overnight.

RIW WATCHES/WARNINGS/ADVISORIES

Freeze Warning from 11 PM this evening to 9 AM MDT Friday for WYZ005-006-010-011-016>020-028>030.