textproduct: Western and Central Wyoming

KEY MESSAGES

- Dry and cool today behind last night's cold front. Cloud cover decreases through the afternoon.

- A weak weather system brings a few showers late tonight into Sunday, but rain and snowfall amounts will remain on the light side.

- A more potent system arrives Monday night and Tuesday, bringing rain and snow showers to northern and western Wyoming and gusty winds to central and southern Wyoming.

DISCUSSION

Issued at 228 AM MDT Sat Oct 24 2026

We are currently experiencing some rattling at the Riverton Weather Abode. This is coming compliments of our good friend cold advection, following the passage of a cold front. Some of the more wind prone areas, like near Buffalo, have seen wind gusts around 50 mph tonight. These events are usually short-lived though, and most of the wind should be over by sunrise.

We are currently in a fast moving pattern, which will bring a few chances of precipitation to the area. The area will be in between systems today, which should bring a dry but cool start to the fourth weekend of the month, with temperatures averaging around 5 degrees below normal. The next chance of showers arrives tonight as the upper level low now located over Arizona, that has been bringing all the severe weather to the Desert Southwest, moves to the northeast. Thankfully, it will be significantly weaker when it arrives here tonight and Sunday. Recent model trends keep the low further east, taking it over southeastern Wyoming, and also keeping a bulk of the moisture east of the area. As a result, precipitation amounts should remain on the light side, with all locations except the Wind River Range having a less than 1 in 2 chance of a tenth of an inch or more of precipitation. Otherwise, expect a mostly cloudy and seasonable day.

We should then have a period of quiet weather on Monday as there will be another gap in areas of low pressure. Then the second system arrives Monday night into Tuesday. This system is of Pacific origin and will have a bit of moisture and jet energy to work with so impacts will be greater. However, with the flow being zonal and rather fast, the low should be a fast mover to limit the duration of those impacts. As for the precipitation, most guidance shows the highest amounts across northern Wyoming, especially in the western mountains with a period of orographic enhancement. Most areas in the northwest have at least a 3 out of 4 chance of a tenth of an inch or more of QPF, with a 1 in 2 chance of a quarter of an inch or more. Due to the fast movement of the system, chances of a half an inch or more are generally less than 2 out of 5. The next question is how much of this precipitation will be snow. Some guidance shows 700 millibar temperatures falling as low as minus 6C, which would lower snow levels to valley floors. The question is how much moisture will be left over when the cold air arrives. In the probabilistic realm of the ensembles, most of the mountains, as well as the Jackson Valley, have at least a 1 in 2 chance of an inch or snow or more, with a similar chance of over 3 inches above 8500 feet. However, due to the fast movement of the system, the chance of 6 inches is less than 1 out of 5, so advisories look unlikely at this time. Travel could be difficult for a time, since there will be an 100 knot jet over the area at the time, and there could be some blowing snow over the passes that could reduce visibility.

And the strength of the jet, along with some strong southwest flow on the south side of the low, will bring strong wind to central and southern portions of the area on Tuesday. The NBM ensemble shows at least a 1 in 2 chance of wind gusts past 40 mph on Tuesday afternoon, with the area from Muddy Cap through Casper having at least 1 in 2 chance of gusts over 50 mph. The chance of gusts over 60 mph is under 1 in 4 for the major travel corridors, so wind highlights look unlikely at this point, but we will have to watch it closely.

Quieter conditions should then move in for most of the remainder of the work week with ridging building over the area, bringing mainly dry conditions and above normal temperatures. A few orographic showers may occur across western Wyoming, but it should be dry most of the time. A stronger system may approach for next weekend, but guidance diverges substantially this far out so details are very difficult to nail down.

AVIATION /18Z TAFS THROUGH 18Z SUNDAY/

Issued at 1045 AM MDT Sat Oct 24 2026

Extensive cloud cover has been in place across much of the forecast area this morning, with ceilings ranging from LIFR to low end VFR. These ceilings are expected to lift by the start of the TAF period, if not by 19Z. Conditions will be VFR for all terminals through the rest of the period. Winds will also remain light (11kt or less) for all terminals through the period as well, with most locations maintaining some easterly component. An area of light showers will develop between KRKS and KRIW around 12Z, gradually shifting toward the north-northwest through the rest of the morning. Little to no impact is expected with these showers and have left any mention out of the forecast for KRKS, KRIW and KLND at this time.

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

RIW WATCHES/WARNINGS/ADVISORIES

None.