textproduct: Western and Central Wyoming

KEY MESSAGES

- Showers will continue to spread across the state this afternoon and evening. Periods of light to moderate precipitation are expected to develop this evening into Wednesday morning across central and southern WY.

- Snow is expected in the higher elevations of the mountains, especially above 9000 feet. The highest amounts will be in the Wind River Range, where an additional 1 to 4 inches is possible.

- Showers persist through Wednesday and into Thursday with cooler temperatures following in behind. A period of light snow cannot be ruled out for portions of Casper Mtn late Wednesday into Thursday morning.

- A widespread hard freeze (<28F) for many low elevation locations east of the Divide still looks possible for Friday morning. Mild, dry, and breezy conditions are forecast to return for Friday into the weekend.

UPDATE

Issued at 1101 AM MDT Tue Oct 13 2026

Not much to update regarding the short term forecast as the previous forecast discussion remains on track. Temperatures are forecast to remain on the cool side today due to lingering cloud cover and eventual precipitation. Highs are forecast to get into the low to mid 40s for much of the state with some locations east of the Divide possibly warming into the low to mid 50s. As mentioned in the previous discussion, showers will gradually increase in coverage during the afternoon and evening. The greatest chances will be across central and southern WY where the greatest rainfall is expected. The heaviest precipitation is forecast to start Tuesday evening through Wednesday morning. The heaviest precipitation will then shift east over portions of Natrona County where another round of showers will be likely throughout the day Wednesday into Thursday. One concern is how far south the low will track as its possible some locations over central WY such as Riverton and Lander may see precipitation end sooner than originally forecast. Elsewhere, mountain snow will continue across elevations above 9,000 ft for the next 24 to 36 hours. The greatest accumulations are still forecast across the Wind River Range especially the eastern slopes. Winter Weather Advisories remain in place across the Wind River Range through Wednesday morning as a result. Some light additional snow accumulations will still be possible over the next 12 to 24 hours for the higher elevations of the western and northern ranges. The higher elevations (9,000+ ft) of the Tetons, Absarokas, Gros Ventre, Wyoming/Salt River, and Bighorn Ranges could see a few inches of wet snow through Wednesday morning. Additionally its possible for some portions of Casper Mtn to see a light coating of wet snow late Wednesday into Thursday morning as colder temperatures move into the region. Gusty winds are still looking possible for Wednesday night into Thursday morning over portions of the state mainly east of the Divide. Lastly a late first freeze for many low elevation locations east of the Divide is still on the horizon for Friday morning. A few locations may near the freezing mark before then but Friday morning is looking increasingly likely to see lows across many areas hitting 28F or less. At this time no freeze related highlights will be issued but some may be needed within the next 24-48 hours.

DISCUSSION

Issued at 153 AM MDT Tue Oct 13 2026

What I have noticed this year is that when we get a certain kind of weather, is that it sticks around for a while, with a few exceptions of course. Examples include the several heat waves we had this year, the monsoon over the summer that seemed to drag on forever and the period in the latter part of June when we seemed to have a severe thunderstorm somewhere in the area. The past few weeks have been an example, we had a prolonged period of wet weather in the middle of September. We then had a strong ridge across the area for better part of three weeks, bringing dry and warm weather for most of the latter part of September as well as the first several days of October. We are now in the period of the everlasting moisture, courtesy of what was left of Tropical Storm Rachel and now a slow moving bowling ball, AKA and upper level low, now dropping southward over Nevada. And this system will influence our weather for a couple more days.

For the third night in a row, we continue to have areas of showers moving across the area. Satellite imagery shows cloud tops are slowly warming, so coverage and intensity of showers should gradually decrease through the rest of the night, although some will linger through the night. As for today, it will be fairly similar to yesterday with another day of below normal temperatures and plenty of cloud cover. There will also be showers around through the day. However, with the low moving further way, coverage should be less than previous days. This is also the first day of the past few there is not an excessive rainfall outlook, so amounts should be less.

Steadier precipitation may increase tonight though, especially across southern and central Wyoming as the upper level low begins to make a turn to the east and moves across Colorado. This will turn flow to the east and bring some upslope flow into the area. The area looks to be on the northern edge of the deeper moisture though, so rainfall amounts do not look excessive at night. The most favored areas will be across the Wind River Basin to Casper with the upslope flow. I will discuss amounts later in the discussion. And this includes potential snowfall amounts in the mountains. Precipitation will continue into Wednesday, but there is some uncertainty here. There are some differences in guidance in regards to the movement of the upper level low. The bottom line is, the further north it moves, the further to precipitation can wrap back into the area. The greatest confidence for rain will be from Natrona County southwest to Rock Springs and on to the south and east. Chances drop further north and west, with the northwestern part of Wyoming largely dry on this day. And this continues through Wednesday night as well as the low continues to move eastward.

There is one more concern for Wednesday night. As the upper level low moves eastward, lee cyclogenesis will occur over Colorado. This will tighten the pressure gradient across the area, increasing wind. Much of the area East of the Divide as well as southern Wyoming have a greater than 1 out of 2 chance of wind gusts past 30 mph from later Wednesday night through Thursday. The strongest gust would be in the wind prone areas in Johnson County, where there is a 1 in 3 chance of gusts past 50 mph. Low level winds do not look sufficient for high wind though. Following this, all rain ends on Thursday and then ridging builds back over the area, bringing a return to dry conditions and near to somewhat above normal temperatures.

PRECIPITATION AND SNOW AMOUNTS...We still start with precipitation. Reasoning remains similar to yesterday with the highest amounts in the mountain ranges and across central and southern Wyoming. Most of the mountains, except for the far north, as well as much of the Wind River Basin and Natrona County, have at least a 3 out of 5 chance of a quarter of an inch of precipitation or greater through Wednesday night. The 1 out of 2 chance of three quarters of an inch or greater runs roughly from east of Riverton to Casper and southward to the Continental Divide. The smallest amounts would be across northern Wyoming as the low digs to the south.

Now on to snowfall. Snow levels look to bottom out Tuesday night into Wednesday, with 700 millibar temperatures falling to around 7000 to 7500 feet. Most of the mountain ranges have at least a 1 in 2 chance of an inch of snow from Tuesday morning through Wednesday night. However, for advisory level amounts, which is 6 inches or greater, the only location is the Wind River Range. Most areas above 9000 feet continue to have at least a 1 in 2 chance of 6 inches of snow or more. The highest peaks will likely (a greater than 2 out of 3 chance) see over a foot of additional snow, but impacts here are few to none. So, we will keep the advisory going for now. The heaviest snow should end by sunrise Wednesday as the deeper moisture moves to the east of the mountain range. As for the lower elevations, a few flakes can't be ruled out, but no accumulation is expected.

AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/

Issued at 1045 AM MDT Tue Oct 13 2026

MVFR conditions west of the Divide with RKS VFR at least for the remainder of today and into the overnight hours. As the low slowly pushes east, expect shower activity to increase through the first part of the afternoon for all but RKS, lingering overnight into Wednesday morning east of the Divide. There is still some uncertainty on how far east the aforementioned low pushes, but mainly dry conditions expected west of the Divide with lingering low stratus in the morning before improving by the end of the period.

TAF sites east of the Divide will mainly be engulfed in low stratus from IFR to MVFR conditions, looking at worse conditions across the Wind River Basin for LND/RIW due to upslope flow once the low pushes far enough east this evening after around 02-03Z. Rain should then be steady overnight into Wednesday morning with improved conditions for COD/WRL by 12Z. CPR will remain IFR to MVFR as well overnight into Wednesday morning as well. More to come into the next TAF cycle in the afternoon through the overnight but improvement across entire CWA for aviation purposes by late Thursday morning.

Winds remain relatively light less than 10kts for all TAF sites the entirety of the period. Ample mountain obscuration will persist as well lingering overnight Wednesday into Thursday morning as well.

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

Winter Weather Advisory until 6 AM MDT Wednesday for WYZ014- 015.