textproduct: Western and Central Wyoming

KEY MESSAGES

- Elevated to critical fire weather this afternoon, and again Monday afternoon, across the wind prone areas of western and central Wyoming.

- A Pacific weather system will bring snow to western Wyoming and strong to high wind elsewhere from Monday night into Tuesday.

- Another weather system brings the chance of light to moderate snow to much of the area from Wednesday into Thursday.

UPDATE

Issued at 1047 AM MST Sun Feb 15 2026

A busy week for weather. Starting with fire weather concerns, have extended the current Red Flag Warning for today through tomorrow (Monday). Like today's reasoning, Monday sees gusty winds 25 to 40 mph across Johnson and Natrona Counties. Relative humidities (RH) will likely remain above 15 percent (except for very isolated areas, with 40 percent chances for 15 percent across the northern half of Johnson County). However, given the out of season criteria, dry conditions (RHs 18 to 25 percent), and wind, impacts are Red Flag- like even if RH is a little above 15 percent.

Then for wind. A High Wind Watch has been hoisted for Monday night through Tuesday evening for the Wind Corridor of Rock Springs through Casper, where there is good confidence for winds of at least 50 to 60 mph. These are just where the strongest low elevation winds are expected though, with widespread gusts 30 to 50 mph occurring across Wyoming, stronger in the mountains.

Finally, snow. A Winter Weather Advisory has been issued for the western mountains Tuesday, when there is good confidence (70 percent) in at least 6 inches, with high-end amounts roughly around a foot. Main impacts with this snow is to mountain passes, like Teton, Togwotee, and South, especially combined with the expected gusty winds. The period of heaviest snow currently looks most likely about 09z Tuesday through about 18z Tuesday as jet dynamics favor the best lift and snow production.

DISCUSSION

Issued at 231 AM MST Sun Feb 15 2026

It is often said that things happen in threes, both good things and bad. This looks to be the case over the next several days, as we will have three different periods of active weather to deal with. One today, another Monday night into Tuesday and another for midweek with exact timing to be determined.

As for today, things will be fairly quiet across most of the area; another mild and dry day with many locations more than 20 degrees above normal. There is again the small chance of a shower in the northwestern mountains, but these wouldn't even classify as a nuisance. The main focus will be across the southwest flow areas. The showers mentioned above will be caused by a weak shortwave brushing by to the north, and will provide some mixing. With an 100 knot jet moving over Wyoming, gusty wind is likely from Muddy Gap to Casper. Some favored areas, like south of Casper, have a 2 in 3 chance of gusts past 40 mph. This will be combined with low humidity, along with dry vegetation due to our warm and dry winter. Although relative humidity is highly unlikely (less than a 1 in 10 chance) to drop below 15 percent for 3 hours, we will continue the Red Flag Warning for impact reasons.

There will be a bit of a lull on Monday. A gusty southwest wind will continue however, most guidance is showing dewpoints about 5 degrees higher than today except in northern Johnson County. And wind should remain light to moderate here. However, weather maker Number 2 in the form a Pacific trough and cold front will be approaching from the south and west. We still think that the snow in the forecast for Monday is overdone, with most areas in the west largely dry through the daylight hours on Monday. The main impacts will move in Monday night and Tuesday. And like many systems this year, there will be contrasting impacts. This remains me of a British show my mother used to watch on Public Television when I was a wee lad in the 70s, called "Upstairs, Downstairs." Except the weather equivalent would be "Upslope, Downslope." The reasoning in the forecast in the west remains similar to yesterday, with snow spreading in Monday evening. The most impactful conditions continue to look to be from later Monday night through midday Tuesday, with lighter snow after that. Amounts look similar to yesterday at this time as well, with a greater than 1 out of 2 chance of 6 inches or more in the higher elevations of the western mountain ranges. Any chances of 12 inches are small though and largely restricted to southwestern Yellowstone, where impacts would be slim to none. We will likely need some advisories here. As for the valleys, with 700 millibar temperatures starting around minus 3C to minus 4C, there could be some rain and snow mix through the night before becoming all snow by sunrise. Amounts have come up just a bit, with around a 1 in 2 chance of 3 inches or more in portions of the Jackson and Star Valleys. We could see some rather windy conditions as well with the frontal passage. Highlights are possible in the valleys, but not completely convinced yet.

As for the downslope side, east of the Divide, the concern here shifts to strong to potentially high wind. Most of the ingredients are here for high wind. We will have a tight pressure gradient across the area. The 700 millibar winds are also rather strong, approaching 60 knots at times later Monday night into Tuesday. One thing that is concerning is the position of the jet, it is mainly over Colorado, not an ideal location. However, the passing trough and front should provide mixing. Probabilistic guidance agrees as well. Much of the area has at least a 4 out of 5 chance of wind gusts past 45 mph, with many areas having at least a 1 in 2 chance of gusts past 60 mph for the same time period. The most wind prone areas, like the south side of Casper, are showing a 2 out of 5 chance of wind gusts past 75 mph. We will likely need some highlights, but we will wait until the Red Flag Warning ends so as not to confuse people. At this time, we are favoring the high wind over fire in terms of impacts since temperatures will be dropping a bit. As for precipitation, the current forecast is the wettest it would likely be. I highly doubt there will be any precipitation before sunrise Tuesday given the strong downsloping flow. Any chance of showers would be post-frontal when flow turns more westerly, but the best moisture will be gone by then. The whole area should be in a lull Tuesday night.

And then, system Number 3 will approach starting anytime from Wednesday through Wednesday night. The models continue to have timing differences here so start and end times remain in flux. However, this continues to look like the system that may finally bring widespread snow east of the Divide, although not a ton of it. Models continue to show a period of easterly flow as lee cyclogenesis occurs over eastern Colorado, bringing in some more moisture. The real question is where a 700 millibar low may form and enhance snowfall a bit, and there are still differences so we can't nail down amounts yet. In the ensemble realm, many areas have at least a 3 out of 4 chance of an inch or snow or more. The chance of 3 inches drops though. The best chance at this time looks to be from Thermopolis to Casper, around a 1 out of 2 chance. The chance of 6 inches remains relatively small though, no more than 1 out of 5 except in the mountains. The system will also be a fast mover, limiting accumulations as well. However, beggars can't be choosers and we will take every bit we can get east of the Divide. Cooler weather will also dominate from Wednesday through Friday. Nothing really cold, as the airmass is Pacific, but the coldest we have seen in a while. This will be especially so if we can finally get some snow on the ground. So it finally looks like we will have some winter weather across central Wyoming through the week.

AVIATION /18Z TAFS THROUGH 18Z MONDAY/

Issued at 1025 AM MST Sun Feb 15 2026

West of the Continental Divide...KJAC/KRKS/KPNA/KBPI Terminals

Mid/high-level cloud cover to continue sweeping northeast across the region in advance of a longwave trough along the West Coast. Ceilings BKN050-070 accompanied by some virga persist through Sunday afternoon around KJAC. All terminals to be VFR through the forecast period. Southwest terminals see a period of 7-11kt westerly surface wind Sunday afternoon. A light south wind prevails overnight at KJAC and KRKS before slowly beginning to increase at the very tail end of the forecast period. Surface southerly winds increase at all terminals just after 18Z/Monday.

East of the Continental Divide...KCPR/KCOD/KRIW/KLND/KWRL Terminals

Terminals to remain VFR with only passing SCT-BKN150-250 through the forecast period. The primary aviation hazard will be gusty surface wind at KCPR and, to a lesser extent, KCOD. KCPR to see southwest 24G34kt surface wind diminish to 10-14kts overnight before steadily ramping up again between 15Z-18Z/Monday. KCOD to see 12G22kt west- southwest wind decrease overnight before picking up again late Monday morning. Other terminals to see speeds increase just beyond the end of this forecast period.

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

FIRE WEATHER

Issued at 231 AM MST Sun Feb 15 2026

A combination of gusty wind and humidity falling to near or under 20 percent will bring elevated to critical fire weather to portions of the area this afternoon. Elevated to critical fire weather remains on Monday afternoon. Strong to high wind may bring elevated fire weather again east of the Divide on Tuesday.

RIW WATCHES/WARNINGS/ADVISORIES

Winter Weather Advisory from 11 PM Monday to 5 PM MST Tuesday for WYZ001-012-014-024.

Red Flag Warning until 5 PM MST Monday for WYZ280-281.

High Wind Watch from Monday evening through Tuesday evening for WYZ019-020-030.