textproduct: Western and Central Wyoming

KEY MESSAGES

- Similarly warm, dry, and windy on Friday. Widespread critical fire weather conditions will continue. Very isolated showers are possible (10-15 percent) across far northwestern and far southern Wyoming.

- Saturday will again see temperatures 5-10 degrees above normal with breezy winds shifting to the southwest. Clouds will increase from the northwest through the day, and bring isolated showers to NW WY during the afternoon. Elevated to critical fire weather conditions continue from southwest into central WY.

- Forecast guidance still indicates a very good chance of colder and wetter conditions from Sunday afternoon through Tuesday. Moderate rain and snow is possible across much of the area, with some areas in central WY seeing over a half inch of precipitation, and some mountain locations receiving over 6 inches of snow.

UPDATE

Issued at 1255 PM MDT Thu May 14 2026

Very clear skies and breezy/gusty winds are the story today in the post-storm northwest-flow environment. Several areas saw wind gusts of 50-65 mph this morning as the nose of a jet streak passed across northern WY and induced 50 kt 700 mb winds over eh northern Absarokas. Dry zonal flow is keeping temperatures and wind elevated as RH values drop below 10 percent. Thus, elevated to near critical fire weather conditions exist for most of the afternoon for the foothills and lower elevations of southwest WY and east of the continental divide. The USDA HDWI (Hot Dry Windy Index) shows values above the 90th percentile for Thu-Sat to back up the described conditions.

Winds will decrease around sunset, though remain breezy in some areas due to the strong mid-level westerly flow. Friday will be much of the same with some increasing moisture along the MT/WY border near NW WY. Isolated showers are possible along the border during the afternoon. The rest of the state will see mostly clear to partly cloudy skies with continued breezy/gusty west winds. Humidities will again drop below 10 percent after a night of poor to fair humidity recovery, again creating elevated fire weather conditions.

After a day of breezy/gusty southwest flow with increasing clouds on Saturday, Sunday has a high probability of increased moisture and colder temperatures. The forecast solution(s) at this time are expecting an impressive Spring storm to impact the area, with temperatures cold enough to bring snow to the lower elevations of northern, western, and central WY. Snow amounts have increased a bit with the latest guidance, as well as precipitation totals of 0.50-1.00 inches in some areas of central WY. There still remains uncertainty with the system however as the 12Z GFS and 12Z ECMWF now promote more of an open wave moving through the Rockies (as opposed to previous runs of a closed low). Will have to watch this evolving situation and potential impacts over the coming days.

DISCUSSION

Issued at 215 AM MDT Thu May 14 2026

You may remember tongue twisters from when you were younger, like "Peter Piper Picked A Peck of Pickled Peppers." Well, we will have a shorter tongue twister do describe the weather over the next 7 days. It is "Wyoming Weather Whiplash." If dare you to say it fast three times. By the time we get to the weekend, we will be feeling the whiplash compared to the unseasonably warm weather we have had.

And it was very warm yesterday. All nine of our climate stations had record high temperatures yesterday. Three (Riverton, Buffalo and Casper), had their earliest occurrence of 90 degrees in the calendar year. And Buffalo set an all time high for the month of May. Temperatures will remain above normal today, although about 10 to 20 degrees cooler for most behind the passage of the cold front that brought the gusty showers and thunderstorms yesterday.

The main concerns today will be wind and fire weather. I an giving though to possible wind highlights for the Cody Foothills. The area will be in the right front quadrant of an 100 knot jet streak to add some downward forcing. The 700 millibar forecasts are showing an area of 50 to 55 knot wind in northern portions of the zone. However, things don't look as cut and dry as yesterday. The area of 700 millibar wind is smaller. In addition, it only lasts for about 4 to 8 hours. HREF ensemble guidance only gives around a 1 in 3 chance of wind gusts over 55 mph as well and this is mainly for areas very close to the Absarokas where impacts are limited, especially in regards to travel. If may issue something sometime this morning but this will be a game time decision. Elsewhere, there will be a gusty wind but high wind should not occur. In addition, relative humidity will remain very low, under 10 percent in some locations. Elevated to near critical fire weather remains very likely for most locations as a result. Most wind should decrease after sunset as the wind decouples.

Friday at this point looks fairly similar. Although with somewhat less 700 millibar wind, high wind looks unlikely. Relative humidity will remain very low though, so this looks like another day of elevated to near critical fire weather.

The whiplash will begin Saturday. This looks like another day of above normal temperatures, although with somewhat less wind. However, some southern stream moisture will begin to move into southern Wyoming on Saturday with a chance of a few showers and thunderstorms. At the same time, an upper level low will be moving in from the Pacific northwest. Most other portions of the state should remain dry during the daylight hours on Saturday. Precipitation starts to spread into the area Saturday night and especially on Sunday. As for details, there are a few moving parts with this system. In addition, some models open the low into a trough and are more progressive with it, moving it out on Monday while others cut it off and keep unsettled weather over the area into Tuesday. So details on placement of the heaviest precipitation and amounts remain very much in flux. And, this system has a decent amount of cold air with it. So, some of it will be in the form of slow, even in the lower elevations. With 700 millibar temperatures falling to minus 7, most areas will have a chance. We may need some highlights for the mountains, where the NBM ensemble gives a greater than 1 in 2 chance of over 6 inches of snow, especially above 8500 feet. Amounts in the lower elevations are impossible to determine right now. With the recent very warm temperatures, the ground is very warm and a lot of snow may melt on contact, especially on paved surfaces. Anything that falls during the day will likely melt on roads, since we will be less than 5 weeks from the summer solstice and the sun is very strong. It will also be very elevation dependent, with most accumulation largely above 6000 feet. However, with some high temperatures 40 to 50 degrees colder on Sunday and Monday when compared to yesterday, it will be weather whiplash for most of western and central Wyoming.

AVIATION /06Z TAFS THROUGH 06Z SATURDAY/

Issued at 1001 PM MDT Thu May 14 2026

VFR conditions are expected through the period as a dry westerly flow persists over the region. Wind will remain lighter through the overnight hours before increasing again by late morning. West to northwest wind gusts of 25 to 35 knots will be fairly widespread, decreasing after sunset. Skies will remain mostly few/skc through the period.

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

FIRE WEATHER

Issued at 215 AM MDT Thu May 14 2026

Temperatures will be cooler today. However, a combination of a gusty to strong wind and relative humidity falling under 15 percent will bring another day of elevated to near critical fire weather. Friday looks similar although wind may be somewhat lighter. Wind should finally decrease and humidity should begin to rise on Saturday and bring some improvement in conditions.

RIW WATCHES/WARNINGS/ADVISORIES

None.