textproduct: Western and Central Wyoming

KEY MESSAGES

- Isolated showers again possible (20-30%) mainly across the highest elevations of northwestern WY today.

- Ridging builds across the Rockies this week, holding off most precip and allowing temps to jump into the 70s and 80s. A few 90 degree readings are becoming more likely for the upcoming weekend east of the Divide.

DISCUSSION

Issued at 211 AM MDT Mon Jun 1 2026

The first lobe of the trough spinning across the NW US has shifted northward into Montana, taking along with it the showers from yesterday. Another shortwave rotates through during the day today, getting pulled northward into yesterday's wave. This wave is already noted on local radars as high based showers/virga moving into far SW WY this morning. Moisture will be notably lower closer to the surface across the region, with the only areas where humidity remains above 25% would be the highest elevations of the NW mountain ranges. This combined with today's wave being weaker than yesterday's will limit actual accumulation chances to 20% or less, again focused exclusively on the higher elevations.

Tuesday bears some more watching as short-range models have been hinting at some thunderstorm activity with another weak wave shifting through the state. The wave isn't all that notable, but a more defined moisture boundary across central WY may become the focus for thunderstorms for greater Natrona and Johnson Counties during the afternoon. With temperatures jumping into the low to mid 80s, the strength of any capping inversion would be the main factor on where thunderstorms would initially fire before shifting into eastern WY. Right now the placement of these features is not conducive at the same time for convection for central WY, but any adjustments on timing may need an increase of PoPs during the afternoon.

Wednesday sees weak ridging shift into western WY, settling convection down for the day, and bringing temps back into the 70s and 80s. Another wave sweeping by across Montana brings another chance for showers and thunderstorms across the northern half of the state, before ridging return for late week into the weekend.

AVIATION /12Z TAFS THROUGH 12Z TUESDAY/

Issued at 516 AM MDT Mon Jun 1 2026

Cloud cover this morning remains mainly approaching midlevel deck moving in from the southwest across KBPI/KPNA/KRKS, running SCT to BKN around 6000 to 8000 feet. A couple of these clouds are producing a brief raindrop or two, but are not expected to have impacts this morning. Some isolated shower activity is possible again this afternoon in the vicinity of western mountains, but will be much more isolated than yesterday. Most showers will have difficulty moving away from higher peaks, so afternoon impacts at local airports either side of the Divide will be minimal. Best chance for any precipitation would be in the vicinity of KPNA late this afternoon. Any showers that do form would produce locally gusty winds from the southwest. Outside of any showers, southwest winds gusting 25 to 30 kts are expected from KRKS to KCPR. Winds and any showers will decrease quickly near sunset.

RIW WATCHES/WARNINGS/ADVISORIES

None.