textproduct: Cheyenne

KEY MESSAGES

- A cold front will shift winds over the High Plains to the northeast this evening. Breezy north to northeast winds will continue through Saturday.

- Temporary relief from the critical fire weather conditions will come this weekend with cooler temperatures and slight chances for a few showers both Saturday and Sunday.

- Fire weather concerns will escalate once again Monday through Wednesday.

SHORT TERM /THROUGH SUNDAY NIGHT/

Issued at 300 PM MDT Fri Jun 12 2026

We have hardly a cloud in the sky this afternoon as a very dry airmass moves overhead. Most of the area is in the upper 70s to 80s, pushing relative humidity down to the lower teens to single digits! Winds are not as strong as yesterday, but breezy west to northwest winds are continuing to produce widespread critical fire weather conditions. We do expect to find some relief this evening, as a cold front approaches the area. While the cooler air will lag somewhat behind the wind shift, expect the boundary to push into the Chadron area first around 6PM this evening, then slowly move southwestward overnight into Saturday morning. Northeast winds may be gusty at times overnight over the High Plains. This front will be largely dry, as the upper level shortwave looks to remain just to our north. However, forcing may creep as far south as the US-20 corridor late tonight through early Saturday afternoon. PoPs are only around 10 to 25% or so at this time, and widespread rainfall is unlikely, but worth a mention in the forecast. Temperatures will be considerably cooler on Saturday. With more cloud cover further north, the US-20 corridor will struggle to get much above 60 degrees, whereas more sunshine further south will push temperatures in the the upper 60s to low 70s.

The surface cold front will stall somewhere across Carbon and Albany counties Saturday. This will make for a highly uncertain wind forecast (particularly in the wind direction) along the I-80 corridor with gusty westerly winds anticipated south of the boundary, and north to northeast winds to the north. Regardless of where it stalls, expect the boundary to shift south Saturday evening as the core of the surface high pushes up against the higher terrain. A fairly strong reverse pressure gradient will setup, leading to strong, gusty northeast winds in Carbon County, and gusty southeast winds around the Laramie area. In addition, higher humidity and cooler temperatures will push a deck of low clouds in against the higher terrain. East slopes can expect to see some fog, including the I-80 summit area. Another weak shortwave aloft will pass over the area Sunday. While instability looks extremely limited, synoptic forcing and upslope flow may allow for the development of a few light showers across the I-80 corridor, particularly closer to the Laramie Range. Low-end PoPs in the 15 to 30% range were maintained with this update. While appreciable rainfall is unlikely, we may see some light showers across the area in the morning, possibly with a few rumbles of thunder in the afternoon hours. Sunday will be another cool day. Our northern zones will be a touch warmer than Saturday as clearing skies push southward, but the I-80 corridor will see the coolest day of period, with highs around 10F below seasonal averages.

LONG TERM /MONDAY THROUGH THURSDAY/

Issued at 300 PM MDT Fri Jun 12 2026

Monday morning, Another weak shortwave looks to push through the Intermountain West ahead of the ridge pushing eastward off the West coast. However, as this ridge pushes eastward, the ridge begins to flatten due to another low pressure system pushes into British Columbia and travels along the Canadian Providences until dropping into the Northern Plains around Wednesday evening. This will change the flow direction from Northwest on Monday and transition to a westerly downslope by Tuesday evening. This change of flow will result in surface temperatures increasing from the 70's on Monday to the 80's and 90's on Tuesday through Wednesday. Winds will be rather gusty as well while in the downsloping flow to develop another few days of possible Red flag conditions.

AVIATION /18Z TAFS THROUGH 18Z SATURDAY/

Issued at 1122 AM MDT Fri Jun 12 2026

Some smoke from the wildfire is affecting KCDR this morning. This evening a cold front will pass through the area switching the flow from a westerly wind to a Northerly one effectively cutting off the smoke supply to KCDR and raising visibility back to P6SM. Due to the topographic bowl KLAR is in this cold front may keep the winds light and variable overnight before switching to a stronger Northerly mind morning around 15z.

CYS WATCHES/WARNINGS/ADVISORIES

WY...Red Flag Warning until 8 PM MDT this evening for WYZ417-418- 430>433. NE...Red Flag Warning until 8 PM MDT this evening for NEZ434>437.