textproduct: Cheyenne

KEY MESSAGES

- A heat wave will build into the area Saturday through Monday, producing near record high temperatures for Sunday.

- Elevated to critical fire weather conditions are expected Sunday and Monday.

- Some relief of the heat is possible during the middle of next week as a Canadian cold front moves towards the Front Range.

SHORT TERM /THROUGH SUNDAY NIGHT/

Issued at 130 PM MDT Sat Aug 1 2026

High pressure ridging remains firmly in place today, keeping our temperatures warm with minimal concerns outside of the hot weather, at least for today. This afternoon and tonight, while temperatures aren't exceptionally hot, expect highs to max out this afternoon in the 90's across most of our CWA, though a rogue 100 could occur for the upper panhandle or far eastern Wyoming. Overnight lows should remain cool enough, dipping into the upper 50's to low 70's. But then moving into Sunday we'll see a scorcher of a day across the entire region. High temperatures are widespread in the mid 90's to upper 100's, at or above the 99th percentile for the entire region. This has prompted a heat advisory for a majority of the CWA, valid during the day through the evening. Also of note will be the dry conditions coupled with breezy winds, leading to an expected critical fire weather environment. Pressure gradients will be on the rise thanks to a trough overtaking the Pacific Northwest and moving eastwards towards our region, causing surface flow to strengthen and bring elevated winds. The strongest winds will be primarily along our east and west borders, with a Red Flag Warning in effect for tomorrow for the Nebraska Panhandle, and a two-day Red Flag Warning for our far western zones of Carbon County as this environment persists into Monday alongside poor overnight recoveries of 20 to 30%. Finally, some high resolution guidance indicates the potential for some clouds and even a very low risk of a shower or two coming off of the mountains tomorrow, but with a very dry low level environment producing stout inverted V signals and some modest DCAPE, likely these will be nothing more than weak virga with potential for some gusty outflow.

LONG TERM /MONDAY THROUGH SATURDAY/

Issued at 130 PM MDT Sat Aug 1 2026

The work week will begin under zonal flow aloft as the high amplitude, positively-tilted ridge that was responsible for the anomalous warmth over the weekend progresses towards the east. A cold front is expected to push across SE Wyoming and Western Nebraska sometime Monday morning, which will introduce a cooler air mass relative to the near record-breaking temperatures that are expected on Sunday. With PWAT largely below the 50th percentile per long range ensemble guidance and any large-scale forcing for ascent, precipitation chances look minimal at this time. The main noticeable change will be the 10-15 degree drop in high temperatures, with locations west of the I-25 corridor seeing highs in the mid to upper 80s, and our Nebraska counties barely peaking above 90 degrees. Needless to say, these temperatures are still running at or even slightly above average. Gusty winds are also possible on Monday, as gradient flow increases thanks to lee cyclogenesis occurring to our south over Colorado combined with a surface high building in behind the cold front. With 50th percentile wind gusts ranging from 25-30 mph, minimum RH values decreasing to 15-25% during the afternoon, and plenty of dry fuels with the D3-D4 drought conditions, fire weather concerns persist into early next week despite the slightly cooler temperatures.

On Tuesday, a secondary shot of cooler air will extend down into our area as a surface anticyclone becomes established to our north over the Dakotas. With weak isentropic descent/cold advection behind the front, high temperatures are expected to be 10-15 degrees cooler than Monday's highs, with many locations struggling to reach the 80 degree mark. This is a much welcome change to what we have seen so far this summer, but don't get too excited considering trends into next weekend, as I'm sure many of you are burning to know...

Expect a slight increase in high temperatures on Wednesday as a 594 dam mid-level ridge builds across the Desert Southwest, with high temperatures at or slightly below climatology (average high for Cheyenne on Wednesday is 84 degrees). We still look to remain mostly dry as SE Wyoming/W Nebraska remain under WNW flow aloft, which isn't exactly favorable for monsoonal moisture transport from the southwest. The ridge (as does the heat) builds on Thursday, with ensemble guidance suggesting median high temperatures in the low to mid-90s east of the Laramie Range, and upper 80s to the west. With PWAT progged around 15-25% relative to climatology, we look to remain mostly dry. The trend continues on Friday into the weekend (unfortunately), as 500 mb heights rise and the ridge remains well- established over Nevada and Arizona. Under quasi-zonal flow along the northern periphery of the ridge, there aren't any strong signals for any substantial monsoonal moisture moving into our area. Sorry for sounding like a broken record, or for advertising the potential for more heat-relaated records being broken, we look to remain hot and dry into later next week.

AVIATION /00Z TAFS THROUGH 00Z MONDAY/

Issued at 530 PM MDT Sat Aug 1 2026

VFR conditions are expected throughout the forecast period. Winds are generally below 15 knots at all terminals. Starting at 02z a nocturnal low level jet will develop over much of the area. Winds of 20-30 knots out of the south to southeast can be expected. There may be some low level wind shear concerns at KBFF starting around 08z through 11z that may be included at the 06z TAF. High level cloud coverage will increase through the night. Starting around 08z through early afternoon winds at the Wyoming terminals will be calm and variable. Continued VFR conditions of diurnal scattered cumulus clouds and winds generally below 25 knots through late afternoon.

CYS WATCHES/WARNINGS/ADVISORIES

WY...Heat Advisory from 11 AM to 9 PM MDT Sunday for WYZ101-102-104- 107>109-111-118-119. Red Flag Warning from noon Sunday to 9 PM MDT Monday for WYZ421>423. NE...Heat Advisory from 11 AM to 9 PM MDT Sunday for NEZ002-003- 019>021-054-055-095-096. Red Flag Warning from noon to 9 PM MDT Sunday for NEZ434>437.