textproduct: Cheyenne

KEY MESSAGES

- Monsoon moisture will remain in place through Friday across the High Plains, producing widely scattered thunderstorms.

- More heat returns this weekend through Monday, with some near record high temperatures possible along with drier conditions leading to elevated fire weather concerns.

- 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 SATURDAY NIGHT/

Issued at 115 AM MDT Fri Jul 31 2026

Quiet weather early this morning with generally clear skies and light northerly winds observed. Not much has changed with the overall forecast for Friday and this weekend, so kept most of the forecast as is. Still expecting another round of showers and thunderstorms this afternoon, but the outflow from the MCS across the Great Plains is a bit more shallow than previously expected. Dewpoints are still increasing across the area under north to northeast winds with some low clouds around Chadron. Further west, surface dewpoints have returned to the 50s along the I-25 corridor. Models are now showing the subtle upper level shortwave moving south across the area earlier in the day, so adjusted timing for thunderstorm activity a few hours earlier compared to yesterday. This will likely lead to weaker and more disorganized convection with only a few storms seeing some gusty winds and/or small hail. CAPE values have come down quite a bit and only peak at 500 to 800 j/kg MLCAPE in the early afternoon. Low CAPE and a cap inversion across western Nebraska should keep conditions dry over that area with high res guidance showing little to no activity this afternoon. After that, some drier air is forecast to push into the area behind the shortwave, which will reduce the coverage of thunderstorms. Most of the activity should be finished between 6 to 8 PM.

For Saturday, all models show the upper level ridge axis, and 599dm upper level high centered across southern Utah, shifting north and east through the day. Expect a drying trend through the day as the midlevel subsidence is forecast to suppress convection initiation with the drier air gradually mixing down to the surface with inverted V soundings. After a slightly cooler Friday, Saturday will be back to above normal temperatures with highs in the upper 80s to upper 90s (warmest north of I-80). Kept POP below 5 percent through the evening hours. Sunday is forecast to be around 10 degrees warmer compared to Saturday as the brief heat wave continues late in the weekend.

LONG TERM /SUNDAY THROUGH THURSDAY/

Issued at 205 PM MDT Thu Jul 30 2026

Sunday...Main challenge will be the heat as near perfect setup for near record high temperatures, with the dominant 5960 meter 500 mb ridge axis prevailing and centered over the Four Corners. With quite dry air at low and mid levels, and 700 mb temperatures near 20 to 23 Celsius, we expect maximum temperatures in the mid 90s to near 100 degrees west of I-25, with upper 90s to near 108 degrees east of I- 25, with the hottest temperatures up in Sioux, Dawes and Box Butte Counties of the northern Nebraska Panhandle.

Current record high temperatures for August 2nd include...

98 degrees in 2008 at Cheyenne 94 degrees in 2024 at Laramie 98 degrees in 2000 at Rawlins 106 degrees in 2008 at Alliance 104 degrees in 2022 at Chadron 104 degrees in 1938 at Scottsbluff 103 degrees in 2008 at Sidney

Looking at our projected high temperatures, it looks like near record high temperatures expected at Rawlins, Laramie, Cheyenne, Chadron and Scottsbluff. Fortunately, dewpoints will be relatively low and heat index temperatures will peak in the 90s to near 100 degrees east of I-25. We will need to monitor minimum temperature trends to see about the necessity for possible Heat Advisories for Sunday in portions of the Nebraska Panhandle.

On Monday, the ridge flattens somewhat as a weak shortwave trough aloft and its associated cold front enter our counties from the north, cooling off temperatures somewhat and there may be enough available moisture for isolated late day thunderstorms over the southern Laramie Range.

Then on Tuesday, expect a relief from the summertime heat in the wake of a passing Canadian origin cold front, sending maximum temperatures back into the mid 70s to mid 80s. Moisture looks scant, perhaps enough for isolated to widely scattered late day thunderstorms near the mountains.

For Wednesday...synoptically, we anticipate a return flow event as low level southeast winds advect more low level moisture northwestward into our counties and providing enough fuel to help develop scattered afternoon and evening thunderstorms primarily from I-25 eastward, and we will likely need to increase our POPS for this day in the next few days.

On Thursday, a return to the heat is on tap under northwest flow aloft and with drier air infiltrating the counties, more heat is expected as 700 mb temperatures rise to near 15 Celsius, yielding maximum temperatures in the 90s to near 100 degrees.

AVIATION /06Z TAFS THROUGH 06Z SATURDAY/

Issued at 1135 PM MDT Thu Jul 30 2026

Mostly calm conditions expected overnight with clearing skies and decreasing winds through 08Z. KCDR and KAIA may see some low clouds overnight with near-MVFR ceilings possible. Skies clear out again as the sun rises. Winds increase into the afternoon hours with isolated to scattered showers and storms possible once more in the early afternoon through evening. Gusty and erratic winds will be possible in and around any shower or storm that develops.

CYS WATCHES/WARNINGS/ADVISORIES

WY...None. NE...None.