textproduct: Cheyenne

KEY MESSAGES

- Temperatures will warm back up on Tuesday with highs east of the Laramie Range 10-15 degrees above normal, with temperatures backing down through Thursday before another warmup on Friday to end the week.

- Red Flag Warning in effect for eastern Wyoming and all of western Nebraska Tuesday through late Wednesday, with critical fire weather conditions likely extending through late in the week.

SHORT TERM /THROUGH WEDNESDAY NIGHT/

Issued at 153 AM MDT Tue Jun 9 2026

Some showers and thunderstorms this morning lifting up across the Colorado border into the Nebraska Panhandle this morning on radar. The environment is just weak enough that most of this activity is losing it's intensity before it can reach our area, but monitoring for strength as well as overall rainfall in case any additional products are necessary. While thunderstorm activity will relax moving into this afternoon, don't expect our weather to quiet down in the least as we switch gears into critical fire weather conditions and strong, gusty winds through Wednesday.

For today, we'll see the upper level trough continuing to move over our region, shifting flow from southwesterly to more westerly over the course of the day, with this flow persisting into Wednesday for most of the day until very late/overnight when a shortwave will swing in from the northwest and bring a cooler pattern just outside of the short term. This pattern will promote warmer temperatures today thanks to dry and warm desert southwest area overspreading the region. This will primarily impact highs east of the Laramie Range, with temperatures 10-15 degrees above normal, while to the west we should see a a pleasantly cooler day thanks to the incoming trough cutting off the warmer flow in this region earlier on, with highs much closer to normal. But the aforementioned dry air alongside a tightened pressure from this system creating gusty winds will create an critical fire weather environment, with Red Flag Warnings in effect for eastern Wyoming and the Nebraska Panhandle starting at noon today. And with relative humidity recoveries poor with further gusty and dry conditions tomorrow, this Warning is in effect through 9 PM on Wednesday. It must be noted that the Nebraska Panhandle has received notable precipitation recently, with greenup finally beginning to occur. While fuels may finally be exiting a critical status, to limit confusion due to expected critical weather conditions, have elected to keep the Red Flag valid across the area. Finally, this system should still be able to produce a few showers or storms later today, but with dry boundary layer, we'll likely be seeing them struggle to get precipitation to the surface after daytime heating. With elevated instability present alongside inverted V sounding profiles, expecting we'll see gusty virga and the potential for some dry lightning, but locations in the extreme western portion of our CWA may be able to see some precipitation development before the strengthening storms exit our CWA and continue eastwards.

Wednesday marks the cooler day as warm air intrusion begins to wane, but it will still be a relatively warmer than normal day east of the Laramie Range again as highs sit around 2 to 6 degrees above normal. Dry air will remain firmly in place however, continuing the risk of critical fire conditions alongside the strong winds which will be the strongest of the week thanks to notably enhanced pressure gradients. But high wind products are not currently anticipated, as surface pressure gradients lie just outside of where we would like to see them for gusts of 58+ mph, and in house guidance indicates only around a 40% probability of high wind criteria. If anywhere were to hit it though, look to the Chugwater to Wheatland corridor alongside the Arlington/Elk Mountain region as the most likely candidates.

LONG TERM /THURSDAY THROUGH MONDAY/

Issued at 1234 PM MDT Mon Jun 8 2026

The long term forecast appears dry with a switch in the flow regime from southerly flow to a more westerly. This is due to a persistent upper level trough pattern to our north into Canada. A cold front Wednesday will effectively cut us off from the more moist air that has been advecting in from the Gulf. During this period we are watching for conditions favorable for fire weather and high winds.

The high wind conditions spill over from Tuesday as flow at the 700 mb level stays elevated. The GFS is projecting winds at this level at around 50 knots. As daytime mixing commences the risk of these winds being mixed to the surface increases. Additionally enhancement by mountain wave breaking is likely to occur. Taking a horizontal cross section across our west to east ranges depict downsloping winds approaching 55 knots during the late morning to early afternoon hours collocated in areas of negative omega. Higher gusts are certainly possible given the low resolution of global models. This is not a great combination with the expected low relative humidities values. Across most of the area values are expected to plummet below 15 percent and temperatures in the 70s to high 80s. This is following previous poor nighttime recoveries of about 40-50 percent.

Going into Thursday and beyond, winds start to calm down after the departure of the mid level shortwave and ridging builds in. As mentioned our source of moisture has been cut off by the prevailing synoptic pattern, so humidity values remain very low. Winds are likely to remain high enough to warrant continued fire weather products through just about the entirety of the long term. Saturday and Sunday may see enough moisture and a source of lift from a clipper type system to support a few storms. Both GFS and Euro are on board with this solution with the usual caveat being that at this range solutions will change. If you are looking for any bit of good news past the long term, the latest CPC outlook has our area in below average temperatures and increased precipitation chances.

AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/

Issued at 1218 AM MDT Tue Jun 9 2026

VFR conditions are expected over the next 24 hours; however, there is a chance of some low clouds or fog tonight at KCYS. Have elected to leave it out of TAFs at this time, but will continue to monitor for necessary amendments. Precipitation chances should be much lower tomorrow, but cannot completely rule out a weak shower or storm for all terminals. Otherwise breezy winds are expected, with gusts of 30-40 knots possible.

CYS WATCHES/WARNINGS/ADVISORIES

WY...Red Flag Warning from noon today to 9 PM MDT Wednesday for WYZ417-418-430>433. NE...Red Flag Warning from noon today to 9 PM MDT Wednesday for NEZ434>437.