textproduct: Cheyenne

KEY MESSAGES

- This afternoon and Monday will be mainly dry and hot as an upper level ridge builds over the region, expect highs today and again Monday to top out in the mid 80s to mid 90s.

- Conditional thunderstorm chances return Monday through at least Thursday in response to increasing moisture.

- A ridge builds late in the long term, drying us out and perhaps breaking heat records.

SHORT TERM /THROUGH MONDAY NIGHT/

Issued at 131 PM MDT Sun Jul 5 2026

As we start off the short term period, enjoy the beautiful afternoon/evening under a dominating ridge of high pressure. With this, there will there be plentiful sunshine as temperatures soar into the upper 80s primarily west of I-25 and lower to upper 90s east of the corridor. A quick look at winds for this afternoon, expect generally light winds west of the Laramie Range and a bit gusty by this evening to the east as a low-level jet ramps up, expect winds 30 to 40 mph in and around Cheyenne and Pine Ridges. Not only this, due to ample subsidence as a result of the ridge, convection will have a hard time to get started, let alone develop this afternoon. This is confirmed by hi-res guidance as the suite all shows, nothing, no convective development.

Onto Monday, the aforementioned low-level jet will weaken around sunrise as the ridge pushes off to the east. As this does this, moisture will surge back into portions of the CWA, primarily east of the I-25 corridor, with dewpoints bumping back up into the 40s and 50s. As the ridge shifts to the east, a weak shortwave will drop south and clip northern portions of the CWA by Monday afternoon. This energy coupled with the added moisture will help increase chances of isolated showers and thunderstorms. Due to weak convective parameters, any thunderstorm activity should remain sub- severe. Even though, with any shower and/or thunderstorm, gusty outflows will still be a threat. Shifting to temperatures, expect another hot day as temps soar a few degrees warmer than Sunday with highs topping out near 90 for most areas west of I-25 and low to upper 90s east of I-25, with a few locations across the Nebraska Panhandle flirting with the century mark.

LONG TERM /TUESDAY THROUGH SATURDAY/

Issued at 131 PM MDT Sun Jul 5 2026

The long term features some storm chances to start off the period and a slight cooling trend as monsoonal moisture advects in from the west. By next weekend the ridge over the four corners region may strengthen pushing temperatures towards all time record highs.

PWATs Tuesday are expected to anomalously high at about +1.0 to +2.0 sigma values above normal. This monsoonal moisture and an upper level shortwave will flatten the ridge and increase our thunderstorm chances in the afternoon. The thermo profiles at peak daytime heating show a significant dewpoint and air temperature spread of almost 50 degrees. Bulk wind shear is likely to be on the low side (below 30 knots) which would favor multicellular and pulse type storms capable of dry microburst winds. Despite the high PWAT values, and with the sub cloud layer being so dry, these storms are not going to be efficient rainfall makers. Additionally, dry lightning potential could be concern. Minimum relative humidity values in the afternoon will dip into the teens and lower 20s leading to elevated wildfire conditions.

Wednesday and Thursday feature much the same weather as Tuesday. The moisture does potentially increase some allowing more widespread precipitation chances. Wind shear does increase, so we may see a few more organized storms with hail and wind threats. The increased cloud coverage and storms may keep most of the region under 90 degrees. This will be possibly the last good chance we get for rainfall for some time as the ridge builds over the area. Ensemble members have this ridge reaching some 8 to 10 decameters above climatological average. Deterministic models have up to 15 to 18 decameters above average. Such a strong ridge will create significant subsidence in the lower levels, warming and drying us out. Relative humidity values in the single digits and temperatures over 100 are certainly possible over the weekend east of I-25. Critical fire weather would arise from these conditions and receptive fuels. While a ways out, there is a possibility that all time record highs are broken Sunday or Monday at a few locations. If the ridge center shifts to our east we also have a downsloping effect that would nudge temperatures up a few degrees. Hopefully the ridge ends up not as intense as models are suggesting.

AVIATION /18Z TAFS THROUGH 18Z MONDAY/

Issued at 1122 AM MDT Sun Jul 5 2026

VFR conditions are expected throughout the forecast period for all regional terminals as a ridge axis builds over the area. Increasing cloud coverage around 12 kft is being observed on satellite imagery along higher terrain. Limited shower activity is expected from these developing cumulus, though a very low chance of variable gusty winds from dry downburst activity near KLAR is possible. Cloud coverage increases at most terminals overnight and into the morning hours with ceilings remaining within VFR. A low risk of low level wind shear could materialize at KBFF during 8-10z timeframe, but probabilities are too low to introduce into TAFs at this time.

CYS WATCHES/WARNINGS/ADVISORIES

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