textproduct: Cheyenne

KEY MESSAGES

- Red Flag Warning has been issued for portions of southeast Wyoming for gusty winds, low relative humidities, and dry lightning through 9 PM.

- Elevated to critical fire weather conditions will likely persist through Tuesday.

- Hot temperatures start this week before a pattern change begins to occur as precipitation chances rise and temperatures fall, dropping to below normal by the later half of the week.

- Increasing precipitation during the middle to end of the week will also come with increasing risk of severe weather and flooding.

UPDATE

Issued at 934 AM MDT Mon Aug 10 2026

The Storm Prediction Center in Norman, Oklahoma has expanded the Marginal Risk of severe thunderstorms further westward for this afternoon and early evening encompassing much of our forecast area, with a Slight Risk of severe thunderstorms for our southeast Nebraska Panhandle, including Cheyenne County and Sidney.

With the 12Z NAM and 14Z HRRR showing isolated thunderstorms erupting across far southeast Wyoming and the southern Nebraska Panhandle after 20Z, 2 PM MDT, and expanding in coverage and intensity through late afternoon, have boosted POPS (Probability of Precipitation) accordingly. 12Z NAM showing a surface low developing across the central/southern Nebraska Panhandle by late afternoon, with decent low level convergence noted across that area. Progged CAPE by late afternoon will be 500 J/KG across eastern Kimball County Nebraska, up to 3000 J/KG for eastern Cheyenne County Nebraska, with bulk shear values from 35 to 40 knots, thus added mention of isolated damaging winds to the southern Nebraska Panhandle with the strongest storms, and added gusty winds to thunderstorms elsewhere. Gridded forecasts have been sent. -Rubin

SHORT TERM /THROUGH TUESDAY NIGHT/

Issued at 141 AM MDT Mon Aug 10 2026

Main concerns moving into the start of the work week will be further critical fire weather conditions alongside thunderstorms that could be strong to severe, with this activity shifting a bit further east on Tuesday, but into the long term we will likely see severe weather return as more widespread precipitation occurs. For Monday's fire weather concerns, another day of near to critical conditions are expected with the duo of gusty winds and low RH values, primarily occurring along and west of the I-25 corridor. But to accompany this, with how thunderstorms have developed over the past several days, have made mention of dry lightning once again as the inverted V forecast soundings remain, giving us the potential for high based thunderstorms with gusty outflows and lightning with little to no precipitation. The second concern for the day will be strong to severe thunderstorms once again firing off of the stalled frontal boundary located across the Nebraska Panhandle. MUCAPE values in the 1000-2000 J/kg range alongside similar DCAPE values should continue a lower end risk of hail and strong to severe wind gusts, with SPC agreeing and issuing a marginal risk for the eastern portion of the Panhandle. Otherwise, temperatures still remain on the warm side at around 10 to 12 degrees above normal, with highs in the upper 80's to very low triple digits.

Tuesday mirrors Monday in regards to temperatures as we see little change, with highs almost exactly the same for the day. Our critical fire environment should also be largely the same, with gusty winds and low RH for our northwestern zones and the threat of some dry lightning down into the high terrain zones bordering Colorado. While the frontal boundary that helped to fuel severe chances the past few days will still be lingering into the Nebraska Panhandle, the best instability looks to shift just east outside of our forecast area. Therefore we may not get the low end risk of severe weather, but with the continued threat of a dry surface promoting high DCAPE and inverted V soundings, don't be surprised if another storm or two at or near severe level occurs. Following this however we'll begin to see the pattern shifting with cooler and wetter conditions likely as we move into the middle and later half of the work week, hopefully calming our unending fire weather environment and bringing some much needed rainfall to the region.

LONG TERM /WEDNESDAY THROUGH SUNDAY/

Issued at 259 PM MDT Sun Aug 9 2026

As the long term forecast progresses, the 500mb jet moves from the Pacific NW to right over our area on Wednesday. While this jet has winds in the range of 50-60 knots, it is suppressed. As the ridge flattens, chances of moisture increase. PWAT values increase starting on Wednesday, with the highest values being Friday at around 1.5" near the Nebraska panhandle. RH values increase significantly on Thursday, ranging from 60-90%! This moisture sticks around through Sunday, even bringing some chances of thunderstorms with it. Shear increases Friday and Saturday evening, supporting chances of thunderstorms. Surface winds stay in a normal range for the area, typically staying below 35 knots. With this moisture moving in, and winds staying relatively slow, fire weather becomes much less of a concern through this long term period. 700mb temperatures show Wednesday still being quite warm, with much of the CWA being in the 15-17C range. Temperatures begin to cool down Thursday as a cold front moves in, bringing temperatures to the 10-12C range. The area stays cool through Sunday, below 13C.

AVIATION /12Z TAFS THROUGH 12Z TUESDAY/

Issued at 525 AM MDT Mon Aug 10 2026

VFR conditions expected over the next 24 hours. Generally light winds through the morning with speeds then increasing into the afternoon, 10-15 knots with gusts up to 25 knots, with WY terminals seeing mostly westerly to northwesterlies while NE terminals will be more variable due to lingering frontal boundary. Wyoming terminals may see gusty showers with strong winds and little to no rain, while Nebraska terminals will have a chance for strong to severe storms. Any of this activity could produce very strong and erratic winds. CIGs will be mid to high level through the period, even under storms.

CYS WATCHES/WARNINGS/ADVISORIES

WY...Air Quality Alert until noon MDT today for WYZ101>119. Red Flag Warning until 9 PM MDT this evening for WYZ417>427. NE...None.