Radar — KCYS
Surface Analysis — Western U.S. (Central)
Satellite
Nearest monitored road: US-30 (Primary)
- marginal risk of severe thunderstorms tuesday afternoon and evening. Strong gusty winds will be the primary threat.
- monsoon moisture will remain in place through the middle of the week. Heavy rainfall and localized flash flooding possible tuesday through wednesday night.
- more heat returns this weekend through monday, with some near record high temperatures possible.
Issued at 201 PM MDT tue jul 28 2026
Southeastern wyoming and western nebraska continue to remain under SW flow aloft beneath a 594 dam mid-level ridge centered over west texas and new mexico. This is providing US with another fetch of monsoonal moisture, with PWAT approaching the 99th percentile (as high as 1.6" for our nebraska counties). As we remain downstream of a SHEAR-induced vorticity maximum with ample deep-layer moisture, another round of widely scattered showers and thunderstorms are likely this afternoon into the evening.
Showers and thunderstorms have increased in coverage across the nebraska panhandle early this afternoon within a theta-E ridge, collocated with an axis of low to mid 60 surface dewpoints. Due to the aforementioned speed maximum, SPC mesoanalysis has much of the nebraska panhandle under 30-35 of effective bulk SHEAR, resulting in the potential for a few strong to severe thunderstorms. The main hazards with storms today will be large hail and damaging winds, especially with 20-25 degree surface dewpoint depressions and dcape around 1000 j/kg. Any storms that manage to rotate given marginal deep-layer SHEAR will have the potential to produce borderline severe hail, especially with any discrete/semi-discrete storm modes. Heavy rain will also be possible given anomalous PWAT, however parched soils may limit this threat today. One exception will be that any training convection could result in localized flash flooding, especially with cloud-layer mean winds around 15 knots, which is along the "borderline" threshold for favorable flash flooding storm motion. The greatest hydrological threat is mainly along and south of the i-80 corridor where flow aloft is weakest.
Storms should begin to exit the nebraska panhandle by 9-10 PM this evening as the environment becomes overturned by earlier convection and with the loss of any heating. Temperatures tonight along and west of the laramie range will be cooler in the mid to upper 50S with decreasing cloud-cover and light winds below 10 MPH. Overnight lows will remain mild in locations north of the pine ridge (i.E. Chadron) where temperatures may struggle to dip below 70 degrees thanks to southerly downslope flow.
Tomorrow will likely feature another round of afternoon showers and thunderstorms, although storms are expected to be less organized and widespread with the lack of deep-layer SHEAR. Heavy rain and localized flooding will remain possible tomorrow into tomorrow night as PWAT remains within the 85-95th percentile combined with weaker flow aloft. This may be a concern if the same areas that manage to receive heavy rainfall today are similarly impacted tomorrow. High temperatures tomorrow are expected to be in the mid to upper 80S west of the i-25 corridor, with low to mid 90S further east before cloud coverage increases later in the afternoon. A weak shortwave trough will progress across SE wyoming and western nebraska late tomorrow evening into the overnight hours which may keep showers and thunderstorms going well after dark. Similar to the last few days, training convection will have to be watched closely, especially in areas that received heavy rainfall today. Overnight lows wednesday night into thursday will be similar to the previous day.
Issued at 201 PM MDT tue jul 28 2026
Thursday...northwest flow aloft develops in the wake of a passing shortwave trough aloft, with drying noted across southeast wyoming and monsoonal moisture moves into nebraska, we will see isolated to scattered late day showers and thunderstorms across the nebraska panhandle.
Friday...monsoonal moisture plume stretches north to south across far eastern wyoming and western nebraska, and with a ridge runner shortwave trough aloft in northwest flow, we expect to see scattered showers and thunderstorms generally east of a douglas to cheyenne line.
Saturday and sunday...ridging prevails with a decrease in monsoonal moisture and warm temperatures aloft will produce enough CIN, convective inhibition, to prevent thunderstorm development. Hot temperatures return with the hottest day being sunday, and with 700 mb temperatures from 20 to 23 celsius, high temperatures will range from 95 to 105 degrees, with possible heat advisories needed east of i-25 on sunday.
Monday and tuesday...broad troughing aloft develops across the northern rockies with zonal flow over our counties. This will help produce somewhat cooler temperatures as 700 mb temperatures lower to 13 celsius. There may be enough low and mid level moisture to produce isolated late day thunderstorms over and near the laramie valley and southern laramie range.
Issued at 541 PM MDT tue jul 28 2026
The main aviation concern this evening will be the potential for scattered showers and thunderstorms with heavy rain and strong winds at times. Current radar imagery shows storms becoming a bit more numerous. Slow moving storms could drop heavy rain, reducing visibility down to MVFR/IFR criteria. Strong and erratic wind gusts will also be possible in and around storms. Showers could continue into the overnight hours.