229 FXUS65 KCYS 050546 AFDCYS Area Forecast Discussion National Weather Service Cheyenne WY 1146 PM MDT Thu Jun 4 2026 .KEY MESSAGES... - Severe weather chances wrap up Thursday night with a slight risk primarily for our northeastern zones. - Near record high temperatures and near critical fire weather conditions are anticipated this weekend. - Expect a quick cool down on Monday before heat builds back into the area towards the middle of next week. - There is potential for widespread critical fire weather conditions on Tuesday and Wednesday. && .SHORT TERM /THROUGH FRIDAY NIGHT/... Issued at 239 PM MDT Thu Jun 4 2026 Current observations from across the area position the dryline roughly along the Wyoming/Nebraska border. A cumulus field with a few spotty showers have developed behind the dryline as model soundings still show a weakly capped environment in the Nebraska panhandle early this afternoon. This cap should erode away soon and as these showers trek eastward into a more favorable environment, a few isolated thunderstorms could develop. Cannot rule out these storms being severe, with meso analysis showing about 1500 J/kg of CAPE in the panhandle along with pretty good effective shear. Both large hail and severe wind gusts could be possible given the MUCAPE and DCAPE values across the Nebraska panhandle. For areas behind the dryline, strong inverted-v sounding profiles point to gusty showers this afternoon. With how dry the low and mid-levels are, its likely not much, if any, precipitation will make it the ground. Instead, rogue severe wind gusts will be possible in these dry microbursts. Heading into the overnight hours, model soundings from the GFS show pretty good elevated convection will exist as well as a surge of low-level moisture into the northern Nebraska panhandle and Niobrara County. As a result, some strong storms will be possible overnight in the aforementioned areas. Much quieter weather is expected for Friday as zonal flow dominates the upper-levels of the Rockies. Dry air aloft will stay in place, leading to a mostly sunny day across the area. Temperatures will remain on the warm side with highs in the 80s across the CWA. Luckily a breeze throughout the day will help the warm air from feeling stagnant. && .LONG TERM /SATURDAY THROUGH THURSDAY/... Issued at 239 PM MDT Thu Jun 4 2026 Hot temperatures will prevail this weekend. A strong upper level low pushing into the Pacific northwest will amplify a powerful ridge over the Rockies and Plains over the weekend. Warm air will surge northward, sending temperatures well above seasonal averages. Saturday will be the hottest day of the period, and ensemble members have continued to trend more aggressive on the hot temperatures. NAEFS mean 700-mb temperatures climb to around +15 to +17C across the area, which will range from the climatological 90th to 99th percentile across the area. Over most of the area, highs will easily be 15 to 20F above seasonal averages, with the largest anomalies around the Chadron area. Most locations will be within a few degrees of daily record highs, but no records are currently forecast. The Rawlins to Cheyenne corridor can expect highs in the mid 80s to close to 90 degrees, while even hotter temperatures will show up in the lower elevations north and east of Cheyenne. Probabilities for 100 degree temperatures are around 50 to 60% in Torrington, Scottsbluff, and Chadron, and around 20 to 30% in Sidney and Alliance. Despite a dry airmass in place, the heat should be sufficient to kick off high-based shower and thunderstorm activity. There is some uncertainty on the location of the dryline Saturday afternoon, which will determine whether this activity will be able to produce notable rainfall, or if it will just be the typical dry microburst threat. Sunday will be similar to Saturday. Temperatures will be not quite as hot as the Pacific trough approaches from the west, but expect highs well above seasonal averages once again. The convective threat will again be determined by the exact position of the dryline, which could vary somewhere between entirely east of our area, and closer to the WY/NE state line. Expect a modest cool down on Monday as the shortwave trough ejects to our north. However, model guidance has trended weaker and further north with this cold front. As a result, highs may actually remain above seasonal averages on Monday, but just by perhaps 5 or so degrees. The powerful ridge will amplify once again Tuesday through the middle of next week as yet another trough dives into the West Coast. Therefore, expect highs to surge to near record high values yet again for Tuesday, Wednesday, and possibly beyond. Ensembles are not very optimistic for widespread precipitation at any point during the forecast period. Fire weather concerns will be elevated to near critical for most of the next week thanks to the hot temperatures and dry airmass expected to remain in place. Tuesday and Wednesday have the potential to be particularly concerning fire weather days due to increasing southwest winds aloft in between the west coast trough and the powerful ridge over the central Plains. && .AVIATION /06Z TAFS THROUGH 06Z SATURDAY/... Issued at 1124 PM MDT Thu Jun 4 2026 Storms and showers are being detected on regional radars, however the most substantial activity should be on its way east by the start of the forecast period. The chance of remaining storms impacting a terminal is very low through the rest of the overnight. Variable winds underneath complex boundaries left behind from earlier convection may present a low level wind shear hazard to some Western Nebraska terminals in the near term. KAIA appeared to have the best signal from guidance, therefore a short term inclusion of wind shear was included. A cold front is passing through the area and will impart gusty northwesterly winds during the next few hours. Widespread low cloud coverage is expected to develop around 08-15z, after the frontal passage, at most terminals. Some CIGs could approach MVFR or briefly IFR. Fog is uncertain to develop for KCYS and the Nebraska terminals during this period due to the spread in air and dew point temperatures, however the possibility is there. After daybreak skies will clear and stay mostly clear through the rest of the forecast period. A switch of winds from northerly to southeasterly will occur over the high plains, with KLAR and KRWL becoming westerly. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...None. NE...None. && $$ SHORT TERM...SF LONG TERM...MN AVIATION...RV