Area Forecast Discussion
Issued by NWS Cheyenne, WY
Issued by NWS Cheyenne, WY
383 FXUS65 KCYS 141054 AFDCYS Area Forecast Discussion National Weather Service Cheyenne WY 454 AM MDT Sat Jun 14 2025 .KEY MESSAGES... - Thunderstorm threat continues through the weekend, with a daily risk of strong to severe activity expected. - Temperatures notably above average this weekend with highs 5 to 10 degrees warmer than normal. - Strong to severe thunderstorms continue into next week with a quick cool-off to bring us back to near normal before heating back to well above normal late next week. && .SHORT TERM /THROUGH SUNDAY/... Issued at 128 PM MDT Fri Jun 13 2025 Storms are already firing across the region in a favorable environment for strong to severe activity. Current mesoanalysis shows surface CAPE east of the I-25 corridor in the 2000-4000 J/kg range, and low-level lapse rates between 7-10 C/km. High resolution guidance indicates we should see the ongoing storms that are currently moving into the I-25 area will continue to expand into a strong cluster/line of activity moving into the evening hours as it continues towards Nebraska. With Derecho composites 1-2 and MCS maintenance up to 60, the likelihood we see activity becoming linear and a widespread wind risk are becoming higher and higher. But some low to mid level wind shear could be enough to support updrafts of large hail, as well as the support for a very isolated tornado (with a linear based embedded rotation also not out of the question). Activity presses through Nebraska through the evening hours, with storms expected to exit our CWA by the late evening into the early nighttime hours. Clearing is expected overnight, but with the trough remaining over the region alongside a moist airmass, another round of strong to severe activity is anticipated on Saturday. This time though with notable warming and some declining moisture, dewpoints may drop a bit further across Laramie County and along I-25, leading to the primary severe risk further to the north and east where moisture should still remain a bit higher with dewpoints into the 50`s to 60`s. Storms are expected to fire during the afternoon around or just east of I-25, with large hail and winds the primary risks once again. This time the environment should be a bit more supportive of hail with some isolated supercells to clusters of storms likely, though storm motions are still anticipated to quickly propagate the storms east-northeastward and out of the CWA through the evening hours. && .LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/... Issued at 128 PM MDT Fri Jun 13 2025 Moving into the long term, the thunderstorm threat doesn`t end as we see daily risk of activity to end the weekend and start the work week. The threat on Sunday continues to shift a bit more north and eastwards, so thankfully the bulk of the strongest activity should remain just outside of our CWA, but a few severe storms cannot be ruled out. The notably warm temperatures should also help to reduce our RH values and make dewpoints descend a bit more west of I-25, keeping anywhere in this area in general thunderstorms at best, but further east a few stronger cells can`t be ruled out. On Monday the ridge that is primarily controlling the region should begin to break down, but not enough to allow for a stronger severe risk to overspread. A few marginally strong to severe storms are possible, but the highest risk for severe activity still remains just to our northeast. That all changes on Tuesday however, as the ridge will fully breakdown and a stout shortwave trough will move across the region, possibly even taking a negatively tilted orientation at the upper levels. Temperatures will descend notably as highs dive back down into the 70`s, allowing dewpoints to more closely align to our temperatures, and with low level shear much stronger alongside expected instability, we may see an even better day for severe weather across the area. The one caveat though will be if we can get enough clearing to initiate stronger storms, as the drop in temperatures should allow more cloud cover which could limit stronger heating. Still, enough breaks and gaps are possible, and so expect a potentially stout day for severe weather. After this though, the ridge builds back in with a vengeance, and we`ll see temperatures skyrocket through the end of next week and moisture all but depart our CWA. A few showers or storms could be possible on Wednesday for our northeastern counties, but expect a drying trend with temperatures back into the 80`s and some 90`s possible on Thursday. Into the extended term just beyond this forecast, we`re looking at significant warmth, with highs into the low to mid 90`s east of I-25. This could be our last temperate weekend before summer rears its head finally for our region. && .AVIATION /12Z TAFS THROUGH 12Z SUNDAY/... Issued at 450 AM MDT Sat Jun 14 2025 Zonal flow aloft will continue. Isolated to widely scattered thunderstorms will develop Saturday afternoon and evening, mainly along and east of Interstate 25. Scattered to broken clouds from 6000 to 15000 feet will prevail. Winds will gust to 23 knots at Rawlins from 17Z to 01Z. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...None. NE...None. && $$ SHORT TERM...CG LONG TERM...CG AVIATION...WFO-RIW