671
FXUS65 KCYS 051830
AFDCYS

Area Forecast Discussion
National Weather Service Cheyenne WY
1230 PM MDT Thu Jun 5 2025

.KEY MESSAGES...

- Cooler and wetter conditions expected through the end of the
  work week. Strong to marginally severe storms expected
  Thursday.

- Warming trend possible during the weekend through early next
  week with daily chances of showers and thunderstorms.

&&

.SHORT TERM /THROUGH FRIDAY/...
Issued at 244 PM MDT Wed Jun 4 2025

A few showers and thunderstorms noted this afternoon across the
CWA including a particularly impressive cell that went directly
over the office and produced quite a bit of hail. Scattered
activity is expected to continue through this evening, with a
bit more widespread coverage into the evening and nighttime
hours possible as better moisture moves into our CWA. During
this time, soundings also indicate the presence of enough low-
level moisture to be conducive of low clouds and fog, so have
added in fog chances for the Laramie Summit and into Cheyenne.
Expecting similar to what we`ve seen recently with passing
showers followed by periods of lowered visibilities.

Looking at Thursday we are expecting a marginal risk of severe
thunderstorms primarily for southern portions of our CWA from
Cheyenne to Sidney. Instability will be modest at best, with an
average MUCAPE from the HREF around 500-1000 J/kg but the
potential to max out around 1500 could fuel a stronger storm or
two. This will be largely dependent upon both our temperatures
as well as how much clearing we can get from overnight activity,
but with highs expected only in the low to mid 60`s we will
definitely need some assistance if we`re going to see anything
stronger. Shear will be favorable though, so if we do get any
storms that can produce stronger activity look for marginally
severe hail and wind gusts to be possible. Some lingering
activity could be possible into the evening and nighttime hours,
but it shouldn`t be as prevalent as tonight.

&&

.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
Issued at 244 PM MDT Wed Jun 4 2025

Friday into Saturday, westerly flow starts to dominate the pattern
allowing us to get a small break from the precipitation chances. Dry
air looks to start filing into the lower elevations giving us a dry
layer near the surface that may possibly not allow precipitation
from reaching the surface.

Sunday and Monday, Northwesterly flow sets in as the front side of
the upper ridge pushes into the Intermountain West. This will allow
for ridge riders to increase the precipitation chances as they send
vort maxes across the area providing sufficient lift for garden
variety storms to develop.

Tuesday, an upper level low traverses across the southwestern US to
give us a short lived ridge on Tuesday that should limit any
precipitation chances. This looks to be the day to go outside and
enjoy the sunshine before another shortwave reviving our
precipitation chances occurs on Wednesday.

&&

.AVIATION /18Z TAFS THROUGH 18Z FRIDAY/...
Issued at 1219 PM MDT Thu Jun 5 2025

Showers and thunderstorms expected across the region this
afternoon and evening, which could bring localized reductions to
VIS to sites. Winds could be breezy at times from local storms,
with predominant winds also bringing breezes to Wyoming TAF
sites. Overnight into tomorrow CIGs are expected to lower with
MVFR to IFR ceilings expected outside of KRWL. A passing shower
could also be possible overnight but activity is expected to
settle a bit more than this morning`s widespread activity in the
NE Panhandle.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...None.
NE...None.

&&

$$

SHORT TERM...CG
LONG TERM...MM
AVIATION...CG