Bill, Wyoming Weather Forecast Discussion

448
FXUS65 KCYS 050534
AFDCYS
Area Forecast Discussion
National Weather Service Cheyenne WY
1134 PM MDT Thu Sep 4 2025
.KEY MESSAGES...
- A strong cold front will push through the CWA this afternoon,
  bringing a winds shift along with stronger winds.
- A warming trend will develop for the Saturday through Thursday
  period, with chances for isolated to scattered late day
  showers and thunderstorms each day.
&&
.SHORT TERM /THROUGH FRIDAY NIGHT/...
Issued at 202 PM MDT Thu Sep 4 2025
Skies are generally clear, but you wouldn`t necessarily know it as
smoke from Canadian wildfires has drifted into our CWA, reducing
visibility for a number of locations as low as two miles. Expect
these conditions to continue over the next several hours with some
improvement later this evening as the smoke begins to mix out across
eastern portions of Wyoming. If you are in western portions of our
CWA, I have some bad news, smoke will linger through most of Friday,
bringing reduced visibility along with poor air quality. Why has
this smoke drifted into our area, well, in part due to a stout
upper level low, that is vertically stacked, near the Great
Lakes that is helping transport smoke into our region. This low
will swing a front south across our CWA today, causing the winds
to become more northerly along with gusts topping out in the
30-35 kt range, with some locally stronger gusts possible,
through this afternoon. In addition to the winds, this front
will bring a substantial temperature drop into Friday through
early Saturday, before a warming trend ensues into next week.
Temperatures will struggle to reach the upper 60s to low 70s
across most of Wyoming and the Nebraska panhandle on Friday with
lows generally bottoming out near 40. Precipitation chances
with the passing of the cold front will be limited due to drier
conditions in place, with the greatest threat of showers or
storms near the I-80 corridor in southeast Wyoming later this
afternoon. Then, weather conditions become relatively benign
heading into the weekend, with no significant weather concerns
as we transition into a different pattern that will help
temperatures rebound along with bringing lighter winds to most
locations. Also, isolated chances of scattered late day showers
and thunderstorms heading into the long term for each day.
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
Issued at 200 PM MDT Thu Sep 4 2025
Saturday...Northwest flow aloft continues with a slow warming trend
as 700 mb temperatures rise to near 8 Celsius. Looks like enough
residual moisture over the far southern Snowy Range and far southern
Laramie Valley for isolated afternoon showers and thunderstorms.
Sunday...As ridging aloft develops over our counties, return
southeast low level flow develops, advecting low and mid level
moisture across our counties, and producing scattered afternoon and
evening showers and thunderstorms, mainly west of I-25. The warming
trend continues with 700 mb temperatures near 10 Celsius.
Monday...The warming trend continues with low amplitude ridging
aloft and 700 mb temperatures rising to near 14 Celsius. Adequate
low and mid level moisture for isolated late day showers and
thunderstorms mainly west of I-25.
Tuesday...As the ridge aloft transitions over the Central Plains
states and our flow aloft turns southwest, temperatures will remain
about the same. Enough low and mid level moisture for isolated to
widely scattered late day showers and thunderstorms, mainly west of
I-25.
Wednesday...Southwest flow aloft strengthens, and with warm
temperatures aloft providing convective inhibition, only isolated to
widely scattered late day showers and thunderstorms will be
possible, mainly west of I-25. High temperatures about the same as
on Tuesday.
Thursday...South southwest flow aloft prevails, and with adequate
low and mid level moisture, we expect to see isolated to widely
scattered late day showers and thunderstorms. Perhaps slightly
cooler compared to Wednesday due to more clouds and
precipitation.
&&
.AVIATION /06Z TAFS THROUGH 06Z SATURDAY/...
Issued at 1133 PM MDT Thu Sep 4 2025
A cold front moving through the area will turn wind directions more
out of the north as well as usher in some mid-level cloud cover.
Cannot rule out an isolated stray shower overnight, mainly for
terminals along Interstate 80. Hi-Res guidance also hints at
the possibility of low CIGs developing around KLAR early in the
morning, however did not have enough confidence to put this in
the TAF just yet. Smoke aloft may also persist into the day
Friday.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...Air Quality Alert until midnight MDT tonight for WYZ101>119.
NE...None.
&&
$$
SHORT TERM...RZ
LONG TERM...RUBIN
AVIATION...SF

NWS CYS Office Area Forecast Discussion