033
FXUS65 KCYS 040734
AFDCYS

Area Forecast Discussion
National Weather Service Cheyenne WY
134 AM MDT Thu Jun 4 2026

.KEY MESSAGES...

- Our continued chances of severe weather wrap up today with a
  slight risk (2/5) primarily for our northeastern zones.

- Temperatures will slowly warm to well above seasonal averages
  by the weekend, with a quick cooldown on Monday before further
  warmth returns into the middle of next week.

&&

.SHORT TERM /THROUGH FRIDAY NIGHT/...
Issued at 1233 AM MDT Thu Jun 4 2026

Latest analysis of today`s thunderstorm setup remains largely
dependent upon where the dryline sets up. Current analysis of
high resolution guidance favors the Nebraska Panhandle with a
surface low right along the NE/SD/WY border area. With a cold
front along this low and draping into Wyoming, it wouldn`t be
out of the question to get some development into Laramie County
before we see the main show across our northeastern zones in
Niobrara County and the northern Panhandle, but the severe
potential in southeastern Wyoming will be very limited.
Primarily the strongest storm activity should be limited to the
tri-state area as mentioned above (at least for our CWA) where
instability will be most conducive (500-1000 J/kg of MUCAPE,
isolated 1500) alongside SRH values of 200-300 m2/s2. Most of
our convective allowing models show some scattered development
across the area with a stronger storm or two moving across our
northeastern zones between 21Z-02Z, with many indicating another
quick stronger development around 06Z in Niobrara County or the
northern Nebraska Panhandle before activity should fully exit
during the overnight hours. While storms will be capable of an
isolated tornado alongside some stronger winds (DCAPE values
looking hearty in the 1000-1500 range), overall the primary
hazard expected will be hail with these storms, including larger
hail in the 1.5-2 inch range.

Otherwise the other notable feature for today will be gusty
winds under an enhanced pressure gradient for our far western
zones in Carbon and Albany Counties. While overall speeds are
not expected to near even close to high wind warning criteria,
the combination of these gusty winds and dry surface conditions
will lead to elevated fire weather concerns. Last contact with
partners suggests fuels are still not conducive of a critical
environment and the need for a Red Flag Warning, but the area
should be watched from how dry it has been alongside this
elevated environment. Once the shortwave promoting this activity
exits the region today, Friday will see high pressure taking
control as a ridge moves in over the Central US while a Pacific
trough sweeps across the western portion of the country. Between
these systems we should encounter subsident flow cutting off
pretty much all chances of precipitation while warming us
significantly as we move into the weekend. For Thursday and
Friday however, we should see relatively similar conditions as
highs range in the 80`s to low 90`s. But by the weekend, look
for temperatures to rocket into the upper 80`s to 90`s, and even
some triple digits making their first appearances of the year.

&&

.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
Issued at 248 PM MDT Wed Jun 3 2026

Drier and hotter weather will return to the area Friday through the
weekend. On the synoptic scale, an upper level low will dive into
the Pacific Northwest, which will then amplify the downstream ridge
over the Rockies and Plains. A very dry airmass with considerable
subsidence will move in overhead Friday. An inversion aloft around
600-mb will limit the development of convective instability, likely
suppressing most if not all afternoon shower and thunderstorm
activity. 700-mb temperatures will climb to around +10 to +15C,
supporting widespread highs in the 80s. The day may start off with
gusty northwest winds in the wake of a front passing through during
the morning hours, but expect this to weaken through the day.

This weekend will feature the first taste of the season of real
summer heat across the area. As the ridge amplifies aloft, expect
700-mb temperature to climb to around +13 to +18C by Saturday. This
should easily be the hottest day of the year so far across the area.
Interestingly, for Scottsbluff, Sidney, and Alliance, the hottest
day of 2026 through June 3 occurred in March! This should be easily
bested Saturday, with widespread mid to upper 80s along the I-80
corridor in Wyoming, and 90s elsewhere. Locations around
Scottsbluff, Torrington, Chadron, and Crawford have a 40 to 50%
chance to see their first 100 degree day of the season. While it
will certainly be hot, most locations have forecasts several degrees
away from daily record highs. The hot temperatures moving down to
the surface will lead to a deeper mixed boundary layer and thus a
weaker or absent inversion aloft. We should be able to get a few
high-based showers with perhaps a rumble of thunder going on
Saturday, but the chance for rainfall actually reaching the ground
is fairly low.

The Pacific trough will approach from the west on Sunday, knocking
down temperatures by several degrees for the western half of the
forecast area. East of Cheyenne`s longitude, highs will be slightly
cooler, but closer to Saturday`s values with another day of
widespread upper 80s to mid 90s. Look for a few widely scattered
showers and thunderstorms Sunday afternoon and evening, but again,
rainfall may be limited due to the warm and dry boundary layer. A
leading shortwave ejecting from the western Trough will pass through
Monday, knocking down temperatures and also perhaps providing some
lift for additional convective activity. Increased chances for
showers and thunderstorms will continue through the early part of
next week, but the details remain quite uncertain several days
out.

&&

.AVIATION /06Z TAFS THROUGH 06Z FRIDAY/...
Issued at 1050 PM MDT Wed Jun 3 2026

Outflow from thunderstorms across the northern plains Wednesday
evening will result in a poorly defined frontal boundary, which is
forecast to stall near the North Platte River Valley tonight.
Another round of isolated thunderstorms are possible near and east
of the boundary Thursday afternoon.

HAZARDS/WEATHER TRENDS: VFR conditions will prevail for most
terminals tonight through Thursday afternoon. Increasing confidence
that KCDR will see low CIGS and stratus. Added IFR to LIFR
conditions in low clouds, but kept fog out of the TAF for now.
Westerly winds will increase over the southeast Wyoming terminals
with gusts between 25 to 35 knots possible after 16z. Added PROB30
groups for KCDR, KAIA, and KSNY after 21z for afternoon
thunderstorms.

&&

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

&&

$$

SHORT TERM...CG
LONG TERM...MN
AVIATION...TJT