150
FXUS65 KCYS 081142
AFDCYS

Area Forecast Discussion
National Weather Service Cheyenne WY
542 AM MDT Mon Jun 8 2026

.KEY MESSAGES...

- A Slight Risk (2 of 5) of severe thunderstorms is possible
  Monday for eastern Wyoming and the Nebraska Panhandle, with
  all severe hazards possible.

- Expect a quick cool down on Monday before a quick warmup on
  Tuesday, and then temperatures moderate through the end of
  the week though still around 5 to 10 degrees above normal.

- Fire Weather Watch in effect for the eastern high plains of
  southeast Wyoming and all of western Nebraska Tuesday through
  late Wednesday, with critical fire weather conditions likely
  extending through late in the week.

&&

.SHORT TERM /THROUGH TUESDAY NIGHT/...
Issued at 1249 AM MDT Mon Jun 8 2026

Another day of severe weather impacts is expected on Monday as
the cold front is pushing through the region tonight while aloft
southwesterly flow will overspread the CWA, causing storms along
the front range that will overspread into the Nebraska Panhandle
by the late afternoon hours. Into Tuesday we`ll see troughing
aloft progress over the region, bringing dry, warm air
advection and causing our precipitation chances to dwindle while
warming significantly and returning us to critical fire
conditions for our southeast Wyoming and Nebraska Panhandle
zones.

Forecast for today includes more severe weather as we start the
morning in a post-frontal environment. Flow should become
easterly to southeasterly promoting moist upslope flow, perhaps
even bringing some fog chances along the foothills of the
Laramie Range this morning, with a convergence zone setting up
along this area and southwards into Colorado through the
afternoon hours. We should then see thunderstorm development
during the afternoon hours as initially discrete cells form
along the high terrain and move eastwards. Along the border of
Colorado and through the I-80 corridor is where the best
ingredients for severe weather development will be located as
around 1000-1500 J/kg of MLCAPE develops alongside 100-300 m2/s2
of 0-3 km SRH and 0-6 km bulk shear of 50-65 knots. With these
parameters alongside cooler temperatures thanks to the front, we
should have a prime environment for some large hail development,
alongside strong wind gusts and perhaps a tornado or two with
favorable low-level rotation. There will be a cap however and
around 100-200 J/kg of CIN to overcome, but we`re starting to
see some agreement in the models on storm development. In fact,
the GFS and HRRR actually look notably similar, producing a
cluster of activity for the northern and central Nebraska
Panhandle, and another line of activity into the I-80 corridor
stretching down into Colorado. Nonetheless, it is likely that
storms will congeal into clusters or a line as they move further
east, and by around sunset the bulk of these storms should be
moving into Central Nebraska and exiting the CWA. Otherwise,
look for a much cooler day than yesterday, with widespread highs
mostly in the 80`s (Cheyenne itself may not make it, with a
forecast high of 79 for the day).

Into Tuesday we`ll see conditions mostly dry out as the trough
aloft moves over the region and brings dry surface conditions
and gusty winds. With this comes once again the return of
critical fire weather conditions for southeast Wyoming and the
Nebraska Panhandle where fuels are still currently receptive to
rapid fire spread. While the day shift did issue a Fire Weather
Watch, going to let that ride tonight and then allow the
incoming shift to determine on how to upgrade as portions of the
region including the I-80 corridor and the Nebraska Panhandle,
particularly Cheyenne County, have seen a noteworthy amount of
rain from yesterday`s activity and another round of storms
expected today. Maybe some of our fuels can come out of critical
status, but for now we continue with the assumption that fires
can spread if they start. Meanwhile, as mentioned precipitation
should be nearly done with the region, but we`ll still see
another round of development potential during the afternoon.
With dry boundary layer conditions and much more meager severe
potential, expectation is that this activity will struggle to
even produce precipitation. Soundings indicate inverted V
profiles with some elevated CAPE, and DCAPE exceeding 1000 J/kg.
If anything, this activity may produce dry lightning and some
gusty winds (further enhancing the critical fire environment),
with the SPC just barely clipping us with a marginal risk in the
Nebraska Panhandle. But, nonetheless can`t rule out at least a
small potential of a gusty shower before activity quickly moves
out of the CWA. Finally, the aforementioned warmth will also
bring us to the hottest day of the work week. Highs east of the
Laramie Range jump back into the 80`s and 90`s, but cooler
conditions west of the Laramie Range should see only 70`s into
80`s for this area. Once again these warm temperatures could
border on daily records just like this past weekend.

&&

.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
Issued at 100 PM MDT Sun Jun 7 2026

Tuesday into Wednesday, the Intermountain West switches from
southerly flow to a downsloping westerly flow as the upper level
low becomes stack moving along the Canadian Border. This will
lead to the continuation of warmer temperatures, but also a more
likely chance to break the cap when combined with the progged
frontal boundary moving through Wednesday afternoon/evening. Our
windiest day looks to be Wednesday as the 700mb ramps up to
about 50- 55 knots by the afternoon giving us gusty winds but
possibly not enough to meet the high wind criteria if those
winds stay below 55 knots.By Thursday and area of high pressure
looks to build in that may stay through the weekend. Fire
Weather remains a concern throughout the long term as RH values
look to bounce between 15 and 20 percent and some isolated
places dropping as low as 10 percent. The severe chances look
minimal through the long term as the stout dry layer looks to
stick around with minimal CAPE when glancing at the global model
soundings. It shouldn`t be a surprise if a Red Flag warning
gets issued through Saturday. Another trough looks to push
through Saturday evening into Sunday morning giving us another
chance for some light rain to possible thunderstorm chances
Sunday.

&&

.AVIATION /12Z TAFS THROUGH 12Z TUESDAY/...
Issued at 536 AM MDT Mon Jun 8 2026

Expecting primarily VFR conditions over the next 24 hours. Winds
will pick up this afternoon, with breezy conditions and gusts of
15-35 knots. Thunderstorms are possible this afternoon and
evening for KCYS and Nebraska Panhandle terminals, with strong
to severe activity. Storms could bring all severe threats,
including gusty variable winds. Cloud decks will drop down to
mid levels when this activity comes through. While overall decks
should lift thereafter, some mid to lower level clouds could be
possible for KCYS and KSNY, but have not put them in TAFs at
this time due to uncertainty.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...Fire Weather Watch from Tuesday afternoon through Wednesday
     evening for WYZ430>433.
NE...Fire Weather Watch from Tuesday afternoon through Wednesday
     evening for NEZ434>437.

&&

$$

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