711
FXUS65 KCYS 071137
AFDCYS

Area Forecast Discussion
National Weather Service Cheyenne WY
537 AM MDT Sun Jun 7 2026

.KEY MESSAGES...

- A Marginal (1 of 5) to Slight Risk (2 of 5) of severe weather
  is expected on Sunday and Monday for eastern Wyoming and the
  Nebraska Panhandle, with all severe hazards possible.

- Near to record warmth possible again on Sunday.

- Expect a quick cool down on Monday before heat builds back into
  the area towards the middle of next week.

- Confidence is growing in widespread critical fire weather
  conditions Tuesday through Thursday.

&&

.SHORT TERM /THROUGH MONDAY NIGHT/...
Issued at 118 AM MDT Sun Jun 7 2026

Today the region will lie under southwesterly flow as ridging
shifts a bit more eastwards over the Great Lakes while a Pacific
trough also moves eastward with the central and strongest part
of the low lifting up across Canada. This will force a strong
shortwave across the upper Rockies, with a second and weaker
embedded shortwave passing across on Monday. At the surface, a
cold front stalled out across Wyoming will pass across the
region through Monday morning, with cooler upslope flow
expected thereafter through the day.

For Sunday, the strongest part of this system will be located
further north than our CWA, but thunderstorm development is
still anticipated with a mostly Marginal Risk (1 of 5) of seeing
severe weather. Analysis of the environment though shows little
to be excited about as the environment present will hardly be
conducive of stronger to severe storms. The best instability
will be both north and east of our area, with perhaps some
favorable CAPE in excess of 1000-1200 J/kg during the evening
hours and a low-level jet strengthening and bringing 50-60 knots
of bulk shear during that time as well, but forcing should be
mostly out of the CWA at that time. As mentioned in the previous
discussion, it appears the best chance for any new storm
development to take advantage of the environment will be limited
to outflow driven evening development or along the cold front,
and with unfavorable sounding profiles during the day coupled
with this limited forcing, high resolution guidance is
struggling to produce much noteworthy convection for the area.
Expectation is that we`ll see a few stronger storms that could
reach severe status during the evening and into the early night
hours before activity wanes or moves out of the area.

Moving into Monday in the post-frontal environment, another day
of shower and thunderstorm development is expected for southeast
Wyoming and the Nebraska Panhandle, but this day looks to be a
little more impactful than Sunday`s risk. Moist upslope flow in
a cooler environment should allow for a few storms to develop
into the mid-afternoon timeframe, and with lingering CAPE values
around 1000-1500 J/kg right along the WY/NE/CO border region
coupled with bulk shear values eclipsing 50-60 knots, we might
just have enough ingredients to produce a few stronger storms or
supercells that could include all severe hazards, but notably
large hail and perhaps a tornado or two. This activity should
quickly depart though and by right around sunset or the very
early evening most activity should be consolidating into a
clustered or linear system and moving across Central Nebraska.
Also of note though is the fact that we will still be seeing a
fairly dry boundary layer, as minimum daytime RH values will
reach as low as 20-25% east of the Laramie Range. Because of
this, we could see a mix of wet and dry convection depending how
strong storms are, and if any storms can`t quite strengthen up
and produce falling precipitation, we could see dry lightning
thunderstorms creating an elevated fire weather environment.
But with some activity expected to produce precipitation,
confidence is not high enough to issue a Red Flag Warning
currently.

Finally, look for a couple of breezy days thanks to the enhanced
low level pressure gradients across the area, with temperatures
on Sunday once again giving us some early summer heat with highs
west of the Laramie Range in the 80`s, and east in the upper
90`s to near triple digits. The cold front into Monday will drop
us back into the widespread 80`s, giving us a quick reprieve
before temperatures rebound into the beginning of the long term
on Tuesday.

&&

.LONG TERM /TUESDAY THROUGH SATURDAY/...
Issued at 203 PM MDT Sat Jun 6 2026

Monday night into Tuesday, A negatively tilted trough
pushes through the Rocky mountains giving us some weak jetstream
dynamic support while in southwest flow. The system will advect in
some moisture at the mid-levels during this time giving us some
shower potential in the afternoon. However, the model soundings
aren`t to convincing as they show a stout residual dry layer near
the surface and a capped environment that may put a pause to any
convection and prevent any rain from reaching the surface. As this
low pressure system begins to become stacked Tuesday into Wednesday,
the Intermountain West switches from southerly flow to a downsloping
westerly flow. 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 in the
afternoon. Our windiest day looks to be Wednesday as the 700mb ramps
up to about 50 knots by the afternoon giving us gusty winds but not
enough to meet the high wind criteria. 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.

&&

.AVIATION /12Z TAFS THROUGH 12Z MONDAY/...
Issued at 533 AM MDT Sun Jun 7 2026

VFR conditions expected over the next 24 hours. Winds breezy
again today, with gusts in the 20-35 knot range. CIGs will be
high level until this afternoon and through the late evening
hours when they will drop to mid level. A few thunderstorms are
possible, primarily impacting KCYS as well as the NE Panhandle
sites, bringing lightning and variable gusty winds. Once the
storms depart, expect winds to lessen, with speeds around 5 to
15 knots.

&&

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

&&

$$

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