939
FXUS65 KCYS 132026
AFDCYS

Area Forecast Discussion
National Weather Service Cheyenne WY
226 PM MDT Sun Jul 13 2025

.KEY MESSAGES...

- An upper level trough brings a Marginal Risk for severe
  thunderstorms Monday evening.

- A cold front will bring thunderstorms on Tuesday/Wednesday
  alongside cooler temperatures on Wednesday, but a gradual
  warming trend will occur thereafter alongside daily shower and
  thunderstorm chances.

&&

.SHORT TERM /THROUGH MONDAY NIGHT/...
Issued at 226 PM MDT Sun Jul 13 2025

Easterly upslope flow look to likely produce a couple brief showers
in the mountains south of Laramie this afternoon and evening. There
may be a couple bolts of lightning as there will be a couple
hundred joules of CAPE to play with but overall rather uneventful.

Monday, An upper level trough dives down from the Alberta providence
of Canada to give us scattered thunderstorms with some severe
chances for the Intermountain west in the evening and early
overnight period. Model soundings depict an inverted V sounding
indicative of severe winds with hail up to the size of quarters.
CAPE values look for modest between 1000 to 1500 joules with the
higher values located in the Northern portion of our CWA.
Temperatures look to reach into the 90`s with some areas reaching
100 providing a buoyant environment with some mid level
moisture advecting into the region. Some models suggest some
warm air advection occurring overnight, which would sustain some
stratiform rain if that does occur overnight. SPC has a
Marginal Risk for Monday afternoon through Tuesday morning with
the primary threats being wind and hail.

&&

.LONG TERM /TUESDAY THROUGH SATURDAY/...
Issued at 226 PM MDT Sun Jul 13 2025

The long term will remain active as a trough and cold front cool
the region off early, but a deep ridge will begin trying to
overspread and warm us up, but systems to the north will stave
off a stronger and faster warming trend as we move into next
weekend. The long term begins Tuesday as a cold front is
approaching the region and will slowly pass across through
Wednesday morning. This will promote areas of showers and
thunderstorms across the CWA with the most likely areas for
storms including some stronger activity across Converse/Niobrara
Counties in Wyoming, and the Nebraska Panhandle (highest for the
northernmost counties here). Any stronger storms will be capable
of large hail and damaging winds. On Wednesday with the cold
front through the region and stalling along our southern
counties and just south into Colorado, cooler temperatures with
highs in the 70`s to low 80`s are expected alongside another
round of showers and storms. With more moisture moving into the
region, the stalled boundary, and another shortwave passing
through, even more widespread precipitation is likely with
conditions supportive of another day of strong to severe
activity. Thursday we begin warming back up though and will
continue to do so through the weekend, but the ridge will be
slow to build due in part to passing systems to the north.
Expect a gradual increase in temperatures with 80`s to 90`s by
Saturday alongside daily showers and thunderstorms thanks to the
aforementioned passing systems. Enough moisture should be
present to help fuel this activity while also keeping our
western and northern zones just above critical fire thresholds.

&&

.AVIATION /18Z TAFS THROUGH 18Z MONDAY/...
Issued at 1135 AM MDT Sun Jul 13 2025

VFR conditions expected over the next 24 hours. Skies will be
either clear or mid to high level clouds at FEW to SCT primarily
for Wyoming terminals. Winds 10-15 knots with some gusts to near
20 knots possible. Winds may begin to increase tomorrow morning
for Nebraska terminals right as the forecast period ends.

&&

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

&&

$$

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