659
FXUS65 KCYS 020540
AFDCYS

Area Forecast Discussion National Weather Service Cheyenne WY 1140
PM MDT Tue Jul 1 2025

.KEY MESSAGES...

- There is a Marginal to Slight Risk of strong to severe
thunderstorms  this afternoon for portions of western Nebraska and
far   eastern Wyoming.

- Warm temperatures and daily chances for PM showers and
thunderstorms will continue late this week and into next  weekend.

&&

.SHORT TERM /THROUGH THURSDAY/...
Issued at 1249 PM MDT Tue Jul 1 2025

A mid to upper level shortwave will kick off thunderstorms this
afternoon. Most of the Panhandle is in a Marginal Risk as dewpoints
and shear are more favorable in that area. The far eastern portion
of the panhandle of our CWA is in a slight as the thunderstorms are
likely to intensify the further east the storms travel. Effective
shear looks to range between 25 to 35kts with 1000-2000 joules of
CAPE. These storms if they do develop are likely to be messy and
pulsy as the shear and mid level lapse rates of 7.5C are quite
lackluster. However, looking at model soundings severe winds and
hail look to be the main threats as the classic inverted v soundings
are displayed by the models. Later in the evening, a developing low
level jet may enhance this thunderstorm activity, but most of the
activity may be moving into central Nebraska by then.

For Wednesday and Thursday, a pretty typical summer weather pattern
sets up across the region as a slow moving upper level ridge moves
east of the area. High temperatures will remain in the 80s west of I-
25, and upper 80s to mid 90s east of I-25.
Secondary 590 dm ridge axis will push into the area Wednesday.
With increasing midlevel subsidence and the lack of any notable
forcing, kept mention of precipitation west of the Laramie Range.
Showers and thunderstorms will return to most of the region on
Thursday as a broad eastern Pacific trough moves into the Great
Basin Region and finally into the Intermountain West Thursday
afternoon. This feature is expected to bring some subtropical
moisture to the area as PWATs increase between 1.00 to 1.50 inches.
Continued to increase POP across southeast Wyoming with some heavy
rainfall possible. High temperatures will be slightly cooler
Thursday afternoon due to cloud cover, but still near or slightly
above average for this time of the year.

&&

.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
Issued at 455 AM MDT Tue Jul 1 2025

Models show the pacific upper level trough continuing to lift
northeast across the area Friday with another round of showers and
thunderstorms. Thunderstorm coverage is forecast to lower this
weekend due to the lack of forcing as weak zonal flow develops
across the Intermountain west and across the Rocky Mountain Region.

Temperatures remain in the upper 70`s to the mid 80`s across the
forecast area. 700mb temperatures stay around 16 celsius which
translate surface temperatures into the low to mid 80`s for the
lower elevations and upper 70`s to low 80`s for our more mountainous
regions.

As we head into next week, models show another slow warming trend as
a 595 to 600dm upper level high develops near the four corners
region. The position of this high is a bit far south, so any
shortwave activity digging south of of Canada will be enough to
trigger showers and thunderstorms each afternoon. Kept thunderstorms
in the forecast Monday and Tuesday as all models do not show this
upper level high drifting northward until the middle of next week.

&&

.AVIATION /06Z TAFS THROUGH 06Z THURSDAY/...
Issued at 1140 PM MDT Tue Jul 1 2025

Shower and thunderstorm activity has ended for the night with skies
becoming mostly clear through early Wednesday morning. Upper level
ridge axis will build over the area Wednesday resulting in less
coverage of showers and thunderstorms Wednesday afternoon into
Wednesday evening.

HAZARDS/WEATHER TRENDS: VFR conditions will prevail over the next 24
hours. Another round of showers and possible thunderstorms are
forecast for Wednesday afternoon, but should mainly impact KRWL and
KLAR. Further east, can`t rule out some shower activity and an
embedded thunderstorm, but confidence is too low to include for KCYS
and the western Nebraska terminals.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...High Wind Watch until 6 PM MDT this evening for WYZ109-110.
NE...None.

&&

$$

SHORT TERM...TJT/MM
LONG TERM...TJT/MM
AVIATION...TJT