278
FXUS65 KCYS 151759
AFDCYS

Area Forecast Discussion
National Weather Service Cheyenne WY
1159 AM MDT Tue Jul 15 2025

.KEY MESSAGES...

- There is a Marginal Risk for severe thunderstorms Tuesday and
  Wednesday.

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

&&

.SHORT TERM /THROUGH WEDNESDAY/...
Issued at 148 PM MDT Mon Jul 14 2025

Scattered thunderstorms are ongoing across the region this
afternoon in an environment conducive of marginally strong to
severe thunderstorms. Current mesoanalysis indicates areas of
mostly favorable instability, MUCAPE values 1000-2000 J/kg, with
bulk shear primarily relegated to our northern zones. Its in
these locations that the strongest storms are currently ongoing,
but have remained sub-severe. High resolution guidances expects
this to continue through this evening and with the trough moving
eastwards into the NE Panhandle alongside a brief increase in
wind shear, guidance is honing in on at least one storm taking
advantage of this environment in the northern Panhandle and
producing stronger winds and perhaps some hail. Activity is then
expected to wane through the late evening and early nighttime
hours.

On Tuesday we continue with more thunderstorm activity as a
cold front begins to approach and move into the CWA, but this
feature is expected to stall out as it reaches the I-80
corridor. Along this boundary we can once again expect stronger
to severe thunderstorms, with the best risk for severe activity
currently lying just east into Central Nebraska. CAMs are
showing two rounds of activity with this system - one round
during the afternoon hours, and another round during the late
afternoon/evening timeframe. It`s this second round that is
showing signs of becoming linear and passing across northern and
central Wyoming and then the northern Nebraska Panhandle
through around midnight, bringing a higher risk of stronger
winds with it. Not all of the high res guidance is in agreement
however, with some showing a more clustered style grouping of
thunderstorms, but nonetheless it appears tomorrows activity may
last a bit longer compared to today, and all storms will have a
risk of hail and strong winds. The aforementioned front and
cloud cover should assist in cooling highs for at least our
northern zones, but expect locations along the I-80 corridor to
see similar highs as today.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
Issued at 148 PM MDT Mon Jul 14 2025

- Wednesday will be a cooler, cloudy and relatively wet day in the
wake of a cold front. Warmer temperatures and scattered late day
showers and thunderstorms will occur for Thursday through Monday.

Wednesday...Looks like a cloudy and cooler day in the wake of the
passing cold front. With copious amounts of moisture, deep moist
upslope and a passing shortwave trough aloft, expect scattered to
numerous showers and thunderstorms in the afternoon and evening.

Thursday...With temperatures warming aloft and a decrease in
available moisture, we expect only isolated to scattered afternoon
showers and thunderstorms near the Colorado state line from Laramie
to Kimball. Will see a warming trend.

Friday...The warming trend continues under zonal flow aloft. 700 mb
temperatures near 17 Celsius will yield high temperatures from the
mid 80s to mid 90s. Expect isolated to widely scattered late day
showers and thunderstorms, mainly from I-25 eastward.

Saturday...With an increase in low and mid level moisture, and a
passing shortwave trough aloft, we should see an attendant increase
in afternoon and evening shower and thunderstorm coverage. Slightly
cooler with additional cloud cover and more precipitation coverage.

Sunday...A low amplitude shortwave ridge aloft will move overhead,
and with warmer temperatures aloft and drier air aloft, expect less
coverage of late day showers and thunderstorms. 700 mb temperatures
near 18 Celsius will yield maximum temperatures in the mid 80s to
mid 90s.

Monday...Hot temperatures continue with 700 mb temperatures near 19
Celsius, yielding highs in the mid 80s to upper 90s. Perhaps enough
moisture for isolated late day showers and thunderstorms near the
southern Laramie Range, though warm temperatures aloft may produce
enough convective inhibition to limit thunderstorms and keep it
dry.

&&

.AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/...
Issued at 1142 AM MDT Tue Jul 15 2025

VFR conditions expected to prevail initially, but incoming
showers and thunderstorms will first bring lowering CIGs and
localized reductions in visibilities, and then further lowered
decks will bring areas of IFR to LIFR to the region. Showers and
storms expected this afternoon and again potentially overnight.
This will bring CIGs between 5-10k feet. Tonight, lowered CIGs
move in, with all sites aside from KLAR/KRWL expected to see
heights between 500-1500 feet alongside some BR reducing
visibilities. CIGs should begin to lift after sunrise tomorrow,
though lowered CIGs may linger through the late morning hours.

&&

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

&&

$$

SHORT TERM...CG
LONG TERM...RUBIN
AVIATION...CG