091 
FXUS65 KCYS 181111
AFDCYS

Area Forecast Discussion
National Weather Service Cheyenne WY
511 AM MDT Sat Oct 18 2025

.KEY MESSAGES...

- High Wind Warnings remain in effect through 6 AM for the wind
  prone regions of southeast Wyoming.

- A strong cold front will move through Saturday leading to
  freezing temperatures across the entire region Saturday night
  into Sunday morning. Freeze Watches have been upgraded to
  Freeze Warnings.

- Strong winds look to return Sunday afternoon into early next
  week. High Wind Watches have been hoisted for the Bordeaux and
  Arlington wind prone zones. Breezy pattern expected to
  continue through Monday.

&&

.SHORT TERM /THROUGH SUNDAY NIGHT/...
Issued at 237 AM MDT Sat Oct 18 2025

Very gusty conditions overnight tonight in many of the wind prone 
regions of southeast Wyoming. The Bordeaux wind prone along I-25 has 
gusted to 80 mph overnight with current gusts dropping back towards 
60 mph. The Arlington/Elk Mountain wind prone zone has seen 
consistent gusts overnight in the 60 to 66 mph range. Winds will 
begin to decrease this morning, dropping below high wind criteria by 
6 AM. The approaching cold front is currently over northeastern 
Wyoming and western South Dakota, making its trek towards the CWA. 
Expecting this front to be in Converse and Niobrara Counties within 
the next hour. Winds behind the cold front are currently gusting ti 
around 40mph, which is expected to continue into the CWA as the 
front passes. The frontal passage will signal the end to the high 
winds, but very gusty winds will continue behind the front.

Forecast remains largely unchanged as the upper-level trough 
continue to push through the region today and an attendant cold 
front dives north to south across the CWA. The cold front is 
currently progged to reach northern portions of the CWA by 09Z, with 
Chadron seeing a cold frontal passage closer to 10Z. The cold front 
is expected to be through the region by 14Z this morning. 700mb 
temperatures will tank into the -9 to -6C range today, leading to 
daytime highs in the 40s and low-50s. Gusty winds behind the cold 
front will make today feel much colder, with apparent temperatures 
in the 20s and 30s this morning. High Winds in the typical wind 
prone region of southeast Wyoming will see an abrupt end to high 
wind criteria winds as the cold front pushes through and wind 
directions turn northwesterly, an unfavorable direction for high 
winds. Expecting winds to gust in the 40mph range for much of 
morning and afternoon hours for the entire region behind the 
departing cold front. There is a chance for precipitation with the 
passing front, however, the biggest uncertainty remains whether this 
precipitation will reach the surface. Downsloping winds yesterday 
and early this morning have lead to very dry conditions east of the 
Laramie Range, with dewpoints in the 20s and 30s, not overly 
favorable for significant precipitation, especially not rain. Some 
of this precipitation reaching the ground cannot be ruled out, so 
increased PoPs over the southern CWA to around 20%. Northern 
portions of the CWA are the most likely to see precipitation, as 
downsloping winds have not impacted the moisture as much in these 
locations. Rain, changing to a rain/snow mix, then light snow is 
expected across Niobrara and Converse Counties, with a rain 
transitioning to rain/snow mix expected across southern portions of 
the region. With how warms its been the past few days, accumulation 
is not expected outside of the mountains, as most snow that reaches 
the ground will melt on contact. However, it is still possible to 
see some flakes flying early this morning into the late morning 
hours.

Clearing skies are expected behind the cold front and departing 
upper-level trough as an upper-level ridge starts to build in. 
Temperatures behind the front will remain fairly cool, as the 
warmest air from the upper-level ridge does not arrive until Sunday 
morning. With clear skies, radiational cooling will quickly tank 
temperatures into the 20s and 30s across the entire CWA. As a 
result, the Freeze Watches for the remaining counties has been 
upgraded to a Freeze Warning for Saturday night into early Sunday 
morning.

Temperatures will rebound quickly Sunday afternoon, with highs 
returning to the 60 and 70s once more. As is typical with cool 
season systems, the upper-level ridge will flatten out over the CWA 
with increasing height gradients at 700mb as a 700mb low develops 
over southern Canada. The 700mb jet will once again strengthen to 
around 50 to 55 kts. Lapse rates are favorable for these strong 
winds to mix down to the surface in the wind prone regions of 
southeast Wyoming. As a result, a High Wind Watch has been hoisted 
from 3am Sunday to 6pm Sunday for the Arlington/Elk Mountain and 
Bordeaux wind prone zones. A period of weaker winds is expected 6pm 
Sunday onwards, before 700mb height gradients strengthen once more 
early Monday morning with a secondary developing 700mb low and a 55 
to 60kt jet develops. The break between wind events looks to be long 
enough to not warrant the Sunday High Wind Watch to continue into 
Monday, but future model runs may decrease this time frame. 
Therefore, the High Wind Watches may need to be extended in time or 
a second set of Watches may be need for the Monday event. Will leave 
this decision to day crew as newer model runs come in.

&&

.LONG TERM /MONDAY THROUGH FRIDAY/...
Issued at 313 PM MDT Fri Oct 17 2025

The long term remains active as we start the period in between
systems with a calm Sunday to end the weekend before another
system moves in to bring more high winds, precipitation, and 
cold morning lows on Monday. On Tuesday, a flat ridge should 
allow for us to warm on through Wednesday, with a slight chance
at some precipitation grazing us on Wednesday due to a weak low
passing to our south, with further ridging holding on to end 
the long term on Thursday. Under this pattern, the primary 
hazard we can expect will be another round of strong winds, 
continuing from this weekend into Monday before finally 
lessening during the evening. Based on ensembles and in house 
guidance, high wind warnings are likely once again through the 
start of the week for our wind prone regions. Meanwhile this 
system should bring a quick shot of precipitation early Monday, 
but the bulk of this should occur in the high terrain and 
overall QPF will be limited at best. Into Tuesday morning skies 
will clear, and with a cooler airmass in place behind this 
system, a widespread freeze is likely with some locations that 
haven't quite seen a hard freeze below 30 degrees for the 
morning. Warming should occur after that however, and highs will
bounce back into the upper 50's to upper 60's through the end 
of the forecast period. The aforementioned weak system passing 
just to our south on Wednesday may bring a glancing shot of 
precipitation, but this will be overall weak and impacts will be
minimal to nil at best, with another seasonably warm and clear 
day on Thursday to usher in the end of the work week.

&&

.AVIATION /12Z TAFS THROUGH 12Z SUNDAY/...
Issued at 510 AM MDT Sat Oct 18 2025

Gusty conditions ongoing KRWL, with KLAR and KCYS slower to see 
winds increasing this morning. The cold front is currently moving 
across northern portions of southeast Wyoming and the western 
Nebraska Panhandle, moving a bit slower than originally expected. 
Briefly MVFR ceilings expected with the cold front passing and 
associated precipitation. Gusty winds will continue behind the cold 
front throughout the day. Cold front is still expected to leave the 
region between 13 and 14Z this morning. Winds begin to decrease this 
evening with skies clearing for the overnight hours.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...High Wind Warning until 6 AM MDT early this morning for WYZ106-
     107-110-116-117.
     High Wind Watch from late tonight through Sunday afternoon for 
     WYZ106-110.
NE...Freeze Warning from midnight tonight to 7 AM MDT Sunday for 
     NEZ019-021-055.

&&

$$

SHORT TERM...AM
LONG TERM...CG
AVIATION...AM