NWS Cheyenne, WY wrote its last area forecast discussion before the first event at May 14, 12:55 AM MST, 2 hours 51 minutes earlier. Its key messages:
Area forecast discussion, May 14, 12:55 AM MST, 2 hours 51 minutes before
Area Forecast Discussion
National Weather Service Cheyenne WY
155 AM MDT Thu May 14 2026
.KEY MESSAGES...
- Red Flag Warnings have been expanded to include all of western
Nebraska and extended through Friday evening.
- High Wind Warnings remain in effect for the typical wind prone
regions of southeast Wyoming from through Thursday evening.
- Next chance for precipitation returns during the weekend
alongside cooler conditions.
- Another late season snowfall event is taking shape to start
the work week.
&&
.SHORT TERM /THROUGH FRIDAY NIGHT/...
Issued at 117 AM MDT Thu May 14 2026
Upper-level ridging is slowly pushing off to the east this
morning as an upper-level low over southern Canada starts to
move closer to the region. Southwesterly flow aloft will develop
through the afternoon hours before switching to westerly then
northwesterly as the base of the trough slides eastward just to
the north of the CWA. A very dry airmass is moving into the
Intermountain West today, leading to significantly limited
precipitation chances, despite broad lift associated with the
base of the trough axis. Additionally, strong westerly flow at
700mb develops this morning as height gradients strengthen
across the region. A 50 to 55kt jet is anticipated to develop by
9AM this morning across the Laramie Range, with modest
subsidence expected along and east of the Laramie Range, as well
as near the Arlington/Elk Mountain wind prone zone. With dry,
downslope winds anticipated this morning, the surface will dry
out even more, further prevent any precipitation development
this afternoon, as well as drop afternoon humidity values into
the single digits across much of the CWA. 700mb temperatures
remain warm, though cooler than Wednesday, in the 7 to 10C
range. These temperatures, combined with dry, warm downslope
winds along and east of the Laramie Range will lead to
temperatures topping out in the mid-70s to upper-80s east of the
Laramie Range and upper-60s to mid-70s west. Strong surface
pressure gradients are expected this afternoon as relatively low
pressure in western Nebraska and relatively high pressure
across western Wyoming develop. As a result, strong surface
winds are expected today, but especially in the typical wind
prone areas of southeast Wyoming. High Wind Warnings remain in
effect for the typical wind prone areas through 6PM tonight,
while other locations will gust upwards of 35 to 45mph. Combined
with very dry surface conditions, critical fire conditions are
expected everywhere this afternoon, but fuels are only critical
in western Nebraska. So elevated conditions are anticipated
across southeast Wyoming, even though fuels currently remain in
greenup. Outdoor burning is not recommended anywhere and Red
Flag Warnings for the Nebraska Panhandle remain in effect
through Friday evening. Poor overnight humidity recoveries are
expected today and Friday night, due to very dry surface
conditions.
Another dry, warm, and crispy day is expected for Friday as
largely zonal flow develops aloft ahead of the next incoming
upper-level trough. Largely westerly flow will continue at
700mb, favoring continued, though lighter, downslope flow along
and east of the Laramie Range. As a result, the surface will
remain quite dry with afternoon humidity values dropping back
into the single digits to low teens. Winds will continue to be
breezy across the area, with increasing potential for dry
lightning Friday afternoon. Temperatures Friday afternoon with
max out in the mid-70s to mid-80s across the area. Combined with
dry and breezy conditions, the Red Flag Warnings will remain in
effect through Friday evening.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
Issued at 117 AM MDT Thu May 14 2026
No major chances with the forecast update tonight. Please see
previous discussion for more details...
A wet and unsettled pattern is taking shape for the the long term
period for southeast Wyoming and western Nebraska. This pattern
will be largely driven by an approaching trough embedded in
westerly flow over the northwest CONUS. This trough will move
inland on Saturday and pass through the region on Sunday,
bringing lowering heights and a plume of pacific moisture aloft
over the higher terrain. After a mild day on Saturday with a
high likelihood (over 75% chance) of above average temperatures
throughout the high plains, a the surface frontal boundary is
expected to drop south through the northern high plains. This
boundary will reach east-central Wyoming by daybreak on Sunday
and push south throughout the day, bringing easterly upslope
flow and overcast skies as well as a cooldown in temperatures.
While isolated showers will be possible on Saturday afternoon
and evening in a deeply mixed, prefrontal airmass, Sunday
appears to bring high confidence of area-wide light to moderate
rainfall, especially in the favored easterly upslope regions of
the Cheyenne Ridge and Laramie Ranges. Currently, the ECMWF
ensemble is a bit wetter than most NAEFS members, supporting
perhaps up to an inch of rain in the south Laramie Range into
the Cheyenne Ridge from Sunday through Sunday night. Confidence
remains only moderate for these heavier rainfall amounts, as
subtle differences in ensemble clustering suggest some of the
deeper upslope moisture may sneak a bit too far south into the
Colorado front range and leave eastern Wyoming slightly drier.
From Monday onward, models begin to diverge as GEFS members
quickly push this system eastward transitioning us into a drier
pattern, whereas ECMWF ensemble guidance generally supports a
developing mid-level low over western Wyoming and continued
rainfall over much of the state as well as western Nebraska on
Monday. Given the post-frontal airmass in place and generally
suppressed jet pattern we have been in lately, the instinct
currently is to favor the slightly wetter pattern for early next
week. Higher confidence exists in continued near-average
temperatures, with any days of particularly heavy rainfall
likely resulting in lower than average weather. As far as snow
for our late-season winter enthusiasts, chances are looking
increasingly likely for a snowfall refresh in the higher
terrain. Most ensemble guidance keeps mid and upper-level
temperatures cooler through early next week, resulting in lower
snowfall levels in the Snowy Range, Sierra Madres, and even
Laramie Range by Mon-Tues. Up to a foot or more of late-season
snowfall is being suggested by at least 30% of ensemble guidance
from the Sunday-Tuesday timeframe, especially at elevations
above 10kft. We will have to see if this trend continues in
guidance but confidence is certainly growing in another late-
season snowpack boost.
&&
.AVIATION /06Z TAFS THROUGH 06Z FRIDAY/...
Issued at 1122 PM MDT Wed May 13 2026
VFR conditions will continue across all terminals for the duration
of this TAF period. Breezy conditions for a majority of the sites
with gusts up to 30 knots through the overnight hours, while KCYS
and KCDR will see winds taper off to generally less than 10 knots. A
strong pressure gradient will tighten over the region Thursday
morning, causing winds to ramp up across all terminals by 15Z with
westerly gusts 25 to 45 knots. Wind shear is also expected to impact
most of the Nebraska sites during the overnight and early morning
hours before surface winds increase.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...High Wind Warning from 6 AM this morning to 6 PM MDT this
evening for WYZ106-116.
High Wind Warning until 6 PM MDT this evening for WYZ110.
NE...Red Flag Warning until 7 PM MDT Friday for NEZ434>437.
&&
SHORT TERM...AM
LONG TERM...MAC/AM
AVIATION...RZ