048
FXUS65 KCYS 071754
AFDCYS

Area Forecast Discussion
National Weather Service Cheyenne WY
1154 AM MDT Tue May 7 2024

.KEY MESSAGES...

- Strong winds continue today and tonight for southeast
  Wyoming, but will be lighter compared to Monday. Wind-prone
  locations will still see wind gusts 60-70 mph.

- Cool and unsettled weather continues for Wednesday and
  Thursday with a warming trend headed into the weekend.

&&

.SHORT TERM /THROUGH WEDNESDAY/...
Issued at 315 AM MDT Tue May 7 2024

Latest observations across southeast WY and western NE show
winds gusting 40-50 mph across the high plains with gusts up to
65 mph over wind-prone areas near Arlington and Vedauwoo. This
is considerably lower than the 75-85 mph wind gusts reported
closer to midnight, but follows suit with the decreasing winds
continuing into this morning noted in hi-res guidance.

High Wind Warnings continue across much of southeast WY today,
however high winds will likely not be as strong and widespread
as Monday. Looking at wind gusts 45-55 mph for the high plains
across southeast WY, while wind-prone locations will see gusts
55-65 mph. 700mb flow will be gradually weakening today with
relaxing height gradients as the upper level low in northwest SD
begins to retrograde westward, but still remaining above the
climatological 99th percentile. A secondary vort max will move
across the CO/WY border today increasing showers and storms
today, mainly for south-central WY mountains with light
accumulating snowfall. As this vort max passes through, expect
winds to see another spike this evening and tonight with strong
subsidence across wind-prone locations along the Laramie Range
as much of the area moves underneath the left entrance of a 120
kt 250mb jet. This will persist until early Wednesday morning as
mslp gradients begin to relax with the weakening occluded
cyclone. In-house random forest guidance highlights this
resurgence in winds after 00z Wednesday or at least an increase
back up to near 70 mph for the Laramie Range and adjacent
foothills.

The retrograding upper level low will begin to slide south
Wednesday increasing moisture across the CWA with snow showers
along and west of the Laramie Range and rain farther east.
Accumulating snowfall is likely in the mountains with sub-
advisory amounts and overall precipitation rates being on the
lower side. With the large scale troughing pattern remaining
over much of the central CONUS, expecting below average
temperatures to continue with highs in the 40s and 50s.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
Issued at 315 AM MDT Tue May 7 2024

Minimal changes made from the previous forecast. We are still
looking at a gradual warming trend as we transition into a
ridging pattern toward the end of the week.

While part of the low pressure system will continue eastward, models
show a portion of the closed low retrograding southwest. This
transition will expand the pressure gradient along the Rockies,
weakening the winds across southeast Wyoming and western Nebraska
(finally). Precipitation chances hang on through at least Wednesday
night as the low continues to move eastward, but weak easterly,
upslope flow remains across southeast Wyoming and western Nebraska.
By Thursday afternoon, the ridge starts to creep into northern
portions of the forecast area, increasing temperatures, and pretty
quickly drying out the air. Due to the uncertainty of the timing of
all the moving parts, the exact timing and impacts will need to be
further refined as we get closer to Wednesday night.

By Friday the low is further shifted southwestward and the ridge
moves further east, long range models show southeast Wyoming and
western Nebraska positioned on the eastern edge of the ridge until
Sunday. Temperatures are forecast to be near- to just-above-normal.
If the ridge shifts a bit further east, positioning the forecast
area closer to the ridge axis, then we can expect much warmer
temperatures. Sunday night into Monday, the ridge axis shifts
further east, but is simultaneously squashed by a stronger shortwave
and ejects out of the PACNW. The portion of the low that retrograded
to the SW CONUS is also finally pushed eastward by the Subtropical
Jet, and taps into moisture as it gets closer to the southern
plains. This combination of dynamics from the upper-level shortwave
to the north and the closed low to the south has the potential to
cause more widespread precipitation headed into early next week.

&&

.AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/...
Issued at 1143 AM MDT Tue May 7 2024

Strong, gusty winds remain the primary aviation concern today.
While not quite a strong as yesterday, expect consistent gusts
of 40 to 45 knots in WY with occasional gusts to 50 to 55 knots.
In Nebraska, expect consistent gusts of 30 to 40 knots and
occasional gusts of 45 to 50 knots, though this may be more
frequent at KSNY. Additionally, a few scattered showers will
develop over the next few hours. While this should be mostly
virga, this activity may temporarily cause a surge in wind
speeds or directional change as they pass by a terminal.
a brief VIS/CIG drop can`t be ruled out with this activity.

Winds will ease after sunset once again, but remain breezy to
windy for most. While temporary decoupling from the surface is
possible, expect significant LLWS if winds do ease at the
surface overnight. Expect more consistent gusts by Wednesday
morning with increasing clouds.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...High Wind Warning until 9 PM MDT this evening for WYZ103>105-
     107>109-115-117>119.
     High Wind Warning until 6 PM MDT Wednesday for WYZ106-110-116.
NE...None.

&&

$$

SHORT TERM...MB
LONG TERM...LEG
AVIATION...MN