276
FXUS65 KCYS 070539
AFDCYS

Area Forecast Discussion
National Weather Service Cheyenne WY
1139 PM MDT Mon May 6 2024

.KEY MESSAGES...

- Strong winds today for southeast Wyoming and western Nebraska
  with a prolonged period of elevated winds continuing through
  midweek. Wind gusts of 70-80 mph are possible for wind-prone
  locations the rest of today into Tuesday.

- Cool and unsettled weather continues for Wednesday through
  Friday with a chance of late day showers and thunderstorms.

&&

.SHORT TERM /THROUGH WEDNESDAY/...
Issued at 330 PM MDT Mon May 6 2024

Cold front currently pushing into central Nebraska this
afternoon with a surface low analyzed near Sturgis in western
South Dakota. Anticipated strong winds have developed over much
of southeast Wyoming with mid 70 mph gusts widespread. Current
Craig to Casper 850/700mb height gradients running in the low to
mid 90 mtr range. Current wind headlines looking good and no
changes can be expected to whats already out.

As for the winter headlines...area SNOTELS are really ramping up
on precipitation in Mesowest. Most SNOTELS in the Sierra Madre
have reported 24 hour precipitation in excess of 1 inch on
Mesowest and the Snowy Range reporting 24 hour precipitation
between .5 and .8 inches. The north Laramie Range SNOTELs are
about the same as the Snowy Range...so will keep the Winter
Storm Warning and Winter Weather Advisories going as they are
through expiration times.

We remain in strong winds tonight into Tuesday as in house
WRKHGT and Random Forest guidance continue to show gradients
over 75mtrs and high wind probabilities over 80 percent at least
through the day Tuesday. May need to keep an eye on the rest of
the Panhandle though tonight into Tuesday morning as GFS
800/850mb winds forecast at 45-55kts mainly from 06Z through 12Z
tonight. May need to expand the wind headlines further east with
these stronger winds.

Stacked vertical low finally moves into central North Dakota
Tuesday afternoon with wrap around moisture ending in our
northern zones and winds easing slowly across southeast Wyoming.
GFS does retrograde the low back into eastern Montana Tuesday
night into Wednesday morning and we get another secondary vort
max that swings through the CWA Wednesday afternoon.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
Issued at 330 PM MDT Mon May 6 2024

We will gradually break out of the cool and windy pattern with a
warming trend carrying us through the weekend. Chances for light
precipitation will be frequent through this period.

The potent upper level closed low responsible for the extended
period of strong winds across the area through mid-week will split
Wednesday or Wednesday night, finally bringing down wind speeds. One
piece of the closed low will retrograde into the southwest, while
the other will clear out to the east. Expect the flow aloft to turn
more northerly to northeasterly as this occurs. A surface high
sliding down the east side of the Rockies will also shut off the
cross-barrier pressure gradient. While the winds will be coming
down, we`ll remain unsettled into Thursday as the retrograding low
moves through. Weak upslope flow and isentropic lift will keep
scattered rain and snow showers around the area through the day. We
could see a few rumbles of thunder during the afternoon and evening
hours. Temperatures will remain on the cold side Thursday, still
stuck in the upper 40s to 50s across the area as 700-mb temperature
remain in the -2 to -4C range. The closed low will get pushed
further south on Friday, but there is still some uncertainty on how
quickly this will happen which will impact how quickly skies clear
and precipitation fades away to the south. Regardless, expect a
gradual warming trend to begin Friday with 700-mb temperatures
creeping back up to around 0 to -2C. Temperatures will still likely
be a few degrees cooler than average for this time of year.

Nicer weather is likely for the upcoming weekend as the cutoff low
dissipates to our south and a broad ridge over the western US
expands eastward across the Rockies. 700-mb temperatures will climb
to around +4 to +6C Saturday, and then towards +5 to +7C Sunday.
Most of the area should see highs near normal to perhaps a few
degrees above normal. This ridge won`t be totally dry though.
Precipitable water values are expected to be near normal Saturday.
Then beyond that, ensemble means show values creeping just slightly
above normal for Sunday and Monday. As temperatures warm, we may
have enough moisture and instability to return convection and
thunderstorms to the forecast. This should be mostly confined to the
higher terrain (where it may be snow) Saturday, then expanding in
coverage Sunday and Monday. The next shortwave may arrive as early
as Monday, but some models also delay it until closer to the middle
of next week. This may manage to add some extra lift and
precipitation if it passes close enough to the area.

&&

.AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/...
Issued at 1138 PM MDT Mon May 6 2024

Strong winds remain the primary concern across southeast Wyoming and
western Nebraska. Strong winds are expected to remain overnight, but
may decrease 5-10kts for a few hours before strengthing again.
Showers will linger across southeast Wyoming and western Nebraska
tomorrow afternoon, with showers ongoing at KCDR at this time.
Ceilings at KCDR are above MVFR criteria, but ceilings could drop
into the MVFR category as heavier rain showers move into this
terminal. Additionally, low-level wind shear will be a threat
overnight as surface winds decrease slightly, but strong winds
remain aloft. Expect low-level wind shear at KCYS, KLAR, KBFF, KSNY,
and KAIA overnight.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...High Wind Warning until 9 PM MDT Tuesday for WYZ103>105-
     107>109-115-117>119.
     High Wind Warning until 6 PM MDT Wednesday for WYZ106-110-116.
NE...High Wind Warning until 6 AM MDT Tuesday for NEZ019-020-054.

&&

$$

SHORT TERM...GCC
LONG TERM...MN
AVIATION...AM