378
FXUS63 KUNR 060944
AFDUNR

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
344 AM MDT Mon May 6 2024

.KEY MESSAGES...

-Very windy with a slight chance of stronger thunderstorms today.

-Very strong winds possible tonight and Tues across northeast WY,
 the Black Hills, and northwest SD.

-Unsettled and cool through mid week, then slowly warming.

&&

.DISCUSSION...(Today Through Sunday)
Issued at 311 AM MDT Mon May 6 2024

09Z upper level analysis has strong closed low over southwest WY
with 110kt jet rounding the base of the main trof. Showers and
isolated storms are lifting north across the area at the moment.
At the surface, low pressure is located across southeast WY with
in inverted trof extending into eastern MT. Strong southeast winds
are present across the forecast area, with temperatures in the
50s.

Vigorous and complex system will affect the area for the next
several days, as the upper low lifts across western SD, pinwheels
through western ND, then finally shifts southeast by mid week.
Cool and unsettled conditions, along with a lot of wind, will be
the main weather story for the next several days.

On the precip side of things, surface low pressure and associated
trof will swing northeast across the area today. Along the trof, a
few stronger storms are expected early this afternoon to the north
and east of the Black Hills. Modest CAPE, good shear, and low
level helicity could produce an isolated tornado with these
storms. Threat is short lived as the trof shifts quickly northeast
by late afternoon. More widespread rains will impact northeastern
WY, the western portions of the Black Hills, and northwestern SD,
as abundant moisture wraps around the backside of the low. Some
light snow will be possible across the higher elevations of the
Black Hills tonight into Tuesday night.

On the wind side of things, very windy conditions are expected
with this very dynamic system. West to southwest winds will
increase again today as the surface trof swings north of the
area. Have issued a Wind Advisory for much of the SD plains
starting at noon today with winds persisting into the evening. As
the surface low and upper low become stacked tonight, winds could
increase even more across parts of northeastern WY, the Black
Hills, and northwestern SD. A High Wind Watch remains in affect
for this evening into Tuesday.

Precip chances decrease on Tuesday as the system spins across
western ND, but very windy conditions will persist across western
SD, especially far northwest SD where Warning criteria winds will
be possible. Upper low finally starts to weaken on Wednesday, as
it tracks back southeast across central and eastern SD. Windy
conditions will persist along with chances for showers and
isolated thunder.

Drier and less windy conditions will slowly work back into the
area late Thursday into Friday as weak high pressure slides into
the area from the northwest. Temperatures will climb back into the
60s for Friday and Saturday, with some 70s returning for Sunday.




&&

.AVIATION...(For the 06Z TAFS Through 06Z Monday Night)
Issued At 1058 PM MDT Sun May 5 2024

Scattered showers and thunderstorms are possible overnight, from
east of KGCC into the western SD plains. MFVR/IFR conditions are
possible with any stronger cores. Moist, upslope flow has resulted
in MVFR ceilings developing across the Black Hills into KRAP;
these will persist through much of the forecast period.

Additional showers and storms are possible after 10-12z Monday
morning, spreading eastward throughout the day. Winds will shift
out of the west-northwest throughout the day Monday, with gusts
35-50 knots possible by early afternoon through the late evening
hours.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...Wind Advisory from noon today to 11 PM MDT this evening for
     SDZ001-002-012>014-026-027-030>032-041>043-073>075-078.
     High Wind Watch from this evening through Tuesday afternoon for
     SDZ001-012-013-025-072-073-078.
     Wind Advisory until 11 PM MDT /midnight CDT/ this evening for
     SDZ044-046-047-049-076-077.
WY...High Wind Watch from this evening through Tuesday afternoon for
     WYZ060.
&&

$$

DISCUSSION/KEY MESSAGES...15
AVIATION...SE