969
FXUS63 KUNR 031137
AFDUNR

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
537 AM MDT Mon Jun 3 2024

.KEY MESSAGES...

- Warm today, with passing cold front late today and tonight bringing
  chances for showers and storms into Tuesday, along with gusty
  winds on Tuesday.

- Warm weather expected for mid week into next weekend, with
  chances for showers and storms returning by the weekend.

&&

.DISCUSSION...(Today Through Sunday)
Issued at 300 AM MDT Mon Jun 3 2024

Current surface analysis shows weakening cold front south and
east of the forecast area, with a couple of areas of low pressure
along it over western MN and central WY. Another area of low
pressure is located across southwest Canada, with a cold front
moving into the northern Rockies. Upper level analysis shows near
zonal flow across the area at this time, with a trough moving into
the Pacific NW. Skies are variably cloudy across the area with a
couple of showers over far southwest SD. Temps are mostly in the
upper 40s and 50s and light north to northwest winds.

Weakening cold front to the south becomes a warm front today and
lifts north-northeast back into SD. Very warm temperatures develop
across the area, with highs reaching the upper 70s to near 90
degrees, warmest to the east and southeast of the Black Hills. It
looks dry through at least the midday hours, with increasing chances
for showers and isolated thunderstorms in the afternoon and
especially tonight as developing southwest flow aloft brings upper
level energy into the area along with a cold front. The better
chances for rainfall later today through Tuesday morning will
generally be from far northeast WY to northwest SD, in closer
vicinity to the upper level trough tracking across MT, ND, and the
Canadian Prairie Provinces during that time. Buoyancy and shear are
forecast to be relatively weak later today, but would not totally
rule out a strong storm or two toward south central SD where MUCAPE
of over 500 j/kg is forecast. Showers will start to exit the area
later tonight and Tuesday morning. Temps will drop back to near
average levels for Tuesday, with highs in the upper 60s to mid 70s,
60s over the Black Hills. West to northwest winds will increase late
tonight and Tuesday as cooler and drier air pushes into the area,
with some gusts to over 40 mph across northwest into west central
SD. There is a 30 to 60 percent chance for some advisory level wind
gusts across far northwest SD and the Rapid City area on Tuesday.

The mid to late week period looks to be warm and dry as ridge builds
over the western US and large trough covers the eastern US. Highs
will generally be in the 70s to mid 80s for Wednesday through
Friday, warmest toward the end of the work week as the ridge moves
over the Rockies. Gusty west to northwest winds will develop again
on Wednesday across at least northwest SD as upper low moves across
south central Canada. Chances for thunderstorms could return later
on Friday, but more likely over the weekend, as the ridge
potentially gets pushed westward toward the west coast. This would
also bring some cooler air back to the area, dropping temps to near
or slightly below average levels.

&&

.AVIATION...(For the 12Z TAFS Through 12Z Tuesday Morning)
Issued At 535 AM MDT Mon Jun 3 2024

Isolated showers and thunderstorms will develop after 20Z this
afternoon. Scattered showers will then cross the area from west
to east between 00Z tonight and 16Z on Tuesday morning. VFR
conditions will continue until 06Z tonight, then a band of LCL
MVFR conditions will develop along a secondary cold front as it
passes through northeastern Wyoming and western South Dakota early
Tuesday morning. Windy conditions will develop behind the cold
front on Tuesday.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...None.
WY...None.
&&

$$

DISCUSSION/KEY MESSAGES...26
AVIATION...10