794
FXUS63 KUNR 052256
AFDUNR

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
456 PM MDT Wed Jun 5 2024

.KEY MESSAGES...

- Warm temperatures through the forecast period.

- Chances for showers and storms returning this weekend.

&&

.DISCUSSION...(This Evening Through Wednesday)
Issued at 311 PM MDT Wed Jun 5 2024

Upper level analysis has an upper ridge over the western CONUS with
a longwave trough extending southward through the Mississippi River
Valley. A strong jet streak (100kt+) is rounding the ridge and
diving into the Northern Great Plains (ern MT, ND, SD, MN, IA) in a
northwest flow pattern. At the surface, an area of low pressure is
centered over Manitoba and Ontario with high pressure over the
Rockies. Currently, skies are clear to partly cloudy with temps in
the 60s and 70s. Northwest winds of 25 to 40 mph are common across
the western South Dakota plains, with the strongest winds across
northwestern South Dakota. Lighter northerly winds are common over
the Black Hills and northeastern Wyoming.

Winds are currently within warning and advisory criteria, therefore
plan to continue highlights through late this afternoon/early
evening until mixing decreases.

The low pressure system over Canada will gradually move east-
southeast into the Great Lakes region by the end of the week while
the ridge over the western CONUS continues to build. This will bring
mainly dry weather and warmer temperatures for Thursday and Friday,
mostly mid 70s to mid 80s on the plains and 70s over the Black
Hills. Breezy northwesterly winds will linger on Thursday from
northwest to south central SD. A disturbance will move across the
central Plains Friday into Friday night, which will bring a chance
for showers and thunderstorms to the Black Hills and southern South
Dakota (south of I-90).

The forecast becomes more uncertain for the weekend into early next
week. The ridge to the west will likely either flatten out or get
pushed back toward the west coast as shortwave energy tries to push
into the northern Plains from the north. There looks to be some
chances for showers and storms early next week, especially Monday,
but timing and coverage is unclear right now. Temperatures will
likely slip back close to average levels Sunday and Monday.

Looking further ahead, if the western CONUS ridge is able to build
east into the Plains as many of the models are suggesting, it will
be dry and very warm by the end of next week - we could see some of
the warmest temperatures so far this year.

&&

.AVIATION...(For the 00Z TAFS Through 00Z Thursday Evening)
Issued At 455 PM MDT Wed Jun 5 2024

VFR conditions are expected through the forecast period. Gusty NW
winds will diminish early this evening.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...High Wind Warning until 6 PM MDT this evening for SDZ001.
     Wind Advisory until 6 PM MDT /7 PM CDT/ this evening for SDZ002-
     012>014-025-031-032-043-046-049-072-073-077-078.
WY...None.
&&

$$

DISCUSSION/KEY MESSAGES...MLS
AVIATION...13