FXUS63 KUNR 250436

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
1036 PM MDT Sat Aug 24 2019

.DISCUSSION...(This Evening Through Saturday)
Issued at 328 PM MDT Sat Aug 24 2019

Current surface analysis shows weak frontal boundary remaining
across western SD. Low pressure is located across western SK, with
cold front stretching back into the Pacific NW. Upper level
analysis shows weakening trough over the western Dakotas into the
central Plains, with fast zonal flow to the west of the region.
Skies are variably cloudy, with the most sun across northeast WY.
Temps range from the 70s to lower 80s across the area, with some
drier in place across northeast WY into the Black Hills. KUDX
radar showing a couple of showers and storms over the northern
Black Hills and some showers/storms wrapping northward into south
central SD. Southerly winds are breezy across the SD plains.

Unsettled weather will continue at times across a good portion of
the area through the rest of the weekend, especially to the east of
the Black Hills. The best chances for rainfall and storms will come
later Sunday into Sunday night as the cold front to the northwest
crosses the region. For late today into tonight, the best chances
for showers and storms will be east of the frontal boundary,
especially toward central SD, as trough moves east of the area. A
strong storm or two is possible late today, but the risk for severe
storms is low as instability and shear are progged to be marginal at
best. Temps will drop to the upper 50s and lower 60s in most areas
by early Sunday.

Sunday will start off relatively nice, with just a chance for a few
showers across northwest SD in the morning. Highs will mostly be in
the upper 70s and 80s, with the higher humidities to the east of the
Black Hills. More active wx will likely develop later in the
afternoon into the evening, especially for areas north and east of
the Black Hills, as the cold front and upper level shortwave slowly
moves into the area. Frontal boundary will remain to the east of the
Black Hills, with the best instability east of the Black Hills into
central SD, 1000 to 2000 j/kg MUCAPE. Shear will increase as the
front approaches. Isolated supercells could develop later in the
afternoon into early evening, especially from northwest into central
SD, with a stronger storm or two also possible in the Black Hills
area. Chances for severe storms drop greatly to the west into
northeast WY. However, widespread chances for showers and storms can
be expected Sunday night as the front moves through the area.

The front will usher in cooler conditions for much of next week,
with highs in the upper 60s and 70s across the Plains, 60s over the
Black Hills. Northwest flow develops behind the trough as it
strengthens to the northeast of the region. This will bring at least
breezy conditions early in the week during the late morning and
afternoon hours. The drier flow should keep pcpn chances to a
minimum for much of next week, but cannot rule a few showers or
storms will any weak disturbance that may slide through the area,
especially late week.


.AVIATION...(For the 06Z TAFS Through 06Z Sunday Night)
Issued At 1033 PM MDT Sat Aug 24 2019

During the rest of the night and into Sunday morning, there is a
chance of showers, and possibly a thunderstorm over far
northeastern Wyoming and northwestern South Dakota local MVFR
conditions are possible over those areas. There is also a chance
of showers over parts of south central South Dakota. Areas of IFR
CIGS are expected over that area. There is a better chance of
showers and thunderstorms on Sunday afternoon over parts of
western South Dakota.




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