617
FXUS63 KUNR 301103
AFDUNR

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
503 AM MDT Tue Apr 30 2024

.KEY MESSAGES...

- Cold front today with scattered showers. Gusty northwest winds
  behind the front.

- Cool and unsettled through Saturday.

&&

.DISCUSSION...(Today Through Monday)
Issued at 215 AM MDT Tue Apr 30 2024

Current surface map places low across southeastern Montana with
cold front extending through eastern/central Wyoming. Showers are
increasing in coverage across western South Dakota with an uptick
in QG forcing as shortwave moves into eastern Wyoming. For today,
shortwave moves through this morning, with most of the shower
activity shifting east of the forecast area this afternoon. Steep
lapse rates/marginally buoyancy may result in a few rumbles of
thunder, mainly east of the Black Hills. Cold front moves into
western South Dakota shortly after daybreak and through central
South Dakota early this afternoon. 3mb/3hr pressure rises behind
the front with modest cold advection will result in a period of
gusty northwest winds. HREF paints 70-100% probability of wind
gusts >40mph along and north of I-90. The peak in wind will come
this morning with best pressure rises and stronger winds at the
top of the mixed layer. Have issued a Wind Advisory for
northwestern South Dakota extending east of the Black Hills along
I-90. Upper low lingers across the southern Canadian Prairies
through the end of the week with shortwaves rotating through the
Northern Plains. Strongest impulses move through late
Wednesday/early Thursday and on Friday. QPF amounts will generally
be on the light side...though LREF 24-hour precipitation is
showing 30-50% probability of >0.25" QPF on Thursday.

Upper low eventually shifts east this weekend, allowing ridge
to build over the plains as next trough digs over the western
CONUS. Robust warm advection over the plains should push highs
back into the 70s on Sunday/Monday. Overall, it will be drier over
the weekend but there could be some terrain induced
showers/thunderstorms around the Black Hills.

&&

.AVIATION...(For the 12Z TAFS Through 12Z Wednesday Morning)
Issued At 501 AM MDT Tue Apr 30 2024

A cold front will move through the area by 18z leaving gusty
northwest winds (gusting around 40kts) in it`s wake through this
afternoon, especially across northwest SD. A period of MVFR CIGS
just behind the front over northeastern WY/northwest SD is
expected this morning. Otherwise, VFR conditions will prevail. A
few showers this morning associated with the front will wane this
afternoon.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...Wind Advisory until 6 PM MDT this evening for SDZ001-002-012>014-
     031-032-073-078.
WY...None.
&&

$$

DISCUSSION/KEY MESSAGES...7
AVIATION...Helgeson