898
FXUS63 KUNR 071728
AFDUNR

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
1128 AM MDT Sat Jun 7 2025

.KEY MESSAGES...

- Isolated showers and storms today, some of the stronger storms
  could produce gusty winds.

- Gusty (gusts of 40-50 mph) northwest winds on Sunday,
  especially across the western SD plains.

- Warming trend mid week with highs potentially reaching the upper
  80s to low 90s (5-10F above average)

- Active weather and increasing potential for thunderstorms in
  the mid to late week.

&&

.DISCUSSION...(Today Through Friday)
Issued at 300 AM MDT Sat Jun 7 2025

Current WV and nighttime microphysics imagery shows weak upper
disturbance/wave over central NE with subsidence and clearing
skies over western SD. Another wave sits off to the west over the
Rockies with upper low centered over northern AB/SK. This wave
will cross the northern plains this morning as the upper low
grazes the CWA. Increasing mid-level moisture and forcing supplied
from a weakly baroclinic front should be enough to support a few
showers/storms this morning and afternoon. Severe threat looks
minimal with NAM depicting SB CAPE of 250-700 J/kg and effective
shear of around 30kt this afternoon. However, inverted-V profiles
indicate that any stronger storms will be capable of gusty winds.

3-hr pressure rises of 2-4 mb will support breezy northwest winds
tonight with gusts of 30-40 mph possible. Stronger northwest
winds expected tomorrow as core of 35-45kt winds at 850-700 mb
moves over the region. HREF guidance depicts low (0-20%) probs for
gusts to exceed 45 mph while NBM guidance is a little more
bullish with 70- 90% probs for gusts to exceed 45 mph over
northwestern SD and portions of south central SD. Wind gusts
across northwestern SD could reach low end advisory criteria with
gusts of 40-50 mph, however confidence too low to make any
determination on wind headlines at this time.

Upper low digs southeastward into the Great Lakes region with
upper level ridging building in behind it. This should facilitate
a warming trend for the early to mid week as low level thermal
ridge develops across the plains. By the mid week, highs across
the CWA could reach into the upper 80s to low 90s, which would be
5-10F above average.

Deterministic models in good consensus of zonal flow
transitioning to southwesterly flow over the region by the mid to
late week. A few disturbances passing over the region will bring
periodic chances for showers and storms - though models diverge on
the timing and strength of these disturbances as they cross the
region.

&&

.AVIATION...(For the 18Z TAFS Through 18Z Sunday)
Issued At 1127 AM MDT Sat Jun 7 2025

ISO/SCT SHRA/TSRA may develop from north to south across the area
as a front arrives this afternoon, which could bring localized
MVFR/IFR conditions. In addition, gusty northwest winds are
anticipated along/behind the front, with 30-40 kt gusts likely
18-00z over much of northwestern SD and portions of the
northeastern WY plains. Outside of showers/storms, expect VFR
conditions.

&&

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

$$

DISCUSSION/KEY MESSAGES...Wong
AVIATION...Dye