441
FXUS63 KUNR 181043
AFDUNR

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
443 AM MDT Tue Jun 18 2024

.KEY MESSAGES...

- Ongoing showers and storms will be out of the region by late
  morning.

- Isolated showers and storms may be possible mid-week, but better
  chance towards the weekend.

- Below normal temperatures through mid-week, warming up for the
  weekend.

&&

.DISCUSSION...(Today Through Monday)
Issued at 216 AM MDT Tue Jun 18 2024

Current surface analysis shows surface low over the south central
SD/NE border, with frontal boundary stretching northeast into MN.
Showers and storms continue north of the boundary for much of
eastern SD, as well as areas east and north of the Black Hills in
our forecast area. Severe threat has diminished and storms will
slide east of the forecast area through this morning. Upper level
picture shows southwest flow over our region, as an upper trough
swings over the northern plains today. Temperatures sit in the mid
50s to mid 60s over most of the forecast area, while south central
SD still has temperatures in the mid 70s.

With the upper wave swinging across the northern plains today and
low level northwesterly winds, another cool day is in store, with
highs ranging from the low 60s to mid 70s. Once the morning
showers/storms lift out, mostly dry conditions will be on tap the
remainder of the day. The exception will be far northwestern SD
nearer the disturbance, and in south central SD. Depending how
well we are able to mix, gusty northwest winds may be possible
late morning into the afternoon, with near advisory level winds
for some parts of northwestern SD and east of the Black Hills,
with 850 winds showing 30-45 kts, though diminishing as the wave
slides eastward. Upper flow remains southwesterly for the
remainder of the week, with mild disturbances that likely wont
amount to much aside from isolated precipitation at least through
Thursday. Another upper trough develops over the PAC NW late
Wednesday into Thursday and slides across southern Canada towards
the weekend. Out ahead of the trough we do see a mild ridge build
over the mid-west into the central plains, coupled with low level
south and southeasterly flow that will allow for a warming trend
later in the week. Added moisture along with more disturbances
will increase precipitation chances for Thursday into the first
half of the weekend. Behind the upper trough upper ridging builds
over the Rockies on Saturday/Sunday, sliding over the northern
plains early next week, and we may see hotter and dry conditions
ahead.

&&

.AVIATION...(For the 12Z TAFS Through 12Z Wednesday Morning)
Issued At 440 AM MDT Tue Jun 18 2024

MVFR/IFR conditions across parts of northeastern Wyoming and much
of western South Dakota will gradually become VFR this morning
through early afternoon. The MVFR/IFR ceilings will persist across
far northwestern South Dakota into this evening. Gusty northwest
winds will continue through this afternoon with winds diminishing
this evening.

&&

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

$$

DISCUSSION/KEY MESSAGES...Dye
AVIATION...7