019
FXUS63 KUNR 062150
AFDUNR

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
350 PM MDT Thu Jun 6 2024

.KEY MESSAGES...

- At or above normal temperatures through next week.

- Mostly dry with chances for showers and storms returning over the
weekend and into next week.

&&

.DISCUSSION...(This Evening Through Thursday)
Issued at 347 PM MDT Thu Jun 6 2024

Current upper air analysis depicts a ridge over western CONUS with a
upper low centered over the Great Lakes region. A strong jet streak
(100kts+) is located along the ridge and into the trough entrance
resulting in a northwesterly flow over the Northern Great Plains
(MT, ND, SD, NE, MN, IA). At the surface, an area of low pressure is
centered over Manitoba and Quebec with high pressure located over
the Rockies and into Northern Great Plains. Northwesterly winds (25
to 35 mph) are present across northwestern South Dakota, with weaker
northwesterly winds present around the Black Hills region along with
northeastern Wyoming. Temperatures are currently in the 70s for the
forecast region.

Temperatures will rise into the 80s Friday before sliding back
into the 60s to low 70s for Saturday and Sunday.

The formation of a new low pressure center over Saskatchewan along
with the formation of a 700 mb lee shortwave, developing early
Friday, will lead to a chance of showers and storms across
southeastern and south central SD beginning early Friday morning and
lasting through Saturday afternoon. ML CAPE of 1000-1500 J/kg will
be present Friday afternoon across south central SD and into central
NE. Higher shear values (50kts+) will also be present over this
region potentially result in a few strong to marginally severe
storms over southern SD Friday afternoon. Limiting factors will be
higher CIN values (-25 to -50 J/kg) and a lack of moisture. Chances
for showers and storms will increase again Sunday for the forecast
region.

Forecast uncertainty increases into next week as the models do not
quite agree on the progression on the low pressure center that will
form over Saskatchewan. There is agreement in the flattening of the
ridge into more of a zonal flow over western and central CONUS by
mid week, but the exact timing and position remain to be determined.
How this plays out will determine the the likelihood for storms
later in the week as well as temperatures (which are trending
towards above average by the mid next week).

&&

.AVIATION...(For the 18Z TAFS Through 18Z Friday)
Issued At 1109 AM MDT Thu Jun 6 2024

VFR conditions are expected through the forecast period. Isold
SHRA/TS are possible toward dawn Friday across scentral SD.

&&

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

$$

DISCUSSION/KEY MESSAGES...CAS
AVIATION...MLS