709 
FXUS63 KUNR 302249
AFDUNR

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
449 PM MDT Fri Jun 30 2023

.DISCUSSION...(This Evening Through Friday)
Issued at 105 PM MDT Fri Jun 30 2023

Split upper flow continues over the Rockies, with 
water vapor imagery indicating a couple of shortwaves over WY. Ahead 
of the shortwave energy, some showers and weak storms are moving 
cyclonically over the northern plains. A stationary boundary is 
draped across SD, and winds are light. Under mostly cloudy skies, 
temperatures early this afternoon are in the 70s.

Showers/storms will continue to increase this afternoon as shortwave 
energy crosses the CWA and MLCAPE reaches 750-1500 J/kg. However, 
weak 0-6 km shear will limit severity. The main concern with storms 
will be heavy rain/flash flooding due to slow storm motion, PWATs 
130-150% of normal, and recent rainfall. Storms will dissipate and 
shift southeastward this evening with the upper-level support. 

Upper ridging Saturday will result in a mild and mostly dry day. The 
exception could be a few orographically induced storms over the BH 
in the afternoon; additionally, very weak shortwave energy ahead of 
an approaching Pac NW trough could spark a stray shower/storm over 
NW SD and northeastern WY. 

The potential for showers/storms increases slightly on Sunday. 
Buoyancy will increase ahead of the shortwave trough crossing the
northern plains; however, best upper support may pass before peak
heating, and best shear will be across NW SD where CAPE will be 
weakest. Looks like ingredients would come together better on 
Monday for any severe weather potential. Independence Day is still
looking cool, showery, and breezy, although the extent of these 
conditions will depend on the timing of the cold front. Current 
forecast calls for highs ranging from the mid 60s across 
northeastern WY and the BH to the mid 80s across south central SD.
The upper trough is projected to keep cool/showery weather around
through the middle of next week. 

&&

.AVIATION...(For the 00Z TAFS Through 00Z Saturday Evening)
Issued At 447 PM MDT Fri Jun 30 2023

Scattered showers/thunderstorms will continue into early evening,
dissipating after. Local IFR conditions expected with the 
strongest storms. Otherwise, expect mainly VFR conditions through 
the period. Additional afternoon storms are then possible Sat 
across NW SD and the Black Hills.

&&

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

$$

DISCUSSION...Pojorlie
AVIATION...JC