377 
FXUS63 KUNR 070449
AFDUNR

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
1049 PM MDT Fri May 6 2022

.DISCUSSION...(This Evening Through Friday)
Issued at 154 PM MDT Fri May 6 2022

A relatively active weather pattern will bring near daily chances
for showers and thunderstorms this weekend and through much of
next week.

A N-S oriented surface trough is located over western South Dakota
this afternoon and diurnal heating has helped to push MLCAPE to 
around 500J/KG in the vicinity of the trough. The combination of 
low level instability and enhanced ascent to due to a shortwave 
trough and weak CAA advection aloft have produced isolated showers
over western South Dakota this afternoon, especially along the 
convergence zone over the Black Hills. A couple of lightning 
strikes are possible. Expect to see the convection end early this 
evening. 

On Saturday, an upper low over Alberta with swing a shortwave
trough across the northern plains, with an associated surface cold
front crossing the area. The cold front will be crossing western 
South Dakota during the period of peak heating on Saturday 
afternoon. Although moderate CIN will be in place, especially to 
the east of the front, MLCAPE around 1000J/KG and enhanced lift 
due to the front may be enough to overcome the cap, resulting in 
scattered thunderstorms. Severe storms are possible as indicated 
by a band of 50kt 0-6km bulk shear along and to the east of the 
front, east of the Black Hills into south central South Dakota, 
Saturday afternoon and evening. Gusty southerly winds are 
expected ahead of the front with gusty northwesterly winds 
developing to the west of the front. 

Southwesterly flow aloft will persist over the forecast area
though much of next weak. A series of disturbances in the flow
will bring near daily chances for at least some showers and 
thunderstorms. Some long term guidance suggests Thursday might be 
the most active day, although strong storms could occur at anytime
during peak heating next week. 

&&

.AVIATION...(For the 06Z TAFS Through 06Z Saturday Night)
Issued At 1045 PM MDT Fri May 6 2022


Mostly VFR conditions are expected through the forecast period.
Isolated to scattered showers/storms are expected in the forecast
area Saturday afternoon and locations may see intermittent MVFR 
conditions.



&&

.FIRE WEATHER...
Issued at 154 PM MDT Fri May 6 2022

Southwesterly winds gusting to 35 to 40 mph will create enhanced
fire weather conditions on Saturday, especially over northeastern
Wyoming and far southwestern South Dakota where the minimum
relative humidity will fall to around 20 percent. A few 
thunderstorms are also possible.

&&

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

$$

DISCUSSION...10
AVIATION...Dye
FIRE WEATHER...10