520
FXUS63 KUNR 080439
AFDUNR

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
1039 PM MDT Fri Jun 7 2024

.KEY MESSAGES...

- Showers and storms continue through this afternoon over parts
  of western SD. An isolated storm or two may be severe.

- Near daily chances for isolated for storms/showers continue
  into early next week.

- Temperatures are expected to be at or above normal through next
  week.

&&

.DISCUSSION...(This Afternoon Through Thursday)
Issued at 1136 AM MDT Fri Jun 7 2024

Current Water Vapor and upper air models depict broad ridge over
the western CONUS, while an upper low sits over SK/MB with a
longwave trough dipping into the Great Lakes region. At the
surface, low pressure has moved over the forecast area, with
frontal boundary stretching west/east across the region. Current
radar has showers/storms mainly over central and south central SD.
Temperatures generally sit in the upper 60s and 70s early this
afternoon.

As mid-level wave treks across the forecast area today, isolated
storms are expected to re-develop in the afternoon. CAMS generally
show the bulk of expected storms south and east of the forecast
area, with our main concern being our south central SD counties.
Severe models depict modest to strong 0-6km shear over much of
western SD, however the best CAPE (1000-1500 j/Kg) noses up from
Nebraska into south central SD. The main concern continues to be
capping this afternoon, with CIN values expected in the -50 to
-150 j/Kg range. Cannot rule out some storm development in other
 areas of western SD this afternoon, however given the severe
 parameters, any other storms will be more pulse like in nature.
 The threat for storms should be out of the region by 6-7 pm MDT.
 Weak LLJ set up following passage of the low, and we could see
 another round of overnight showers develop across parts of
 western SD.


Models are finally starting to agree more on pattern development
over the weekend into early next week, with GFS/NAM/Canadian now
pointing to the upper low sitting mostly stagnant over the SK/MB
region and eventually sliding easterly by mid-week. Another mid-
level wave makes its way across the region late Saturday into
Sunday, however staying a bit to our south, and given the timing
of the wave, unlikely to see any severe potential. Stronger low
level winds and decent moisture will allow for near daily
potential for showers/storms through Tuesday. As the upper low
begins to shift east middle of next week, upper flow becomes more
zonal over the region, allowing for a more dry end to the week,
with rising temperatures.

&&

.AVIATION...(For the 06Z TAFS Through 06Z Saturday Night)
Issued At 1037 PM MDT Fri Jun 7 2024

VFR conditions are expected through most of the forecast period.
Isolated to scattered SHRA/TS will return early this morning to
portions of western to central South Dakota. Most thunderstorms
will be possible late Saturday afternoon into the evening.

&&

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

$$

DISCUSSION/KEY MESSAGES...Dye
AVIATION...13