139
FXUS63 KFSD 072338
AFDFSD

Area Forecast Discussion
National Weather Service Sioux Falls SD
638 PM CDT Sat Jun 7 2025

.KEY MESSAGES...

- Areas of showers and/or thunderstorms this afternoon into
  Sunday morning. Severe weather is not expected, but a few
  stronger storms north of I-90 this evening could produce
  isolated gusts in excess of 40 mph.

- There is a possibility of a few funnel clouds east of
  Interstate 29 this afternoon and evening.

- Gusty west-northwest winds will become prevalent Sunday into
  Monday, with afternoon gusts 30-40 mph (strongest Sunday west
  of I-29). The northwest flow may bring areas of wildfire smoke
  back into the region, with surface impacts possible by Sunday
  morning.

- Near to below normal temperatures continue through Monday,
  then warmer air with highs in the 80s to lower 90s builds in
  by mid-late week. Sporadic rain/thunderstorm chances return
  late next week, but low confidence in timing/location.

&&

.DISCUSSION...
Issued at 240 PM CDT Sat Jun 7 2025

Currently seeing quiet conditions across the area with temperatures
in the mid 70s to lower 80s. Hi-res guidance continues to indicate
the possibility of isolated showers/thunderstorms developing over
parts of northwestern Iowa/southwestern Minnesota in the late
afternoon and evening as an upper level shortwave exits to the east.
Current mesoanalysis shows MLCAPE of 500-1000 J/KG along the eastern
edges of our CWA - though effective shear is weak at around 20 kts.
Because of that, not expecting any severe storms if anything
develops. Even so, cannot rule out a few funnels clouds with any
showers/storms that develop over that area - this located in an axis
of optimum surface vorticity, steep low level lapse rates, low level
convergence, and an enhanced stretching potential.

Toward 00Z this evening, an upper level jet/upper level shortwave
begins to plunge southeastward through the Northern Plains as a
surface cold front slides into our area. Hi-res guidance continues
to show showers and isolated thunderstorms developing in the
vicinity of this front as it moves across the CWA during the
overnight hours. Although effective shear will be running around 30
to 40 kts in the vicinity of the front, any instability quickly
wanes in the evening. In light of that, current thinking is that any
storms will remain sub severe. Model DCAPE is also unimpressive at
500 j/kg or less, though with a dry sub cloud layer cannot rule out
a few gusts around 40 mph with any showers/storms. Although the
surface front will be to the southeast of our area by very late
tonight, there could be a few lingering sprinkles through the lower
Missouri River corridor into early Sunday morning in association
with the midlevel front, although most recent hi-res guidance has
most of the precipitation remaining to the south of our CWA.

With the flow turning from the northwest behind the system, it
appears that smoke will make a return to our area on Sunday - with
latest guidance suggesting that some of this may make it to the
surface during the day. With a push of cold air advection and
increasing winds aloft, it will become a breezy day with soundings
indicating winds of 35 to 40 kts at the top of the mixed layer. With
the CAA, it will be a slightly cooler day with highs in the lower to
mid 70s.

Our next potential for showers comes on Sunday and Monday as a
closed upper level low drops from Canada into the Upper Mississippi
Valley and Great Lakes region through the period. The best chances
for precipitation will reside through east central South Dakota into
southwest Minnesota, though probabilities are on the lower side (20-
40%). Temperatures will remain below normal for Monday with highs in
the upper 60s to lower 70s, along with gusty northwest winds
continuing.

The main theme for the remainder of next week will be for
temperatures warming back to above normal as upper level ridging
builds over the region - with NSAT ensembles indicating 700/850 mb
temperatures in the 90th percentile with respect to climatology for
Tuesday into Thursday. Temperatures will warm into the 80s during
the week, with some locations having high probabilities (GFS/Canadian
ensemble probabilities of 60-90%) of exceeding 90 degrees on
Wednesday. In terms of precipitation chances through the week, the
upper level ridge begins to flatten out a bit for later on Wednesday
into Friday as a series of shortwaves round the ridge - this in
conjunction with a frontal boundary draping across the region.
Confidence in timing and location of precipitation remains on the
low side with model differences in the handling of various
shortwaves.

&&

.AVIATION /00Z TAFS THROUGH 00Z MONDAY/...
Issued at 637 PM CDT Sat Jun 7 2025

VFR conditions begin the TAF period. A line of showers/weak
thunderstorms is just beginning to enter the area from the northwest
early this evening. Expect this line of showers to push
southeastwards through this evening and into the overnight hours.
Stronger wind gusts are possible in the showers as gusts up to 30-40
knots have already been reported across central and north central
South Dakota.

Any chance for rain will come to an end by tomorrow morning.
However, surface smoke will move into the area tomorrow morning and
generally persist through most of the day on Sunday as winds turn to
out of the northwest. As of this time, the highest concentration of
smoke looks to reside mainly along the Missouri River Valley. Winds
will strengthen by tomorrow afternoon with gusts up to 20-30 knots
expected. The breezy northwest winds will finish out the TAF period
along with decreasing surface smoke.

&&

.FSD WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
IA...None.
NE...None.

&&

$$

DISCUSSION...JM
AVIATION...Meyers