134
FXUS63 KFSD 220754
AFDFSD

Area Forecast Discussion
National Weather Service Sioux Falls SD
254 AM CDT Mon Jun 22 2026

.KEY MESSAGES...

- Patchy fog leads to briefly reduced visibility this morning;
  be prepared for changing conditions on the Monday morning
  commute.

- Isolated sprinkles are possible this afternoon. Confidence in
  occurrence and coverage is low (< 20%).

-  Additional shower and thunderstorm chances (50%-80%) return
   by Tuesday. Stronger storms Tuesday afternoon and evening may
   be capable of producing large hail and strong winds. However,
   uncertainty remains regarding severe storm potential.

- Below normal temperatures continue through mid week before
  more seasonable temperatures return from late week into the
  weekend. Periodic shower and storm chances continue as well.

&&

.UPDATE...
Issued at 251 AM CDT Mon Jun 22 2026

Isolated sprinkles and patchy drizzle continue to diminish across
southeastern SD into the southern MO River Valley this morning.
Beginning to see some patchy fog develop with light winds and
clearing skies near US Highway 14, although scattered stratus and
more widespread mid clouds may prevent widespread fog. Expect clouds
to clear somewhat late morning before diurnally driven cumulus
develop. Can`t entirely rule out an isolated sprinkle but have
omitted mention with scant moisture both in the unstable layer and
sub cloud layer. Highs in the upper 60s to upper 70s.

Shower and storm chances return late tonight west of I-29 as the
next wave ejects east. CAMs are quite varied on how quickly
convection races out of the Black Hills, and lower res deterministic
guidance remains quite varied on the timing of the mid/upper level
forcing. Shower and storm chances continue through the day Tuesday
and into Tuesday night as surface cold front and another mid/upper
trough swing through the area. A few storms Tuesday and into Tuesday
evening could be strong to severe; however, uncertainty remains due
to timing issues and cascade effects of any morning convection (how
strong the AM storms might be, how much do we recover later in the
day, etc). Main threat with any stronger storm would be hail to half
dollar size and wind gusts to 60 mph. Main forecast change was to
edit pops through Tuesday evening to better fit some of the latest
trends.


&&

.DISCUSSION...
Issued at 208 PM CDT Sun Jun 21 2026

CURRENTS & TONIGHT: A dreary day continues! Taking a look across the
area, we`re continuing to watch areas high-based showers and drizzle
progress through portions of the area this afternoon. While we`re
still on track for this intermittent activity to continue through
early evening, we`re starting to see an influx of drier air via
water vapor satellite imagery lift into the area which could
gradually erode at this activity over the next few hours. If this
continues to hold true, things could taper down rather quickly with
most activity becoming focused across southcentral SD into the
evening. From here, we`ll probably continue to have spotty showers
across portions of southcentral SD and the Missouri River Valley
through Monday morning as the surface low stalls out across
northcentral NE and gradually weakens. Otherwise, another cool night
will be on tap as lows decrease into the low to mid 50s.

MONDAY & TUESDAY: Looking into the early week, could still have a
few spotty showers to start the day on Monday mainly across
southcentral SD. While accumulations will be light, could see
coverage expand in the early afternoon as a weak wave moves through
the area and a couple hundred Jules of instability develop above the
mixed layer. Nonetheless, should see this spotty activity gradually
diminish after sunset as we lose diurnal heating. By Tuesday,
additional shower and thunderstorm chances (50%-80%) are expected as
a cold front progresses through the area. However, the severe
weather risk looks more uncertain than yesterday. Still a wide range
of solutions as far as how things could evolute during the day. With
this in mind, this is probably the reason why our friends at SPC
just blanketed most of our area in a Day 3 Marginal (Level 1 of 5).
Nonetheless, another high shear/low CAPE environment will make for
at least a marginal risk for large hail and damaging winds along and
ahead of the surface front. Won`t know many additional details up
until guidance latches on a solution though. Lastly, temperatures
will continue to hover near to just below normal with highs mainly
in the low to mid 70s on both Monday and Tuesday.

WEDNESDAY ONWARDS: Heading into the midweek, quieter conditions
should return for Wednesday and Thursday as a surface high tracks
through our area. From here, the wave train returns by Friday as
quasi-zonal flow helps usher in multiple shortwaves increasing the
chances from showers and potentially thunderstorms almost daily
(every 24-36 hours) into the following week. While the chances for
severe weather are still uncertain at this time, this is another
period that will need to be monitored closely moving forward.
Lastly, we`ll start to see temperatures build towards more seasonal
conditions with highs increasing from the low to mid 70s on
Wednesday to the low to mid 80s by Saturday.

&&

.AVIATION /06Z TAFS THROUGH 06Z TUESDAY/...
Issued at 1034 PM CDT Sun Jun 21 2026

Latest radar shows diminishing light showers across the area. Cloud
bases remain mostly at VFR levels with one or two locations showing
ceilings just falling down to MVFR levels. Ceilings will remain
mainly at VFR levels through the night. The exception will be
locations along and southwest of a line from K9V9 to KAGZ where
lower ceilings down to all flight categories are expected. Patchy
fog is possible in all other locations but confidence is not high
enough to include in a TAF. Will monitor trends throughout the
night.

Light winds are expected for the day tomorrow. A CU field is
expected to develop by tomorrow afternoon. A few light showers are
possible within the CU field but the location of these showers is
uncertain. Thus, have not mentioned any chance for showers in all
TAF`s for now. Any chance for light showers will come to an end
tomorrow evening, leaving dry conditions to end the TAF period.

&&

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

&&

$$

UPDATE...SG
DISCUSSION...05
AVIATION...Meyers