065
FXUS63 KFSD 111740
AFDFSD

Area Forecast Discussion
National Weather Service Sioux Falls SD
1240 PM CDT Fri Jul 11 2025

.KEY MESSAGES...

- Scattered showers and isolated storms will persist through the
  morning hours, mainly over the lower Missouri River Valley
  into northwest Iowa. Locally heavy downpours will be possible
  over that area through early morning.

- A low end (level 1 of 5) risk of severe storms develops by
  late this afternoon, as a front brings scattered thunderstorms
  southward into the region. The main threats with the
  strongest storms will be up to quarter sized hail, strong
  winds up to 60 mph, and heavy downpours.

- Temperatures cool Saturday, but heat and humidity build back in
  for Sunday through Tuesday.

- Thunderstorm risks return for Tuesday into Wednesday, with
  some threat of severe storms possible.

&&

.DISCUSSION...
Issued at 307 AM CDT Fri Jul 11 2025

Scattered showers and isolated thunderstorms continue across the
lower Missouri River Valley into northwest IA very early this
morning - this in association with an upper level trough situated
over the region. Latest guidance indicates a downward trend in
shower coverage over that area through the morning into the early
afternoon as the trough slowly shifts to the east, but will keep
the flood watch in effect until 12Z for possible heavier
downpours. Additional showers and thunderstorms are expected to
develop over central SD by late afternoon - pushing eastward
through the evening as a cold front moves slowly across the
region. Although MLCAPE will be in the range of 1500-2000 J/KG
by afternoon, 0-6 bulk shear looks to be generally 20 kts or
less. In addition, mid level lapse rates are not overly
impressive at 6-7 C/KM, so the severe threat looks to remain on
the low side - though cannot rule out an isolated stronger
storm with large hail and brief gusty winds. It will be another
warm and muggy day with highs in the mid to upper 80s combined
with dew points in the upper 60s to lower 70s.

Could see a few lingering showers early tonight as another upper
level trough moves through the region, though this activity will
diminish later in the night with little additional rainfall
accumulation expected. With cold air advection behind the
aforementioned front, temperatures will fall into the upper 50s to
lower 60s by Saturday morning.

A much nicer day in store for Saturday as weak surface high pressure
builds into the area and an 850 mb thermal trough swings through the
region. Highs in the upper 70s to mid 80s will feel quite pleasant
as dew points fall into the 50s to low 60s.

The cooler conditions will be brief however, as high pressure pushes
off to the east and a southerly flow returns to the region for
Sunday into Tuesday of next week. With warming 850 mb temperatures,
highs will climb back into the upper 80s and 90s each day. In
addition, with a return of low level moisture dew points will push
back into the 60s to lower 70s. Our next best chance of showers and
storms will come on Tuesday into Wednesday as a strong cold front
moves through the region. Too soon to get a handle on the severe
storm potential for that period, though it will be something to keep
an eye on. With the passage of the front, much cooler temperatures
will drop back into the area for Wednesday and Thursday.

&&

.AVIATION /18Z TAFS THROUGH 18Z SATURDAY/...
Issued at 1239 PM CDT Fri Jul 11 2025

Mainly VFR conditions begin the TAF period. Light rain persists this
afternoon along and southeast of a KSLB to KSUX line and should
slowly push southeastwards over the next several hours. To the west,
a cold front has begun to push into the area, turning the winds at
the surface to out of the northwest in its wake. Some brief
reductions in visibility is being observed behind the front but
confidence is too low to include in a TAF at this time. Will keep an
eye on the lowered visibilities though.

Showers and thunderstorms are expected to develop along the front
later this afternoon. While storms look to develop along and east of
the James River, have decided to include a PROB30 group in KHONs TAF
for trailing light rain showers. Showers and storms will push
eastwards through the rest of the afternoon and evening hours before
sliding east of the area around midnight. This will leave clearing
skies and light northwest winds for the rest of the night and TAF
period.

&&

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

&&

$$

DISCUSSION...JM
AVIATION...Meyers