160
FXUS63 KFSD 240919
AFDFSD

Area Forecast Discussion
National Weather Service Sioux Falls SD
419 AM CDT Fri Jul 24 2026

.KEY MESSAGES...

- One more day of seasonable late-July temperatures today.

- Summer heat returns this weekend with multiple days of highs
  in the 90s to around 100, warmest toward central SD. Heat
  related headlines may be needed.

- While details are uncertain, if storms develop Sunday evening
  into Sunday night, some may be strong to severe with damaging
  winds, isolated large hail and heavy rain possible.

&&

.UPDATE...
Issued at 415 AM CDT Fri Jul 24 2026

If you are not a fan of heat/humidity, be sure to enjoy today
before the heat returns this weekend. Confidence is fairly high
that highs in the 90s to around 100 will return for Saturday and
Sunday, with warmest readings most likely toward central South
Dakota. The questions come in just how high temperatures and/or
dew points will get. For that reason we have opted to hold off
on any heat headlines for now and will give the day shift another
look at low level thermal profiles and coverage of upper level
smoke which could hold temperatures down a bit from model output
if it is thick enough.

With the building heat, storm chances are generally on the low
side through the weekend. However, will have to watch a couple
of periods for a possible increase in rain chances. First will
be toward central South Dakota late Saturday. Forcing is weak,
as is deep layer shear, but several CAMs are hinting at spotty
storms developing as this area heats out, which could potential
drift into our western counties. There is currently a Level 1 of
5 (Marginal) risk for severe storms just west of our CWA in the
Day 2 outlook, but if these storms are able to grow upscale as
seen in some of the high-res output, this risk area may need to
be expanded for an isolated damaging wind threat. Confidence in
this potential is low at this time.

A second period of concern would come Sunday evening into the
overnight hours, as detailed in the Day 3 SPC outlook which
bring a Marginal to Slight (Level 1 and 2 out of 5) risk across
the eastern half of the forecast area. Once again, details are
low confidence as the risk is conditional on storms developing
as a wave and associated boundary move through the Dakotas and
Minnesota. Damaging winds would again be the primary threat, but
large hail and heavy rain are also possible.

&&

.DISCUSSION...
Issued at 148 PM CDT Thu Jul 23 2026

An upper level wave and saturation aloft will move through the area
later this afternoon through tonight. While some very weak
instability is expected aloft, thunder is very unlikely. Saturation
aloft is most prominent between I-90 and the Missouri River and with
the dry layer in the low levels not excessively dry, some quarter to
possibly half inch rainfall amounts are possible over about a 6 hour
period.

Friday should generally be dry and mild, maybe a few showers in
northwest IA during the morning. Highs remain below normal, but will
be a bit higher with most locations climbing into the 80s, coolest
in northwest IA.

Hot conditions return for the weekend into early next week. The
latest bias corrected data is running about 5 degrees cooler
than the model output for Saturday through Monday. Will have to
keep an eye on trends as the heat approaches as last weeks warm
up the NBM overdid the heat almost every day. This time around
there will be a better potential for southwest winds at the
surface which generally aids in heating out, so maybe the 3-6
degree warm bias that was seen with the past warm up will be a
little less. Long story short, the bias corrected output falls
just short of a heat advisory both Saturday and Sunday while the
NBM is basically in heat advisory both days.

Convective chances are pretty small through Monday. A slightly
stronger wave will drop south on Sunday and bring a small threat for
severe storms. The better chance should be north and east of the
area. This will be the main time frame to track over the
upcoming days.

Tuesday through Thursday should see upper level ridging just west of
the area with stronger northwest flow aloft just northeast of the
area. This leaves the area in position for above normal
temperatures, but possibly not on the excessive side as weak waves
will at times allow slightly cooler air to move in. With these weak
waves will come periodic chance for showers and thunderstorms but
for now confidence in this activity is low.

&&

.AVIATION /06Z TAFS THROUGH 06Z SATURDAY/...
Issued at 1208 AM CDT Fri Jul 24 2026

Scattered light to moderate rain showers continue to move
southeast through the overnight. Severe weather is not
anticipated but a few strikes of lightning are possible, as well
as brief heavy downpours. The majority of the activity will be
south of I-90. A few lingering showers over northwest Iowa are
possible into mid-Friday morning.

The stratus deck is expected to gradually lower over the next few
hours resulting in widespread MVFR with occasional IFR
possible. Some patchy fog is also possible along water ways and
low areas. Stratus slowly begins to rise as clouds erode through
the morning and afternoon.

Winds will be southerly and increase through the morning. Gusts of
15-25 kts are expected with the highest gusts along the Buffalo
Ridge area in southwest Minnesota. Winds decrease in the evening
through the end of the period.

&&

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

&&

$$

UPDATE...JH
DISCUSSION...08
AVIATION...AJP