657
FXUS63 KFSD 231851
AFDFSD

Area Forecast Discussion
National Weather Service Sioux Falls SD
151 PM CDT Thu Jul 23 2026

.KEY MESSAGES...

- Light to moderate showers will progress through areas along
  and south of I-90 as early as this afternoon. Accumulations of
  a 0.25" to 0.50" of an inch will be possible near and just
  north of the Missouri River Valley.

- Below normal temperatures expected through Friday, then summer
  heat returns over the weekend with multiple days of highs in
  the 90s to possibly low 100s ahead. Heat-related headlines
  may be needed.

&&

.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 /18Z TAFS THROUGH 18Z FRIDAY/...
Issued at 1206 PM CDT Thu Jul 23 2026

An area of showers will move through later this afternoon
through tonight. The better chances will be near and south of
I-90. During and after the rain tonight, MVFR and possibly IFR
ceilings are expected, which should improve back to VFR in most
locations by the end of the TAF period.

&&

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

&&

$$

DISCUSSION...08
AVIATION...08