489
FXUS63 KFSD 231146
AFDFSD

Area Forecast Discussion
National Weather Service Sioux Falls SD
646 AM CDT Thu Jul 23 2026

.KEY MESSAGES...

- Localized fog will continue mainly in our waterways and low lying
  areas through mid-morning.

- 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 along the Missouri
  River Valley.

- After another day of below normal temperatures, the summer
  heat will return over the weekend with multiple days of highs
  in the 90s to low 100s ahead. Heat-related headlines may be
  needed.

&&

.UPDATE...
Issued at 328 AM CDT Thu Jul 23 2026

Taking a look across the area, quieter conditions persist as cloud
cover continues to fill in west of Huron to Sioux Falls to Storm
Lake, IA line. While the forecast still remains on track, a drearier
day is ahead as cloud cover gradually spreads eastwards. However,
with increasing southerly surface winds in place, expect highs to
top out in the upper 70s to low 80s for the day. Shifting gears
here, we`ll see the return of light to moderate showers during the
second half the day as another shortwave progresses through the
area. While areas as far north as the I-90 corridor could see light
accumulations, the highest accumulations are expected along the
Missouri River Valley where a 0.25" to 0.50" of an inch will be
possible. While flash flooding is not expected, deep warm cloud
processes could lead to localized ponding if heavier showers
persist over certain areas. Lastly, could see this activity
persist across portion of the Highway-20 corridor and the lower
Missouri River Valley through early Friday morning.

&&

.DISCUSSION...
Issued at 142 PM CDT Wed Jul 22 2026

Light rain showers continue to drift through part of the area this
afternoon. The abundant cloud cover has keep high temperatures on
the cooler side with highs only warming to 60s and 70s. Rainfall
amounts up to a few hundredths to a tenth or so remain mainly across
south central South Dakota. Any chance for rain will come to an end
by this evening, leaving partly cloudy to cloudy skies for the
overnight hours. Despite the cloud cover, a surface high pushing
through the area will keep light east/southeast flow going through
the overnight timeframe, allowing for low temperatures to fall to
the 50s to low 60s across the area.

Cloudy skies will persist through the day tomorrow, keeping high
temperatures near to below average again in the 70s with a few spots
reaching into the low 80s. Southerly return flow will pick up as the
previously mentioned surface high departs to the southeast. Winds
will still remain on the lighter side but a few gusts up to 20-25
mph is expected. Another shortwave trough will push through the
forecast area, resulting in showers across the area once again.
These showers look to be more widespread though remaining along and
south of I-90 for the day. Forcing will be a bit stronger with this
chance for rain along with very minor instability being present at
or below 100 J/kg. This will bring overall higher rainfall amounts
to locations along and south of a Chamberlain, South Dakota to
Beresford, South Dakota to Storm Lake, Iowa where rainfall amounts
between a quarter to a half an inch are possible (20-60%). Lighter
amounts are expected north of this line. With the very minor
instability in play, an isolated rumble of thunder is possible. This
light rain will persist into the night before pushing southeast of
the area by Friday morning.

Upper level ridging will begin to build over the central Plains on
Friday, raising high temperatures back to the upper 70s, 80s, and
low 90s. This trend will continue through the weekend as the thermal
ridge slides eastwards. High temperatures look to return to above
average with highs in the 90s to low 100s. The ensembles support
this as they show high probabilities (60-100% chance) for high
temperatures to exceed 90F along and west of I-90 over the weekend.
Their probabilities drop to a 30-40% chance for highs to break 100F
over the same area. The EFI also supports this as it shows 60-100%
of its members suggesting anomalously warm temperatures this weekend
and a shift of tails exceeding 1. Thus, will have to continue to
monitor the potential for heat headlines being needed, especially as
dew points look to remain in the 60s and 70s.

The heat looks to begin to wane on Monday as high temperatures look
to only warm to the 90s. Highs will slightly cool into the middle of
next week. With the forecast area being just on the northern
gradient of the upper level ridge, ridge riding shortwaves could
bring rain and perhaps storm chances back to the area. The ensembles
only show low probabilities ranging from 0 to 30% so confidence is
low in this potential as of now. Machine learning guidance also only
shows a half a percent to about a 5% chance for severe storms Sunday
through the middle of next week. Something to keep an eye on as we
head into another hot and humid pattern.

&&

.AVIATION /12Z TAFS THROUGH 12Z FRIDAY/...
Issued at 638 AM CDT Thu Jul 23 2026

Mainly VFR conditions will transition to a mix of VFR and MVFR
conditions this TAF period. Taking a look at satellite imagery,
mid-level clouds continue to gradually fill in this morning
mostly in response to an approaching system. Besides a few
showers at KFSD and KSUX this afternoon/evening, we`ll also see
cloud bases lower overnight into MVFR (and possibly IFR) territory
and this will continue into Friday morning. Otherwise, southerly
surface winds will become a bit breezy this afternoon with gusts
between 15-25 mph expected to end the TAF period.

&&

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

&&

$$

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