125
FXUS63 KFSD 281840
AFDFSD

Area Forecast Discussion
National Weather Service Sioux Falls SD
140 PM CDT Tue Jul 28 2026

.KEY MESSAGES...

- Warm and dry conditions are expected for the rest of today and
  most of Wednesday.

- Chances for showers and storms develop Wednesday evening and
  continue through most of the day Thursday. A second round of
  showers and thunderstorms could develop Thursday evening. Some
  may be strong to severe with strong wind gusts and heavy rain
  the main threats.

- Beneficial rainfall is expected Wednesday night through
  Friday morning. A 55-75% probability of 0.50 inches or more
  across most of the region.

&&

.DISCUSSION...
Issued at 135 PM CDT Tue Jul 28 2026

A very subtle wave continues to move to the southeast. As it does so
clouds will dissipate, gradually becoming scattered to clear.
Similar to yesterday, smoke from wildfires will result in an overall
milky appearance to the sky. Highs today will warm into the upper
80s to low 90s. Dew points will be lower than the past couple of
days but still in the mid 60s to low 70s, highest over northwest
Iowa. Localized higher values are possible in areas with large corn
fields, as the plants add moisture through evapotranspiration. Heat
Index values remain below critical today. However, it is still
important to take care of yourself while working in hot conditions.
Winds today will be southerly and light. Overnight they become light
and variable. Patchy areas of fog are possible as overnight lows
fall to the mid 60s and low 70s, which is right around the dew point
temperature. Most of the fog should be contained to water ways and
low areas, and will burn off by mid-morning Wednesday.

Northwest flow aloft continues for Wednesday, keeping the smokey
skies in place. Wednesday during the day will be very similar to
today with highs in the upper 80s and low 90s. Southerly winds
increase in the afternoon as a shortwave approaches from the west.
Gusts of 15-25 mph are expected with gusts increasing as you move
toward central South Dakota. Showers and thunderstorms form in the
late afternoon and evening over western South Dakota and progress
east. Storms will reach central South Dakota and our western CWA
border around midnight. There remains some variance in mid-
range guidance on how this wave and resulting storms will
evolve, therefore uncertainty in severity remains high. Model
soundings show a dry subcloud layer and tall skinny CAPE. This
indicates the most likely threats will be strong to marginally
severe wind gusts and periodic heavy rainfall. A weak LLJ helps
to maintain convection through much of the day Thursday.

Meanwhile, an upper level trough develops over the Pacific Northwest
and speeds east. The mid-level and upper troughs deepen and a
surface low forms over eastern Wyoming and western South Dakota.
Similar to Wednesday night`s storms, uncertainty in storm evolution
is high due to wide variance in guidance. In addition, the
activity and outflows from storms earlier in the day will likely
play a role in evening development. The most likely scenario is
a few isolated strong to severe supercells form over central
South Dakota and quickly grow upscale into an MCS with damaging
wind gusts and periodic heavy rain the primary threat. This
tracks east through the overnight and early Friday morning,
bringing beneficial rainfall to much of the area. LREF
probabilities of 0.50 inches of rain or more are 55-75% region
wide. This probability is for total rainfall from Wednesday
night through Friday morning.

Thursday will be cooler due to clouds and rain with highs in the low
to mid 80s. Friday continued CAA will result in highs slightly
cooler in the upper 70s to low 80s. A beautiful weekend is in store
with mostly sunny skies and highs right around average for this time
year in the mid 80s.

&&

.AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/...
Issued at 1217 PM CDT Tue Jul 28 2026

VFR conditions are expected to prevail for the period. Scattered
clouds will continue to dissipate leaving mostly clear skies.
Smoke from wildfires remains in the upper levels but has not
been mixing down enough to impact flight operations. Winds will
be light and variable for the majority of the period.

&&

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

&&

$$

DISCUSSION...AJP
AVIATION...AJP