876
FXUS63 KFSD 040911
AFDFSD

Area Forecast Discussion
National Weather Service Sioux Falls SD
411 AM CDT Mon May 4 2026

.KEY MESSAGES...

- Thunderstorm chances are waning for today, but isolated light
  showers or sprinkles could follow a cold front through the
  area. Any light showers could produce isolated wind gusts of
  40 to 45 mph.

- Cooler than normal temperatures return midweek. Areas of early
  morning frost or near-freezing temperatures are possible near
  the Highway 14 corridor early Tuesday, and could expand south
  by early Wednesday and Thursday.

&&

.UPDATE...
Issued at 410 AM CDT Mon May 4 2026

Another mild morning with pre-dawn temperatures mostly in the
upper 40s to mid 50s. A little more elevation dependence to the
temperatures this morning compared to yesterday, with valleys in
northwest Iowa dipping into the lower-mid 40s at times and the
downslope areas east of the Buffalo Ridge in southwest Minnesota
still in the upper 50s.

A cold front will move south through the region today, currently
projected to reach Highway 14 around daybreak, and quickly push
south of Highway 18 by midday before exiting the CWA 3-4 pm. A
decent push of cold advection will result in many areas seeing
their high temperatures by midday-early afternoon, with readings
dropping off more quickly than a typical diurnal cycle. That
said, highs will still be close to early May normals ranging
from around 60 north to lower 70s toward Sioux City/Storm Lake.

North winds become gusty behind the front, generally peaking in
the 30 to 35 mph range. However, lift from an associated mid
level wave could produce some high-based sprinkles/light rain
showers. While chances of measurable rain are quite low, if
these develop we could see isolated 40 to 45 mph wind gusts. The
faster frontal timing should push the threat of thunderstorms
farther south this afternoon, with areas south of Sioux City to
Storm Lake seeing a very low risk for a stray storm as the front
moves through mid-afternoon.

Cooler than normal air then returns for a few days through the
middle of the week. Highs Tuesday and Wednesday will be in the
50s (10-15 degrees below normal), with nighttime lows dipping
near to below freezing. This will bring back a risk for areas of
late night/early morning frost, beginning tonight/early Tuesday
for portions of the Highway 14 corridor. Moving forward, extent
and location of frost potential are still somewhat uncertain as
models indicate periods of greater cloud cover which could hold
temperatures a bit higher than the NBM forecast. Similar to late
last week, will likely handle any frost/freeze headlines on a
day by day basis as confidence in location/timing increases.

&&

.DISCUSSION...
Issued at 152 PM CDT Sun May 3 2026

Northwest winds will gradually diminish through the afternoon
and turn more westerly this evening. Some very localized
elevated fire weather conditions are expected where some of the
warm season grasses remain fairly cured.

A broad trough to the north will settle south tonight into Monday.
This will initially turn winds to the west and southwest tonight,
before turning north on Monday morning.  For the most part this will
be a dry front, but some mid level moisture and very weak
instability may allow for a light shower. Otherwise, in the
afternoon in mainly northwest IA some weak instability could allow
for an isolated shower or thunderstorm, with no severe weather
expected. As with last nights showers some gusty winds will be
possible with any showers.

The main changes with this incoming front will be cooler, below
normal temperatures. Highs on Tuesday and Wednesday will be in the
50s, with morning lows Tuesday, Wednesday and Thursday mostly in the
30s. Areas north of I-90 could see some frost and freezing
temperatures all 3 mornings while areas near and south of I-90 will
see the better chances for frost and freezing temperatures on
Wednesday and Thursday mornings.

Otherwise, northwest flow aloft will be in place Wednesday into the
next weekend which suggests that even if we can get a few waves to
move through the area, moisture and instability will be a bit
lacking. Temperatures Thursday into the weekend do climb back to
around or a bit above normal with highs mostly in the mid 60s to
lower 70s. Very little consistency in the model output for these
weak waves so confidence on any isolated to scattered showers is
pretty low.

&&

.AVIATION /06Z TAFS THROUGH 06Z TUESDAY/...
Issued at 102 AM CDT Mon May 4 2026

VFR conditions expected through the period. LLWS concerns are
expected mainly north of I-90 through just before sunrise as
the nocturnal low level jet continues to strengthen. A cold
front will move through the area through the daytime hours
Monday morning, turning southwesterly winds to northwesterly.
Winds behind the front will also increase, with gusts to 30 to
locally 35 kts this afternoon, strongest west of I-29. Isolated
to scattered sprinkles/light showers are possible mainly this
afternoon and evening, and some of these showers could bring
down some higher gusts as well. Instability continues to trend
downward, so thunder is unlikely. Winds will begin to diminish
this evening across the area.

&&

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

&&

$$

UPDATE...JH
DISCUSSION...08
AVIATION...Samet