578
FXUS63 KFSD 090330
AFDFSD

Area Forecast Discussion
National Weather Service Sioux Falls SD
1030 PM CDT Fri Aug 8 2025

.KEY MESSAGES...

- Severe storm chances look to be lessening across the area.
  There could be an isolated severe storm with large hail and
  damaging wind east of Interstate 29 into the early morning
  hours.

- Isolated showers and thunderstorms will be possible near the
  Missouri River into northwest IA Saturday into Sunday.

- Seasonally warm and mainly dry Monday through Wednesday.

&&

.DISCUSSION...
Issued at 229 PM CDT Fri Aug 8 2025

An outflow boundary from morning convection to the north raced south
this morning turning winds to the north and east. Scattered ACCAS
showers and thunderstorms have brought a few lightning strikes and
some brief rain to a few locations, and continues to lift northeast
into southwest MN. The combination of the clouds and slightly cooler
air behind the outflow slowed warming today, but did not have much
of an effect on humidity and surface dew points. Still plenty humid
and uncomfortable outside.

Overall this outflow boundary had little effect on afternoon and
early evening convective potential as a very strong capping
inversion was already in place. Even with a surface front near and
west of the James River convection is not expected to try to develop
until roughly after 8 pm when upper level support moves into the
area and aids in breaking down this cap as some mid level moisture
streams out ahead of it. Some of the latest models even struggling
to get development during the evening. With the timing of this wave
and some hints in the model soundings convection should end up being
elevated which will keep the threat a mainly hail and wind threat. A
very isolated surface based storm will be possible near and west of
the James River before 8 pm. As the upper level wave moves across
the area a secondary area of thunderstorms will be possible with the
better chances across northwest IA. This would be later in the
night, roughly around 9z to 12z. Isolated severe storms will be
possible with this as well. Overall confidence in this next 12 hours
is a bit low given the strong cap, but decent incoming wave.

Once this morning activity exits the area, Saturday should prove to
be mostly dry with decreased humidity and temperatures. some
scattered showers and thunderstorms will be possible near the
Missouri River and into northwest IA in the afternoon and evening.
This is in response to some lingering troughiness in the area. Right
now severe weather looks unlikely.

Sunday should be another mainly dry day as the upper level trough to
the north slides east and allows some drier and slightly cooler air
to settle southward. Morning lows should be 60 to 65 with afternoon
highs of 80 to 85.

Monday into Wednesday will see seasonally warm temperatures settle
over the area with northwest flow aloft. Overall this pattern looks
to support very little if any thunderstorm activity during this
time. Lows from the upper 50s to mid 60s and highs in the 80s.

Wednesday into Friday temperatures rise above normal as troughiness
develops to the west. A few shortwaves will be possible during this
time which could lead to a couple of chances for showers and
thunderstorms. Some isolated severe storms will be possible.
Otherwise lows should be in the mid 60s to lower 70s with highs from
the mid 80s to lower 90s.

&&

.AVIATION /06Z TAFS THROUGH 06Z SUNDAY/...
Issued at 1030 PM CDT Fri Aug 8 2025

A strong inversion aloft has kept storms from developing this
evening, with only isolated thunderstorms expected east of
Interstate 29 through about 07Z. Some guidance is indicating
another round of thunderstorms lifting out of NE into
northwestern IA toward 12Z on Saturday, though confidence
continues to be low.

&&

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

&&

$$

DISCUSSION...08
AVIATION...JM