491
FXUS63 KFSD 040337
AFDFSD

Area Forecast Discussion
National Weather Service Sioux Falls SD
1037 PM CDT Tue Jun 3 2025

.KEY MESSAGES...

- Periodic chances for showers and isolated thunderstorms
  through the weekend. For now the threat for severe weather
  remains low.

- Temperatures will be seasonably mild with highs mainly in the
  70s through the weekend.

&&

.DISCUSSION...
Issued at 238 PM CDT Tue Jun 3 2025

The broad area of warm advection and weak instability ahead of the
main upper level wave will continue to shift east of the area with
drier and more stable air building into the area. High pressure at
the surface builds into the area as well with light winds and cool
temperatures in the 40s expected for Wednesday morning. With the wet
ground and not much cloud cover some patchy fog will be possible but
for now not anticipating any widespread visibility problems.

Wednesday will see the continuation of light winds as surface high
pressure slowly drifts east. Temperatures will be mild with highs in
the 70s. A fast moving fairly weak wave will move through area to
the north and bring small chances for showers. Instability looks
too weak to produce any showery activity, so will rely on forcing
in and around the dendritic layer. Saturation and forcing in the
dendritic layer looks most likely in central SD and that area also
looks to have less dry air below this forcing which may allow for
some very light rainfall. By Wednesday night this wave skirts by
to the north and some very weak elevated instability above 800 mb
may allow for some showers activity to continue with the better
chances north of I- 90. This potential showery activity will be
fighting a lower level dry layer, so again only expecting light
activity.

A pair of waves move onto the Plains Thursday and will bring the
next chance for some light rain and a very low chance for thunder.
Instability remains very low, generally less than 200 J/kg CAPE.
Saturation aloft is a bit better with this system and expect more
widespread cloud cover and a better chance for maybe a tenth of an
inch of rain or so. Model sounding suggest that this chance for rain
will be a bit better west of I-29.

Friday into Friday night will see another weak wave/s, this time to
the north of the area. One moves through on Friday morning and
another moves through Friday night. Saturation and forcing look to
be better to the north, but some weak instability near highway 14
and into southwest MN, generally about 500 J/kg, may allow for some
showers or isolated thunderstorms to develop. For now these storms
do not look to be severe. Will have to monitor for the potential for
a few funnel clouds on Friday afternoon and early evening if any
storms can develop as low level winds are pretty light and there may
be a weak boundary near highway 14 into southwest MN.

Shower and thunderstorm chances continue into Saturday as a wave to
the north dives southeast and swings a cool front into the area. A
slightly better chance for isolated severe storms, so will need to
keep an eye on trends and timing.

Sunday into Tuesday looks mainly dry as northerly flow aloft settles
into the area. Temperatures during this time should be near to above
normal.

&&

.AVIATION /06Z TAFS THROUGH 06Z THURSDAY/...
Issued at 1028 PM CDT Tue Jun 3 2025

Winds become light and variable tonight. VFR conditions should
prevail, although there are low to moderate (60% chance or
less) of MVFR fog developing tonight across northwestern IA and
into area river valleys. Not enough confidence that it will
impact the KSUX terminal at this time, so have left out for now.
Diurnal cumulus clouds return during the afternoon and evening
Wednesday. Isolated showers and sprinkles are possible Wednesday
afternoon and into the evening west of the James River. Given
soundings and uncertainty in coverage, will keep out of KHON for
now. If showers develop, could see brief MVFR conditions. Light
and variable winds return Wednesday night.


&&

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

&&

$$

DISCUSSION...08
AVIATION...SG