147
FXUS63 KFSD 162340
AFDFSD

Area Forecast Discussion
National Weather Service Sioux Falls SD
640 PM CDT Thu Oct 16 2025

.KEY MESSAGES...

- Scattered showers and thunderstorms most likely west of
  highway 81 this afternoon into the evening. Severe weather is
  not expected.

- Strong wave moves through on Saturday but moisture is
  limited. Scattered showers, possibly some thunder, and windy
  behind the cold front in the afternoon and evening.

- Cool and dry Saturday night into Sunday with near normal
  temperatures. Small threat for frost on Sunday morning.

- Above normal temperatures Monday before another cool front
  drops temperatures back to near or a bit below normal the
  remainder of the week.

&&

.DISCUSSION...
Issued at 218 PM CDT Thu Oct 16 2025

Broad warm air advection ahead of an incoming upper level wave along
with relatively weak instability, generally less than 600 J/kg, will
allow for scattered showers and thunderstorms into the night. The
better chances for thunderstorms will be before about 10 pm. Severe
weather is very unlikely. The low level dry air is fairly shallow
which does not support enhanced downburst potential and the freezing
level is close to 12 kft which would need a fairly strong updraft to
produce larger hail that could fall through the 2 miles of above
freezing air, and 600 J/kg CAPE is not going to produce that strong
of an updraft. So, the main threats from any thunderstorms will be
brief heavy rain and lightning and if a storm can get strong enough
pea sized hail. Otherwise temperatures will be very mild, especially
near and east of highway 81 with lows from the mid 50s to lower 60s.
Cooler air will begin to filter into central SD later tonight with
lows in the mid 40s more likely.

Friday should be a mild day in the wake of the exiting wave and
ahead of the next wave expected later Friday night into Saturday.
Westerly surface flow and temperatures in the upper 60s to lower 70s
are expected under sunny skies. Fire weather should be kept mostly
in check with surface relative humidity expected to remain at or
above 40 percent.

Late Friday night into Saturday a wave will dive southeast and bring
the next shot for showers. Precipitation chances will remain
scattered with some weaker elevated instability. The main concern
with this wave will be some gusty winds with gusts of 35 to 40 mph
possible. This may bring some elevated fire weather concerns but
once again the afternoon relative humidity is expected to remain
above 40 percent.

An active upper level pattern will not leave much room for lighter
winds as we head into Sunday and early next week. Cooler air will
filter in behind the wave Saturday, dropping lows into the 30s and
lower 40s Sunday morning. It does look like wind will remain around
5 to 10 mph so the threat for frost is fairly low. If winds can drop
off long enough Sunday morning then there may be a few more
locations in the mid 30s and we could see a little frost.

Another fast moving system will move through on Monday but
precipitation is not expected. The flow will remain fairly active
throughout the next week, but precipitation chances are pretty low.
Temperatures should be near to a touch below normal.

&&

.AVIATION /00Z TAFS THROUGH 00Z SATURDAY/...
Issued at 640 PM CDT Thu Oct 16 2025

Latest radar shows a band of showers between KMHE and KFSD streaming
northeastwards early this evening. These showers will persist on a
slowly waning trend. Ceilings remain at VFR levels though a few
sites have shown visibilities falling to MVFR thresholds. These same
showers produced an outflow boundary that just pushed through KFSD,
turning winds at the surface to out of the west. A second round of
showers and a few thunderstorms is developing on a cold front
generally southwest of the area. Should see these showers and storms
push northeastwards along the front as the front translates
eastwards. Think that this round of showers and storms will become a
bit more expansive in coverage over the next few hours and push into
locations west of the James River. These same showers will drift
eastwards through the night before exiting the area tomorrow
morning. Ceilings look to lower to MVFR levels for a short period of
time while the showers push eastwards. Winds will also turn to out
of the west with gusts up to 15-25 knots. The westerly winds will
finish out the TAF period.

&&

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

&&

$$

DISCUSSION...08
AVIATION...Meyers