963
FXUS63 KFSD 141738
AFDFSD

Area Forecast Discussion
National Weather Service Sioux Falls SD
1238 PM CDT Fri Aug 14 2026

.KEY MESSAGES...

- Pockets of heavy rain will be possible mainly near and south
  of highway 20 in northwest IA late this morning into this
  afternoon. Confidence on the extent of heavy rain is low.

- Low stratus and fog remain possible tonight into Saturday
  night. Lower confidence for stratus and fog Sunday into Sunday
  night with a small push of drier air.

- Monday night into Tuesday night is the next better chance for
  showers and thunderstorms. Isolated severe storms and pockets
  of heavy rain will be possible.

&&

.DISCUSSION...
Issued at 1236 PM CDT Fri Aug 14 2026

Low pressure continues to track east northeast into western IA
through this afternoon. Scattered showers and isolated thunderstorms
will be possible with this feature. The main effects should be this
afternoon and confined to areas near and south of highway 20 in
northwest IA. With PWAT values around 1.75" to 2", locally heavy
rain will be possible, especially near this low pressure along and
south of highway 20. Some question marks surround the air mass in
Woodbury and Ida counties, locations that have received the most
rainfall the past two days, as the morning stratiform rainfall seems
to be providing some stability to the area and suppressing stronger
convective activity. The latest Hi-res models continue to trend away
from heavier rain near highway 20, with mainly spotty activity
expected. A few downpours could lead to very localized amounts
around an inch or so, but flash flooding is unlikely. Farther
northwest, spotty showers will be possible with weak, diurnally
driven instability. The overall effects of these diurnally driven
showers will be low.

Saturday will likely start with stratus and fog in many locations. A
weak wave will move through the area and likely lead to spotty
showers and thunderstorms. Some hints that the better instability
(about 1000 J/kg) will be north of I-90, but overall weak shear and
13 kft freezing levels suggest that pockets of heavy rain will be
the main threat.

By Saturday night this wave will move southeast of the area, leaving
mainly dry conditions in place for much of Saturday night into
Sunday morning. Model soundings hint at the potential for some
morning fog, but the depth of the low level moist layer looks much
shallower, so a better chance to burn off in the morning. Drier
northerly flow should lead to a pleasant Sunday with highs of 75 to
80 and dew points likely in the lower to mid 60s for most locations.

Sunday night into Monday should see mostly dry and warm conditions
continue. Monday night into Tuesday night will be the next better
chance for showers and storms as a trough digs in to the north and
northeast. For now, the threat for severe storms and heavy rain
looks low, but this will be a time frame to watch for changes.

Cooler and more stable air should settle in behind this system, with
highs mostly in the 70s Thursday and Friday and only isolated
chances for showers and storms.

&&

.AVIATION /18Z TAFS THROUGH 18Z SATURDAY/...
Issued at 1236 PM CDT Fri Aug 14 2026

Widespread MVFR and IFR conditions are expected through most of
the TAF period. Scattered showers, drizzle and isolated
thunderstorms, mainly northeast NE, southeast SD and northwest
IA are expected through about 2z. Spotty heavy rain is possible
in northwest IA this afternoon.

&&

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

&&

$$

DISCUSSION...08
AVIATION...08