Scotland, South Dakota Weather Forecast Discussion

083
FXUS63 KFSD 171153
AFDFSD
Area Forecast Discussion
National Weather Service Sioux Falls SD
653 AM CDT Wed Sep 17 2025
.KEY MESSAGES...
- Periodic showers and storms are expected today, with locally
  heavy rainfall the main threat though some weak funnels can`t
  be ruled out.
- Rainfall totals today into tonight will be around a half an
  inch for most of us, though locally higher amounts up to an
  inch or more are possible mainly north of I-90 (20-40%
  chance).
- Continued rain chances and cloudy skies will keep temperatures
  mainly cooler than normal through the start of the weekend,
  though another warm-up is possible heading into next week.
&&
.DISCUSSION...
Issued at 355 AM CDT Wed Sep 17 2025
A steady light to moderate rain continues along the Missouri
River Valley early this morning, with widely scattered showers
and pulse storms elsewhere. Expect a re-invigoration of showers
and storms as a shortwave from the main upper-low just off to
our west pivots through the area this morning. After this
morning push, some drier air may try to enter into the system
and create another lull in at least some of the heavier
rain/storm activity for the early afternoon. Guidance currently
indicates the surface low lifting north into central South
Dakota through the day today, leaving most of the area east of
the circulation and so we`ll have to watch developing confluence
bands later today as the focus for additional showers and
storms late this afternoon into the evening. The tricky part of
the forecast today is nailing the location of where these bands
set up, but tall, skinny CAPE profiles are likely and so the
threat for severe weather is low, but storms will likely produce
locally heavy downpours. Some minor urban and small stream
flooding will be possible in these storms and so a broad
Marginal Risk is in place for excessive rainfall. The best
chance for this thunderstorm activity will be east of I-29 where
some breaks in the cloud cover may lead to more
destabilization. Can`t rule out a few weak funnels with this
activity, but tornadoes are not expected. Highs today will be
running from the upper-60s west where cloud cover will be
greatest, to the low-80s east where more cloud breaks are likely
and where we`ll be squarely in the warm sector.
For tonight, the low pressure system will meander around the area,
centered over south-central South Dakota. We`ll continue to see
waves of showers develop east of the low`s center, but coverage will
likely be more widely scattered as instability wanes. Still enough
CAPE for some rumbles of thunder overnight, but torrential
downpours appear less likely compared to what we`ll see this
afternoon. Temperatures tonight will drop to the upper-50s to
low-60s. In terms of rainfall for today into tonight, we`ll see
around a half an inch of rain for most of the area, but locally
up to an inch to an inch and a quarter will be possible, with
GEFS and ECMWF ensemble probabilities of an inch plus of rain
highest (20-40%) north of I-90.
The upper-low will begin to lift north on Thursday, but as
another shortwave pivots into the area, more showers and storms
are expected through the day. A second upper low coming out of
southern Canada on Friday will finally provide the kick to start
gradually getting the rain and storms out of the area from west
to east. With that said, rain and storms are still likely on
Friday, especially east of I-29 (50-70% chance). Small shower
chances (

NWS FSD Office Area Forecast Discussion