Groton, South Dakota Weather Forecast Discussion

985
FXUS63 KABR 200556 AAB
AFDABR
Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
1256 AM CDT Sat Sep 20 2025
.KEY MESSAGES...
- Areas of fog are expected again overnight into Saturday morning
  over portions of the region, with visibility down below 1 mile
  at times.
- Temperatures are expected to warm up through the weekend, with
  high temperatures reaching the upper 70s on Monday, 5-10 degrees
  above normal. Highs will become near-normal by the middle of
  next week.
&&
.UPDATE...
Issued at 1242 AM CDT Sat Sep 20 2025
Aviation discussion updated below for the 06Z TAFs.
&&
.DISCUSSION...
Issued at 308 PM CDT Fri Sep 19 2025
Slow-moving low pressure center supporting showers persists today,
focused mainly over northeastern South Dakota into western
Minnesota. Rain rates continue to be fairly light, but still
monitoring the potential for flooding in that area. This area is in
fairly good shape compared to the rest of the CWA, and over the last
72 hours (ending at 12Z earlier this morning) has only seen a broad
0-2 inches of rain, with some localized areas greater than 2 inches.
Soil saturation remains in the 30% range, so concern is not high as
ranges closer to 45-50% are more conducive to flooding. Scattered
showers will stick around over this same area through Saturday, so
have held onto some slight chance PoPs through this time period.
However, areal coverage of rain is expected to be much less tomorrow
as the low continues to move out.
Fog will again be likely tomorrow morning, mainly over northeastern
South Dakota and western Minnesota. Coverage is not expected to be
widespread, but there may be localized pockets where visibility dips
below 1 mile. A Dense Fog Advisory will likely not be needed due to
the patchy nature of the lowest visibilities, but as always trends
and observations will be monitored overnight to better assess that
potential.
As this low pressure center moves out, a brief warming trend is
expected due to a weak upper level ridge building in. Lows will
remain fairly consistent through the week (lower 50s) but highs will
gradually warm to the upper 70s to low 80s by Monday, about 5-10
degrees above normal for late September. Temperatures then settle in
to be closer to normal for the rest of the week with the ridge
giving way to a positively tilted trough.
There are still slight chances for early-week rain over central
South Dakota Monday into Tuesday. The latest model runs give less of
a concern for flooding than was seen yesterday from a pure
meteorological standpoint. However, should this system come to
fruition and impact the CWA, the best chances for rain are currently
located over central South Dakota, where rain from this system has
created highly saturated soils. Therefore still keeping an eye on
flooding potential as this system draws nearer. The good news is
that there is still a lot of uncertainty on where this system will
track, and will depend quite heavily on where the positively tilted
upper level trough will set up. The GFS ensemble remains the most
favorable in terms of providing precipitation chances to the area,
as opposed to the Euro ensemble, which swings precip a bit further
south, providing lower chances over central South Dakota. Ensemble
guidance on QPF amounts also helps abate the potential flooding
threat, showing 50th percentile values of about 0.1" of accumulation
over a 24 hour period. A reasonable "worst case" scenario (90th
percentile) still only gives up to an inch of rain over 24 hours,
which would hopefully come over a long enough period as to not be
problematic for the saturated soils.
&&
.AVIATION /06Z TAFS THROUGH 06Z SATURDAY/...
Issued at 1242 AM CDT Sat Sep 20 2025
Terminals KABR,KATY,KPIR,KMBG
MVFR/IFR CIGs will affect the region through much of the TAF
period, with areas of FG/BR reducing VSBY to IFR potentially.
Light showers are still possible for KATY during the early morning
hours as well, with lower confidence for the other terminals.
Look for gradual improvement for CIGs/VSBY through the day
Saturday, although CIGs likely won`t reach VFR until late in the
day. Gradual clearing from west to east expected, so KMBG/KPIR
will improve first before KABR/KATY.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
&&
$$
UPDATE...TMT
DISCUSSION...BC
AVIATION...TMT

NWS ABR Office Area Forecast Discussion