Maple Leaf, South Dakota Weather Forecast Discussion

886
FXUS63 KABR 121945
AFDABR
Area Forecast Discussion
National Weather Service Aberdeen SD
245 PM CDT Fri Sep 12 2025
.KEY MESSAGES...
- There is a Marginal Risk (level 1 out of 5) of severe weather
  over portions of central and north central South Dakota tonight
  and Saturday, as well as northeast South Dakota on Sunday. Hail
  up to an inch in diameter and wind gusts up to 60 mph are the
  primary threats.
- Marginal and slight risks for excessive heavy rainfall are in
  place over portions of the region over the next 3 days.
  Torrential rainfall is a concern over the next few days.
- High temperatures will run 5 to 15 degrees above normal through
  Tuesday, before returning to seasonal values.
&&
.DISCUSSION...
Issued at 244 PM CDT Fri Sep 12 2025
At 2 PM CDT, skies are mostly sunny and temperatures are warming
through the 80s, except over far northeast South Dakota into west
central Minnesota, where cloud-cover and ongoing
showers/thunderstorms have held temperatures down in the 60s and
70s. Winds are variable across the forecast area, generally around 5
to 15 mph. Earlier convection that initiated from south of Redfield
to southwest of Watertown has evolved/moved over into the far
northeast corner of the forecast area. Occasionally, hail potentially
up to dime/nickel has appeared in radar interrogation. And, pockets
of heavy rainfall from training/slow moving storms has been observed.
Over the next couple of days, as upper level ridging over the region
gradually gives way to an upper level trof/closed low system
approaching from the west, surface low pressure/inverted surface
troffing will anchor itself over the western/southern CWA. With
ample surface to mid-level moisture around through Sunday, the
potential for efficient/heavy rain-producing (south-to-
north-moving) thunderstorms will exist.
Starting tonight into Saturday, the first installment of
precipitation chances (40-80%) shows up. Deep layer shear is around
25-35kts, and instability is progged at or above 2000J/kg CAPE over
the western third (basically the Missouri River valley westward) of
forecast zones. A marginal risk (1 out of 5) for severe weather is
in place across the western/northern counties in case any multi-
cellular to supercellular convection can produce hail up to an inch
in diameter or wind gusts up to 60 mph. Hi-Res ensemble guidance
depicts the potential for excessive heavy rainfall across portions
of north central South Dakota between 7 PM CDT this evening and 7 PM
CDT Saturday. There is a marginal/slight risk for excessive heavy
rainfall in place across Corson/Dewey counties tonight.
A similar set up is in place across the CWA (perhaps 50-100 miles
further east) Saturday afternoon into early Sunday morning,
including a marginal risk for severe thunderstorms and a marginal
risk for excessive heavy rainfall across portions of central and
north central South Dakota.
As the bulk of the upper low moves through on Sunday, the marginal
risk for severe weather and excessive rainfall expands over into
northeast South Dakota, with a slight risk for excessive heavy
rainfall covering the Missouri River valley region, westward.
The remainder of the 7-day forecast looks similar to what it was 24
hours ago. Keeping in mind, the relative blocky pattern that will be
happening across the lower 48 and southern Canada "beneath" a
broader upper level ridge in place, spanning coast to coast, over
northern Canada, there is much variability potential out beyond day
4 right now. That said, still seeing a system in the models moving
from the Pac NW into the northern plains Tuesday/Wednesday, while
the upper ridge now shifted to over the Great Lakes region
amplifies. With this ridge "blocking" the way, upper level
troughiness may be sticking around over the northern plains through
the end of next week. This would support a less than stable
environment, with precipitation chances expected to persist past
Tuesday/Wednesday.
Based off deterministic solutions and ensemble guidance,
temperatures are expected to remain up to 15 degrees above normal
through next Monday, before 850hpa thermal progs ratchet down to
something closer to 5 to 10 degrees above normal for mid to late
next week.
&&
.AVIATION /18Z TAFS THROUGH 18Z SATURDAY/...
Issued at 1219 PM CDT Fri Sep 12 2025
Terminals KABR,KATY,KPIR,KMBG
VFR conditions are expected over the next 24 hours. There could be
some fog forming and running up onto the Coteau as far as KATY
early Saturday morning. Will monitor that potential for now. The
primary concern is when thunderstorms will impact the KPIR/KMBG
terminals during the overnight hours into Saturday morning.
Hail/wind and heavy rainfall are possible with thunderstorms later
tonight into Saturday morning. PROB30s have been introduced for
TSRA/SHRA at KPIR/KMBG.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
&&
$$
DISCUSSION...10
AVIATION...10

NWS ABR Office Area Forecast Discussion