Onida, South Dakota Weather Forecast Discussion

563
FXUS63 KABR 182010
AFDABR
Area Forecast Discussion
National Weather Service Aberdeen SD
310 PM CDT Thu Sep 18 2025
.KEY MESSAGES...
- Rain will continue today. Rain will come to an end over south
central SD tonight, and end over north central SD Friday morning,
and most of northeastern SD Friday afternoon.
- Light to moderate rain tracking over the same area for an extended
period may result in ponding water, and may result in localized
flooding concerns through the day Friday.
- Temperatures are expected to warm up through the weekend, with
high temperatures reaching the low 80s on Sunday, 5-10 degrees above
normal. Highs will become near-normal beginning next week.
&&
.DISCUSSION...
Issued at 303 PM CDT Thu Sep 18 2025
Low pressure center continues to sit over the forecast area today,
supporting continued showers on the back side over central and north
central South Dakota. Most areas have seen up to two inches over the
past 48 hours at this point, with areas near and west of Pierre
having observed upwards of 4 inches. We continue to monitor the
flooding potential, and soils over north central and central South
Dakota have been thoroughly saturated. While flash flooding is not
expected, water over roadways is still a threat, and enough rain
could make roads impassable. Showers are expected to continue
through tonight and into tomorrow, mainly impacting north central
and northeastern South Dakota on Friday. Additional accumulation of
an inch to an inch and a half will be possible before showers move
out Saturday. A stray rumble of thunder may be possible this
afternoon, but no severe weather is expected.
A weak ridge attempts to build in after the current trough moves
out, with the accompanying height rises allowing for a slight warmup
through the weekend. Temperatures will reach the upper 70s to low
80s, about 5-10 degrees above normal for late September. Highs
settle to be closer to normal through next week.
The next chances for rain look to be early next week. There is some
disagreement in the models, but currently looking at about a 15-30%
chance across the area on Monday supported by a positively tilted
upper-level trough. A severe threat is not currently anticipated,
with early looks at CAPE at around 1000 J/kg. There will be a
distinct lack of shear however, which will present problems for any
aspiring thunderstorms. Flooding could be a concern still however,
especially over any areas that were saturated with this week`s
event. PWATs topping out at about 1.2-1.3", while not overly
impressive, will be at minimum at the 90th percentile for late
September. A warm cloud layer of about 10k feet is also favorable
for flooding, as well as cloud layer winds and corfidi
upshear/downshear vectors all below 10 knots. This sets up slow-
moving storm potential, and while forecasted QPF is not impressive,
it is worth monitoring moving forward. The main question will be how
potential rainfall totals evolve over the next couple days, as well
as if two days without rain will de-saturate soils enough to lessen
the concern, especially over central South Dakota.
&&
.AVIATION /18Z TAFS THROUGH 18Z FRIDAY/...
Issued at 1228 PM CDT Thu Sep 18 2025
Terminals KABR,KATY,KPIR,KMBG
Low pressure center continues to sit over the area, and will slowly
slid eastward through the duration of the TAF period. Showers are
expected to continue, and will remain fairly scattered. The main
aviation impacts comes from low clouds with this system. Clouds are
expected to be in MVFR status through the period, with occasional
dips down to IFR, especially where rain is heaviest. Rain is
expected to come to an end over central South Dakota this evening,
but north central and northeastern South Dakota into western
Minnesota will see chances for rain continue through the TAF period.
There has been a signal for some light fog early tomorrow morning in
some of the model guidance, mainly over northeastern South Dakota
into western Minnesota, as well as parts of north central South
Dakota. However fog is not expected to be dense this morning,
dropping down to 1 mile at the lowest, keeping the categorical
impacts from visibility similar to that from ceilings and rain -
MVFR dipping down to IFR at times.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
&&
$$
DISCUSSION...BC
AVIATION...BC

NWS ABR Office Area Forecast Discussion