867
FXUS63 KABR 280655
AFDABR

Area Forecast Discussion
National Weather Service Aberdeen SD
155 AM CDT Wed Oct 28 2026

.KEY MESSAGES...

- Patchy to areas of fog expected through the morning and could be
dense at times, especially between the Missouri and James River.

- Rain chances return to portions of north central SD this morning
before shifting into portions of northeastern SD and west central MN
midday through this afternoon. Confidence is highest (50-85%) along
and east of the Sisseton Hills where isolated thunderstorms are
possible.

- There is a Marginal Risk (level 1 out of 5) for isolated severe
storms this afternoon east of Interstate 29 through west central MN.
Main threats include 1" diamater hail and 60 mph wind gusts.

&&

.DISCUSSION...
Issued at 155 AM CDT Wed Oct 28 2026

As of 1am temperatures are in the upper 30s to the upper 40s with
winds mainly out of the southeast between 5-10mph. Satellite
imagery continues to indicate low stratus surging northward east of
the James River with KATY reporting a cloud deck of 600ft. Otherwise
patchy to areas of fog continue to develop between the Missouri and
James River with webcams indicating some of that being dense in
areas. Have not issued a Fog Headline just yet as winds continue to
keep things above criteria for now but will continue to monitor
webcams and obs through the morning.

Our next shortwave continues to move in from the west and by 12Z,
the axis of this wave will be over WY through CO with the region on
the PVA side of it in southwest flow. At the surface the center of
the low is forecast to be over west central SD with a weak trough
connecting to a secondary low over northwestern KS. This is all
within a large area of low pressure extending from a system in
central Canada. On the northern side of the quasi stationary/warm
front to start (mainly west to east across the center half of the
state), CAMs do indicate a band(s)of elevated rain showers
developing over WY/western SD and tracking northeast across portions
of north central and northeastern SD into ND early this morning and
more on the northern/northeast side of the low (as it tracks
northeast) through the midday. By 18Z the center of the low will be
near ND/SD/MN border with its fropa extending through eastern SD.
With additional forcing from its shortwave and an 85-100kt jet
aloft, dewpoints warming into the lower to mid 50s, and daytime
heating, additional showers and even thunderstorms will develop
ahead/along the front James Valley and eastward ~late morning/midday
through the afternoon.

The resulting pops per NBM is 50-85% chance east of the James River
with the highest pops Coteau and eastward. Coteau and eastward is
really where HRRR/REFS does indicate spotty convective development
(right along the front) over this area around ~17-18Z with these
cells quickly moving into MN by ~22-23Z. NAMNest and RAP are a bit
slower on the exit and a bit more westward extent of convection. NBM
does a good job overall with coverage and timing due to a bit of a
difference between the CAMS. Not too much SFC CAPE to work with
(MUCAPE under 1000j/kg) but we do have the shear of 40-50kts and
steep lapse rates of 6-7C/km Coteau and eastward between ~19-22Z
this afternoon. So low cape high shear scenario. So for a few hours
there will be enough energy for weak thunderstorms. Further east
(far eastern SD/MN) if we can get enough vertical development into
the cooler air aloft there could be the threat for an isolated cell
or two to become severe(60 mph gusts/quarter hail), however, any
more organized convection is forecast to remain further east into MN
with better moisture/forcing. Very far portions of east central SD
is within the 5% chance of severe weather for hail, per CSU ML
guidance, which does back this up. WIth this threat, the SPC has
expanded the Marginal Risk westward east of Interstate 29 through
west central MN. Main threats include 1" diameter hail and 60 mph
wind gusts. The last of the precip is forecast to exit by 00Z.

As the front track across the CWA winds will shift to the
west/northwest behind it as drier air moves in aloft and high
pressure filters in from the west/northwest. As winds become light
tonight and ongoing moisture at the surface from the recent rains,
plus radiational cooling, soundings once again do indicate this low
level saturation below a strong inversion from the surface up to
950mb or so. REFS/HREF do indicate the formation of "low clouds"
over the region overnight so lower confidence on if this is just low
stratus forming or in fact fog. Probably of visibility at a 1/4th
mile or less is 45-65% mainly across the James Valley and the Coteau
per both HREF/REFS and once again NBM keeping low chances. So will
watch the potential for this. Otherwise, high pressure keeps the
area dry Thursday and Friday before another shortwave/low brings in
additional chances of rain Friday night through Saturday night and
again early next week.

&&

.AVIATION /06Z TAFS THROUGH 06Z THURSDAY/...
Issued at 1232 AM CDT Wed Oct 28 2026

Terminals KABR,KATY,KPIR,KMBG

Fog and low stratus will continue to remain at a few of our TAF
sites early this morning. IFR/LIFR cigs will remain prevalent at
KABR/KATY through midday into this afternoon at KABR/KATY. LIFR
to even VLIFR vsbys at these terminals will develop and persist
through most of the morning hours. KMBG will see cigs fall to
MVFR/IFR through the morning before improving closer to midday.
KPIR looks to be the only terminal that will maintain VFR
conditions through this TAF cycle. Light rain is anticipated to
affect KABR/KATY/KMBG sites during by late morning through the
afternoon.

&&

.ABR WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.

&&

$$

DISCUSSION...MMM
AVIATION...Vipond