Barnard, South Dakota Weather Forecast Discussion

439
FXUS63 KABR 181609 AAA
AFDABR
Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
1109 AM 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 moving over the same area will result in
ponding water, and may result in localized flooding concerns
through the day Friday.
- There is only around a 20% chance of thunderstorms over eastern SD
and west central MN into Friday. No severe weather (1" hail or
larger or damaging winds) is expected.
- A 20% chance of showers will return to far northeastern SD and
west central MN Saturday afternoon.
&&
.UPDATE...
Issued at 1056 AM CDT Thu Sep 18 2025
Fog has moved off this morning, and visibility over northeastern
South Dakota has improved. Low pressure center continues to circle
over the area this morning, currently bringing the heaviest rain
to north central and central South Dakota. 24 hour rainfall totals
over those areas have been reported to be in the 2-4" range, with
1-3" estimated to have fallen elsewhere. Therefore monitoring the
flooding potential closely this morning, although expecting less
rain today than was observed yesterday. Showers are expected to
continue through tonight and into tomorrow. No lightning strikes
have been observed on satellite yet this morning, but there are
chances (~20-40%) of some scattered weak thunderstorms over
northeastern South Dakota this afternoon and evening. No severe
weather is expected from this system.
&&
.DISCUSSION...
Issued at 358 AM CDT Thu Sep 18 2025
A 500mb low is set up from eastern MT through SD and northern NE.
This feature will only slowly slide to ND/northeastern SD/MN by
early Saturday morning, and be reinforced by a secondary through
diving in from Canada Saturday into early Sunday. Any zonal flow or
ridging will be brief across our area late Sunday afternoon through
Monday morning. While there are some differences in strength, the
next 500mb low looks to cross MT Monday morning and slide across
SD/NE late Monday into Tuesday morning before surging/deepening
across the Central Plains States on Tuesday. Increased uncertainty
slides in by Wednesday on how progressive the low will be to our
south/southeast and just how quickly ridging will return Thursday.
Overall though, the sensible weather differences for our area look
minimal with mainly dry weather expected after Tuesday.
Looking at current conditions, the 08Z surface weather map showed
the low over our south-southwestern counties, centered over
K9V9/Chamberlain. A large swath of moisture continues to pinwheel
around the low, with the most steady rain north and west of the low.
This is where (mainly southwest of a line from Eureka through
Ipswich, Redfield, and Clark) radar estimated rainfall amounts range
from 1.5 to 3 inches. Localized higher amounts have been reported
south of PIR at the Bad River and Fort Pierre National Grasslands.
We`ll continue to monitor the rotating bands of rain for areas of
that near flash flood guidance and rising area rivers. The area of
most concern remains west-south of PIR. The Bad River at Fort Pierre
continues to rise, and is forecast to top out near to above flood
state late this morning/early this afternoon. While thunderstorms
remain possible, the coverage is limited and will be mainly focused
over eastern SD/western MN today into tonight.
The surface low will slowly slide east and set up across the SD/MN
border by 06Z Friday before shifting over west central MN 18-21Z
Friday and sliding north along the ND/MN border on Saturday. While
mainly dry weather will take hold by late Friday, moisture around
the surface sfc-500mb trough will keep off and on 15-25% chance of
showers in the forecast into Saturday afternoon.
Highs should be back into the 70s Sunday and Monday, with a few
readings in the low 80s over central SD on Sunday. As noted in the
previous discussion, fog will become a concern again due to the
lighter winds and abundant low level moisture. This will be true
east of the Prairie Coteau this morning, Friday morning over
eastern SD/west central MN. There also indications (ECMWF ENS
visibility meteogram) of additional fog each morning Saturday
through Monday across much of the area. However, probabilities are
around 20% or less for most locations, but if it does occur
visibilities could fall to less than a half mile.
&&
.AVIATION /12Z TAFS THROUGH 12Z FRIDAY/...
Issued at 644 AM CDT Thu Sep 18 2025
Terminals KABR,KATY,KPIR,KMBG
Rain remains at MBG and PIR, with the back edge of the more
steady rain just south of ABR. A large area of limited rain has
moved over ATY, with TEMPO and PROB30 precipitation expected there
early this morning and again after around 22Z. While there could
be a few thunderstorms later this afternoon at ATY, confidence is
too low to include it in the TAFs at this point. There are some
concerns of fog development near daybreak Friday at ATY. Most
locations will experience IFR to low end MVFR ceilings during
much of this period.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
&&
$$
UPDATE...BC
DISCUSSION...06
AVIATION...06

NWS ABR Office Area Forecast Discussion