253
FXUS63 KABR 161957
AFDABR

Area Forecast Discussion
National Weather Service Aberdeen SD
257 PM CDT Thu Oct 16 2025

.KEY MESSAGES...

- Scattered showers are expected through tonight, mainly for the
James River Valley and eastward into western MN. A strong
thunderstorm or two cannot be ruled out through sunset. Main threats
would be small hail (pea sized) and wind gusts up to 50 mph.

- Winds increase Saturday out of the northwest, with gusts of 30 to
40 mph. This will lead to elevated fire danger over portions of
central South Dakota.

- Lows for Saturday night will be near or at freezing ranging in the
30s.

&&

.DISCUSSION...
Issued at 256 PM CDT Thu Oct 16 2025

As of 1pm, current surface map indicates the center of the surface
low over the ND/SD border with its cold front extending southward,
hovering right along the Missouri River as obs over our far western
counties indicate west to northwest winds. Its parent upper low
continues to spin in place over WY and its trough axis extending
southward. Through 00Z, this low will continue to track into ND as
the fropa will track eastward, forecast to be over ~James River
Valley by 00Z, and over west central MN through southeastern SD by
06Z Friday. By 12Z, this occluding low will continue its track north
into Manitoba with the CWA in the drier air behind the cold front.

Radar currently indicates a few broken line of showers/tstorms
extending from Nebraska and tracking northeast over the eastern half
of SD, within the warm sector. CAMs and HREF Z>40dbz paintballs
agree on these broken lines (as shear is parallel to forcing) of
showers and thunderstorms continuing, along with additional
development within the warm sector ahead and along the front. This
would be from Lyman County northeastward through the James River
Valley into MN through ~06Z. As the front shifts further east
overnight, so will the precip, with the last of it to exit our far
eastern CWA by ~09-10Z. Looking at the 19Z meso parameters per SPC,
for James River Valley and eastward, bulk shear is 40-60kts here
ahead of the cold front with values behind it up to 100kts over
western NE behind front/closer to UL low. Mid level lapse rates
range from 6-7C/km and MUCAPE up to 500 j/kg. With some sunshine
over this area today, high shear/low CAPE, low level forcing, and
dewpoints in the upper 50s to around 60, thunderstorms within the
warm sector will continue to be a possibility through sunset.
Although not anticipating any severe a few storms could become
strong over portions of northeastern and east central SD. Small hail
and wind gusts to 50 mph will be the main threat. Latest HREF/GEFS
keeps the wrap around moisture from this low now more north and west
of the CWA with ENS/NBM clipping Corson County, so left 20% pops
over this area just to be safe. Probability of rainfall>0.10" 00Z-
12Z Friday is 25-30% along and east of a line from Miller to
Wheaton. However, any stronger storm could produce brief heavy
downpours leading to higher rainfall amounts.

The good news is that with the winds shifting more westerly (with a
bit of a southwesterly component) this will bring in drier air which
will help to keep any fog from forming overnight. With the ongoing
tight pressure gradient around the exiting stacked low and gustier
winds aloft (25-35kts at 850, 06Z) winds will continue to be breezy
overnight into Friday morning with gusts up to 25kts. Friday
afternoon, gusts are forecast to range between 20-30kts, highest
over the Coteau and north central SD.

Otherwise, another shortwave will move in over the Pacific Northwest
into MT Friday evening and its surface lee trough/cold front to our
west by Saturday morning, shifting southeastward through the day.
ENS/GEFS agree on the possibility of light precip over the CWA with
this but do not really agree on overall timing/placement with ENS
being a bit further east on precip chances. Latest NBM as a 20-30%
chance over our far western CWA Saturday morning with pops of 20-30
shifting over our southern CWA through the day. Winds will pick up
Saturday, out of the northwest per weak pressure rises and CAA
behind the exiting low/cold front to our east and southeast. Mixing
heights over the CWA look to be around 750-700mb by peak heating
with momentum transfer at the top of the mixed layer between 20-
30kts, highest over central SD. Probability of wind gusts of 35mph
is 30-65% west of the James River, highest over north central SD.
Another shortwave and its surface low will sweep across the Northern
Plains Sunday evening/Monday that could bring the return of precip.

Lows will range from the lower 40s to the mid 50s, coolest west of
James River behind front. Average highs for Friday ranging in the
60s. With the incoming cooler air Saturday, highs will only range in
the 50s with lows in the 30s. Highs for Sunday will rebound into the
upper 50s to lower 60s.

&&

.AVIATION /18Z TAFS THROUGH 18Z FRIDAY/...
Issued at 1225 PM CDT Thu Oct 16 2025

Terminals KABR,KATY,KPIR,KMBG

IFR to LIFR conditions are currently over KPIR and KMBG, while KABR
and KATY are in VFR conditions. These conditions continue through
the afternoon, with KABR seeing a decrease in ceilings during the
late afternoon and KATY seeing a decrease during the evening.
Overnight conditions should improve to VRF. There is a chance for
scattered showers late this afternoon into the late evening for
KATY, while KABR has a chance for scattered showers during the
evening. There will be stronger winds and gusts through the
afternoon and into Friday morning for all terminals. KATY and KABR
could see gusts up to 30kts during the afternoon, and all terminals
could see gusts up to 25kts overnight into Friday morning.


&&

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

$$

DISCUSSION...MMM
AVIATION...12