228
FXUS63 KABR 181523 AAB
AFDABR

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
1023 AM CDT Fri Sep 18 2026

.KEY MESSAGES...

- Moderate to heavy rains will persist through the morning hours
  before tapering off west to east by midday through the
  afternoon. Heaviest swath of rainfall still expected from
  parts of south central SD into east central and southeast SD.

- An active pattern will persist this weekend into early next week
  with a 40-70 percent chance of rain Sunday into Monday.

- Temperatures will remain below seasonal normals the next
  several days before returning to near normal readings the
  latter half of next week.

&&

.UPDATE...
Issued at 1017 AM CDT Fri Sep 18 2026

Rain showers from the system continue to move east this morning
into the afternoon, where areas east of the James river could
see additional rainfall amounts between 0.4 inch to 0.75 inch
by the time these showers leave this afternoon. Though, there
could be some lingering scattered showers exiting eastern SD
this evening.

Low clouds and misty conditions are occurring over central and
northeastern SD in areas where the rain has move out of. These
misty conditions will cause some patchy areas of lower
visibilities at times through the afternoon and into the
evening. These visibilities should stay above a mile.

UPDATE Issued at 609 AM CDT Fri Sep 18 2026

Updated discussion for the 12Z TAFs below

&&

.DISCUSSION...
Issued at 340 AM CDT Fri Sep 18 2026

Moderate to heavy rains have been spreading northeast across parts
of central and northeast SD early this morning as a sfc low pressure
system shifts out of the Colorado Front Range into Nebraska.
Southwest flow aloft remains present across the region with an
embedded shortwave trough tracking northeast across SD/NE per water
vapor imagery. The sfc low is expected to shift east across the
SD/NE border area through the morning into the afternoon and then on
into western IA late this afternoon and evening.

The main focus in the next 12 hours or so will be the ongoing
precipitation falling across our forecast area. Model guidance
continues to remain in fair agreement in keeping the heaviest bands
of rain across parts of south central SD north and east into
sections of east central and southeast SD today. Still anticipate a
1-2 inch type rainfall to occur along and east-southeast of a line
from the Pierre area toward the Redfield area and then east toward
the Watertown area. Lesser amounts, generally around an inch or
less, will be found north and west of this line across the ND/SD
border area back into the north central portion of SD. Ensemble mean
PWAT values of 1.75 inches remain concentrated across those
aforementioned areas and points south and east. These higher values
remain near the maximum climatological percentiles for this time of
year. As the sfc low tracks south of our area today, a tighter
pressure gradient develops between it and high pressure across
Ontario leading to an east to southeast breeze gusting up over 30
mph at times from north central into northeast SD. With the rain and
thick cloud cover in place today, temperatures will remain steady in
the upper 50s to mid 60s east. With the rain ending by midday across
central SD, afternoon readings will make the mid 60s to low 70s.

The rainfall will come to an end from west to east today. Central SD
will see the rain taper off by mid morning. The James Valley region
will hold onto the showers longer through about late morning and
midday. Any lingering showers this afternoon will likely be confined
to our far eastern zones. Drier conditions will take hold tonight
and persist through most of Saturday. Cloudy skies will persist
however so temperatures are expected to fall short of climatological
normals with daytime reading likely remaining in the 60s. The break
from the rain will be brief as guidance wants to bring in the next
upper level disturbance on southwest flow aloft by the end of the
weekend into Monday. Rain chances with this event currently sit at a
40-70 percent chance with the highest probabilities of precip across
central and parts of northeast SD. After another weak disturbance
brings some showers to to parts of the area around the middle of the
week, shortwave ridging is progged to build in the latter half of
next week. This should bring our temperature trends back closer in
line with late September normals.

&&

.AVIATION /12Z TAFS THROUGH 12Z SATURDAY/...
Issued at 609 AM CDT Fri Sep 18 2026

Terminals KABR,KATY,KPIR,KMBG

-RA to +RA continues to fall mainly east of the Missouri River
 as the back edge of the rain, and overall dry conditions (or
 sprinkles) west of the Missouri River. Rain will continue to
 diminishing west to east across the region with the last of
 the rain exiting eastern SD by this afternoon. Overall MVR/IFR
 cigs continue at all TAF sites and will continue through the
 afternoon and evening with possibility some sites dropping to
 IFR/LIFR tonight and overnight with the possibility of fog
 developing.

&&

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

&&

$$

UPDATE...12
DISCUSSION...Vipond
AVIATION...MMM