243
FXUS63 KABR 261937
AFDABR

Area Forecast Discussion
National Weather Service Aberdeen SD
237 PM CDT Sun Apr 26 2026

.KEY MESSAGES...

- Widespread rain expected through Monday night. One inch of rain or
more is possible over portions of south central through northeastern
South Dakota and western Minnesota. Locations along and east of I29
could receive upwards of 1.5 inches, with locally higher amounts
possible.

- Northerly winds increase Monday afternoon, with gusts of 35 to 45
mph, with locally higher gusts possible. The strongest gusts are
currently expected between the Missouri and James River. Winds will
diminish Monday night.

- High temperatures 5 to 15 degrees below normal expected through
the middle of the week. Highs are expected to be in the upper 40s to
50s through that period.

&&

.DISCUSSION...
Issued at 237 PM CDT Sun Apr 26 2026

As of 2pm rain is currently falling over south central and portions
of east central and northeastern SD. The bulk of the precip is on
the WAA side, ahead of the low, still to our south through NE/KS.
Through the late afternoon, CAMs continue to indicate this rain
tracking further north and northeastward over the CWA and becoming
more widespread.

By 00Z, HREF indicates the axis of the negative tilted shortwave
from CO and southeastward through TX with the Central and Northern
Plains on southwest flow/PVA side of shortwave with a fairly good
amount of diffluence over this area. Being on the north/northeastern
side of the CO low, we continue with an increase in dewpoints/PWAT
as moist air surges northward ahead of the low into the region. With
this forcing, HREF mean composite reflectivity along with CAMS
overall agree on the rain being widespread from south central
through northeastern SD (mainly east of the Mo River) tracking
southwest towards the northeast. Through the overnight not much of a
change in track since the previous run as ENS still a bit more
southward with the track of the low than GEFS/HREF as it tracks
eastward across KS/OK. This first wave of rain will continue to
track northeast with HREF/CAMS showing the bulk of the rain
extending from northeastern SD into ND/MN by midnight or so. HRRR
indicates the possibility of weak thunderstorms developing over east
central SD/MN border with CAPE pretty marginal at 500j/kg or less
and shear of 30kts. No severe weather is anticipated.
HRRR/HREF/HiRESARW/RAP indicate a bit of a break in the precip as
the first wave of rain exits the northeastern CWA and before the
next wave moves in over south central SD between ~9-11Z. Other
models show less of a break or continue rain here and there.

By 12Z, the negative tilted shortwave will continue to deepen over
the Central/Southern Plains with the low tracking northeastward with
EC members overall showing the center of the 998mb low over
northeast KS, by 12Z Monday (and a secondary weaker center over
SD/IA/MN border within this elongated area of low pressure). Once
again, the ENS is still tracking a bit more southward than GEFS whos
low is more over NE/KS/IA border. With the CWA now on the northwest
side of the low, we will see a second wave of CAA/wrap around rain
moving in over south central SD and spreading northeastward through
east central and northeastern SD and western MN. Again north central
SD stays mainly north and west of this wrap around rain. As the low
continues to track through IA into MN through the early afternoon,
ongoing wrap around rain will continue over the James Valley and
eastward. Pops will diminish west to east from here with the the
last of the precip looks to exit the far eastern CWA by the late
evening.

Total QPF continues to vary a bit based on which model you look at.
ENS has even less totals then 24 hours ago with half inch to an inch
mainly east of the Mo River, highest along the SD/MN border. GEFS
still is more aggressive/westward with the QPF (as mentioned due to
a stronger low/forcing and northern track) with 1-1.5" inches east
of the James River. HREF/NBM fall within this and are actually
really close to each other with rainfall of an inch or more along
and east of a line from Ft Thompson SD to White Rock MN. Potential
of 1.5 to 1.7" is highest east of the Sisseton Hills into MN. Prob
of 2 inches or higher is about 10-15% along and east of I29.
Therefore, we have higher confidence on this area receiving the most
rainfall due to the track of the low with amounts decreasing further
west in the CWA. Lower confidence on where that "inch" line will lie
over the eastern two thirds over the CWA. 25-75th spread runs about
a quarter to a half inch giving a bit of lower confidence in exact
precip amounts.

Behind the low as CAA/dry air surges in from the north/northwest
along with a tightened pressure gradient and pressure rises. Due to
this, did a blend of 2 parts NBM/1 part NBM 90th to bump up the
winds a bit. Probability of gusts>45 mph is only 20-40% with
potential max wind gusts between 40-50 mph across the CWA. With
lower confidence on winds, held off on any headlines just yet as
pressure rises are really only on the order of +2 to +5mb/6 hr per
GFS and weaker CAA. As the low shifts further away from the region,
winds will diminishing Monday night from west to east.

Otherwise, upper level troughing still expected over the Northern
Plains with colder then climo air over the region from 850mb-Sfc.
Highs are only forecast in the 40s and 50s through Tuesday. Clusters
still indicate split flow setup with a ridge setting up over the
northwestern US, shifting eastward and becoming less amplified. This
will help temps rise back up in the 60s to low 70s for the end of
the week into the weekend. Tuesday/Wednesday could bring the
potential for light rain per mid level energy within this overall
troughing pattern.

&&

.AVIATION /18Z TAFS THROUGH 18Z MONDAY/...
Issued at 1224 PM CDT Sun Apr 26 2026

Terminals KABR,KATY,KPIR,KMBG

Cigs will drop to MVFR through this afternoon to IFR cigs at all
TAF sites this evening as a strong storm system will bring
widespread rain to the region this evening through Tuesday
morning. Light rain is moving in over south central SD affecting
KPIR soon. The rain will spread northeastward through the
evening and tonight, affect all TAF sites (lightest at KMBG).
Could see a bit of a break (or very light rain/drizzle) early
Monday morning before the second wave of rain moves in. A
thunderstorm or two is possible at KATY this evening through the
overnight but with low confidence did not add it to the TAFs.
Drops in vsbys are possible with heavier pockets of rain or any
tstorms. Winds will increase Monday out of the north/northwest,
behind the low, with gusts of 35 to 45 mph with higher gusts
possible.

&&

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

&&

$$

DISCUSSION...MMM
AVIATION...MMM