222
FXUS63 KABR 262006
AFDABR

Area Forecast Discussion
National Weather Service Aberdeen SD
306 PM CDT Sat Apr 26 2025

.KEY MESSAGES...

- Showers, and few thunderstorms, are possible across parts of
  northeastern South Dakota and west central Minnesota tonight.

- Additional showers and thunderstorms expected Sunday night and
  Monday. There is a Slight Risk (level 2 out of 5) of severe
  storms for central South Dakota and a Marginal Risk (level
  1 out of 5) for eastern South Dakota and west central Minnesota
  Sunday night.

- There is a Slight Risk (level 2 out of 5) of severe storms for
  northeastern South Dakota and west central Minnesota on Monday.

&&

.SHORT TERM /THIS EVENING THROUGH SUNDAY NIGHT/...
Issued at 305 PM CDT Sat Apr 26 2025

Upper level ridging will remain over the region tonight, with just
some weak shortwave energy riding over it and across the CWA. As the
ridge slides east on Sunday, will see a more southwesterly flow
develop ahead of a western US trough, with more abundant shortwave
energy reaching the CWA Sunday night as the trough reaches the
Rockies.

At the surface, the region will be situated between high pressure to
the east and low pressure to the west tonight. A somewhat tight
pressure gradient will keep southerly winds in the 15 to 30 mph
range overnight, with some higher gusts possible, especially across
parts of the Sisseton Hills. A 30 to 40 knot low level jet is
currently developing across portions of central South Dakota, and
will develop further to the east and strengthen a bit tonight. This
will likely aid in keeping some rain shower development, along with
the potential for a few thunderstorms, across the eastern half of
the CWA tonight. Sunday looks mostly quiet during the day, but will
see southerly winds usher warm and moist air into the region ahead
of the low, which will reach western South Dakota by 00Z. The main
low center looks to reach central South Dakota during the night. A
very strong low level jet will develop across the plains states
overnight, with the northern edge of it (30 to 40 knots) over
eastern South Dakota. Will see 1000-2000 J/km of MUCAPE develop in
the same area, along with 50 to 55 knots of bulk shear. Will likely
see an area of shower and storms develop over southwestern South
Dakota during the evening, with this area tracking northeastward and
additional development occurring across parts of northeastern South
Dakota into west central Minnesota overnight. The Storm Prediction
Center has issued a Slight Risk (level 2 of 5) for areas along and
west of the Missouri River, with a Marginal Risk (level 1 of 5)
across eastern South Dakota and west central Minnesota. At this
time, it appears that large hail and strong wind gusts will be the
main threats with any thunderstorms that develop Sunday night.

Low temperatures tonight will be in the mid to upper 40s. High
temperatures on Sunday will be in the mid 60s to the mid 70s. Lows
Sunday night will be in the lower to mid 50s.

&&

.LONG TERM /MONDAY THROUGH SATURDAY/...
Issued at 305 PM CDT Sat Apr 26 2025

Monday, the low pressure system continues to move over and through
SD. A dry line looks to move through eastern SD during the early
morning with a dry slot moving in behind it for a bit during the
day. During the afternoon into the evening, a cold front will move
through central and eastern SD. This looks to be when there is the
highest potential for severe weathers over eastern SD, with CAPE
values increasing during the day and the cap being decreased. While
there had be a dry line earlier reducing moisture in central and
eastern SD, the models are suggesting a TROWEL/moisture wrapping
around the low and back into eastern SD/western MN. The models do
vary how far to the north the CAPE values of 500+ J/kg are, as well
as how large of a cap over eastern SD and the speed of the low as it
moves over central and eastern SD. Depending on the cap and speed of
the low, there may be a lower risk for severe storms developing in
eastern SD Monday. The higher chances for severe development look to
at least be east of the James River Valley and mainly over western
MN Monday afternoon.

Behind the cold front, mid-level cold air starts to advect into
central and eastern SD Monday. The winds behind this front will
start to increase over central and eastern SD, with widespread non-
convective gust over 30kts. Additionally, areas west of the Missouri
River could potentially have gusts over 35kts Monday afternoon.
These stronger winds will move through central and eastern SD, and
by Tuesday morning, the winds will start to calm down as a surface
high pressure moves over SD. Temperatures will also start to cool
behind the cold front, with Tuesday and Wednesdays temperatures
looking to be around normal for this time of the year. Temperatures
early Tuesday morning look to drop around if not slightly below
freezing.

The upper-levels create a cut-off low over the Four Corners region
Tuesday that is then pushed to the east as another upper-level
trough starts to move towards and over SD Wednesday and Thursday.
This troughs passage looks to cause another cold front to move
through the state, creating another chance for showers Wednesday
into Thursday. There is still disagreement in the models as to the
location and timing of this precipitation, which causes lower
chances (20-40%) for rain.

&&

.AVIATION /18Z TAFS THROUGH 18Z SUNDAY/...
Issued at 1223 PM CDT Sat Apr 26 2025

Terminals KABR,KATY,KPIR,KMBG

VFR conditions will prevail across the area through the afternoon
hours, with scattered rain showers possible. MVFR cigs will
overspread the area from west to east tonight, with increased
chances for rain showers over northeastern South Dakota and west
central Minnesota overnight. Brief periods of MVFR vsbys are
possible with the rain.


&&

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

$$

SHORT TERM...Parkin
LONG TERM...12
AVIATION...Parkin