224
FXUS63 KABR 271732 AAC
AFDABR

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
1232 PM CDT Mon Apr 27 2026

.KEY MESSAGES...

- Rain continues this morning, coming to and end from west to
  east this afternoon and evening. An additional half an inch
  of rain is expected along and east of I-29. West of the
  highway, between a tenth and a quarter of an inch of rain is
  still to come.

- Northerly winds increase Monday afternoon, with gusts of 35 to
  45 miles per hour possible. The strongest gusts are currently
  expected over the James River Valley. Winds will diminish
  Monday night as low pressure continues off to the east.

- 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.

&&

.UPDATE...
Issued at 1223 PM CDT Mon Apr 27 2026

Updated aviation discussion below.

UPDATE Issued at 939 AM CDT Mon Apr 27 2026

Made some minor changes to the forecast for today, mainly to
increase pops based on radar trends.

UPDATE Issued at 639 AM CDT Mon Apr 27 2026

See below for an aviation forecast discussion for the 12Z TAFs.

&&

.DISCUSSION...
Issued at 229 AM CDT Mon Apr 27 2026

Rain is ongoing this morning due to a Colorado Low ejecting into the
northern plains. As of 06Z, the Codington/Hamlin/Clark County area
has seen the most rain, roughly 1"-1.25" over the past 24 hours
according to MRMS estimates (which matches up well with observations
so far this morning). Expecting a brief lull in the rain early this
morning, although the persistence of low clouds may continue to
support some drizzle. Rain will begin once again between sunrise and
noon this morning (depending on location). Rain is expected to end
over central and north central South Dakota this afternoon,
lingering over northeastern South Dakota and western Minnesota
through the evening. The latter area has the highest remaining
rainfall totals expected, around half an inch (with perhaps locally
higher amounts up to three quarters of an inch) through tonight.
Values decrease moving west, around a quarter of an inch still
expected over the James River Valley and central South Dakota, down
to around a tenth of an inch still to come over north central South
Dakota.

As the low pressure center moves off to the east, a northerly low-
level jet will move into northeastern South Dakota this afternoon.
Up to roughly 40 knots will be possible at 850mb, which will mix to
the surface under the well-mixed boundary layer this afternoon.
Latest guidance has shown a downward trend in the strength of the
winds aloft, and therefore the strength of the winds at the surface.
Latest probabilities from the NBM give a 10-30% chance to see gusts
at Wind Advisory levels (45 mph), the highest chances located over
the James River Valley. McPherson County in particular boasts the
best chances, and if anywhere needs a headline, that would probably
be the place. However, the NBM is by far the most enthusiastic about
gusts, and other short term ensemble guidance (namely HREF and REFS)
show less than a 10% chance through the afternoon. The cold air
advection behind this system also does not appear to be overly
strong, which limits some of the concern that model guidance is
underdoing the gusts. Therefore, no headline will be issued for
strong wind gusts this afternoon at this time.

An upper-level trough will sit over the northern plains through mid-
week, allowing colder air into the Aberdeen CWA. 850mb temperatures
at or near freezing sit between the 10th and 25th percentiles for
this time of year, which translates to highs in the 50s through
Thursday, roughly 5 to 15 degrees below late-April normals. There
will be some chances for rain to develop Wednesday and Thursday
afternoons due to jet streaks moving overhead on the back side of
the trough. There is still some uncertainty as to the development of
these showers, and a drier near-surface layer may limit the ability
of developing rain to reach the surface. With both of those
considerations in mind, there is low confidence in any significant
accumulation on either Wednesday or Thursday afternoon at this time.

Pattern will transition to an upper-level ridge moving into the area
for the weekend. This will bring about a return to near-normal to
slightly above normal temperatures through the weekend. This pattern
will not be favorable for precipitation development, with little
chance through the weekend.

&&

.AVIATION /18Z TAFS THROUGH 18Z TUESDAY/...
Issued at 1223 PM CDT Mon Apr 27 2026

Terminals KABR,KATY,KPIR,KMBG

A storm system is producing IFR cigs for all terminals. Drier
air should move into the area later this evening and through the
overnight with VFR flying conditions expected. Northerly winds
with gusts exceeding 25-30 knots will slowly subside later this
evening as well.

&&

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

&&

$$

UPDATE...SD
DISCUSSION...BC
AVIATION...SD