854
FXUS63 KFSD 260405
AFDFSD

Area Forecast Discussion
National Weather Service Sioux Falls SD
1105 PM CDT Sat May 25 2024

.KEY MESSAGES...

- Scattered showers and storms slides in near the Missouri River
  Valley this evening & the U.S. Highway 20 corridor overnight.
  A stronger storm is possible, though better chances look to
  remain south of the Highway 20 corridor.

- Periods of off and on scattered showers and storms continue
  through Sunday and Monday. Severe weather is unlikely with
  this activity.

- Dry, seasonal conditions develop Monday night through
  Wednesday.

&&

.DISCUSSION...
Issued at 244 PM CDT Sat May 25 2024

TONIGHT: At 2 PM, radar shows mid to high based scattered showers
lifting north of the Hwy 14 corridor with the warm sector. Further
south, clouds are clearing nicely which should still allow areas in
far southeast SD, northeast NE, and northwest IA to warm into the
upper 70s and near 80 degrees. Mixing into a 30-40 kt low level jet
will still bring occasional gusts in the 30s.

This evening, expect another area of scattered showers and storms to
develop near the inverted sfc trough in south central SD at the nose
of an axis of 1000 J/kg skinny MLCAPE as the upper level wave
upstream ejects into the High Plains. This activity tracks east
through the evening with greater coverage of rain the further south
you go. Can`t entirely rule out a strong to marginally severe
thunderstorm or two overnight with the main threat 9 PM to 4 AM.
This is most likely in south central SD early this evening,
spreading east to the Hwy 20 corridor overnight, but decreasing deep
layer shear and instability will make it difficult to maintain a
strong updraft as the night progresses. Main threat is more likely
to be wind gusts up to 60 mph with collapsing storms due to dry
subcloud layer air, with a secondary threat of hail up to quarter
size.

Winds turn more northeast and north behind the sfc trough with
temperatures falling to a mild 50s overnight. Cloudy skies linger
overnight with model profiles favoring widespread low level stratus
by early Sunday morning.

SUNDAY: Showers and isolated thunderstorms will continue in
northwest IA, northeast NE, and far southeast SD through Sunday
morning as the mid level wave tracks through near the I-90 corridor.
Stratus should lift to a cumulus field in the afternoon, leaving
areas north of I-90 mostly dry for the day but some lingering
showers possible near and south of I-90. Expect a breezy north
northeast winds with temperatures rising into the 70s.

Another round of showers and storms will slide into central and
eastern SD Sunday evening and eventually southwest MN overnight.
With very weak winds aloft and <1000 J/kg MLCAPE, severe weather is
not expected with weaker airmass thunderstorms.

MONDAY: Low to moderate (<50%) chance of showers and weaker storms
comes again Monday through early Monday evening near and east of I-
29 as an upper wave slides to our north. Expect another day with a
breezy northwest gradient wind as well.

MONDAY NIGHT AND BEYOND: Little to no noteworthy weather impacts
with seasonal temperatures expected Monday night through Wednesday
as dry high pressure builds through. A strong upper level trough
tracking east through Canada drags a front and narrow warm sector
into the Plains late week, bringing the next rounds of showers and
storms.

&&

.AVIATION /06Z TAFS THROUGH 06Z MONDAY/...
Issued at 1057 PM CDT Sat May 25 2024

Showers and embedded thunderstorms west of U.S. Highway 81 at
the start of this period are expected to diminish in coverage
through 10Z as thunderstorms over Nebraska expand eastward
toward U.S. Highway 20 corridor and northwest Iowa.

Convective activity exits east of the area by daybreak Sunday,
replaced by areas of MVFR-locally IFR ceilings/visibility along
with a chance of light showers lingering over portions of
northwest Iowa into the morning hours. Improvement to more
widespread VFR conditions expected again after 18Z, however
additional showers/storms may move into the James River Valley
late in this period.

&&

.FSD WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
IA...None.
NE...None.

&&

$$

DISCUSSION...BP
AVIATION...JH