446
FXUS63 KFSD 261737
AFDFSD

Area Forecast Discussion
National Weather Service Sioux Falls SD
1237 PM CDT Sun May 26 2024

.KEY MESSAGES...

- Scattered to isolated showers and thunderstorms are expected
  late this afternoon and evening near and west of the James
  River. Main threats are small hail and wind gusts to 50 mph.

- Scattered showers and thunderstorms possible near and east of
  an Ivanhoe to Cherokee line Monday late morning through
  afternoon. Small hail and wind gusts to 50 mph will be the
  main threats.

- Next chance for thunderstorms will come Wednesday night with
  some threat for severe weather in central SD on Thursday
  afternoon and night.

&&

.DISCUSSION...
Issued at 313 AM CDT Sun May 26 2024

The weak support for showers and thunderstorms will exit the area
early this morning with just a lingering chance across parts of
northwest IA. Some weak LLJ forcing into northwest IA and residual
weak instability are the main drivers. A few sprinkles will be
possible over mainly southwest MN within a region of mid level
moisture and weak forcing/instability through about sunrise.

Overall most of today will be dry with only very spotty chances for
showers and thunderstorms. Model soundings indicate some weakness in
the cap this afternoon with daytime heating, but instability is weak
so right now not expecting anything other than isolated lightning
and brief heavy downpours. A push of lift and weak elevated moisture
and instability move into central and northern SD this evening and
overnight but once again severe weather is unlikely and
precipitation amounts will be on the light side. Some minor
potential for small hail and wind gusts to 50 mph west of the James
River late this afternoon and evening. This wave is expected to move
through the area on Monday with scattered diurnally driven showers
and thunderstorms expected Monday afternoon and evening. While the
overall environment is not very supportive of severe weather a
fairly low freezing level (about 7000 ft AGL) and unidirectional
northwest flow with decent speed shear may support hail to dime size
and wind gust of 50 to 60 mph. The better chance will be east of a
line from roughly Ivanhoe to Cherokee.

Otherwise temperatures both today and Memorial Day will be near
normal with windy conditions expected on Memorial Day.

Tuesday should see northwest flow aloft continue, but the diurnally
driven instability looks much weaker, so even afternoon showers and
isolated thunderstorms look unlikely. Upper level ridging builds in
Tuesday afternoon into Wednesday which supports additional drier
conditions. Temperatures will be seasonally mild with highs in the
70s and lows from the mid 40s to lower 50s.

Wednesday night into Saturday will see a series of waves move
through the flow over the Northern Plains, bringing chance for
showers and storms. Right now the better instability appears to be
just west of the area on Thursday so Thursday night might be the
better chance for some severe weather. While instability is not as
high there is some moderate agreement that a wave will move onto the
Northern Plains Saturday. Seasonal temperatures are expected with
highs mainly in the 70s and lows in the 50s. Maybe a few 80s in
central SD on Thursday.

&&

.AVIATION /18Z TAFS THROUGH 18Z MONDAY/...
Issued at 1232 PM CDT Sun May 26 2024

VFR conditions will prevail much of the period. Low VFR cumulus
are expected this afternoon with a weak northeast wind
occasionally gusting in the teens. Expect isolated to scattered
showers and storms to spread in from the west this evening,
impacting Huron after 00z. Higher chance of rain the further
north you go. Light north winds turn more northwest and west by
Monday morning. Low level wind shear is possible early Monday
morning, but confidence was too low to include in TAF at this
time.

&&

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

&&

$$

DISCUSSION...08
AVIATION...BP