892
FXUS63 KFSD 270805
AFDFSD

Area Forecast Discussion
National Weather Service Sioux Falls SD
305 AM CDT Mon May 27 2024

.KEY MESSAGES...

- Scattered showers and thunderstorms near and east of a line
  from Huron to Sioux Falls to Storm Lake this afternoon and
  evening. An isolated stronger storm east of MN/IA State
  Highway 60 could produce wind gusts to 60 mph and hail to
  quarter size, but overall severe risk remains very low.

- Isolated showers and storms are possible again Tuesday for the
  same locations, but most stay dry. Otherwise, more widespread
  rain and storm chances return Wednesday night into the
  weekend.

- Temperatures largely near average for this time of year with
  periodic breezy conditions. Strongest winds expected today and
  Thursday.

&&

.DISCUSSION...
Issued at 304 AM CDT Mon May 27 2024

TODAY: First wave of the day continues to move east across the area
early this morning, with showers and brief heavy rainfall. Amounts
this morning have generally been around or less than a tenth of an
inch. This continues to move east through mid morning, although some
isolated showers may linger in southwestern MN into mid morning.
Showers are occasionally mixing down some stronger wind gusts to
around 30 mph. Temperatures through this morning remain in the 50s.

Next wave poised to impact the area is currently evident on water
vapor across southwestern ND and northwestern SD. This tracks
southeast through the day. Surface low pressure swings across
southern MN through the afternoon hours, tightening the surface
pressure gradient (SPG). We`ll see breezy conditions today not only
from the strengthening SPG, but also as we mix into stronger winds
aloft. Sustained northwesterly winds will reach as high as 25 mph,
with gusts around 35 mph (although a few gusts to 40 mph are
possible if mixing is a bit deeper into the stronger and colder air
aloft). Scattered showers and storms are possible with this wave,
mainly along and east of a Huron to Sioux Falls to Storm Lake line.
Deterministic models and soundings have increased the amount of
expected instability, with anywhere from 500 to 1500 J/kg of CAPE.
Severe risk remains very low given overall lack of shear (less than
30 knots) and instability, but can`t rule out a stronger storm or
two which may produce wind gusts to 60 mph or quarter sized hail.
Greatest concern with any storm, especially a stronger storm, would
be the potential for strong wind gusts as high as 60 mph given the
stronger and colder air aloft. Freezing levels around or less than
6kft could support hail to the very isolated instances of quarter
sized hail. Rainfall amounts less than a tenth of an inch for most,
although 0.25" is possible with thunderstorms. Highs today in the
upper 60s to mid 70s.

TONIGHT THROUGH WEDNESDAY: Shower and storm chances taper off
through the evening hours, as do the stronger winds. Lows tonight
fall into the mid/upper 40s. By Tuesday morning, another mid level
wave drops through MN, bringing isolated showers and storms to the
same areas Tuesday morning into the afternoon. Coverage should be
more isolated given the wave being a bit further off to the
northeast and weaker than today`s wave. Rainfall amounts less than a
tenth of an inch expected. With less instability to work with,
severe weather is not expected. Highs will be a couple degrees
cooler on Tuesday with the next push of CAA and northwesterly flow.
Quick moving ridge and surface high slide overhead into Wednesday,
with dry and warmer conditions prevailing. Winds increase west of
the James River late in the day as the next system ejects out of the
Rockies.

WEDNESDAY NIGHT ONWARD: Aforementioned system ejects out of the
Rockies Wednesday night into Thursday. This will continue to move
northeast through the latter part of the week, keeping shower and
storm chances in place. Additional short waves are progged to move
through late week into the weekend, although past mid day Friday,
solutions vary too widely to stray from the NBM for
timing/location/strength of any system. Ensembles continue to show
low (< 40%), but non-zero chances for severe weather late week into
the weekend; however, very low confidence given the model
uncertainty. Ensemble guidance shows a moderate to high chance (>
60%) of rainfall totals along/west of I-29 exceeding 0.25" Thursday
into Friday. Regardless of storm chances, periodic breezy conditions
with temperatures near normal.

&&

.AVIATION /06Z TAFS THROUGH 06Z TUESDAY/...
Issued at 1054 PM CDT Sun May 26 2024

Scattered showers and perhaps a few thunderstorms in southeast
SD will slide east into southwest MN through daybreak Monday.
Showers are fairly high-based (ceilings at or above 6-8kft AGL),
so brief gusty winds are possible. The threat of thunder is low,
so will not include in TAFs at this time.

Additional showers/scattered storms may redevelop Monday
afternoon, mainly northeast of our TAF sites so will just show
an increase in clouds through the afternoon. Greater impact on
Monday will be increasing northwest winds, which will gust
25-30kt at times.

&&

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

&&

$$

DISCUSSION...SG
AVIATION...JH