590
FXUS63 KFSD 090838
AFDFSD

Area Forecast Discussion
National Weather Service Sioux Falls SD
338 AM CDT Sun Jun 9 2024

.KEY MESSAGES...

- Pleasant conditions prevail today and Monday with seasonable
  temperatures and breezy afternoons for portions of the area.

- Periodic chances for showers and storms return Monday evening
  and continue through much of the week.

- Uncertain severe weather risks focused mainly on Wednesday
  afternoon and evening.

- Temperatures rise by the middle of the week above normal. High
  probabilities (>80%) of highs above 80 degrees, with low
  probabilities (up to 40%) of highs at or above 90 degrees by
  Wednesday.

&&

.DISCUSSION...
Issued at 335 AM CDT Sun Jun 9 2024

A quiet day is in store across the area as surface high pressure
over west central Canada builds southward into the Northern Plains.
In spite of weak cold air advection into the area as a mid/upper
level trough swings southward through the Mississippi valley, deeper
mixing will allow for warming temperatures for today. Look for highs
in the mid 70s to lower 80s. The stronger winds aloft will reside
through MN and IA where cold air advection is most notable, and with
the deep mixing it will be a breezy day east of Interstate 29 - with
sustained winds of 20-25 mph/gusts of 25 to 35 mph in the afternoon.
Winds quickly die off this evening, and with continuing cold air
advection lows will fall to below normal levels for this time of
year - in the upper 40s to lower 50s.

Monday will start off dry with the surface ridge axis over our area
moving into the Mississippi Valley during the day. At the same time,
a surface trough will deepen over the western portions of SD and NE.
This will produce breezy conditions west of Interstate 29 during the
afternoon - this as the surface pressure gradient steepens and a low
level jet develops through central SD. With surface winds
transitioning to southeasterly during the day behind the exiting
high, temperatures will be a little warmer - mostly upper 70s to
lower 80s.

Shower and thunderstorm chances then increase for Monday night into
early Tuesday as the aforementioned surface trough/frontal boundary
to our west pushes eastward through the area. Models are in pretty
decent agreement on timing, with the front pushing into our western
CWA very early Tuesday morning, then exiting to the east around by
21Z on Tuesday. Severe chances look low with the system, with models
indicating the better instability/shear remaining to our west on
Monday evening, then the precipitation exiting our area on Tuesday
before instability recovers in the afternoon. Weak cold air
advection behind the system will not have much of an impact on
temperatures on Tuesday as highs warm well into the 80s.

With the departure of Tuesday`s trough, the upper level pattern
takes on a quasi-zonal flow for midweek, before an upper level ridge
builds eastward into the region for the end of the week into the
weekend. It looks to remain rather unsettled through the period with
periodic shower and thunderstorm chances - perhaps focused more so
on Wednesday afternoon/evening and Friday night. Latest model
convective parameters would suggest at least some potential for
severe weather during those periods, though with model variability
confidence remains on the low end. Guidance would suggest that
temperatures will be above normal for mid to late week.

&&

.AVIATION /00Z TAFS THROUGH 00Z MONDAY/...
Issued at 958 PM CDT Sat Jun 8 2024

VFR conditions and light winds are expected to continue into
Sunday morning. Narrow band of mid-lvl moisture will gradually
dissipate after midnight, with cirrus remaining spread through
areas south of Interstate 90 into mid-morning.

Given the fall of low temperatures into the upper 40s to lower
50s, some shallow valley and river fog may be possible, but is
not anticipated to impact many of the TAF locations.

VFR conditions continue through Sunday, with an increased risk
for diurnal CU in the afternoon.

&&

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

&&

$$

DISCUSSION...JM
AVIATION...Dux