487
FXUS63 KFSD 100854
AFDFSD

Area Forecast Discussion
National Weather Service Sioux Falls SD
354 AM CDT Mon Jun 10 2024

.KEY MESSAGES...

- An active pattern aloft will promote periodic rain chances
  for most of the week.

- While uncertainty continues with the potential severe weather
  risk, the focus continues to be on Wednesday and Thursday
  afternoon.

- Temperatures will continue to trend above normal towards the
  middle and latter parts of the week with highs expected to be
  in the 80s and potentially low 90s.

&&

.DISCUSSION...
Issued at 348 AM CDT Mon Jun 10 2024

The Short Term (Today & Tonight):

A warm and marginally breezy day will be on tap for the day. Taking
a look across the area, mostly clear conditions continue as an upper
level ridge moves into our area from the northwest. After a
relatively mild start to the day, ample mixing along with increasing
warm air advection (WAA) on the backside of the ridge will lead to
temperatures peak in the upper 70s to mid 80s with the warmest
conditions expected west of I-29 and along the Missouri River
Valley. Southeasterly surface winds will become a touch breezy
this afternoon especially west of the James River as the SPG
tightens leading to wind gusts between 20-30 mph.

By tonight, heights begin to fall as an mid to upper level
trough pushes eastwards across the Dakotas late this evening
with its associated cold front leading to development of
scattered showers with a few isolated thunderstorms. Current
model trends continue to have any developing activity pushing
into our western-most counties after 00z. While the likelihood
of severe weather continues to be low, there is some potential
for stronger wind gusts if a strong thunderstorm can develop a
strong enough cold pool in our western most counties. However,
with a statically stable environment overhead due to the
departing surface ridge; any lingering activity should gradually
weaken as it approaches the I-29 corridor. Nonetheless,
accumulations should be fairly light with up to tenth or two
possible as most of the activity exits the region by Tuesday
morning.

The Long Term (Tuesday-Sunday):

Heading into the extend period, the warming trend continues into the
midweek as quasi-zonal flow returns aloft behind the cold front. As
heights begin to rise with the arrival of a mid-level ridge by
Tuesday afternoon strengthening WAA along with deep mixing will lead
to much warmer temperatures through Wednesday as temperatures reach
up to 97th percentile of climatology according to the ESAT Tables.
With this in mind, highs will sharply increase from the low to upper
80s on Tuesday to the upper 80s to mid 90s by Wednesday. On top of
that, most ensemble guidance continue to hint at increasing low
level moisture on Wednesday as the heat continues to build. With
over 30 percent of members showing dew points in the upper 60s to
low 70s, conditions will likely feel hot and muggy for a good bit of
the afternoon. Make sure to wear lighter clothing if possible!

Shifting gears to our precipitation chance, another mid-level wave
will slide through the region along with its associated cold front
by Wednesday afternoon bringing some increased precipitation chances
(40%-50%). Looking at the environment, the heat and humidity will
help promote moderate instability values (1500-2500 J/kg) of MLCAPE
and 40-50 kts of deep layer shear which are consistent among
deterministic guidance. However, now the question becomes if the
wave will arrive early enough to take advantage of the unstable
environment. With slight timing differences among guidance with
the waves arrival, its still a bit hard to say at this moment
which has led to a bit of uncertainty on the severe weather
risk. Nonetheless, we`ll continue to monitor the trends over the
next few days to get a clearer picture.

The uncertainty will continue into Thursday as another cold front
swings through our area throughout the day promoting more
precipitation chances (10%-20%) by the afternoon. While the
environment doesn`t look quite as good as the previous day,
strong deep layer shear (40-50 kts) and isentropic lift ahead of
the near-surface boundary could help promote a few scattered
showers and thundershowers. However, the risk for severe weather
should be low given the better instability vector is to our
south. Looking into the weekend, heights will begin to rise as a
strengthening ridge moves into the region by Friday. While
there is some potential for increased precipitation chances by
Saturday, timing and intensity differences among long-range
guidance has led to uncertainty. Lastly, the above normal
temperatures will continue into the weekend with highs expected
to vary between the upper 70s to upper 80s.

&&

.AVIATION /06Z TAFS THROUGH 06Z TUESDAY/...
Issued at 1042 PM CDT Sun Jun 9 2024

VFR conditions are expected to prevail this TAF cycle. Should see
light and variable winds continue overnight and most of the morning
hours, with direction turning more southeasterly during the
afternoon. Gust between 15 to 25 MPH will be possible along and west
of the James River. Otherwise, could see some showers and storms
impact those along and west of I-29 after sunset, though confidence
remains too low to include anything more than a PROB30 at this
time.

&&

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

&&

$$

DISCUSSION...Gumbs
AVIATION...SST