942
FXUS63 KFSD 150334
AFDFSD

Area Forecast Discussion
National Weather Service Sioux Falls SD
1034 PM CDT Sat Sep 14 2024

.KEY MESSAGES...

- Wildfire smoke aloft is projected to linger over the region today,
  but trends pointing to improvement tonight into Sunday.

- Isolated to scattered showers/storms impact mainly central to northeast
  South Dakota again later today-tonight, with a low (20%)
  chance mainly west of a Huron to Wagner line this evening.
  Gusty winds are possible with storms, but severe weather is
  not expected.

- Temperatures remain above mid-September normals through much
  of next week, with nighttime lows showing greater departures
  above normal due to anomalously high low level moisture/dew
  points.

- Greater chances for rain (50-80+%) return mid-late week next
  week, though details in exact timing/rainfall amounts are
  uncertain.

&&

.DISCUSSION...
Issued at 226 PM CDT Sat Sep 14 2024

Upper level troughiness will be in place today, with the better
focus to the west of the area. With some marginal instability, CAPE
values around 1000 J/kg mostly west of the Missouri River, a few
thunderstorms may develop. Near and east of the James River there is
less instability and stronger capping. Given the deep south to
southwest flow any storms that do develop west of the area will
struggle a bit to push eastward given the main storm motion will be
in a northeast direction. So overall the main chances will be on the
lower side, 20 to 30 percent chance, and mostly west of the James
River. Some very weak, very elevated instability may allow for a few
showers into the late evening and overnight towards I-29, but with a
deep dry layer the impacts will be minimal. Warm overnight lows in
the low to mid 60s, generally 5-10 degrees above normal, are
expected with southerly surface flow continuing. A small chance for
a little fog late tonight as well but confidence low.

Sunday should be dry as the wave tonight lifts northeast of the
area. A small tail of instability could tail into the area and
produce very isolated showers or a thunderstorm but for now not
thinking that will be a problem as everything looks capped. The
exception could be near and east of the Buffalo Ridge into northwest
IA where model soundings indicate the weakest capping. Southerly
flow will be fairly strong with humidity a bit on the higher side,
dew points in the lower to mid 60s, with highs topping out in the
mid to upper 80s.

Sunday night into Monday continues the warm southerly flow and only
low chances for showers and thunderstorms. Lows in the 60s and highs
in the 80s. Central SD will again see the slightly better chances
for showers and storms, but still generally 20 percent or less.

Monday night into Tuesday will see troughing mainly west of the area
with the better chances for any showers and thunderstorms remain
mostly west of the James River. Continued very warm with lows in the
60s and highs in the 80s.

Tuesday night into Wednesday will be the next better chance for
showers and storms. A wave will eject north into Montana with the
tailing energy spreading into central SD. Still a few question marks
with the upper level wave so far west. Right now the GFS and EC
ensembles are showing about a 20 percent chance and 50 percent chance
for a half an inch of rain Tuesday night into Wednesday west of I-29.

Getting pretty far out, but looks like upper level ridging will move
across the  area Wednesday into Wednesday night, then the next piece
of energy will move into the area Thursday with additional support
for showers and storms Friday into Saturday, so for now looking like
a busier time frame for precipitation next week. Highs remain mostly
in the 80s through the week with lows in the upper 50s to 60s.

&&

.AVIATION /06Z TAFS THROUGH 06Z MONDAY/...
Issued at 1033 PM CDT Sat Sep 14 2024

VFR conditions are expected for the TAF period. Showers and some
thunderstorms continue to weaken along and west of the James River
this evening. Should see mostly quiet conditions overnight along
with light southeasterly winds. Think the winds will be strong
enough to preclude fog development tonight. However, if winds were
to go calm, then the potential for fog will increase. As of now,
confidence remains too low to include in a TAF at this time.
Otherwise winds will turn southerly tomorrow morning and persist
through the rest of the period. Gusts up to around 20 knots is
expected.

&&

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

&&

$$

DISCUSSION...08
AVIATION...Meyers