712
FXUS63 KFSD 160328
AFDFSD

Area Forecast Discussion
National Weather Service Sioux Falls SD
1028 PM CDT Tue Apr 15 2025

.KEY MESSAGES...

- Wind gusts up to 30 mph and relative humidity around 25
  percent will result in near critical fire danger this
  afternoon east of Interstate 29.

- Warm, dry, and breezy conditions on Wednesday will result in
  elevated fire concerns.

- Shower and thunderstorm chances return Thursday into Friday
  morning. The highest chances (60-80 percent) are east of
  Interstate 29. Some thunderstorms may be strong to severe,
  especially Thursday afternoon and evening, mainly along and
  southeast of a line from Yankton to Spirit Lake.

&&

.DISCUSSION...
Issued at 335 PM CDT Tue Apr 15 2025

Late this afternoon, the SPG remains strong enough ahead of an
eastward advancing high pressure system to keep northwest wind
gusts up to 30 mph for the next few hours across parts of
southwest MN and northwest IA. This, combined with relative
humidity around 25 percent will result in near critical fire
danger. Winds are expected to diminish region-wide late
afternoon into the evening.

For tonight, despite mostly clear skies, increasing southeast
wind on the backside of the departing surface high and warm air
advection will keep lows elevated in the upper 40s to lower
50s.

Short-wave ridging and low-mid level warm air advection on
Wednesday will allow temperatures to soar into the 70s region-
wide. Could even see some areas along the Missouri River flirt
with the 80 degree mark. 20-25 kts within a well mixed boundary
layer will allow for some southeast wind gusts up to 30 mph and
when combined with relative humidity dropping again into the 25
to 30 percent range, will result in elevated fire weather
concerns. Do not think winds will be quite strong enough or long
enough in duration to necessitate a Red Flag Warning.

Attention turns to Thursday with increasing chances for showers
and thunderstorms. A transition to southwest flow aloft will
allow multiple waves/disturbances to move across the region. A
surface trough moves into central SD by 12Z Thursday with a
northward-lifting northwest to southeast arching warm front. May
see some convective development in the vicinity of this front
early Thursday morning into the afternoon. With some instability
climbing above 500 J/kg and increasing shear aloft, may see some
isolated strong to severe storms with the primary threat being
large hail to the size of quarters.

The better chances for strong to severe thunderstorms will be
in the afternoon and evening hours Thursday mainly along and
southeast of a line from Yankton to Spirit Lake, although this
is highly conditional. Model soundings are good agreement,
showing an impressive thermal CAP for much of the day. There is
roughly 1500 J/kg of CAPE aloft and 30-40kts of 0-6 km shear.
However, outside of a narrow window ahead of an advancing cold
front, don`t expect storms to be surface-based, limiting hazards
to large hail and perhaps some isolated damaging wind gusts. The
Day 3 SPC Convective Outlook highlights these threats well.

Some lingering precipitation is possible Friday morning, but
otherwise expect dry conditions and much cooler temperatures in
the wake of a cold frontal passage. Afternoon highs in the 50s
will be the rule. Saturday will also be dry with moderating
temperatures.

For Sunday/Monday, 12Z GFS/ECMWF guidance are now digging a
more potent short-wave farther south and east, limiting
precipitation chances across the forecast area. For now, will
keep NBM 20-50 POPs for this period, but if trends continue, the
majority of precipitation will be farther east from central
IA/MN into the Great Lakes.

&&

.AVIATION /06Z TAFS THROUGH 06Z THURSDAY/...
Issued at 1027 PM CDT Tue Apr 15 2025

VFR conditions are expected for the TAF period. Light winds persist
late this evening but should see winds pick up out of the east
tonight with marginally breezy gusts up to about 20 knots. Some low
level wind shear (LLWS) is expected at KSUX late tonight into the
early morning hours tomorrow. Winds will turn to out of the
southeast by tomorrow morning and remain breezy throughout the day.
Gusts up to 15-25 knots is expected, strongest along and east of I-
29. The breezy winds will finish out the TAF period.

&&

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

&&

$$

DISCUSSION...Rogers
AVIATION...Meyers