National Weather Service Weather Forecast Office

• Home
• Site Map
• News
• Organization
• Search for: NWS All NOAA 

000
FXUS63 KFSD 240322
AFDFSD

Area Forecast Discussion
National Weather Service Sioux Falls SD
1022 PM CDT Tue Apr 23 2024

.KEY MESSAGES...

- Areas to widespread frost is likely late tonight as low
  temperatures fall to the 30s.

- Multiple rounds of rain are expected late Thursday through
  the weekend.

- A few strong or severe storms are possible Thursday night and
  Friday across northeast Nebraska and Iowa.

&&

.DISCUSSION...
Issued at 305 PM CDT Tue Apr 23 2024

Gusty northwest winds are in place this afternoon as an upper
low tracks southeast over the Upper Mississippi Valley. Diurnal
CU have become more widespread as we reach peak heating, but
they remain shallow enough to keep any risk of showers or
sprinkles near zero. The clouds and winds will diminish this
evening after sunset. A center of high pressure will push in
behind the upper low tonight, reaching just north of Lake
Superior by early Wednesday morning. A ridge axis extending
southwest into the area will allow winds to drop off and
temperatures to fall into the low to mid 30s, resulting in
areas of frost to developing. The greatest coverage of frost
will be centered within a couple hours of sunrise, and
temperatures should largely remain above freezing, so held off
on frost/freeze headlines. Duration of frost will be longer
farther east.

Quiet weather will prevail into early Thursday, but the pattern
will undergo a significant shift later Thursday and into the
weekend. Moisture advection associated with an approaching
system near the coast of southern California and a building
ridge over the central U.S. will begin Wednesday. Moisture flux
will increase Thursday as deeper moisture is tapped into from
the Gulf and the system begins to emerge over the central
Plains. As that occurs, showers and thunderstorms will break out
over the Plains and will advance northeast to the northern
Plains and Upper Midwest late Thursday into Friday. The LLJ will
strengthen throughout Thursday night, and could reach 50 kts by
early Friday morning. This, combined with moderately steep lapse
rates above the inversion, and MUCAPE values potentially as
high as 1500 J/kg, could result in a few strong or severe
storms over northeast NE, northwest IA and far southeastern SD.
The main risk would be large hail. As Friday continues on,
periods of showers and embedded thunderstorms will likely
continue and it could be difficult for the atmosphere to
recharge for another round of potential severe thunderstorms.
Ultimately, this will depend on the track of the low center and
currently model consensus has it tracking over Sioux Falls
Friday evening. Therefore, any subsequent rounds of severe
weather would probably occur over northwest IA or even farther
south.

The lead wave will clear out by Saturday, but a second wave
behind it will be moving in as early as Saturday night. This
system will behave similarly to its predecessor, bringing more
rounds of showers and thunderstorms. The track may be a bit
farther southeast than the first one, which should keep much of
the severe threat away from the area. However, more widespread
rain will help with the lingering abnormal dryness of late.

A brief cool down will follow early next week, but signs
indicate a large mid level ridge developing over the
southeastern U.S. mid to late next week. This will keep the
pattern active across the Plains with temperatures returning
above normal.

&&

.AVIATION /06Z TAFS THROUGH 06Z THURSDAY/...
Issued at 1022 PM CDT Tue Apr 23 2024

VFR throughout the period. Light winds are starting to become
variable, which will continue for the overnight hours. Winds will
settle to be out of the south-southeasterly direction Wednesday
morning, becoming marginally breezy west of I-29 with gusts into the
teens and 20s during the afternoon hours. Areas west of I-29 may see
some LLWS overnight Thursday into Friday.

&&

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

&&

$$

DISCUSSION...Borghoff/WFO MPX
AVIATION...APT