Harrisburg, South Dakota 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

429
FXUS63 KFSD 302333
AFDFSD

Area Forecast Discussion
National Weather Service Sioux Falls SD
633 PM CDT Sun Mar 30 2025

.KEY MESSAGES...

- A quiet start to the work week gives way to another strong
  Spring storm by early Tuesday through Wednesday.

- Details remain uncertain, but this storm will bring a wintry
  mix to the region by early Tuesday, risk for widespread rain
  into Tuesday night, and a transition back to snow and wind by
  Wednesday.

- 48 hour precipitation probabilities exceed 80% for 0.50" of
  liquid, with nearly 50% probability of 1.0" of liquid in
  portions of the forecast area.

- Snow risks are HIGHLY dependent on temperatures within the
  lower 2,000 ft of the atmosphere, but general potential for
  accumulating snow remains high over portions of the Buffalo
  Ridge in southwest Minnesota and into central and northern
  South Dakota.

- Quiet weather anticipated for the end of the week and into
  next weekend.

&&

.DISCUSSION...
Issued at 236 PM CDT Sun Mar 30 2025

THIS AFTERNOON: Upper trough continues to move towards the Great
Lakes this afternoon, with wrap around TROWAL moving just east of
the CWA border.  Northwesterly wind gusts will continue to pull in
only slightly drier air into the evening.

TONIGHT: While low cloud cover may move out of the area, mid-lvl
clouds will filter back in through the night. This is in part to
a continued stream of mid-lvl vorticity moving across South Dakota
and Nebraska. Cannot completely discount some seeder-feeder process
in South Central portions of the area that would bring a risk of
spits of rain/snow early into the overnight hours. Otherwise, clouds
will keep temperatures up slightly, but lows by Monday morning will
fall into the lower to mid 20s.

MONDAY: Mid-lvl clouds will prevail through Monday as surface winds
turn quite light and variable.  High temperatures will remain below
normal, rising into the lower 40s in SW Minnesota to the upper 40s
near the Missouri River.

TUESDAY-WEDNESDAY:  Clouds continue to increase quickly Monday night
as an upper jet begins to move into the Plains. This jet in in
response to a deepening upper trough crossing the Rockies through
the middle of the week.  By early Tuesday morning, models remain in
strong agreement that moderate to strong warm advection will develop
an area of precipitation over northern Nebraska late in the evening
and then lifting northward into the Tri-State area by daybreak.  The
biggest questions with this initial push of precipitation will be
how much low-lvl cold air lingers, how quickly the surge of warmer
low-lvl temperatures arrives, and then how warm boundary layer
temperatures rise. A band of snow is likely to develop and lift
northeast, mixing with sleet on the nose of the warm layer and
then moving to rain on the backside of the precipitation area.
The greatest potential for a few inches of snow accumulation
will be along the Buffalo Ridge, with NBM suggestion a 60%
probability of 2"+ in those areas. By the afternoon, temperatures
rise further into the 40s, and I wouldn`t rule out some drizzle
developing as persistent low-lvl isentropic lift continues.

There remains a bit more uncertainty into Wednesday, especially
with the track of the upper low and developing surface low moving
into the Plains. Latest guidance continues to push the greatest
risk for any stronger convection south of the CWA, with a stronger
likelihood of considerable shower activity moving through the CWA
into the overnight. By Wednesday colder air will begin to filter
back into the region returning the risk for snow, along with some
stronger wind gusts. As with all early April storms, the lowest
2000 ft of the atmosphere will hold all the crucial details, with
a 1 degree swing enough to produce more or less snow. 48 hour
precipitation probabilities exceed 80% for 0.50" of liquid, with
nearly 50% probability of 1.0" of liquid in portions of the
forecast area. PoPs remain very high.

THURSDAY-SATURDAY:  In the wake of this system a high amplitude
pattern will develop over North America. Deep troughing over the
eastern half of the CONUS and a REX block over the western CONUS
will favor cooler than normal and mostly dry conditions in the
extended.

&&

.AVIATION /00Z TAFS THROUGH 00Z TUESDAY/...
Issued at 633 PM CDT Sun Mar 30 2025

MVFR-locally IFR conditions persist across much of the CWA to
start this period, with the exception of areas north of I-90 in
eastern South Dakota where the lowest stratus deck has cleared.
This improvement to VFR conditions will expand south through
this evening and continue through the end of this TAF period,
especially for areas along and east of the James River.

North winds gusting to around 20kt will diminish by 02Z with
winds becoming variable at or below 12kt after daybreak Monday.

&&

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

&&

$$

DISCUSSION...Dux
AVIATION...JH