Harrisburg, South Dakota 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

096
FXUS63 KFSD 230856
AFDFSD

Area Forecast Discussion
National Weather Service Sioux Falls SD
256 AM CST Tue Dec 23 2025

.KEY MESSAGES...

- Midweek temperatures have trended cooler, but still 10-20
  degrees above normal for much of this holiday week.

- Dry weather will prevail through Christmas Day. May have to
  watch for light wintry precipitation during the post-holiday
  travel period, however confidence in timing/location details
  is low.

- Elevated fire danger will be possible on breezier days in
  snow-free areas, mainly across south central South Dakota
  through the Missouri River Valley.

&&

.DISCUSSION...
Issued at 255 AM CST Tue Dec 23 2025

TODAY/TONIGHT: A cooler but still mild day in the wake of a
weak cool front moving through the area early this morning.
Mixing will be limited as a surface ridge brings relatively
light and variable winds. However, the lack of snow cover and
at least partial sunshine should still support highs in the 30s
and 40s. As the surface ridge axis moves east of the area this
evening, modest southerly flow and strong warm advection aloft
should result in steady/slowly rising temperatures overnight.

CHRISTMAS EVE-CHRISTMAS DAY: NAEFS/ECMWF ensembles continue to
indicate a strong mid-upper level ridge with 850-500MB temps
near the top of seasonal climatology. However, latest models
are showing some trends beneath this unseasonably warm 850mb
level that limit the potential of seeing strong warming at the
surface. Most notably, a surface low which a few days ago was
forecast to develop in the Red River Valley/northern Minnesota
by Christmas Day is now located over the High Plains of the
Dakotas. This shifts the warm sector from a large part of the
northern Plains to just southwest South Dakota and western
Nebraska, with our area seeing stronger influence from surface
high pressure across the Canadian Prairies. Some indications
that stratus could become trapped beneath the strengthening
inversion, which would further limit temperatures on Christmas
Day, especially east of the James River Valley. With the lack
of snow cover, still favor temperatures slightly warmer than
the NBM (which is near to below the ensemble`s 50th percentile),
but record-setting warmth is less likely.

This period still looks mostly dry, and as of now the stratus
layer looks too shallow to support much of a drizzle threat, but
this will be something to monitor in the coming model cycles.

FRIDAY-MONDAY: Overall, the chances for precipitation through
this post-holiday travel weekend remain low for our forecast
area. However, cannot confidently say the period will be 100%
dry as the upper ridge breaks down and the jet stream settles
southward into the northern CONUS. Moisture currently appears
sparse, but subtle waves could produce spotty light wintry
precipitation.

Temperatures look to remain on the mild side of normal for the
end of this week, but a strengthening mid-upper level trough
drags a strong cold front through the region late Saturday to
Saturday night, dropping highs for Sunday/Monday back into the
teens and 20s. The cool-down currently appears short-lived with
mild air building back into the region beyond this forecast
period.

&&

.AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/...
Issued at 955 PM CST Mon Dec 22 2025

VFR conditions will persist this TAF period. Looking at satellite
imagery, high level clouds continue to filter into the region
this evening. Expect the could cover to continue into the day on
Tuesday with veering surface winds. Otherwise, a strengthening
LLJ will lead to a few hours of LLWS mainly north of I-90. Lastly,
lighter winds overnight will eventually become more southeasterly
by the evening hours on Tuesday to end the TAF period.

&&

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

&&

$$

DISCUSSION...JH
AVIATION...05