Spencer, Iowa 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

795
FXUS63 KFSD 200442
AFDFSD

Area Forecast Discussion
National Weather Service Sioux Falls SD
1042 PM CST Fri Dec 19 2025

.KEY MESSAGES...

- Low probability (less than 30%) risk for very light wintry
  precipitation after midnight. Any accumulation is expected to
  be minimal.

- Confidence remains high in an extended period of warmer and
  quiet weather through the holiday travel week.

- Temperatures themselves may approach or surpass record values
  as we move towards the end of next week, including Christmas
  day.

&&

.DISCUSSION...
Issued at 149 PM CST Fri Dec 19 2025

THIS AFTERNOON: An initial wave of warm advection has moved east of
the area, but spread a large corridor of mid-lvl clouds through the
CWA. Temperatures under this cloud cover have been stuck in the
20s. Gusty southerly winds of 25 to 30 mph will slowly weaken
by evening.

TONIGHT: Zonal mid-lvl flow pushes another sheared out area of
vorticity through the Dakotas overnight, along with a surface
frontal boundary. CAM guidance shows a trailing corridor of light
precipitation trying to develop behind the passage of this frontal
boundary.  While there will likely be some dry air issues as the
forcing moves through overnight, soundings do suggest a very narrow
possibility of flurries to light freezing rain sliding southeast
through daybreak.  Again, QPF is anticipated to remain very light,
so no impacts are anticipated.

SATURDAY-SUNDAY: The initial front moves southeast early in the day,
with quasi-warm downslope flow moving eastward through the day. This
will push high temperatures back near to above normal, with the
coolest highs over SW Minnesota and northern Iowa.  A secondary cold
front arriving in the evening drops temperatures down into the
single digits to teens by Sunday.  However with mid-lvl heights
rising on Sunday, we`ll again see warm advection develop early
Sunday with southerly surface winds also developing. Should mid-lvl
clouds remain transient enough to prevent any impact to surface
temps, we should see highs climbing above freezing in all areas of
the CWA.

MONDAY-FRIDAY:  Confidence remains high that we`ll have a quiet and
warmer than normal holiday travel week ahead of Christmas.  Rising
heights on Sunday will continue to rise through the week, with 500
mb heights by mid-week pushing the 99th percentile or outer edge of
all climatology for late December.  The broad ridging will also
surge warm low-lvl temperatures across much of the Lower 48,
resulting in 850mb temperatures sitting outside of the 30 year CFSR
reanalysis centered around late December. The result will be
highs rising well into the 40s through Wednesday. The broad mid-
lvl ridge axis shifts ever so slightly eastward by Christmas
day, with all signs pointing to one of the warmest Christmas
days on record for much of the region. While much can change
over the next 6-7 days, the current deterministic NBM and mean
high and low temperature forecast resides closer to the 75th
percentile. This suggests that even further increases in highs
may be possible as Christmas approaches. The GFS/EC/CMC
ensembles all point to a greater than 50% probability of 50
degree or warmer temperatures at 00Z/26, suggesting highs will
be favored to be even warmer.

For those dreaming of a white Christmas, the synoptic pattern won`t
support those wishes as of this moment.  While it may take some time
to melt away the glacier of ice that still remains in some areas,
the vast majority of the area will remain under 1" of snow unless a
major shift happens in guidance between now and Christmas.

&&

.AVIATION /06Z TAFS THROUGH 06Z SUNDAY/...
Issued at 1039 PM CST Fri Dec 19 2025

VFR conditions through the period. Southerly winds late this
evening continue to shift to the northwest, with gusts through
the period around 20 to 25 knots. May see some marginal LLWS at
times if gusts drop off early this overnight while a strong LLJ
moves across the area. Given the anticipated gusts, did not
include mention at any sites.

Still anticipating isolated snow or rain showers overnight, but
believe coverage and impacts will be limited to due very dry sub
cloud layer. Therefore, have continued the mention for KHON and
KFSD in a PROB30 group. Greatest chances for any precip would be
north of I-90 and into northwestern IA.

&&

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

&&

$$

DISCUSSION...Dux
AVIATION...SG