Spencer, Iowa 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

765
FXUS63 KFSD 232333
AFDFSD

Area Forecast Discussion
National Weather Service Sioux Falls SD
533 PM CST Sat Nov 23 2024

.KEY MESSAGES...

- Mild temperatures and mostly dry conditions will dominate this weekend.
  A slight uptick in potential for snow north of I-90 tomorrow
  evening, but still a half an inch or less accumulation
  expected.

- Below to well below normal temperatures move in Monday and
  persist through the Thanksgiving holiday week. Aside from a
  brief reprieve in southern areas Tuesday-Wednesday, confidence
  is high (>80%) that temperatures will remain below freezing,
  with moderate (40-60%) chances that highs will not reach 20F
  by the end of the week.

- Light precipitation chances remain low, with chances for light
  snow/flurries peaking at 10-20% Wednesday night. Those with
  more distant travel plans will want to monitor forecast
  trends, though, with higher precipitation chances south of
  I-80 and in northern Minnesota during the holiday travel
  period.

&&

.DISCUSSION...
Issued at 237 PM CST Sat Nov 23 2024

An upper level jet streak will spread from west to east tonight into
Sunday with low pressure developing to the north. This will spread a
broad area of mid level warm advection across the area tonight, but
for now this layer looks very dry so precipitation should not
develop. This trend continues into the day Sunday, then by late
Sunday afternoon and evening a mid level wave moves through as low
and mid level cold air advection increases. This will be the
slightly better chance for light rain or light snow, but still a
struggle to saturate the low and mid levels. Not to mention the
dendritic growth zone is sitting up around 14-16kft. So, overall no
real changes to the forecast with mainly sprinkles/flurries
expected. Latest GEFS through the 75th percentile sitting at zero
precipitation with the 90th kicking out a few hundredths. Will need
to keep an eye on the EC and its` ensemble members as the 50th
percentile is about 0.05" liquid north of I-90 with the 90th around
0.15", which would equate to about 0.5" to 1.5" of snow.

While tomorrow will be on the mild side again, once this wave passes
colder air will spill into the area with lows in the teens to lower
20s Monday morning and highs mainly in the mid 20s to lower 30s. Not
only will it be colder but winds will remain fairly windy with gusts
around 35 mph likely, especially near and east of I-29. These colder
temperatures and stronger winds will combine to produce wind chills
in the single digits above and below zero.

While there will be a few chances for light precipitation Tuesday
through Friday the main story will be continued below normal
temperatures with another shot of colder air expected Thursday into
Friday, dropping highs back into the teens to lower 20s Friday. One
thing to watch will be Thanksgiving afternoon through Friday
morning. With the incoming colder air the dendritic growth zone will
lower and deepen and could lead to a little patchy light snow.
Nothing overly predictable at this range but if we can squeeze out a
little moisture in this layer or generate some shallow convection in
the marginally strong cold air advection we could get some light
snow amounts.

&&

.AVIATION /00Z TAFS THROUGH 00Z MONDAY/...
Issued at 533 PM CST Sat Nov 23 2024

VFR conditions begin the TAF period. High level cirrus blankets the
area early this evening along with light easterly winds. Winds will
go light and variable tonight which could allow for patchy fog to
develop. However,confidence is not high enough to include in a TAF
at this time. At the same time, MVFR/IFR stratus will expand
westwards during the overnight hours. Should see the stratus cover
the majority of the area by tomorrow afternoon. Precipitation is
possible by KHON towards the end of the TAF period. Given lower
confidence in timing, have omitted from KHON`s TAF but will monitor
trends. Otherwise, winds will turn out of the north/northwest to end
the TAF period.

&&

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

&&

$$

DISCUSSION...08
AVIATION...Meyers