Spencer, Iowa 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

792
FXUS63 KFSD 301701
AFDFSD

Area Forecast Discussion
National Weather Service Sioux Falls SD
1201 PM CDT Sun Mar 30 2025

.KEY MESSAGES...

- Light precipitation, with a wintry mix at times, persists
  throughout the day today. Minimal accumulations are expected.

- The Winter Weather Advisory remains in effect until 7 am for
  locations in southeast South Dakota and Pipestone county in
  Minnesota. The rest of the Advisory in southwest Minnesota
  will expire at 1 pm this afternoon.

- The next chance for precipitation arrives for Tuesday and
  Wednesday. Chances for precipitation are high (near 100%) but
  some details are uncertain.

&&

.DISCUSSION...
Issued at 354 AM CDT Sun Mar 30 2025

Precipitation continues to push northeast of the area this morning.
Despite the better forcing and associated precip exiting the
forecast area, light snow and mixed precipitation persist across
parts of the area as thermal profiles remain saturated in the low
level despite a loss of saturation in the dendritic growth zone
(DGZ). Thus, light snowfall accumulations generally less than an
inch is expected through the rest of the overnight hours. Isolated
higher amounts are possible across parts of southwest Minnesota. A
light glaze of ice is also possible given the mixed precipitation
and light freezing drizzle due to the loss saturation in the DGZ.
Southwest Minnesota is again the area most likely to see light
icing. Did extend the Winter Weather Advisory for locations along
and west of the James River until 7 am this morning to account for
the lingering light precipitation.

Light precipitation remains on track to persist through the morning
hours today. Thus, think the bulk of the Winter Weather Advisory for
locations across southeast South Dakota can expire at 7 am but will
keep the Advisory in place until 1 pm this afternoon for parts of
southwest Minnesota. However, the light precipitation will slowly be
sliding eastwards but could see a small resurgence in precipitation
as a another weak upper level passes through the area. This will
resaturate the DGZ east of I-29. Thus light snow will be possible
during the afternoon hours in this area. Additional amounts will be
light at below an inch. High temperatures will be below average in
the 30s to up to about 40F along and west of I-29. Breezy northerly
winds will persist as well. Any chance for light precipitation will
come to an end by this evening along with weakening winds, leading
to quiet conditions for the overnight hours. Low temperatures will
fall to the 20s overnight.

Monday will be a quiet day as shortwave ridging slides through the
Northern Plains. High temperatures will rebound a bit as highs warm
into the upper 30s and upper 40s. The shortwave ridging will slide
east quickly as heights begin to fall Monday evening. Warm air
advection (WAA) will strengthen in response to the indirect thermal
circulation of an upper level jet`s exit region pushing into the
Plains. With thermal profiles cooling to saturation, precipitation
is likely to develop. This is supported by the ensembles as they
show increasing probabilities for liquid precipitation values to
exceed a tenth of an inch. Given how temperatures will be a little
above freezing, precipitation looks to begin as rain but will mix
with snow during Monday night as temperatures cool to near to below
freezing. Low temperatures will fall to the upper 20s to low 30s.
For the overnight hours, snowfall amounts look to remain light at
below an inch.

Snow will continue through Tuesday as greater quasi-geostrophic
ascent strengthens across the Plains. The precipitation that was
falling from Monday night will continue to push off to the northeast
through the morning hours on Tuesday. With the best forcing for
ascent coming Tuesday morning, a few inches of snow is possible
during this period of time. Chance for both rain and now persists
through the rest of Tuesday as the upper level wave continues to
eject into the Plains. High temperatures will warm to the upper 30s
to low 50s from north to south. The upper wave will strengthen and
transition to a closed low as it encroaches on the forecast area
Tuesday evening. Ensembles strongly support precipitation lasting
through the day on Tuesday as the GFS, Euro, and Canadian ensembles
all show a near to 100% chance for liquid QPF amounts to exceed a
tenth of an inch. The ensembles also continue to show a near 50%
chance for both a rain and snow precipitation type (p-type).
Although these probabilities will persist into Tuesday evening and
night, weak elevated instability will be advected into locations
along and south of I-90. Thus, some weak thunderstorms will be
possible Tuesday night.

No break in chances for precipitation as upper level low moves
overhead on Wednesday. Although high temperatures look to warm to
the upper 30s to upper 40s, could still see chances for snow
throughout the day as a colder air on the backside of the system
pushes through the area. This creates some uncertainty in high
temperatures as a faster shot of cold air advection (CAA) will
result in cooler highs. For now, will stick with the NBM highs.
Despite this uncertainty, the GFS and Euro ensembles continue to
suggest that rain will be the predominant p-type during the day on
Wednesday before transition to snow during the evening. The
ensembles remain consistent though in continuing to show a near 100%
chance for exceeding a tenth of an inch of liquid QPF. Chances for
precipitation will come to an end Wednesday night as the upper low
pulls away. In terms of amounts, new liquid QPF amounts up to a half
an inch or more is likely (60-100% chance) as supported by the
ensembles. Snowfall amounts are a bit more uncertain as the
ensembles differ in where the majority of the now will fall. The
Euro and Canadian ensembles show a 70-100% chance for snowfall
amounts to exceed 1 inch along and north of I-90 while the GFS
ensemble is keeps these same probabilities along and north of
highway-14. Tough to say which is right this far out so will keep
model blended PoPs and temperatures for the time being.

Thursday will be a quiet day due to large scale subsidence residing
over the forecast area on the backside of the departing wave.
However, this break in precipitation looks to be another short lived
one as another round of precipitation may be possible late Friday
and Saturday. This will be dependent on how another western CONUS
upper level trough evolves. Medium range guidance shows varying
solutions so again have stuck with the NBM PoPs. Temperatures look
to warm back to near seasonable levels in the 40s, 50s, and
potentially 60s.

&&

.AVIATION /18Z TAFS THROUGH 18Z MONDAY/...
Issued at 1158 AM CDT Sun Mar 30 2025

IFR to MVFR ceilings will continue to move eastward though the
afternoon hours. Precipitation at this point will be focused
over portions of Southern Minnesota and northwest Iowa through
mid-afternoon.

We`ll see improvement to VFR ceilings later this evening with
mid-lvl clouds persisting into Monday morning. Winds generally
remain light to breezy from the north or northwest into Monday.

&&

.FSD WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...Winter Weather Advisory until 1 PM CDT this afternoon for
     MNZ072-080-081-089-090.
IA...None.
NE...None.

&&

$$

DISCUSSION...Meyers
AVIATION...Dux