Area Forecast Discussion
Issued by NWS Sioux Falls, SD

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000
FXUS63 KFSD 280337
AFDFSD

Area Forecast Discussion
National Weather Service Sioux Falls SD
1037 PM CDT Wed Mar 27 2024

.KEY MESSAGES...

- With a wet ground and slowly melting snow, some patchy fog
  will be possible. Latest ensemble output indicates better
  chances across the snowpack, especially south central SD.

- Temperatures warm Thursday and Friday, with highs forecast
  to moderate back toward seasonal normals, but lagging a bit
  over fresh snowpack.

- Precipitation chances return Friday and again on Sunday into
  Monday, though confidence in track and amounts remaining low.
  At this time the Sunday system appears to have a better chance
  for more meaningful precipitation amounts and should be a mix
  of rain and snow.

&&

.DISCUSSION...
Issued at 249 PM CDT Wed Mar 27 2024

High pressure will slowly work east through the night allowing for
light winds and mainly clear skies. With a wet ground across the
area and light winds there will likely be some patchy fog. Model
soundings show this potential, but also suggest that any fog will be
very shallow. Latest HREF and SREF output indicate the better
chances over the fresh snowpack, and especially in south central SD
on the back edge of this high pressure where weak southeast flow
will develop. Lows will be wide ranging, from the single digits over
the deeper snowpack to around 20 in northwest IA from Sioux City to
Storm Lake.

Assuming the shallow fog pans out, we will spend a couple of hours
in the morning burning this off, but with a strong late March sun
this should not be a problem. Will see a rebound in temperatures as
high pressure is east of the area and south to southeast flow brings
milder air into the area. Highs should vary from the 30s over the
snowpack to 50 to 55 over bare ground.

Thursday night into Friday will see a system move through the area,
but forcing and moisture are pretty lacking. The better forcing and
moisture track off to the north while the better instability is well
to the south. There is some weak elevated instability, 50 J/kg CAPE,
with some increased mid level lapse rates, but a fairly significant
dry layer below should keep precipitation from reaching the ground.
And anything that may reach the ground should be very light.

Saturday should be dry before the next piece of energy moves into the
area Saturday night. High should mainly be in the 40s.

Saturday night into Monday appears to be the better chance for
precipitation across the area. An upper level trough deepens to the
southwest with a piece of energy expected to eject into the Central
Plains. Both the EC ensembles and GEFS indicate moderate chances for
meaningful precipitation during this time. Model soundings and
ensembles also indicate a threat for more snow with only a very
shallow layer above freezing Sunday night into Monday. At this time
the better chances for snow would be northwest of a Gregory to
Windom MN line, but too far out to really pin down. With abundant
cloud cover and precipitation chances, temperatures will be below
normal Sunday and Monday.

Upper level ridging builds into the area Tuesday into Wednesday as
troughing deepens over the northwest U.S. This should bring
temperatures back to near or above normal, but this will be
dependent upon any snow that falls Sunday into Monday, so confidence
in temperatures Tuesday and Wednesday is low.

&&

.AVIATION /06Z TAFS THROUGH 06Z FRIDAY/...
Issued at 1037 PM CDT Wed Mar 27 2024

VFR conditions are expected for the TAF period. Light and variable
winds begin the period beneath mainly clear skies. Hi-res guidance
has backed off a bit on the chance for fog tonight. As such, have
continued to keep any chance for fog out of all TAFs. Given the
current snowpack, still think a low probability (<=30% chance) still
exists for at least some patchy fog potential. Will continue to
monitor conditions through the overnight hours.

Light southeasterly winds are expected for the day tomorrow with
speeds up to 5-10 knots. Winds will slightly strengthen towards the
end of the TAF period with gusts up to 15-25 knots possible.

&&

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

&&

$$

DISCUSSION...08
AVIATION...Meyers


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