Sioux Falls, South Dakota 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

032
FXUS63 KFSD 211652
AFDFSD

Area Forecast Discussion
National Weather Service Sioux Falls SD
1152 AM CDT Wed May 21 2025

.KEY MESSAGES...

- A few lingering showers/sprinkles today into this evening,
  mainly focused north of Interstate 90. Additional rainfall
  amounts will be less than a tenth of an inch.

- Thursday will be dry before shower and isolated thunderstorm
  chances return Friday into the Memorial Day weekend. Severe
  weather is not expected at this time.

- Temperatures will be seasonably cool through Memorial Day
  weekend with highs ranging from the mid 50s into the 60s and
  lows in the upper 30s and 40s. These highs are 10 to 15
  degrees below late May normals.

&&

.DISCUSSION...
Issued at 325 AM CDT Wed May 21 2025

The upper level low which has been spinning over the Northern Plains
for the past few days will finally begin to weaken and shift off to
the east for today into tonight. This will result in a decrease in
coverage of showers, with most of the activity focused north of
Interstate 90 through the period. Any additional rainfall looks to
be only a few hundredths at best. Momentum transfer winds are
running around 20 kts, so it will be a breezy day with northwesterly
winds gusting around 25 mph. Temperatures will again be much below
seasonal averages (15-20 degrees) with highs only in the 50s.

Although any remaining showers will continue to decrease this
evening, could see a slight resurgence of showers in southwestern
Minnesota later tonight as the remnants of the upper level low
finally shifts southward out of the area. Any additional rainfall
amounts would be minor however - a trace to perhaps a hundredth.
Dependent on how quickly clouds clear out tonight, with temperatures
dropping into the mid/upper 30s cannot rule out some patchy frost in
lowest lying locations.

Surface high pressure builds into the region on Thursday and
Thursday night. With that, we will finally get a break in
precipitation. 850 mb temperatures will moderate a bit through the
day, and although still remaining below normal, highs are expected
to make it into the lower 60s.

Heading into the Memorial Day weekend, a return to unsettled
conditions with increasing rain chances (30-70%) on Friday as an
upper level trough over the Northern Rockies begins to impinge on
our area. Deterministic models and ensembles are in decent agreement
on showers lifting from west to east during the day, with the higher
rainfall probabilities residing from the James River Valley through
the Missouri River Valley. No severe weather is expected. With the
clouds and showers it will be another relatively cool day with highs
in the upper 50s to mid 60s.

For Saturday and Sunday, a threat of showers will remain through the
period as a secondary western CONUS upper level trough pushes to the
east. Although model specifics begin to diverge through the period,
ensembles do support (30-70% probability) of at least a 0.10" of
rainfall for Saturday, with lesser probabilities(20-30%) of
receiving this amount on Sunday. Any instability remains weak both
days so no severe storms are expected. Below seasonal average
temperatures continue with highs only in the low 60s.

As for Memorial Day itself, although we cannot rule out a stray
shower with the upper level trough residing overhead, both
deterministic models and ensembles support a mainly dry day (with
ensemble probabilities of less than 20% for a 0.10" of rainfall on
that day). Although temperatures will remain below normal for the
date, there will be a bit of warming with highs into the upper 60s,
and with relatively light winds it should not be a bad day
overall.

&&

.AVIATION /18Z TAFS THROUGH 18Z THURSDAY/...
Issued at 1150 AM CDT Wed May 21 2025

Ceilings continue to lift this afternoon, though for most areas
are still expected to remain at MVFR to low VFR levels. Some
self-destructing sunshine could lead to a few sprinkles through
the afternoon. A persistent northwest wind may gust up to 20 to
25 mph at times.

Skies may briefly thin this evening before additional stratus
pivots southward by Thursday morning. Ceilings may fall back to
MVFR to IFR levels Thursday morning with occasional spits or
drizzle.

&&

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

&&

$$

DISCUSSION...JM
AVIATION...Dux