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713
FXUS63 KFSD 110345
AFDFSD

Area Forecast Discussion
National Weather Service Sioux Falls SD
1045 PM CDT Fri May 10 2024

.KEY MESSAGES...

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- Mostly clear skies are expected tonight for aurora viewing,
  though thin upper level clouds can`t be ruled out.

- Warmer and mainly dry conditions on Saturday will make for
  excellent conditions for outdoor activities. Expect current
  minor river flooding across portions of northwest Iowa to
  improve.

- Low (10% to 40%) chance of scattered showers and thunderstorms
  on Sunday with a low chance of severe weather. Another chance
  for showers and thunderstorms on Tuesday, but the severe
  weather threat looks to remain isolated.
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&&

.DISCUSSION...
Issued at 250 PM CDT Fri May 10 2024

On the heels of a surface front that has just about finished moving
through, afternoon satellite imagery shows a scattered cumulus field
moving in from the north. At the surface, observations show
temperatures climbing into the upper 60s to mid 70s, with an
additional degree possible before temperatures start to cool off.
Relative humidity values behind the front have dropped down into the
mid 20s to mid 30s, though given the current conditions of the
grasslands, will forgo any fire headlines. The over achieving breezy
northwesterly winds will subside throughout the evening hours, with
in general weak winds expected overnight. Overnight, we`ll be
watching as a surface ridge axis slides across the area from
northwest to southeast, swinging the winds around to the west-
northwest by Saturday morning. Early morning lows in the mid to
upper 40s expected.

Saturday will see the 850mb ridge slide across the area throughout
the day, keeping winds out of the west-southwest. As the surface
heats up we will be able to mix up into the 750-700mb layer, and
bring down 850mb temperatures in the +11 to +15 deg C range (roughly
5-9 deg C above normal). As a result, expect temperatures to rapidly
warm after the mid-morning hours, likely peaking into the mid 70s to
lower 80s across the region. Normally this is where we say
"unfortunately this will require very breezy winds to mix down those
warmer temperatures," but Saturday looks like winds will only be
gusting into the teens and lower 20s! Thus, Saturday is poised to be
a lovely spring day. Overnight lows will also be warmer than normal,
with most staying in the lower to mid 50s.

Low pressure moves through NE on Sunday with broad mid level warm
advection moving through areas mostly south of I-90. Soundings
indicate the potential for some weak to moderate instability,
generally less than 1000 J/kg. The combination of the instability
and incoming lift should allow for scattered showers and
thunderstorms with a very small chance for isolated lower end severe
weather. The better chances should be Sunday afternoon and Sunday
night. Strong wind gusts appear to be the main concern with a fairly
deep dry layer below about 6000 kft. Otherwise a very warm day with
highs mostly in the upper 70s to mid 80s and seasonable winds.

This system moves through Sunday night and there may be some
lingering showery activity in mostly northwest IA Monday. Another
weak system will move into central SD Monday afternoon but not much
to work with so very isolated at best. While Monday will be a bit
cooler as northeast flow settles into the area highs should still be
in the 70s.

A bit stronger system with fairly good model agreement should move
through the area on Tuesday. The overall severe threat looks fairly
low but with some weak shear and weak instability Tuesday afternoon
and night will at least see a small chance for isolated severe
storms. Another day with highs in the 70s.

Wednesday into Thursday model divergence increases so confidence on
any solution is pretty low. Looks like a chance to remain in an
active pattern with continued precipitation chances, just not real
confident on any of the details. Some increasing confidence on a
cold front coming through on Friday so maybe another threat for
showers and thunderstorms and if enough instability some isolated
severe storms.

&&

.AVIATION /06Z TAFS THROUGH 06Z SUNDAY/...
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Issued at 1044 PM CDT Fri May 10 2024

VFR conditions are expected to prevail through the period. Light
northwest winds turn more westerly on Saturday with another
round of diurnal cumulus possible in the afternoon.
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&&

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

&&

$$

DISCUSSION...APT/08
AVIATION...BP