Area Forecast Discussion
Issued by NWS Sioux Falls, SD

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FXUS63 KFSD 040817

National Weather Service Sioux Falls SD
317 AM CDT Tue Oct 4 2022

.SHORT TERM...(Today and Tonight)
Issued at 317 AM CDT Tue Oct 4 2022

Latest water vapor loop shows a nicely wound up system moving into
western SD. This will keep the corridor of southerly flow in place
in the low levels across the area today as well as decent mid level
frontal forcing. While instability within this corridor is fairly
minimal and low level moisture is still tough to come by forcing
within a saturated dendritic layer should allow for periods of light
rain/rain showers through the day, which should gradually shift into
northwest IA and southwest MN. As the upper level low pressure moves
into NE and south central SD late this afternoon and evening a small
axis of instability is expected to develop. The highest CAPE in any
of the models pushes about 1000 J/kg with the average a little
closer to 500 J/kg. While this is not overly supportive of severe
weather there is a weak boundary moving into central SD, the low
level wind field appears fairly light and the LFC`s are fairly low
so maybe a few concerns for funnels or brief landspouts. The overall
trend should continue to be for lighter rainfall but any convection
that can develop late this afternoon and evening may produce some
scattered higher amounts around a half an inch or so.

By tonight the upper level low will drift further southeast and take
the better chances for rainfall with it. Parts of northwest IA and
northeast NE will see chances linger the longest. Lows will again be
mild with most locations only falling into the 50s.

.LONG TERM...(Wednesday through Monday)
Issued at 317 AM CDT Tue Oct 4 2022

Wednesday will see conditions improve from west to east with
the final mild day before a stretch of cooler air moves in. Highs
should mostly be in the 70s with northwest winds gusting to 20 to 25

Wednesday night into Thursday will see a surge of colder air drop
south with fairly strong cold air advection from about 3 am through
noon on Thursday. This should support some wind gusts around 30 to
35 mph, especially with the stronger cold air advection. By Thursday
afternoon the wind and cold advection will slacken, so gusts likely
more around 20 to 25 mph by mid afternoon. Thursday morning lows
should be mainly in the 40s with highs on Thursday mainly in the 50s.

A ridge of high pressure at the surface will nose into the area by
Friday morning allowing winds to drop to near zero. This should give
the area a very good chance for a frost or freeze, especially near
and west of I-29. There is a slightly better chance that winds will
remain around 5 to 7 mph in southwest MN and allow temperatures to
stay more int he mid 30s. Areas near and west of I-29 should see
lows near 30 and near and west of the James River some mid and upper
20s are likely. Temperatures on Friday afternoon will only climb
into the 50 to 55 degree range for most locations as surface high
pressure slowly drops southeast.

The threat for frost and freeze will continue on Saturday morning,
but it appears that chances will be a little lower as a light south
to southwest wind will develop and radiational cooling will not be
maximized. Still a time to watch for cold morning lows with
northwest IA seeing the better chance for frost and freeze on
Saturday morning.


.AVIATION...(For the 06Z TAFS through 06Z Tuesday Night)
Issued at 1025 PM CDT Mon Oct 3 2022

Linear band of 800 mb frontogenesis will continue to lift
northeast across the area overnight. There will be a very slow
eastward track, and there is some uncertainty on if this area of
rain will be able to move past I-29 into Tuesday morning. Within
areas of rain, VFR conditions are still likely, with no
restrictions anticipated.

Scattered light showers or rain will persist into Tuesday, through
it will be along a very narrow corridor near the I-29 corridor.
Slightly higher rain chances may develop in the afternoon through
the Tri-State area, but again little in the way of restrictions
are anticipated.




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