000
FXUS63 KFSD 062321
AFDFSD

AREA FORECAST DISCUSSION
National Weather Service Sioux Falls SD
621 PM CDT Thu Oct 6 2022

.SHORT TERM...(This Evening through Friday Night)
Issued at 252 PM CDT Thu Oct 6 2022

FORECAST HIGHLIGHTS:

1. Sub-freezing temperatures most areas tonight and/or Friday night.

2. Warmer air builds back in through first half of next week.

3. Could see a cool-down again late next week.

Still on the breezy side early this afternoon, with temperatures in
the 50s most areas. Dew points currently in the 30s-lower 40s, but
readings in the mid-upper 20s poised just north of the forecast area
as of 2 pm.

Low temperature forecast for tonight is a bit more complex that we`d
like for a couple of reasons. First, center of the surface high will
likely remain off to our northwest until after daybreak, which could
provide at least a light northerly breeze over our area much of the
night. Second, a couple areas of clouds could impact different parts
of the forecast area, in our west/southwest this evening, and in our
east after midnight. That said, given upstream drier air filtering
southward, and persistently dry ground in response to deteriorating
drought conditions, think any clearing will allow for quick drops in
temperatures. We saw this during our brief cool snap last week, when
at least isolated locations fell several degrees below anticipated
lows. Thus have hedged most areas toward the cooler side of guidance
options. Exception to that is in our far east, where aforementioned
cloud cover may hold readings up more in the mid 30s. Again, though,
confidence in the cloud cover is moderate at best, so opting to err
on the side of caution with our headlines tonight. Will convert the
remaining Freeze Watch to a Freeze Warning, expanding a bit farther
south toward Yankton-Orange City. Will blanket the remainder of the
forecast area with a Frost Advisory tonight.

Surface high slides over the CWA on Friday, providing a fair amount
of sunshine and light winds. While this should make it feel a bit
nicer than the temperature would suggest, it will be a generally
chilly day with highs in the upper 40s-lower 50s, about 15F below
seasonal normals.

This will lead into another cold night for this time of year. Not
expecting any issues with cloud cover Friday night, but instead may
see readings in some areas impacted by a light southwest breeze
developing on the back side of the departing surface high. For this
reason, have a bit more elevation dependency to forecast lows, with
coldest readings in the valleys of northwest Iowa where light and
variable winds are more likely for most of the night. Will almost
certainly need additional freeze headlines for some areas tomorrow
night, but given the existing headlines for tonight, will hold off
to avoid confusion.

.LONG TERM...(Saturday through Thursday)
Issued at 252 PM CDT Thu Oct 6 2022

Once we get beyond Friday night, we could still see some patchy
early morning frost over the weekend, but we should see a general
warming trend as the cold upper trough slides east and building
heights begin working eastward into the northern Plains. Models
continue to show a weak wave/back door cool front drop southward
through the area on Sunday, though some disagreement regarding how
far west the wave will track. Farthest west solution would bring
some light showers to our eastern areas during the day on Sunday,
but greater consensus is weaker/farther east with the wave, so will
keep things dry for now.

Begin to see some increase in southerly flow work into our western
counties by Monday afternoon, though Tuesday continues to look like
the breeziest day in the southerly flow, bringing an increased risk
for elevated fire danger.

By late Tuesday-Wednesday, models continue to trend toward solutions
which split the southern stream wave away into the lower West Coast,
while the stronger northern stream track east through Canada and the
northern CONUS. Moisture remains rather limited as this next trough
digs eastward, so will have minimal precipitation chances. Though
timing/strength varies, looks like another shot of colder air will
push into the forecast area by late next week.

&&

.AVIATION...(For the 00Z TAFS through 00Z Friday Evening)
Issued at 621 PM CDT Thu Oct 6 2022

An area of showers west of the James River in central South Dakota
is currently traversing southeastwards, with vast majority of the
rainfall not able to reach the ground due to a dry sub-cloud layer.
There is low potential for these showers to reach over as far east
as the I-29 corridor, though again most of the rain won`t be able to
reach the ground. Otherwise, look for winds to settle down
overnight, with a surface high pressure sliding down throughout the
day leading to winds shifting from northerly to west-
northwesterly.

&&

.FSD WATCHES/WARNINGS/ADVISORIES...
SD...Freeze Warning from midnight tonight to 10 AM CDT Friday for
     SDZ038>040-050-052>067.

     Freeze Warning from 4 AM to 10 AM CDT Friday for SDZ068>071.

MN...Freeze Warning from midnight tonight to 10 AM CDT Friday for
     MNZ097-098.

     Frost Advisory from 4 AM to 10 AM CDT Friday for MNZ071-072-080-
     081-089-090.

IA...Freeze Warning from midnight tonight to 10 AM CDT Friday for
     IAZ001.

     Frost Advisory from 4 AM to 10 AM CDT Friday for IAZ002-003-013-
     014-020>022-031-032.

     Freeze Warning from 4 AM to 10 AM CDT Friday for IAZ012.

NE...Frost Advisory from 4 AM to 10 AM CDT Friday for NEZ014.

     Freeze Warning from 4 AM to 10 AM CDT Friday for NEZ013.

&&

$$

SHORT TERM...JH
LONG TERM...JH
AVIATION...APT

NWS FSD Area Forecast Discussion