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Area forecast discussion...updated
National Weather Service Aberdeen South Dakota
1128 PM CST Mon Dec 9 2019

issued at 1126 PM CST Mon Dec 9 2019

Extended pops tonight through 8z as the showers continue to slowly
spread east but remain persistent west of the James Valley.

Update issued at 520 PM CST Mon Dec 9 2019

With clouds streaming over the area, will leave the current temp
forecast alone. However, will continue to monitor for any breaks
as they could send temps plummeting even further tonight. The rest
of the forecast remains on track.


Short term...(this evening through Tuesday night)
issued at 211 PM CST Mon Dec 9 2019

The main concerns through the period are temperatures, and then pcpn
chances. For tonight another surge of Arctic air is expected to move
south over the region during the evening. This next shot of cold air
will probably produce some light snow across the region as lift
interacts with the low level dendritic growth zone, but coverage
should only be isolated to scattered. Even though there has been
some thinning of the clouds this afternoon, suspect much of the
cloud cover up north will flow into the region behind the next
surge. Thus didn't go too cold overnight given expectations of
broken to possible overcast skies. Tuesday should bring some
sunshine, but only slight temperature recovery, particularly over
the east. Tuesday night also presents some interesting issues that
could affect overnight lows. A few models indicate that a weak
baroclinic zone will form over the western cwa, with some chance for
pcpn, and consequently broken cloud cover. This will likely put a
crimp on overnight lows, especially over the Missouri Valley,
perhaps even the James Valley. For now will keep pretty cold
temperatures over the east where less cloud cover is expected.
Windchill values remain mostly warmer than -25f over the forecast
area through Tuesday. But, Tuesday night may bring a broader area of
colder windchills and perhaps the need for a headline.

Long term...(wednesday through monday)
issued at 211 PM CST Mon Dec 9 2019

High pressure will be over the region as we start off Wednesday
morning. It will help to contribute to the cold start to the day and
maintain this chill through the daytime hours. By days end, this
high will begin sliding away from US to the southeast. Some mid
level energy traversing through the Dakotas late Wednesday into
early Thursday will provide for a chance of some light snow across
our northern and northeastern forecast area. This system should
quickly move through to not make much of an impact other than maybe
some minor snow accumulations. Through the remainder of the week
into the weekend, there will be a couple of systems moving through
the region. These also look to be fairly benign in nature, but each
will bring in a chance for some light snow.

As mentioned, there will be a chilly start to the extended. However,
the Arctic airmass will be on it's way out of here on Thursday as
daytime temps modify to warmer levels. This warmer trend looks to
hold through Friday as daytime readings top the freezing mark in
some areas. However, with the passage of one of the aforementioned
systems and frontal boundary late in the week, colder air will work
back in for the weekend into early next week.


Aviation...(for the 06z tafs through 06z Tuesday night)
issued at 1126 PM CST Mon Dec 9 2019

A mix of MVFR and VFR cigs will persist until snow showers taper
off by 9z. Improvement to all VFR is then expected.


Abr watches/warnings/advisories...
South Dakota...Wind Chill Advisory until noon CST Tuesday for sdz007-008.

Minnesota...Wind Chill Advisory until noon CST Tuesday for mnz039-046.



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