Area Forecast Discussion
Issued by NWS Aberdeen, SD

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FXUS63 KABR 120521 AAC

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
1121 PM CST Thu Jan 11 2018

Issued at 605 PM CST Thu Jan 11 2018

With the next weak system set to affect the region on Friday just
now coming on shore in the Pac NW, hi-res guidance has slowed down
the onset of precip quite a bit. Adjusted grids to reflect the
slower entrance which pushed any mention of precip into the
morning hours as opposed to late tonight. Precip has also shifted
south a bit more quickly so dropped accumulation potential across
north central SD.


.SHORT TERM...(This Evening through Friday Afternoon)
Issued at 227 PM CST Thu Jan 11 2018

Snow chances and wind chills are the primary forecast challenges
through Friday.

Currently...there`s plenty of cold sunshine and windy northerly
winds in the forecast area. Temperatures range from the single
digits below zero to single digits above zero. The cold temperatures
and strong winds are fueling wind chill values generally in the 10
below to 20 below zero range.

Tonight should start off clear and cold, with wind chill values
quickly falling to advisory criteria levels (-25F or colder), mainly
along and north of U.S. Highway 212 first. Then later after
midnight, those wind chill values start showing up as far south as
State Highway 14. Got a wind chill advisory headline in place for
this, which runs to 18Z Friday.

Also after midnight, precipitation chances (snow) begin to show up
in the forecast mainly west river, and then expand further east
after 12Z Friday, but not going much farther east across the state
than approximately the James River valley. The low pressure system
responsible for these snow chances can be seen on water vapor
satellite imagery this afternoon moving onshore across the Pac.
Northwest. Lacking moisture and strong forcing/lift when it reaches
the northern high plains, this system may only generate a trace to
around an inch of snow, primarily west and south of a line from
Eureka to Redfield. The snow chances have pretty much vacated the
cwa by the end of the Friday forecast period.

Temperatures tonight and Friday are going to be much below normal
cold. Guidance generally seems to be rallying around low
temperatures tonight dipping into the single digits below to teens
below zero. But, a lot of the temperature forecast will depend on
how long the stronger northerly winds persist in the overnight and
how long it takes for clouds to begin moving in from the north/west
overnight in advance of this approaching low pressure system.
Likewise, on Friday, high temperatures may not see "above zero"
attached to them for some areas.

.LONG TERM...(Friday Evening through Thursday)
Issued at 227 PM CST Thu Jan 11 2018

The long term portion of the forecast begins with an Arctic high
pressure sinking southeast across the region. This high will bring
bitter cold temperatures with lows Saturday morning in the teens
below, to 25 degrees below zero. Highs on Saturday will only warm
into the single digits above zero. Two upper level shortwaves will
dive southward across the region Saturday night and Sunday night
with both bringing light pcpn to the CWA. Temperatures will briefly
warm on Sunday between these two systems. Highs on Sunday could
reach the teens and 20s.

Arctic air will return to the region Monday and Tuesday with highs
only reaching the single digits on either side of zero. Buy
Wednesday, an upper level ridge should begin building into the
region with temperatures warming into the teens and 20s. High
temperatures by Thursday could reach the 30s and 40s.


.AVIATION...(For the 06Z TAFS through 06Z Friday Night)
Issued at 1119 PM CST Thu Jan 11 2018

VFR conditions will prevail through the night. A weak low will
move over the Missouri River valley on Friday bringing some light
snow and briefly reduced vsby at KPIR during the morning.


SD...Wind Chill Advisory until noon CST /11 AM MST/ Friday for

     Wind Chill Advisory until noon CST /11 AM MST/ Friday for

MN...Wind Chill Advisory until noon CST Friday for MNZ039-046.



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