Area Forecast Discussion
Issued by NWS Aberdeen, SD

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972
FXUS63 KABR 202327 AAA
AFDABR

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
527 PM CST Sat Jan 20 2018

.SHORT TERM...(This Evening through Sunday Night)
Issued at 228 PM CST Sat Jan 20 2018

Temperatures were again able to rise a few degrees higher over the
James River Valley, and east of the Sisseton Hills. These warmer
readings across the region do not give us extra confidence in an
early evening transition to all snow over our southwest counties.
Early afternoon updates have been to postpone the transition, or
include more of a mix until around 03Z.

Light waa rain continues off and on, from a band stretching from the
far southwest corner of the state through Spink County. Farther to
our southwest, we continue to watch the track of the sfc low (as
well as the nearly stacked 500mb low) over eastern CO as it moves
along the OK/KS border during the day Sunday, and ejects northeast
across eastern KS Sunday evening and into far northwestern MO by
daybreak Monday.

Latest forecast runs are mostly keeping with the trend of pushing
the higher snow amounts to our southeast. The NAM continues to be on
the high side when compared to other solutions, but is quickly
coming more in line with its 18Z run.

SLRs will likely increase from below 8:1 this evening to closer to
13:1 late tonight through Sunday night. Basically have a couple of
different events we`re looking at. While most of the forecast area
will be dry or just experience light snow, the concern is really
south.

Headlines...Upgraded Jones and Lyman Counties to a Warning, and
included a Winter Weather Advisory for Stanley and Hughes. Given the
variability and farther shifting of this system, it may just be the
very far southern parts of those counties, or potentially even just
to the south that receive near Advisory level snow. A decision on
Buffalo County, as well as possibly Hyde and Hand Counties will need
to be made prior to 12Z, when more steady snow begins to potentially
fall/accumulate. Have pushed the Watch for Buffalo County back until
a start time of 12Z Sunday. Did not make any adjustments to the
eastern county headline (Watch for Deuel), along with FSD/MPX on
their counties.

HWO and graphics will mention the potential for a further south
outcome to the current forecast, as this continues to be the trend.

.LONG TERM...(Monday through Saturday)
Issued at 228 PM CST Sat Jan 20 2018

When the period opens Monday morning, the winter storm system is
lifting into the Great Lakes region. TROWAL-forced light
precipitation across the far southeastern forecast zones (basically
southeast of a line from Carpenter to Ortonville) should be ongoing
at 6 AM CST Monday, and there could even be a little bit of freezing
drizzle or very light freezing rain at times, too, during the
morning hours. The primary weather hazard on Monday is the wind.
North winds of 15 to 30 mph with occasionally higher gusts will only
be adding to the travel-hazardous weather.

Beyond Monday, the forecast is dry until next Friday night/Saturday
when another area of low pressure is progged to lift north and east
through the region. Currently, precipitation-type looks to be snow
with any precipitation associated with this potential system. Latest
available deterministic and ensemble thermal progs indicate that
temperatures next week should be near to above normal.

&&

.AVIATION...(For the 00Z TAFS through 00Z Sunday Evening)
Issued at 525 PM CST Sat Jan 20 2018

VFR conditions are expected at KMBG and KABR through the period. A
winter storm will move through the southern part of the forecast
area this evening through Monday. KPIR will change over to all
snow by 6z and will fall to IFR vsby overnight. MVFR cigs will
move into KATY toward the end of the taf period in anticipation of
the snow starting in eastern SD Sunday evening.

&&

.ABR WATCHES/WARNINGS/ADVISORIES...
SD...Winter Storm Warning from midnight tonight to 6 AM CST Monday
     for SDZ045-048.

     Winter Storm Watch from Sunday morning through late Sunday night
     for SDZ051.

     Winter Weather Advisory from midnight CST /11 PM MST/ tonight to
     6 AM CST /5 AM MST/ Monday for SDZ033-035.

     Winter Storm Watch from Sunday evening through Monday afternoon
     for SDZ023.

MN...None.
&&

$$

SHORT TERM...KF
LONG TERM...Dorn
AVIATION...Wise



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