Area Forecast Discussion
Issued by NWS Aberdeen, SD

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FXUS63 KABR 131735 AAC

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
1135 AM CST Wed Dec 13 2017

Issued at 1030 AM CST Wed Dec 13 2017

The current forecast for today looks good overall. The only chance
was to increase sky cover through the rest of the day.


.SHORT TERM...(Today and Tonight)
Issued at 403 AM CST Wed Dec 13 2017

Wind, light mixed precipitation, and falling temperatures will be
the main concerns this period. The 500mb shortwave over the eastern
half of the area will quickly exit to our southeast this morning.

Will start out with light rain as temperatures hover in the upper
30s to mid 40s. Continue to monitor latest trends and update hourly
forecast for the warm conditions. Expect falling temperatures today,
behind the exiting sfc low shifting from south central MN to just
south of Lake Michigan by mid afternoon. This shift will allow winds
to diminish, with the weakening pressure gradient, but will also
allow cooler air to surge in. Temperatures will remain nearly steady
today in the 30s and 40s. Rain initially, may mix with and change
over to light snow by mid afternoon. If roadways cool down fast
enough some icing will be possible.

Given the winds gusting 35 to near 50 mph today, very high grassland
fire danger index values will show up again over Stanley, Jones, and
Lyman Counties. Relative humidity values will fall around or below
40 percent southwest of a line from Mobridge to Miller. A weak sfc
ridge will be overhead around 00z, with winds continuing to slowly

.LONG TERM...(Thursday through Tuesday)
Issued at 403 AM CST Wed Dec 13 2017

The fairly high amplitude long wave pattern across the conus is
expected to continue through the long term. However, the pattern is
showing some signs of shifting its orientation. The west conus mid
level ridge is expected to retrograde back to the west, thus
allowing energy to dig strongly south over the Rockies/western highs
plains by this weekend and early next week. This energy then ejects
east/ne out across the central plains, with pretty decent areal
coverage of pcpn. However, for now, the main storm track looks to be
mainly south of the ABR cwa. Throughout the entire period, the
highest probabilities for measurable pcpn looks to be Thursday, with
light snow expected from the Missouri River valley east to the James
River valley, as a relatively weak system drops south across the
region. Temperatures, overall, will continue to favor near or above
normal through the forecast given a lack of any true arctic air
anywhere near the Northern Plains.


.AVIATION...(For the 18Z TAFS through 18Z Thursday Afternoon)
Issued at 1129 AM CST Wed Dec 13 2017

MVFR cigs will continue to impact all terminals except KPIR
through the rest of the afternoon. Cigs may become low end IFR
later tonight. However another storm system will cross the region
late tonight through Thursday morning. This system will bring
light snow to most terminals. With breezy northerly winds and
falling snow, reduction in visibility can be expected for the
terminals of KPIR and KMBG.


SD...Wind Advisory until 3 PM CST /2 PM MST/ this afternoon for

MN...Wind Advisory until 3 PM CST this afternoon for MNZ039-046.



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