Area Forecast Discussion
Issued by NWS Aberdeen, SD

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FXUS63 KABR 250529 AAC

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
1129 PM CST Sat Feb 24 2018

Issued at 902 PM CST Sat Feb 24 2018

Allowed the winter weather advisory to expire this evening as snow
is exiting. There is still a light band that is moving eastward
through Aberdeen, but it is not generating much in the way of
additional accumulation.

UPDATE Issued at 527 PM CST Sat Feb 24 2018

Snow continues to pull off to the northeast this evening. Radar
still shows some decent return from just east of Aberdeen to the
MN border, so those areas could see up to another inch before the
snow ends in a few hours. Adjusted pops to reflect current radar
trends. Will watch for any fog development with the fresh snow
after sunset and before winds pick up by early Sunday morning.


.SHORT TERM...(This Evening through Sunday Afternoon)
Issued at 304 PM CST Sat Feb 24 2018

As of 20Z, an upper level trough of low pressure is lifting
northward across the region. The heaviest snowfall, at times an
inch per hour, is impacting northeastern South Dakota and western
Minnesota. The back edge of the significant accumulating snow is
north of Huron, and beginning to clear Brookings. Based on a few
reports of 1.5 to 3 inches, plus the expectation of an additional
two inches, storm total snowfall amounts of 4 to 6 inches is
likely east of the James River valley. Will maintain our current
winter weather advisory for our eastern CWA through this evening.

Accumulating snow is ending in Central South Dakota, with mainly
flurries expected through the next few hours. Thus will expire the
advisory early. This system should progress northeast through this
evening with snow ending in this CWA by 3Z or sooner. Westerly winds
will increase some tonight, especially on the lee side of the
Sisseton Hills where patchy blowing snow is possible.

Dry conditions are expected on Sunday with highs in the 20s and low
30s. Breezy westerly winds could cause patchy blowing and drifting
snow, mainly in the higher terrain areas of the Sisseton Hills on

.LONG TERM...(Sunday Evening through Saturday)
Issued at 304 PM CST Sat Feb 24 2018

When the period opens Sunday night, the forecast area is undergoing
a flow pattern shift aloft to westerly and then southwesterly early
in the week. Dry, tranquil and relatively warm conditions are in the
offing for Sunday night through the first part of Wednesday. While
under southwest flow there remains a small chance for seeing some
shortwave energy make it up into the northern plains by Wednesday
night, bringing with it the potential for some light snow. But then
on Thursday/Thursday night, short-wave ridging sets up over the
region and the forecast goes back to being dry for awhile. For
Friday through Saturday, a large/broad upper level longwave trof
appears to be reloading over the western CONUS. There is some
potential, according to the 12Z GSM`s output, for a low pressure
system to be lifting out into the plains by late in the
weekend/early next week, bringing the chance for a wintry mix of
precip-types. This is a little bit outside the window of the current
seven day forecast, though. Model track/timing, etc all subject to
change, so will continue to keep an eye on model trends.

12Z deterministic GSM 925hpa thermal progs never really stray much
from a range of +4C to -5C throughout the entire period (Sunday
night through Saturday), and the 00Z/12Z NAEFS Ensemble table 850hpa
standardized anomaly output never strays much more than one-half
standard deviation either side of climate normal throughout the
period. It is for these reasons that the high temperatures for a
good portion of the forecast are in the 30s and the low temperatures
currently don`t dip below 0F.


.AVIATION...(For the 06Z TAFS through 06Z Sunday Night)
Issued at 1122 PM CST Sat Feb 24 2018

VFR conditions will continue across the west at KPIR and KMBG. An
area of IFR stratus is sitting over the lee side of the coteau and
will affect KATY until the system that has been affecting the
region this evening finally exits. Before the west winds increase,
there could be some patchy MVFR fog near KABR and KATY. The other
concern is some patchy MVFR cigs currently in western ND. Though
not forecast to do so, they could make it far enough south to
impact KMBG.




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