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Area Forecast Discussion
Issued by NWS Aberdeen, SD
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FXUS63 KABR 010255 AAA
AFDABR

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
855 PM CST Tue Jan 31 2017

.UPDATE...
Issued at 855 PM CST Tue Jan 31 2017

Strong cold front moving into the region tonight with low clouds
along with some light snow/flurries along it. Adjusted the
forecast for the night.

UPDATE Issued at 545 PM CST Tue Jan 31 2017

00z aviation discussion updated below.

&&

.SHORT TERM...(This Evening through Wednesday Afternoon)
Issued at 312 PM CST Tue Jan 31 2017

Winds will gradually diminish in speed across the area tonight as
high pressure approaches from the northwest. May still see some
light snow or flurries over the southwestern CWA this evening before
the area of snow that has been affecting mainly southwestern South
Dakota begins to diminish. The high will settle in over the western
half of the state on Wednesday, keeping conditions dry, but allowing
for colder air to begin to move in.

Low temperatures tonight will range from around 5 degrees over the
northwestern CWA, to around 15 degrees across the south. High
temperatures on Wednesday will be mainly in the teens.

.LONG TERM...(Wednesday Evening through Tuesday)
Issued at 312 PM CST Tue Jan 31 2017

To start Wednesday night, the main 500mb low will be across Hudson
Bay, with a ridge across the Pacific Coast of the continuous states
up through Canada. Zonal to slight northwesterly flow will continue
across the Dakotas through much of the period. The exception will be
when the 500mb ridge flattens out and moves across the western tho-
thirds of the nation to end the work week, and the next 500mb low
slides into the Pacific Northwest on Monday. This will briefly bring
southwesterly flow to our region Monday night, before the trough
settles across the Upper Midwest on Tuesday. There are still a few
periods of particular interest.

A 500mb trough over WA Thursday morning will swing across SD Friday,
while high pressure slowly sinks in from the north-northwest. Our
southern counties will experience snow Thursday night into Friday
morning. Amounts of less than an inch are expected (and most of that
falling over Jones and Lyman Counties).

The sfc high will be overhead around midday Friday, and will mark
the last day of below normal temperatures for at least a few days.
WAA will increase Friday evening as the high sinks across IA.
Contrasting the -17 to -19C 850mb temps Thursday morning, they
should be able to increase to the low single digits above 0C
from Saturday night through Sunday night.

Another round of light precip will be possible Friday night into
Saturday morning as the next weak shortwave swings across the
Dakotas. There is plenty of disagreement on timing/track of sfc low,
and how much precip could fall. With warmer air overhead, there will
be a small chance of mixed precip. The best chance of wet weather
looks to be across eastern SD/west central MN, with the introduction
of even some likely pops over far northeastern SD.

The next round looks to hold off until Monday night through Tuesday
as the Pacific 500mb trough swings closer to the area. The 12Z
solutions indicate that our central and eastern counties would be
impacted the most. While the best chance of precip will be snow, a
mix will still be possible. 2 to 4 inches of snow could be possible,
with the potential for higher amounts over our eastern counties, or
across MN. Will need to wait and see on this one, but it could be a
period of travel impacts across the region. The Canadian is much
faster and farther east with the sfc low, while both the GFS and
ECMWF have it set up across eastern CO at 06Z Tuesday, near the
NE/IA/MO/KS border at 18Z Tuesday, before exiting across WI and MI
Tuesday night. The ECMWF is deeper with the sfc low, and indicates
the potential for heavier precip wrapping up across eastern SD than
the GFS.

&&

.AVIATION...(For the 00Z TAFS through 00Z Wednesday Evening)
Issued at 545 PM CST Tue Jan 31 2017

MVFR/low VFR stratus ceilings will move across the region through
the night affecting all locations except for PIR as a cold front
drops through the region. Much of Wednesday will be VFR/clear to
partly cloudy skies as drier air and surface high pressure pushes
towards the region.


&&

.ABR WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
&&

$$

UPDATE...Mohr
SHORT TERM...Parkin
LONG TERM...KF
AVIATION...Mohr
National Weather Service Regional Headquarters
