Area Forecast Discussion


298 
FXUS63 KABR 110006 AAB
AFDABR
Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
606 PM CST Sun Dec 10 2017
.UPDATE...
Issued at 605 PM CST Sun Dec 10 2017
Allowed the Red Flag Warning to expire as winds have dropped off
for now. Expect winds to increase markedly tonight as the cooler 
air pushes in.
UPDATE Issued at 525 PM CST Sun Dec 10 2017
No changes planned for the current forecast mainly due to
lingering uncertainty with the clipper system that will be moving
into the region tonight. Models are not in great agreement over
western extent of precip or timing. Will update as needed later
this evening if the precip trends become clearer. 
&&
.SHORT TERM...(This Evening through Monday)
Issued at 321 PM CST Sun Dec 10 2017
Focus will be on the clipper system moving out of Canada tonight. 
Warm advection mid level precipitation will be focused across the 
far northeast into Minnesota and probably won't amount to much for 
our CWA this evening.  There is some mid level moisture just ahead 
of the surface front and soundings are supportive of snow through 
the profile down to the lowest few hundred feet though, depending on 
location, there may be a deep enough warm layer to melt. We do see 
an intermittent loss of saturation in the dendritic growth zone, so 
precipitation may change over to drizzle as well. We will also have 
to deal with winds, as 1/2km winds are around 50kts, though the core 
of that moves south of the area by morning and mixed winds are not 
nearly that intense. The core of strong winds doesn't match the 
strongest cold advection either, though the northeast where cold 
advection is strongest, will also benefit from a pressure bubble 
with rises upwards of 9mb/6hrs by the afternoon. Over the course of 
the day, mid level dry air will move in, and low level steep lapse 
rates don't move high enough to reach the dendritic growth zone so 
while we may see afternoon shallow cumulus, snow showers are not 
expected to linger behind the low. 
As for temperatures, cold advection will be weak from the James 
valley west, so temperatures there should see some moderation 
despite the change in airmass. East of the James, with convective 
clouds and cold advection, readings will struggle and probably cool 
through the day.
.LONG TERM...(Monday Night through Sunday)
Issued at 321 PM CST Sun Dec 10 2017
The upper level pattern will generally feature northwest flow, with 
a series of shortwaves moving through it and across the Northern 
Plains. The strongest of these waves will move through on Saturday. 
At the surface, high pressure will be dominant over the area Monday 
night through the day Tuesday. Will then see a frontal boundary 
slide across the area Tuesday night, doing little more than shifting 
the winds around to the northwest. May see breezy conditions and 
some light snow showers late Wednesday night into Thursday morning 
before high pressure moves back, bringing a return to dry conditions 
Thursday afternoon through Friday evening. A clipper low will slide 
out of Canada and across North Dakota and northern Minnesota over 
the weekend, possibly bringing some light precipitation to the CWA. 
Temperatures will continue to be mild through the entire extended 
period, with highs mainly in the 30s and 40s, and overnight lows in 
the 20s.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday Evening)
Issued at 525 PM CST Sun Dec 10 2017
As a clipper system moves through the region tonight, winds will
increase out of the northwest with gusts to around 40 kts. VFR
conditions will deteriorate to MVFR and possibly IFR in snow
showers near KABR and KATY.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
&&
$$
UPDATE...Wise
SHORT TERM...Connelly
LONG TERM...Parkin
AVIATION...Wise