Area Forecast Discussion
Issued by NWS Aberdeen, SD

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FXUS63 KABR 130518 AAB
AFDABR

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
1118 PM CST Mon Feb 12 2018

.UPDATE...
Issued at 526 PM CST Mon Feb 12 2018

Adjusted pops a bit tonight to account for the dry air layer that
the moisture is having difficulty overcoming. Not much more than
flurries are occurring along the Missouri River right now. Still
expect there to be some snow showers later this evening as a more
intense band of precip moves northeast out of NE and south
central SD.

&&

.SHORT TERM...(This Evening through Tuesday)
Issued at 216 PM CST Mon Feb 12 2018

Temperatures and pcpn chances are the main issues through Tuesday.
So far today most of the snow has been west river, with mainly just
flurries in the east as WAA band moves north across the region and
into North Dakota. Sfc high has probably been instrumental in
keeping dry air over the eastern CWA this afternoon. Next subtle
wave is expected to cross the region overnight. Model omega doesn`t
look too impressive, nor does potential vorticity, so will hang onto
idea of isold/sct pops with only light pcpn accumulations. Snow
should end by daybreak Tuesday.

As sfc high moves away tonight and Tuesday, WAA will break out
across the Northern Plains. This increasingly mild airmass will
linger into Wednesday, with the warmest temperatures this week
likely occurring Wednesday afternoon. Snow cover over the area will
provide a dampening affect on the temperatures, but for now feel
highs in the 20s to lower and mid 30s looks entirely possible for
Tuesday.

.LONG TERM...(Tuesday Night through Monday)
Issued at 216 PM CST Mon Feb 12 2018

Warm air advection pattern persists Tuesday night and through the
day Wednesday. This will bring mild temperatures to the region, with
highs still forecast in the 40s on Wednesday as 925mb temps rise to
around +2C or +3C by 00Z Thursday. Still have worries about the
west/southwestern CWA where snow pack is deeper. Did shave a couple
degrees off highs in that area. Although, surface pattern does
encourage good warming in a post-warm front air mass characterized
by westerly winds. Backing up to Tuesday night briefly, it appears
there will be a downslope wind event given the orientation and speed
of the 925mb jet and given warm air advection pattern. Hi-res models
are picking up on this and used their guidance while constructing
wind grids for Tuesday night.

Strong cold front with impressive cold air advection surges
southward through the area late Wednesday night into early Thursday
morning, so the warmth will be short-lived. 925mb temps plunge
quickly back down to around -18C to -21C at its coldest, along with
a stiff north breeze. Highs are forecast to drop back down into the
teens with wind chills dipping below zero once again. Pretty good
signals showing up for light snow as this colder air moves in.
Accepted inherited POP grids for the time being, with overall
accumulations remaining rather light. Models agree pretty well in
bringing a surface high through the area Thursday night, with winds
going fairly light. Have therefore dropped temps a touch from
SuperBlend for this time period, as it is usually too warm in these
scenarios, especially in ABR.

Warm air advection quickly ramps back up again Friday into Saturday
as the roller coaster temperature ride ensues. Given the 925mb temps
expected to move in, should once again be looking at highs in the
30s to around 40 degrees. By the time the weekend ends we should
have knocked back some of the snow cover across the region. Models
then show cold coming back in for Sunday and the start of next
week.

&&

.AVIATION...(For the 06Z TAFS through 06Z Tuesday Night)
Issued at 1118 PM CST Mon Feb 12 2018

VFR conditions are expected through the period.

&&

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

$$

UPDATE...Wise
SHORT TERM...TDK
LONG TERM...TMT
AVIATION...Wise



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