Area Forecast Discussion
Issued by NWS Aberdeen, SD

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FXUS63 KABR 172334 AAA

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
534 PM CST Wed Jan 17 2018

Issued at 534 PM CST Wed Jan 17 2018

00z aviation discussion updated below.


.SHORT TERM...(This Evening through Thursday)
Issued at 253 PM CST Wed Jan 17 2018

The downslope wind event on the eastern side of the Sisseton Hills
continues with gusts of 30-40 mph still ongoing.  These winds are
expected to diminish a bit, though remain windy with gusts of 25-30
mph through Thursday morning.

With little snow on the ground, southwest to westerly mixing winds
have allowed for significant warming this afternoon.  Temperatures
are about 10-20 degrees above average throughout the region.  With a
similar set-up Thursday, expect to see another warm day with highs
in the 40s across most of the area and even into the 50s in the
central part of the state.

.LONG TERM...(Thursday Night through Wednesday)
Issued at 253 PM CST Wed Jan 17 2018

Friday: Mild! 925mb temperatures are close to 2 to 4C and even
higher in the downslope areas overnight. A weak surface trough
crosses the area early, with weak cold advection on a light
northwest wind. This will aid mixing, despite temperatures aloft
cooling so the expectation will be that we jump out into the 40s
early in the day and stall/fall from there.

Saturday: 925mb temperatures are a bit cooler, around +1C. There
will be increasing high clouds as the ridge is suppressed by a
trough in the western CONUS, and wind will be generally light, but
maintain a westerly component.

We also begin to see a weak wave drop out of Canada on top of the
ongoing storm organizing to the southwest, in co-location with a
right entrance region of a 150kt jet, and that is the reason for
increasing mid level moisture and forcing that generates light
precipitation as it extends out of western South Dakota. All sets of
guidance have this feature in one form or another, though there will
be some mild air to overcome (although without the re-enforcing
northeast wind direction).

Sunday/Monday: Confidence is high that a Colorado low will develop
and lift northeast. The issue is the exact track which continues to
wobble just to the south of what is the more favorable track for our
CWA. P-TYPE from top down should be cold enough for snow, though
the dendritic growth zone varies with height there shoudn`t be a
melting layer by the time precipitation intensifies. There will
be a northwards gradient in snowfall between the warm advection
bands/pivot point and follow on TROWAL. Blended guidance works for
today as the trend has been a touch northwards but again, if the
track shifts anymore south, much of the CWA could end up snowless.
Thus, while deterministic guidance and ensembles show the system
impacting the CWA the confidence on degree of impact is low.


.AVIATION...(For the 00Z TAFS through 00Z Thursday Evening)
Issued at 534 PM CST Wed Jan 17 2018

VFR conditions are expected through tonight and Thursday at all




LONG TERM...Connelly
AVIATION...Mohr is the U.S. government's official web portal to all federal, state and local government web resources and services.