Area Forecast Discussion
Issued by NWS Aberdeen, SD

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
FXUS63 KABR 222049

Area Forecast Discussion
National Weather Service Aberdeen SD
349 PM CDT Thu Mar 22 2018

.SHORT TERM...(This Evening through Friday Night)
Issued at 349 PM CDT Thu Mar 22 2018

Much of the fog and lower clouds from earlier today have dissipated,
but patches remain across the CWA. Temps have risen nicely into the
40s for most areas, with 50s showing up over the southwest CWA.
Modest easterly breezes continue over the CWA.

During the overnight hours, clouds and moisture will increase from
the west as the storm system moves in. Winds will increase as well,
and used more of a CONSMOS blend for speeds Friday into Friday
night. Difficult forecast shaping up as the placement of the
rain/snow line will be key in just where the heaviest snow will
fall, along with where the sharp cut-off lies. The far northeast CWA
still appears to be in the coldest air the longest, thus better
chances for heavier accumulating snow. Upgraded this area to a
Winter Storm Warning based on latest guidance and forecast snow
amounts. Further west, went with a Winter Weather Advisory as the
rain/snow line should be setting up somewhere in this area, with
reduced totals and maybe more of an icing potential as well. Bufkit
still continues to show a few hours of moderate freezing rain in the
Watertown area, so edited the grids to include more icing potential
in the Coteau/Glacial Lakes region. Still a bit worried what temps
in the 30s will do for accumulating snowfall during the day in late
March - will really need to get some good snowfall rates and large
flakes to make some accumulations. Believe this will happen for the
far east where temps will be around 34 or 35 degrees. In the
advisory area, temps may be a degree or two warmer closer to the
rain/snow line, so could see more difficulty in accumulations, as
well as a sharper cut-off to the snowfall. Of course, a slight shift
in the rain/snow line, or a longer duration of colder air could mean
higher snow totals in the advisory area. In fact, we do have
accumulations near 7 or 8 inches right along the ND border in
McPherson and Brown counties, although it drops off to as little as
an inch over southern Brown. Due to the lack of areal coverage of
the higher totals, decided on the advisory - and also due to the low
confidence. Overall, a rather difficult forecast since we`re dealing
with differing precip types, temps just above freezing, and a
waffling rain/snow line. Unfortunately, it makes the forecast a
medium to fairly low confidence one. But, current headlines seem to
match all available guidance to the best of their ability.
Adjustments to headlines and snow amounts are certainly possible

.LONG TERM...(Saturday through Thursday)
Issued at 349 PM CDT Thu Mar 22 2018

The extended contains several period of potential precipitation. For
the time being, the bar is set at mostly rain or rain/snow p-types
with each of them. Depending on time of day and surface temps, some
of the "rain" chances could end up turning into freezing rain
chances. POPs show up mainly Saturday night into Sunday and then
again Sunday night through Monday. Deterministic and Ensembles
output indicates temperatures should be running near normal
throughout the period.


.AVIATION...(For the 18Z TAFS through 18Z Friday Afternoon)
Issued at 1233 PM CDT Thu Mar 22 2018

BR and low CIGs below 1000 ft will affect KMBG and KATY early this
afternoon, with gradual improvements expected. Over KABR and KPIR,
VFR conditions are occurring and expect VFR to persist into the
evening hours. Although, conditions will deteriorate once again
overnight as a storm system moves in. CIGs will fall to around
1000 ft or lower towards the end of the TAF forecast period, with
VSBY gradually lowering as well as mixed precipitation and BR move
into the region.


SD...Winter Storm Warning from 10 AM Friday to 7 AM CDT Saturday for

     Winter Weather Advisory from 10 AM Friday to 7 AM CDT Saturday
     for SDZ011-019-020-022.

     Winter Weather Advisory from 7 AM Friday to 7 AM CDT Saturday
     for SDZ005-006.

MN...Winter Storm Warning from 10 AM Friday to 7 AM CDT Saturday for



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