|Mesoscale Discussion 1777|
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Mesoscale Discussion 1777
NWS Storm Prediction Center Norman OK
1211 PM CST Mon Dec 04 2017
Areas affected...portions of eastern ND...northeast SD and northwest
and west-central MN
Valid 041811Z - 042215Z
SUMMARY...Heavy snow, with rates of one inch/hour will become more
widespread through this afternoon. Increasing surface winds with
time this afternoon will result in some areas experiencing blizzard
DISCUSSION...Surface low pressure over southeast MN at 18z will move
northeast and deepen rapidly this afternoon and tonight as a strong
upper-level shortwave trough becomes increasingly negatively tilted
across portions of the central/northern Plains and Upper Midwest.
The combination of low-level cold advection and dynamic cooling due
to ascent within the deformation zone will result in the transition
to snow spreading farther east across northwest MN through this
afternoon. Increasing large-scale ascent should also develop
farther south this afternoon, resulting in the area of snow
developing into northeast SD and west-central MN. RAP forecast
soundings support heavy snow with rates of one inch/hour for a few
hours at any location. An occasional lightning strike is also
possible in the presence of modest elevated instability, resulting
in brief locally heavier snowfall rates.
As the surface low deepens this afternoon and evening, increasing
surface winds will result in blizzard conditions developing across
much of the discussion area.
...Please see www.spc.noaa.gov for graphic product...
LAT...LON 48979703 49019591 48929554 48849536 48379529 47989531
47539535 46499574 45599633 45229667 45099680 45169718
45569745 47189750 48979703
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