Area Forecast Discussion
Issued by NWS Bismarck, ND

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FXUS63 KBIS 160846

Area Forecast Discussion
National Weather Service Bismarck ND
346 AM CDT Fri Mar 16 2018

.SHORT TERM...(Today and tonight)
Issued at 304 AM CDT Fri Mar 16 2018

The concern in the short term will be snow amounts across
southwest North Dakota. The southwest will just see a brushing of
snow as an upper low closes off south of the region causing a
pivot in the precipitation area. The dominant high pressure over
eastern North Dakota will keep the region dry for all but the far
southwest. Consensus snow amounts today and tonight across the
southwest will be up to 2 inches. Skies will be cloudy southwest
and partly to mostly sunny north and east.

.LONG TERM...(Saturday through Thursday)
Issued at 304 AM CDT Fri Mar 16 2018

The level of uncertainty in the long term continues to be high.
Model QPF differences and low level temperature profiles make the
weather type, and the eventual snow amounts and potential ice
accumulations, very uncertain for the Sunday through Monday

First, Saturday will see warmer temperatures as the consensus
among models suggests the an upper low across the central plains
will depart, to be replaced with a building h500 ridge over the
northern plains. This ridge forms in response to a three headed
h500 low over the northwest US. The fact this system is dispersed
over the northwest will lead to a spread in the model solutions as
the upper low breaks down and sends a split flow across the
northern plains Sunday into Monday. The more intense portion of
upper low will remain south of the region, which leaves the
northern plains in weak flow aloft dominated by the northern
stream upper low across southern Canada. The spread in model
solutions will impact the weather type as the GFS, the colder
solution, suggests a mix of rain and snow transitioning to all
snow. The SREF precip type suggests more widespread freezing rain,
with the Superblend input resulting also in freezing rain, due
primarily to a lack of ice crystals impacting natural cloud
seeding. Bufkit soundings analysis pegs the mid levels more
saturated than the Superblend depicted so initialized the ProbIce
with the GFS. This gave a more realistic weather type, still a
wintry mix of rain and snow and freezing rain but was judged a
better transition from the wintry mix to snow. Lastly the QPF also
contains significant uncertainty. If the southern system becomes
more dominant and remains further south the higher QPFs suggested
by the GFS may be overdone. So smoothed the QPF with an average of
the GFS and the Superblend. This still leads to fairly high
uncertainty in the the snow fall amounts.

Tuesday through Thursday will become milder owing to a broad
ridge over the northern plains. By Friday rain and snow are
possible with the approach of a shortwave trough in southwest flow


.AVIATION...(For the 06Z TAFS through 06Z Friday night)
Issued at 1214 AM CDT Fri Mar 16 2018

Slow moving surface trough from Nebraska northwest into Montana
will remain nearly stationary through Friday. High pressure across
eastern North dakota will maintain an easterly surface wind. VFR
conditions are forecast through the 06z TAF period. The only
exception will be KDIK which may see some light snow and MVFR
ceilings after 02Z.




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