Area Forecast Discussion
Issued by NWS Bismarck, ND

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FXUS63 KBIS 210930

Area Forecast Discussion
National Weather Service Bismarck ND
430 AM CDT Tue Mar 21 2017

.SHORT TERM...(Today and tonight)

Issued at 430 AM CDT Tue Mar 21 2017

The main forecast highlight in the short term period will be
colder temperatures today.

Currently, cold surface high pressure over Saskatchewan and
Manitoba building southward into central and eastern North Dakota.
Some low stratus and a few flurries accompanying this cold air
push mainly over the eastern third of the state. Light
precipitation in the form of snow continues over the far southwest
near a frontal zone and underneath a mid level impulse moving
east-southeast. Utilized a blend of the latest NAM with our
consensus short term guidance for pops/qpf, and could see some
light snow accumulations in grassy areas.

Light snow over the far southwest will taper off 12-18Z as forcing
diminishes. Main story today will be colder temperatures as high
pressure continues to build south over the Eastern Dakotas and
Upper Mississippi Valley. Highs today will only reach the low 20s
north central and low to mid 30s elsewhere.

Southerly return flow ramps up quickly later today and especially
into tonight west and central along with upper level ridging
aloft. Light precipitation will be possible far south with
favorable LLJ dynamics and as several embedded impulses lift
across the Dakotas. Thermal profiles suggest snow.

.LONG TERM...(Wednesday through Monday)

Issued at 430 AM CDT Tue Mar 21 2017

The extended period will be highlighted by a continued
progressive flow pattern.

An upper level ridge axis will be over the region at the beginning
of the long term period Wednesday. Embedded S/WV cuts through the
ridge coupled with a warm frontal zone moving east across the
Dakotas to bring a chance for rain or snow during the day
Wednesday. Ridge moves east Wed night allowing south/southwesterly
flow to develop ahead of a potent upper level trough/closed low
over the Great Basin. Lead S/WV ejects through the flow across the
Dakotas late Wed night into Thursday bringing a chance for
precipitation to our areas. Thermal profiles suggest a window of
freezing rain possible, so this was added/maintained in the
gridded forecast along with mentioning in the HWO and SFP. Upper
low moves eastward across the Central Plains with best
precipitation chances across the southern half of the state on
Thursday mainly in the form of rain as models have trended a bit
warmer. Active pattern then continues through the weekend though
with much uncertainty given large model spreads.


.AVIATION...(For the 06Z TAFS through 06Z Tuesday night)

Issued at 140 AM CDT Tue Mar 21 2017

With the exception of brief MVFR conditions at KJMS tonight with
cigs currently BKN020, expect VFR conditions through the period.
Satellite imagery shows relatively small patch of lower clouds near
KJMS progressing southward, so have only carried it in forecast for
a couple hours. By Tuesday evening will begin to see lowering
ceilings across western locations along with stronger southerly
winds ahead of an area of low pressure approaching from the west.





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