Area Forecast Discussion
Issued by NWS Bismarck, ND

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FXUS63 KBIS 130920

Area Forecast Discussion
National Weather Service Bismarck ND
320 AM CST Tue Feb 13 2018

.SHORT TERM...(Today and tonight)
Issued at 319 AM CST Tue Feb 13 2018

Currently, there is an upper level split flow, with a trough
extending from California northeastward to the Dakotas, while an
upper level ridge builds into the Canadian Rockies. At the surface,
arctic high pressure had exited the Northern Plains, and was now
situated over the Great Lakes region. Meanwhile a surface warm front
extended from a low over north central Canada across
Saskatchewan/Alberta into western Montana. The area of clouds with
light snow that was over south central ND Monday evening has moved
into eastern ND. Latest radar trends indicated the area of light
snow was dissipating rapidly over central ND.

Today the warm front moves east across the Dakotas with an
increasing pressure gradient to increase southwesterly winds to 15
to 25 mph across western and central ND. Good warm advection with
H850 temps around +3C to +4C spreading over our area, indicative of
the mild Pacific airmass moving into our region. After yesterday`s
highs in the single digits above zero, today`s high temperatures in
the 20s to lower 30s will be a noticeable change.

The southwesterly winds of 10 to 15 mph continue tonight with the
Pacific airmass in place, though the upper level ridge flattens to a
more zonal flow ahead of the anticipated Wednesday cold front.
Expect lows tonight in the teens and lower 20s above zero.

.LONG TERM...(Wednesday through Monday)
Issued at 319 AM CST Tue Feb 13 2018

The long term will be dominated by cyclonic flow aloft as a Hudson
Bay Low develops, and broad low pressure envelopes much of North
America. This will allow shortwaves in the flow to move across our
area, bringing chances of precipitation Wednesday/Thursday, and
Saturday through Monday.

Wednesday and Thursday:

As the upper level Hudson Bay Low develops, the first upper level
shortwave trough develops over the Pacific Northwest, and the Hudson
Bay low expands southward into the north central US states. This
will allow an arctic cold front to drop south and enter northern
North Dakota late afternoon on Wednesday. Ahead of the front, well
above average temperatures are expected, with highs in the low to
mid 30s northern counties and upper 30s and lower 40s over southern
counties. Precipitation develops as the front sweeps in. Chances for
snow will increase from north to south in the afternoon and evening
in the wake of the front, with a little rain/snow mix is possible.
Periods of snow are expected to continue overnight and into Thursday
morning, with generally an inch or two possible over most areas
north of I-94, maybe up to 3 inches over some northern counties.
Areas south of the interstate are expected to receive an inch or
less snow accumulations Wednesday night through Thursday morning.
The cold air spreads south across the state, with lows Wednesday
night from 5 below zero north to around 10 above south. Highs
Thursday should range from the single digits above zero north to 10
to 15 above south.

Warming trend the re-develops for the end of the work week into
the start of the weekend. The next disturbance pushes into the
area this weekend, but models differ a little on the placement and
timing of the system. Will keep elevated chances for precipitation
in the forecast. As of now, there is a chance of snow Saturday
afternoon through Sunday morning, with current model trends favoring
the northern half of the state for some light snow amounts. The next
system for Sunday night and Monday has a fairly large spread in the
ensemble solutions for precipitation amounts/placement. Will keep a
chance of light snow in the forecast, and we await better model
agreement in later model runs.


.AVIATION...(For the 06Z TAFS through 06Z Tuesday night)
Issued at 1217 AM CST Tue Feb 13 2018

At midnight cst, areas of low VFR cigs and vsbys with light snow at
KBIS are expected to move into KJMS by around 07z. Snow ending and
conditions improving to mid clouds before 09z at KBIS and by 12z at
KJMS. Otherwise VFR conditions will prevail.

Areas of MVFR cigs and vis with some light snow possible through
early this evening along to south of Interstate 94 mainly
impacting KBIS-KJMS. Otherwise VFR conditions will prevail.




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