Area Forecast Discussion
Issued by NWS Bismarck, ND

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FXUS63 KBIS 241624

Area Forecast Discussion
National Weather Service Bismarck ND
1024 AM CST Sat Feb 24 2018

Issued at 1024 AM CST Sat Feb 24 2018

Low level water vapor imagery loop clearly shows a shortwave
moving north from Dunn County into Mountrail County. An area of
light snow with a quick burst of around a half inch occurred in
Manning as the shortwave moved through. Have expanded snow into
Minot and eventually the Turtle Mountains early this afternoon.
The NAMNEST seems to have the best handle on the current radar and
locations of snow.

Coordinated with Glasgow Weather Forecast Office to increase
POPS/snow chances in northwest ND 00z-06z Sunday. Upstream,
Canadian Radar shows precipitation shifting southeast associated
with a northern stream shortwave, which will impact northwest ND
this evening.

UPDATE Issued at 828 AM CST Sat Feb 24 2018

Regional radars showing a band of snow that has moved into
southwest North Dakota. This currently not handled well by any of
the short range models. There is a weak shortwave moving through
the region but not expecting snow this far west. Added chance of
snow southwest through the morning. Otherwise still expect the
main area of snow in the south central to the James river valley.

UPDATE Issued at 615 AM CST Sat Feb 24 2018

Minor short term updated to populate latest sensible weather
elements and made some small changes to sky cover this morning.
Otherwise current forecast looks to good.


.SHORT TERM...(Today and tonight)
Issued at 205 AM CST Sat Feb 24 2018

Main forecast issue in the short term period will be snow chances
today and this evening.

Currently, an upper level trough was situated from the northern
high plains into the desert southwest. A weak upper circulation
was located over eastern Montana and a strong shortwave was
rounding the base of the trough over the southern Rockies. At the
surface, broad high pressure was situated from the northern and
central plains into the Upper Midwest and Great Lakes region.

Areas of fog mainly over South Dakota into Minnesota have been
creeping slowly northward into the far southeast portion of the
CWA in a weak return flow. Will add some patchy fog into eastern
portions of Dickey and Lamoure counties early this morning.
Increasing clouds within broad mid and upper level forcing working
northeast through the central plains should limit the areal extent
of the fog over the JRV this morning.

This synoptic scale forcing tracks mainly from the central high
plains early this morning, into Minnesota by early evening,
clipping the far south central into the James River Valley,
similar to the system on Thursday. With the best FG forcing also
well south of the forecast area, light snow amounts are again
expected. Earlier iterations of the mesoscale models were keeping
the snow well south and east of Bismarck/Mandan, but the latest
few runs are inching back towards Bismarck. GFS/ECMWF and GFS
bufkit sounding support at least a brief period of light snow as
far west as Bismarck. For now will keep a slight chance of snow as
far west as Bismarck/Mandan with highest pops farther east into
the JRV, but if the GFS/EC solution pans out later shifts may need
to raise pops and go more with a high pop/low qpf scenario. In the
grand scheme of things, impacts will be minimal with only trace
amounts to under a half inch for a broad area from Selfridge and
Bismarck north and east to Harvey and Carrington. Higher amounts
of a half inch to up to a couple inches are expected from
Jamestown and Ashley east to Lamoure and Oakes.

We lowered forecast highs just a little given the cool start this
morning, limited mixing and increasing cloud cover.

Snow is expected to end over the JRV early this evening. Lows
tonight are expected to be mainly in the single digits above zero.
Could be a stray flurry or snow shower with weak shortwave energy
passing through within a northwest upper flow.

.LONG TERM...(Sunday through Friday)
Issued at 205 AM CST Sat Feb 24 2018

A split flow pattern will persist through the extended forecast
period. A weak northern stream flow is expected with minimal
impacts through the upcoming work week. Temperatures are expected
to be seasonable with highs in the upper 20s to mid 30s and lows
10 to 15 above.

Both the GFS and ECMWF show indications of upper ridging moving in
late in the work week ahead of a deep upper trough moving into
the northern rockies. This could bring a shot of warmer than
normal temperatures followed by better chances of precipitation,
but will see if this trend continues.


.AVIATION...(For the 12Z TAFS through 12Z Sunday morning)
Issued at 1024 AM CST Sat Feb 24 2018

The most recent model guidance suggests a quick burst of light
snow at KMOT with mvfr visibilities between 17Z and 19Z Saturday.

Light snow will move into far south central ND late Saturday
morning and spread northeast with time into the James River valley
for the afternoon. KJMS will likely experience MVFR to IFR
ceilings and visibility with the light snow Saturday afternoon and
early evening. This may only briefly impact the KBIS terminal
during the midday hours. We therefore carried a brief period of
6SM in light snow 18-21 UTC at KBIS with the 12 UTC TAF release,
though brief MVFR conditions could certainly occur.

Model guidance is also suggesting more widespread MVFR cigs/vsbys
in light snow with a northern stream wave tracking from northwest
into central ND late tonight. Did not go quite as aggressive as
model guidance but did bring some MVFR ceilings into KMOT aft 06
UTC Sunday.




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