Area Forecast Discussion
Issued by NWS Bismarck, ND

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FXUS63 KBIS 172117

Area Forecast Discussion
National Weather Service Bismarck ND
317 PM CST Sun Dec 17 2017

.SHORT TERM...(This evening through Monday)
Issued at 309 PM CST Sun Dec 17 2017

Late tonight/early Monday morning a Canadian cold front will begin
a southward descent into ND, progressing across the state through
Monday. The proceeding warm front will make for a mild Monday,
particularly in central and southern areas where high temperatures
are expected to climb into the mid/upper 40s. Forcing with this
system remains concentrated across the north, where the best
chances for precipitation will be. Though we could see some
precipitation track with the cold front as it drops south through
the forecast area. The 12Z model suite is indicating higher QPF
then previous model runs. Chances for precipitation were increased
in the forecast though overall accumulations still look to be
light. Snowfall amounts of a few tenths are forecast with pockets
of 1-2 inches possible in northern areas. Mostly snow is forecast
for the morning with chances transitioning to rain and snow late
morning/early afternoon.

Breezy conditions are also expected Monday though disagreement
within the model blend and guidance continues to create uncertainty
as to how strong winds may become. Though the 12Z guidance is
indicating momentum transfer is possible with phasing between
surface and 850MB winds and steep mid/upper level lapse rates, opted
to go with the model blend in the forecast. The model blend does
highlight southwest and south central areas with breezy conditions
which is also where ingredients align within the guidance for the
potential for gusty conditions with gusts around 40mph.

.LONG TERM...(Monday night through Sunday)
Issued at 309 PM CST Sun Dec 17 2017

Noticeably colder air is expected to spill into the state Monday
night and Tuesday. Late Tuesday night through Thursday will be a
transition period as an upper level trough moves onto the West
Coast and then drops into the Desert southwest. The strongest
synoptic scale forcing will track to the south of our area, with
the upper low, but modest synoptic scale forcing will still exist
over the area ahead of a northern stream trough. This will combine
with a period of decent warm advection associated with a strong
baroclinic zone that moves across the northern plains Tuesday
night and Wednesday. Models continue to wobble on the placement of
precipitation with the system. Latest runs keep higher amounts in
the north Wednesday, with a southward shift in precipitation
Wednesday night into Thursday. No matter where the snow ends up,
at this time it looks like we can be assured of a blast of Arctic
air, resulting in dangerously cold wind chill values, late in the
forecast period, lingering at least through Christmas.


.AVIATION...(For the 18Z TAFS through 18Z Monday afternoon)
Issued at 1128 AM CST Sun Dec 17 2017

Quiet weather through the first half of the 18Z TAF period. Early
Monday morning (after 06Z) a cold front will bring chances for
snow, mainly across the north. The bulk of the snow will likely
arrive between 12Z and 18Z. Areas with snow will experience low
VFR ceilings and possibly MVFR conditions. KISN/KMOT will have the
best chances for snow. Light snowfall accumulations around a few
inches are expected at this time.




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