Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

fxus63 kfgf 081251 

Area forecast discussion
National Weather Service Grand Forks ND
651 am CST sun Dec 8 2019

issued at 639 am CST sun Dec 8 2019

Made some minor tweaks to the timing of the freezing drizzle
moving south across our area, as well as flurries. Accumulations
will hold off until late afternoon/tonight. Increased winds a bit,
with blowing snow mention for this morning. Will also re-issue west-southwest
product to better fit graphical messaging as far as snow totals


Short term...(today through monday)
issued at 400 am CST sun Dec 8 2019

Freezing drizzle this morning and snow tonight will be the main
issues for the period.

Cold front on its way down across the forecast area at the current
time, bringing clouds, strong northerly winds, and spits of very
light precip. There has been a continued area of light freezing
drizzle and a few flurries/snow grains pushing south just behind
the front. Think that this area will continue to move south
through the rest of the early morning. At this point impacts seem
minimal, so will handle by re-issuing an Special Weather Statement and a graphicast.

The mid-level baroclinic zone in our southern counties intensifies
as we head into this afternoon and tonight, just as the main upper
trough axis moves into the Dakotas. There is a good amount of
synoptic lift along with some good 700mb frontogenesis, indicating
the potential for banding mainly south of the Highway 200
corridor. Some of the operational runs go bananas with qpf,
putting out enough for 8 or more inches of snow along the I-94
corridor. Some high resolution runs are similar, but others not as
much. Think there is the potential for 6-8 inches in a narrow band
somewhere across our south, but not sure exactly location at this
point. In addition, breezy north winds will bring some blowing
snow potential, at least where snow is falling. Have a Winter
Weather Advisory for much of the southern half of the cwa,
starting at 21z in the west and 03z in the east.

Monday, the upper trough axis moves past US, and think that most
of our precip will be done during the 12-15z time frame. Winds
will also decrease during the day Monday, becoming light and from
the west as a weak surface low develops ahead of the reinforcing
surge of Arctic air comes down later. Not that Monday will be warm
by any means, just not with highs below zero yet like we will see
later in the week.

Long term...(monday night through saturday)
issued at 400 am CST sun Dec 8 2019

Main story for the long term period will be the season's first
Arctic air intrusion bringing frigid air and wind chill
temperatures region-wide Monday night through Thursday morning.

Arctic air mass plunges into the region as upper polar low meanders
south over the Hudson Bay. Several shortwaves within the low's flow
will reinforce the Arctic air mass into the region starting Monday
night lasting through Wednesday. With these shortwave troughs,
reinforcing Arctic cold fronts will keep winds elevated while
maintaining temperatures near and below zero. One of these cold
fronts early Tuesday will allow winds to gust in excess of 20 mph,
causing patchy blowing snow especially for those who should see
Sunday night/monday's fresh snow in the southern valley. Coldest
conditions are expected Tuesday and Wednesday with temperatures
likely remaining below zero starting Monday night lasting through
Thursday morning. Wind chills in the 20s to 30s below zero continue
to be forecast during this time, something more reminiscent of
January or February. With this type of forecast, an extended length
of wind chill headlines may be needed. It is not until Thursday will
Arctic temperatures gradually loosen their grip on the area as the
responsible upper low pushes east and warmer air slowly advects into
the region.

Northwesterly flow aloft turns more zonal with embedded clippers
passing over the region late next week. This will bring periodic
chances for snow, although likely more on the lighter side given the
lack of quantitative precipitation forecast signals in ensemble guidance likely owing to the lack of
moisture availability behind the exiting Arctic airmass. However,
even light snow events occurring at the right time (i.E, rush hour)
could bring some level of transportation impacts at times towards
the end of the work week into next weekend.


Aviation...(for the 12z tafs through 12z Monday morning)
issued at 538 am CST sun Dec 8 2019

Mostly IFR to MVFR ceilings although a few spots in the forecast
area are borderline VFR. There is an area of freezing drizzle/rain
moving through the kfar area, and based on upstream observations
it should only last an hour or so. A few airports could improve to
VFR or MVFR for a time today, but then go back down tonight as
the main system approaches. Some flurries behind it, but the
better snow will hold off until tonight. Snow will begin in the
kdvl area during late afternoon and evening and spread
southeastward tonight. Have vis mostly in the 2-5sm range except
at kfar where snow is expected to be heavier and may reduce vis to
under 1 mile overnight. Blowing snow may also be an issue at times
today and tonight as north winds gust above 25 kts. Snow will
taper off across the western airports after 06z, but may be
hanging around at kfar and kbji at the end of the period.


Fgf watches/warnings/advisories...
ND...Winter Weather Advisory from 9 PM this evening to 9 am CST
Monday for ndz030-039-053.

Winter Weather Advisory from 3 PM this afternoon to 6 am CST
Monday for ndz014-024-028-029-038-049-052.

Minnesota...Winter Weather Advisory from 9 PM this evening to 9 am CST
Monday for mnz002-003-022>024-027>032-040.



National Weather Service Glossary of Abbreviations