Scientific Forecaster Discussion
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Area forecast discussion
National Weather Service Grand Forks ND
951 PM CST Tue Nov 19 2019
issued at 948 PM CST Tue Nov 19 2019
Temps holding fairly steady under the overcast sky cover. Will
increase lows for tomorrow morning as a result of nearly steady
temps. Onset of snowfall still on track to move into en ND by
sunrise with intensity and coverage increasing throughout the
morning into the afternoon along and north of a Hwy 200 line.
Short term...(this evening through wednesday)
issued at 320 PM CST Tue Nov 19 2019
500 mb trough entering northwestern Montana. 120 kt 300 mb jet
ahead of this feature is providing sufficient forcing to generate
an area of precipitation over southern Alberta, southwestern
Saskatchewan and northern Montana. This 500 mb wave and
accompanied jet will move into northwest and north central ND
Wednesday with sufficient forcing to continue an area of snow east
along the Manitoba border into the far northwest fcst area. Forcing does
weaken Wed aftn along the border, and develops farther south more
so in east central ND, near Grand Forks Wed aftn ahead of 500 mb
system moving northeast from the US southwest. Frontogenesis at
700 mb is quite strong on GFS/NAM 21z period near gfk and this
should provide an enhanced area of snowfall. How long this more
enhanced forcing lasts and snowfall rates will highly determine
snowfall amounts. Enough forcing with the first wave along the
Manitoba border to give a high chance of 3-4 inches to Cando to
Cavalier. Therefore coordinated with weather forecast office Bismarck and issued a
winter wx advisory for up to 4 inches of snow in this area 3 am
Wednesday to 6 PM Wednesday. 2-3 inches forecast Grand Forks
area, but will need to watch this in case heavier snow does
develop. For Grand Forks the range of snow from the probabilities
is from 1-4.
Farther east snow will reach into the Bemidji area Wed aftn with
heaviest not til Wed night.
Southeast ND will be warm enough for rain or drizzle Wed aftn...but a
change to snow is expected Wed eve. Trace to 2 inches expected.
Risk of freezing precipitation has diminished during the day
Long term...(wednesday night through tuesday)
issued at 320 PM CST Tue Nov 19 2019
Wednesday night will see the 500 mb trough and accompanied surface
low move northeast toward Iowa and Wisconsin with western edge of
precipitation with this system in west central, north central Minnesota
and points east. This is when Bemidji area area to see their main
snow with threat for 4-5 inches in this area. Coord with dlh and
due to snow Wed night, will not do an advisory quite yet.
Soundings do show drying aloft with a moist boundary layer on the
backside of the system over east ND Wed night. But forcing by that
time may be quite weak. Collab decision was to not mention fzdz.
Thursday through Saturday
The early portion of the forecast period will see the end of the
winter system associated with the low to the southeast. Some
lingering light snow is possible in north central Minnesota, but
Thursday will be colder with persistent northerly winds. Highs will
be in the lower 20s with winds in the 10 to 20 mph range with gusts
to 30 mph possible. For Thursday night, decreasing winds and
clearing skies, combined with any lingering snow cover, could allow
for temperatures to drop lower than currently forecasted. Teens and
single digits are likely, if not colder.
With a surface high building in the central U.S. Following the
system, drier and more settled weather returns Friday into Saturday.
Temperatures look to return to near normal with highs in the 30s and
lower 40s and lows in the 20s.
Sunday through Tuesday
Towards the end of the period, there is some hint of more active
weather possibly returning. With guidance suggesting a Canadian
surface low to the north on Sunday, westerly flow looks to keep
temperatures above average with temperatures reaching into the 40s.
A small 500mb, suggested by American and Canadian guidance, could
provide chances for some light rain or snow to end the weekend.
Into early next week, global guidance is in agreement for a
potentially weak surface low progressing leeward from The Rockies.
An associated 500mb trough is hinted with global guidance, which
could provide enough forcing for light precipitation chances Monday
and Tuesday. Uncertainty is still high this many days out, but
seasonal temperatures with chances for light precipitation will be
something to watch into early next week.
Aviation...(for the 00z tafs through 00z Wednesday evening)
issued at 559 PM CST Tue Nov 19 2019
Primarily MVFR expected with pockets of low end VFR into the
overnight with cigs then lowering from west to east tomorrow
morning as snow band moves into the area. As snow intensities
increase vsbys will lower tomorrow morning into the afternoon as
low as 1/2 mile where moderate snowfall rates are occurring.
ND...Winter Weather Advisory from 3 am to 6 PM CST Wednesday for