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Area forecast discussion...updated 
National Weather Service Duluth Minnesota
542 am CST Thursday Dec 25 2014

Update...
issued at 542 am CST Thursday Dec 25 2014

Updated for the new 12z aviation discussion below.

&&

Short term...(today through friday)
issued at 250 am CST Thursday Dec 25 2014

A weakening area of low pressure was moving into northwest Ontario at 08z
with a frontal boundary moving through the Red River valley of the
north. A SW flow was over the forecast area ahead of this system with a few
flurries. Meanwhile...a quasi zonal flow was setting up over the
western Great Lakes. This fast flow will continue over the forecast area
through tonight when a middle level trough arrives from the northern
plains. The aforementioned surface low will travel eastward through northwest
Ontario before dissolving. The surface low will push the frontal
boundary through NE Minnesota and reaching northwest WI by 00z Friday. Some
flurries are possible early this morning as an area of fgen at 700 mb
arrives. By middle morning...some light snow will begin to develop
along the southern edge of the forecast area with this fgen and a confluent
flow. The low level moisture will be scoured out leaving middle and
upper level moisture. This will lead to lower quantitative precipitation forecast amounts and lower
snow amounts and have adjusted downward accordingly.

The 700 mb fgen maximum lifts northward a bit tonight with the confluent
flow continuing...exiting northwest WI by 12z Friday. Gradually moved some
probability of precipitation northward as a result...but not as far north as previous
forecast. The axis of greatest snow will be in the vicinity of the fgen
maximum...but still lower amounts than previous forecast as models have
trended downward with their quantitative precipitation forecast amounts and have adjusted
accordingly. Have low confidence on a mention of freezing drizzle
tonight and will leave out. Thus will keep ptype as all snow.

On Friday...the middle level trough departs. The majority of the forcing
will occur in the morning with the trough and deepest moisture. By
afternoon...the forcing has weakened/exited and a drying trend
ensues as surface ridging begins to move into the forecast area from the northern
plains. Left some probability of precipitation in northwest WI in the afternoon in the vicinity of
lingering moisture. Amounts will again be light.

Long term...(friday night through wednesday)
issued at 250 am CST Thursday Dec 25 2014

Friday night and Saturday...a low will lift from the
southern/Central Plains Friday evening to the Great Lakes early
Saturday. The Northland could see light snow on the west side of
this low. The European model (ecmwf)/Gem have a stronger low and more northerly path
than the GFS. The nam12 has a similar track to the ECMWF/Gem...but
the low is not as strong. Leaned on the European model (ecmwf)/Gem solutions which
favors more coverage of light snow over the southern and eastern
forecast area.

Saturday night and Sunday...the passage of a weak Alberta clipper
and cold front could bring a dusting of light snow to much of the
Northland.

Next week...the Northland can expect a stretch of significantly
colder than normal weather Monday through Wednesday. A large area of
high pressure will gradually move out of western Canada into the
central US. Temperatures will likely drop to about 10 to 15 degrees
below normal. Leaned on the colder European model (ecmwf) MOS guidance.

&&

Aviation...(for the 12z tafs through 12z Friday morning)
issued at 542 am CST Thursday Dec 25 2014

Much of NE Minnesota and northwest Wisconsin had overcast MVFR ceilings early this
morning and light SW winds. The MVFR conditions will likely
continue through tonight...but there could be short periods of IFR
ceilings and/or IFR visibilities from -sn that will develop later today. A
cold front will move through the region today...and a band of middle
level frontogenesis could produce -sn. The light winds will become
west-northwest this afternoon in the wake of the front.

&&

Preliminary point temps/pops...
dlh 33 27 30 14 / 10 20 20 10
inl 31 23 24 2 / 10 10 10 10
brd 32 25 27 11 / 20 30 20 10
hyr 33 29 31 18 / 30 30 30 50
asx 34 29 32 20 / 20 30 30 40

&&

Dlh watches/warnings/advisories...
Minnesota...none.
WI...none.
Ls...none.
&&

$$

Short term...gsf
long term...grochocinski
aviation...grochocinski

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