Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 081023

Area Forecast Discussion
National Weather Service Marquette MI
523 AM EST Thu Dec 8 2016

.SHORT TERM...(Today and tonight)
Issued at 523 AM EST THU DEC 8 2016

The SFC trough and associated band of heavy snowfall is currently
moving onshore from Marquette through Whitefish Point. Should see
very poor conditions right along the trough, then moderate to heavy
LES behind that. Elsewhere, NW winds LES will continue through the
short term. Most uncertainty in the short term is where the Lake
Nipigon enhanced band will be today through tonight. Models still
differ on exactly where to place the band and how transient it will
be...but it should be between Marquette and Munising. Best guess
right now is that the band will become more steady tonight when the
land breeze sets up...keeping the band possibly near the
Marquette/Alger border where some heavier snowfall totals will
result. Only change to winter headlines was to add a Lake Effect
Advisory for Delta County as bands get into the northern and eastern
portions of the County. Looks like bands will stay west and east of
southern Schoolcraft County, so left that out for now. See the
forecast and winter headlines for more details.

.LONG TERM...(Friday through Wednesday)
Issued at 412 AM EST THU DEC 8 2016

Nam shows a broad 500 mb trough over most of the U.S. 12z Fri with a
shortwave moving into the northern plains 00z Sun and into the upper
Great Lakes late Sat night. Nam brings in some deeper moisture and
strong 850-500 mb q-vector convergence Sat night across the area.
Went with persistence for the lake effect and made very few changes
to the going forecast. One change though is the system for Sat night
looks to be a bit further south now and lowered pops a bit for this.

In the extended, GFS and ECMWF show a 500 mb trough with 850 mb
temperatures from -15C to -19C over Lake Superior 12z Sun. There is
also a sfc low pressure system passing by to the south near Dubuque,
IA. The upper level trough at 500 mb broadens and deepens across the
U.S. on Mon with colder air poised to come down over the northern
plains and northern Rockies. This colder air sweeps across the upper
Great Lakes on Tue with a sfc cold front moving through the area.
850 mb temperatures drop down to -23C to -28C by then over Lake
Superior at 12z Wed with the core of the coldest air over the area
then. Slow modification takes places on Thu as the cold core moves
over the New England. Prolonged lake effect snow event during this
forecast period with temperatures well below normal.

.AVIATION...(For the 06Z TAFS through 06Z Thursday night)
Issued at 1225 AM EST THU DEC 8 2016

A sfc trough/cold front will push south across the northwest half of
Upper Mi overnight and across the rest of the forecast area Thu
morning. IWD could see a brief burst of heavier snow overnight
with LIFR vsbys as this trough moves through. Otherwise, at CMX and
IWD generally expect occasional lake effect with IFR vsby and MVFR
cigs through the period. At SAW, expect mainly VFR conditions
into the overnight hours and then widespread lake effect snow showers
moving in around or just after daybreak on Thu with IFR vsby and MVFR
cigs through most of Thu. Conditions could improve at SAW Thu
evening as winds back more nw and push heavier lake effect bands

.MARINE...(For the 4 AM Lake Superior forecast issuance)
Issued at 523 AM EST THU DEC 8 2016

NW winds will gust up to 30 kts through Fri. Winds should diminish
to less than 25 kts through the weekend as pressure gradient
weakens. Freezing spray and heavy freezing spray is possible in the
middle of next week.

Upper Michigan...
  Lake Effect Snow Advisory until 7 AM EST Saturday for MIZ006-007-

  Lake Effect Snow Warning until 7 PM EST Friday for MIZ004-005.

  Lake Effect Snow Warning until 7 AM EST /6 AM CST/ Saturday for

  Lake Effect Snow Advisory until 7 PM EST Friday for MIZ013.

Lake Superior...
Lake Michigan...


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