Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 091809 AAA

Area Forecast Discussion...UPDATED
National Weather Service Marquette MI
109 PM EST Fri Dec 9 2016

Issued at 108 PM EST FRI DEC 9 2016

...Some headlines cancelled but other areas will see heavy lake
effect snow especially tonight...

Quite the convergence band that affected far eastern Marquette
county and western Alger county last night into this morning. Based
on radar estimates and the available isolated reports, likely that
at least a foot of snow occurred in narrow area from east side of
Harvey to Sundell/south of Deerton in western Alger county. Most of
that probably fell since daybreak this morning, especially for
Marquette county. Band of snow has shifted east into Alger so
dropped warning for Marquette and winds becoming west over far west
near IWD will also lead to improving conditions enough to drop the
warning for Gogebic.

Shortwave upstream over Manitoba moves across tonight with deep q-
vector convergence/lift noted. This forcing and cooling h85 temps to
near -20c will enhance where the snow is ongoing, probably in a
significant way. Sfc trough/lake induced troughing remains over
Upper Michigan this morning extending from northern Lower Michigan
to near Duluth. Convergent westerly flow in the vcnty of the trough
will produce more heavy lake effect snow tonight as land breeze only
further increases convergence. Appears likely that heavy snow will
affect northern Ontonagon county into Houghton county as enhanced
snow band focuses off tip of Bayfield Peninsula. Also have potential
of mesolow/enhanced convergence band setting up over eastern Lk
Superior into far northeast cwa, further sharpened by land breeze
off Ontario. This area will have added factor of seeing nw winds
across long axis of north central to eastern Lk Superior. Expect
very heavy snow with snowfall rates probably similar to what occured
today with the dominant band eastern Marquette into western Alger
county. Pretty good chance some locations tonight in these two main
convergence areas will see snowfall toward a foot. Exact locations
where heaviest snow sets up still in question though. Beefed up
wording for these two potetntial heavy snow areas in latest wsw

.SHORT TERM...(Today and tonight)
Issued at 544 AM EST FRI DEC 9 2016

NW LES continues, with the heaviest snow associated with the Lake
Nipigon band which is currently over far eastern Marquette and
western Alger County. The Nipigon band will shift east across Alger
County today, dropping up to 9 inches in spots there today. A ridge
pushing toward the area from the SW tonight will cause winds to
veer, which when combined with a shortwave moving through will
amplify the LES over northern Ontonagon and Houghton Counties. This
may lead to 6-9" of snow in that area. The LES out east will
continue to slowly shift east while diminishing some. Only headline
changes were to drop the warnings for Baraga and Keweenaw Counties
as only light LES is expected there. The Marquette County warning
may be able to be cancelled early today as LES shift east.

.LONG TERM...(Saturday through Thursday)
Issued at 350 AM EST FRI DEC 9 2016

Sat through Sun: Continued lake effect setup through the weekend,
with a weak northwest flow along the lee-side of a surface ridge
stretching from the Upper Midwest southeast through Chicago. This
will keep likely POPs going for the Keweenaw and the favored areas
east of Marquette thru Sat ngt. Mid-lvl flow will begin to
transition to more of a zonal orientation briefly Sun with weak
surface ridging sliding over the Upper Peninsula. This should bring
a lull to lake effect snow; however, this may only be temporary as
guidance continues to prog a developing mid-lvl wave across the
Northern Rockies Sun ngt.

By Sun ngt the mid-lvl vort max will be strengthening as it lifts
northeast through the Missouri Valley towards Southeast Wisconsin.
Guidance continues to develop a robust surface low over Chicago
lifting northeast across Lower Michigan early Mon morning. The
challenge for POPs for Sun ngt into early Mon will be heavily driven
by the path the shortwave takes. A further north path and POPs will
need to be adjusted higher for Sun ngt/early Mon, due to the more
favored iscentropic ascent region entering the Eastern U.P. Temps
for the weekend will continue to be seasonal in the 20s with
overnight lows in the single digits above zero Sat ngt due to less
cloud cover, then back into the lower teens Sun ngt with increasing

Mon through Thur: With the surface low lifting northeast of Lower
Michigan, the main focus will be on the arctic airmass poised to
drop south from Central Canada early next week. Flow will quickly
turn northwesterly with optimal conditions for LES to kick-in Mon
ngt through much of the extended periods. Guidance continues to prog
a potent surface ridge over the Missouri Valley, which places a
modest northwest flow over the Upper Peninsula. Thermal trough of -
14 to -18 deg c at 850mb slides overhead and will lock the region
into sub-seaonal temps as highs may struggle to warm beyond the
single digits above zero.

.AVIATION...(For the 12Z TAFS through 12Z Saturday morning)
Issued at 644 AM EST FRI DEC 9 2016

Lake effect will continue at KIWD and KCMX through the TAF period.
KSAW should stay out of the lake effect for the most part.

.MARINE...(For the 4 AM Lake Superior forecast issuance)
Issued at 544 AM EST FRI DEC 9 2016

Winds will remain less than 20 kts through Mon. W to NW winds
increase to 30 kts by later Tue with gales possible Tue night into
Wed as bitter cold air arrives. There is a good chance of heavy
freezing spray by the middle of next week.

Upper Michigan...
  Lake Effect Snow Warning until 7 AM EST Saturday for MIZ002-003-

  Lake Effect Snow Advisory until 7 AM EST Saturday for MIZ007-084-

Lake Superior...
Lake Michigan...


LONG TERM...Beachler
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