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Area forecast discussion 
National Weather Service Marquette Michigan
536 am EST Thursday Feb 11 2016

Short term...(today and tonight)
issued at 535 am EST Thursday Feb 11 2016

Lake effect snow advisories issued for today over Alger...northern
Schoolcraft and Luce counties...

Water vapor imagery this morning shows a wave departing to the east
of the u.P. As well as the next much stronger wave over western
Hudson Bay sinking southward toward the u.P. Radar continues to show
north-northwest oriented lake effect snow showers ongoing from Marquette
eastward across the area.

Today...the eastern Continental U.S. Will still be entrenched in an overall
troughing patter today while the western Continental U.S. Sees a balancing
ridge. The main trough axis will be to the east of the area this
morning...however...the next shot of energy over western Hudson Bay
this morning will begin to slide to near James Bay late this
afternoon. This will help to amplify the ridge to the west while
deepening the trough over the east. At the surface...a weak ridge to
the west of the County Warning Area this morning will slide just south of the u.P.
This afternoon as low pressure slide off the coast in the northeast
U.S. The main impact this surface ridge will have on the area will
be a wind shift...which determines lake effect snow placement. This
morning winds will become northwesterly across the area...and then
shift to the west to west-northwest this afternoon to the north of
the high pressure system. This would effectively shift the favored
les locations from northwest wind favored to the aforementioned west
to west-northwest wind favored snow belts.

850mb temperatures will generally range from -18c to -20c across the
County Warning Area throughout the day...which will continue to be favorable for
lake effect snow. Locations near Ironwood will likely see improved
conditions through the day with the aforementioned wind shift and
the closer proximity to the surface ridge...while the Keweenaw
peninsula and areas from Munising and east see light to moderate
lake effect snow. The heaviest snow totals will be confined over the
eastern u.P. Where the longer fetch would support more moisture as
well as a lake modified airmass. Lake induced inversion heights over
the east will be around 8kft with most of the moisture prognosticated to be
below 6kft through the day. The moisture in the dgz will be fairly
shallow to start the day...but the moisture in the dgz will become
deeper into the afternoon helping to increase snow ratios. The
combination of moderate snowfall in the 2 to possibly 5 inch range
over central eastern Alger...northern Schoolcraft and northwestern
Luce counties along with winds continuing to gust to around 20 to 30
miles per hour along the shorelines has prompted the issuance of a lake effect
Snow Advisory through this afternoon. The lake effect snow warning
for Alger County was replaced with the advisory as the snow bands
will be shifting slowly to the northwest and west northwest
snowbelts. The transient motion of the bands should keep totals from
reaching warning criteria today.

Tonight...the aforementioned re-enforcing shot of energy and cold
air will begin diving south toward the upper Great Lakes. Around
00z/12 the upper level trough is prognosticated to be just west of James
Bay. At the surface...a strengthening trough of low pressure will be
sliding across Lake Superior into the Upper Peninsula as high
pressure south of the area slides into the Ohio River valley. The
flow between the approaching trough and departing low will generally
be westerly across the u.P. Between 00z and 06z this evening...which
will allow most of the lake effect to slide just north of the
shoreline over the eastern u.P. Giving a very short break in the
lake effect snow. At the same time...the Keweenaw peninsula will see
light to moderate lake effect snow on the upslope westerly winds.
Generally only expecting around 1 to 2 inches during the evening
hours in the Keweenaw. Overnight tonight...between 06z/12 and
12/12...the surface trough will slide to the south and east of the
area while continuing to strengthen. On the back side of the trough
winds will become northwesterly across the u.P. 850mb temperatures
will still be fairly the -18c to -20c range as deeper
moisture increase across the area. Lake effect snow will shift back
on shore for all of the northwest wind favored locations. The
heaviest snow is expected over the eastern u.P. Overnight with the
long fetch across Central Lake Superior. Inversion heights are
prognosticated to Jump Up to around 9kft to 10kft with a good amount of
forcing through the layer. Snowfall rates could really pick up later
tonight and we will likely need another headline or need to continue
the headlines that are in place. Current thinking is that areas
Easter of Munising...would have good chance at seeing an additional
2 to 4 inches of snow late tonight as the lake effect sets back in.
The increasing pressure gradient along with cold air advection into the area will
allow winds to become gusty once again...generally in the 20 to 30
miles per hour range close to the shoreline of Lake Superior.

Long term...(friday through wednesday)
issued at 528 am EST Thursday Feb 11 2016

The main story will be the very cold conditions along with strong
winds and additional northwest flow les. Then...models suggest that the
amplified pattern allowing the intrusion of very cold Arctic air
into the northern lakes will become more zonal next week with milder
Pacific air and above normal temperatures returning to the region.

Behind the clipper shortwave and Arctic front...cold air advection with very cold air
will push into the northern lakes. Although the core of the coldest
Arctic air with 850 mb temperatures to around -38c slides to the NE of the
Lake Superior...850 mb temperatures in the -26c to -30c range are expected
across Lake Superior...providing plenty of instability for moderate
to locally heavy les. The higher res models suggest that the 330-340
winds and best low level conv will keep the strongest les bands east
of Marquette with potential for 3 to 5 inch accumulations. A shorter
fetch into the west with lower inversion heights will keep
accumulations mainly below advisory criteria with 1 to 3 inch
amounts...greatest from The Porcupine mountains to Twin Lakes.

By Friday night...the combination of strengthening lake induced
troughing and land breezes will help increase low level conv and
potential for dominant les bands...likely into western Alger County
where additional 3 to 6 inch amounts are expected. Outside the
heavier les bands...a very shallow dgz near the surface will limit
Snowflake size and slr values. However...the small flakes will be
effective at reducing visibility...esepcially with the gusty winds to 30
miles per hour along Lake Superior.

Steady or slowly falling temperatures to around zero north to 5 to 10 south
with the gusty northwest winds will produce wind chills of -15 to -25 by
late in the day and may reach -20 to -30 late Friday night into early

The les will slowly diminsh Saturday and end Saturday night as
riding builds into the region and shifts to the east with winds
becoming srly. Additional 1 to 3 inch amounts will be possible.

Sun...the models have trended weaker with the warm air advection pattern and
moisture inflow supporting light snow into the region. So...only
lower end chance probability of precipitation remain with insignificant snow accumulations.

Mon-Wed...some light les may be possible by late Monday into Tuesday as 850
mb temperatures drop back into the -10c to -15c range. However...only
chance probability of precipitation were mentioned given the weak wind fields and marginal
instability. The GFS and European model (ecmwf) suggest that a stronger shortwave moving
out of the northern plains may bring another chance of snow Tuesday night
into Wednesday but with the higher chances to the south through WI.

Aviation...(for the 06z tafs through 06z Thursday night)
issued at 1223 am EST Thursday Feb 11 2016

Under a northwest flow of Arctic air across Lake Superior...lake effect
snow showers will continue mainly at kiwd and kcmx overnight.
However...increasingly drier from north and west of Lake Superior and
weakening winds should only result at worst MVFR visibility restriction
at kiwd and kcmx overnight under MVFR ceilings. Winds backing more
northwest at ksaw aided by developing land breeze should keep shsn generally
NE of ksaw and conditions at VFR. Winds backing west-southwest by late Thursday
morning will allow conditions to improve to VFR at kiwd while visibility at
kcmx may lower to IFR for a brief time Thursday afternoon under westerly
wind flow. Another Arctic cold front approaching the western taf sites
Thursday evening will bring deteriorating conditions late Thursday evening
into Friday morning for kiwd and kcmx as winds shift back around to the

Marine...(for the 4 am Lake Superior forecast issuance)
issued at 535 am EST Thursday Feb 11 2016

As low pressure approaches the area from the north tonight expect
winds to increase over Lake Superior. Gales are possible late
tonight into Friday night across Lake Superior as next shot of cold
air moves in and the pressure gradient tightens ahead of the low.
Freezing spray will also increase with the heaviest freezing spray
this morning and again tonight through Saturday. Winds will continue
to be gusty through Saturday...up to 30 knots...before high pressure
slides in Saturday night through Sunday bringing winds in the 15 to
25 knot range.


MQT watches/warnings/advisories...
Upper Michigan...
lake effect Snow Advisory until 7 PM EST this evening for miz006-

Lake effect Snow Advisory until 7 am EST this morning for miz005.

Lake Superior...
heavy freezing spray warning until 7 am EST this morning for

Gale watch from Friday morning through late Friday night for

Lake Michigan...


Short term...kec
long term...jlb

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