Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 191000

Area Forecast Discussion
National Weather Service Marquette MI
500 AM EST Mon Nov 19 2018

.SHORT TERM...(Today and tonight)
Issued at 458 AM EST MON NOV 19 2018

WV imagery and RAP analysis indicated a broad mid/upper level trough
from north of Hudson Bay into the ern CONUS resulting in cyclonic
westerly flow through the northern Great Lakes. Moderate 700-300
qvector conv associated with a shortwave trough into northeast MN
supported an area of light snow from ne MN through nrn WI and Upper
Michigan. Low level convergence with a sfc trough over srn Lake
Superior along with the cold air (850 mb temps around -14C)
supported a band of heavier lake effect snow showers from east of
Grand Marais to Big Bay. Otherwise, snowfall rates were generally
light with vsby in the 1-3sm range.

Today, The more widespread snow will diminish quickly from west to
east this morning as the shrtwv moves to northern lower MI by around
18z. As the main sfc low over WI also moves to northern Lake
Michigan the srn Lake Superior trough and snow band will also push
into north central upper Michigan with a period of briefly heavier
snowfall. Northeast to north winds may also be gusty near the
lake shore causing reduced vsby. Snowfall amounts in the 2 to 5
inch range are expected today, with the greatest amounts in the
higher terrain west of Marquette. A winter weather advisory was
issued for Marquette county, where the higher snowfall amounts
will occur. Although the lake effect snow will also increase from
Ironwood to Ontonagon, the low level conv is not expected to be as
strong keeping snowfall amounts closer to the 1 to 3 inch range.
The snow should taper off during the afternoon as high pressure
builds into the area with inversion heights falling to around 5k

Tonight, as the high continues to build into the west, the snow
should diminish to mainly flurries as inversion heights fall further
to around 3k ft. Over eastern Lake Superior, lake induced troughing
with the longer fetch may strengthen low level conv into areas
between Marquette and Munising where additional amounts of an inch
or two are possible. Lake clouds should keep temps from dropping off
too far, but there may be enough partial clearing over the west for
readings to drop into the 5F to 10F range.

.LONG TERM...(Tuesday through Sunday)
Issued at 305 AM EST MON NOV 19 2018

Models suggest that the amplified pattern with a mid/upper level
ridge off the west coast and trough from Hudson Bay into the Great
Lakes will become slowly progressive with the ridge building into
the Plains by the middle of the week. As troughing develops over the
western CONUS and into the southern Plains ridging will extend into
the Great Lakes by late next week. As a result, the colder air over
the region through Wednesday will also give way to warming as the
cold recedes to eastern Canada and northern New England.

Tue-Wed, Models still indicate the potential for WAA light snow
developing ahead of another clipper by late Tue/Tue evening and then
nnw flow LES developing on the backside of the system Tue night into
Wed as h85 temps lower near -20C by Wed. LES accumulations will
likely be limited by sharp ridging/subsidence and associated drying
behind the cold frontal passage.

Thu-Sun, WAA will kick in for later in the week under mid-level
ridging ensuring drier, warmer and breezy conditions for
Thanksgiving, although temps will still be below normal with highs
from the upper 20s to mid 30s. A mid level shortwave trough and sfc
trough moving through the Upper MS valley along with increasing
moisture advection will bring a chance of rain back into the area
from late Friday into Saturday. Snow will likely mix with the rain
Fri night at many locations. Expect high temps to rebound into the
upper 30s to lower 40s for Fri and Sat. Model consensus suggests a
mid-level trough lingering over the region could even sustain
scattered light rain/snow showers into Sunday with high temps in
the 30s.

.AVIATION...(For the 06Z TAFS through 06Z Monday night)
Issued at 1234 AM EST MON NOV 19 2018

Snow bands have setup across the northern portions of Upper
Michigan, impacting KCMX and KIWD late in the evening. A moderate
snow band is anticipated to impact KSAW shortly, with KCMX and KIWD
continuing to see light to moderate snow through the early morning
hours. As winds shift from NE to N later today, KSAW will become the
favorable terminal for prolonged snowfall, thanks to Lake Superior.

.MARINE...(For the 4 AM Lake Superior forecast issuance)
Issued at 458 AM EST MON NOV 19 2018

A period of 20-30 knot NE winds are then expected this morning as a
low pressure system slides quickly to the southeast of the area.
Stronger winds are expected again by Tue night into Wed as another
clipper low pressure system slides by to the north and east of the
area and gets winds up to near gales on the east half of Lake
Superior. The active pattern will continue with south winds to 30
knots developing Thursday. Basically, several periods of winds up to
30 knots are possible with a few gale force gusts possible as well.

Upper Michigan...
  Winter Weather Advisory until 7 PM EST this evening for MIZ005.

Lake Superior...
Lake Michigan...


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