Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 220827

Area Forecast Discussion
National Weather Service Marquette MI
427 AM EDT Wed Mar 22 2017

.SHORT TERM...(This evening through Wednesday)
Issued at 401 PM EDT TUE MAR 21 2017

Deep upper trough has moved across eastern Canada but ridging is
already building upstream over western North America. Sfc cold front
crossed Upper Michigan this morning and the cold air continues to
sweep in this aftn. Certainly cold enough for lake effect but it
also very dry upstream. Thus, have seen lake effect snow showers
spread well inland helped out by daytime heating/instability while
snow showers and even cloud cover over northwest cwa and most
recently into ncntrl cwa have diminished. NW-NNW winds have been
gusty behind the front with gusts many areas over 30 mph today and
over 40 mph across Lk Superior. Temps as of late this aftn have
fallen below the freezing mark over all of Upper Michigan except
far scntrl. Dry air upstream is really taking toll on ongoing snow
showers. Expect current isold-scattered snow showers to continue
diminishing late this aftn and possibly tapering off to flurries
by early this evening.

Despite dry air overhead, expect lake clouds and some snow showers
to redevelop later evening and overnight with nighttime cooling over
mainly ncntrl cwa with N winds and temps at top of inverion/h9 down
to at least -15c. Low inversions will result in light snow amounts
to 1 inch or less in most locaitons, though if snow showers persist
any one area later tonight there could be accums up to 2 inches. As
it looks now, best chance of stronger convergence and persistent
snow showers would be far eastern Marquette county and mostly across
Alger county. Where skies become clear and stay that way through the
night, min temps could drop to around zero as dry airmass tied to
incoming high pressure dominates away from lake effect processes.
Leaned on GEM regional for min temps. That model typically does very
well with radiational cooling situations and shows temps over
interior west and maybe far eastern Luce county dropping to zero to
5 below.

NNW flow and moisture to h9 will keep lake clouds and flurries going
on Wed morning, mostly to the east of Marquette. Eventually h9 winds
back more WNW in the aftn which will disrupt the lake effect as dry
air is advected into the lake effect convective layer. Otherwise,
with the 1035-1040mb high settling overhead, expect lake breezes
near the Great Lakes. Temps will stay near 30 where winds come off
the chilly lake waters and even ice cover in some NSH areas (near Lk
Superior and northern Lk Michigan and into the eastern cwa). Temps
inland west and toward WI border will rise into the mid 30s and
maybe even upper 30s with enough sunshine.

.LONG TERM...(Thursday through Tuesday)
Issued at 427 AM EDT WED MAR 22 2017

Nam shows a 500 mb trough in the desert sw and a ridge across the
central U.S. and a trough in New England 12z Thu. The trough moves
into the central and southern plains 12z Fri as the ridge moves into
the eastern U.S. The trough remains over the central plains through
12z Sat. Pcpn types get to be a mess this forecast period on Thu
night into Fri morning. Warm air aloft over low level temperatures
around freezing spell a problem for weather types. Cannot rule out a
sleet, freezing rain, snow and rain combo for the cwa Thu night into
Fri morning still and will continue to mention this in the hwo
product. Otherwise, did not make too many changes to the going

In the extended, GFS and ECMWF a closed 500 mb low over the southern
plains 12z Sat with a trough in the western U.S. The closed low
heads northeast to the corn belt 12z Sun with the trough moving into
the Rockies. This trough moves out into the central plains 12z Mon.
A shortwave moves into the upper Great Lakes 12z Tue with upper
ridging moving into the area for Wed as another trough moves into
the Rockies. Temperatures look to be above normal for this forecast
period. With temperatures at night and in the early morning hours
near freezing, mixed pcpn continues to look possible and have that
in the forecast. Looks pretty active with systems moving through the
area and to the south for this forecast period.

.AVIATION...(For the 06Z TAFS through 06Z Wednesday night)
Issued at 134 AM EDT WED MAR 22 2017

High pres over se Manitoba will move se, crossing Upper MI this
morning and aftn. Associated dry air mass will maintain VFR
conditions at KIWD/KCMX thru the fcst period. Coverage of any lake
effect clouds that develop overnight will be held to few or sct. At
KSAW, longer fetch across Lake Superior and slightly colder upstream
air mass will result in lake effect clouds and -shsn/flurries into
the morning hrs. However, conditions should remain VFR. Clouds will
then clear out to VFR later in the morning.

.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 401 PM EDT TUE MAR 21 2017

NW gales to 35 kts over eastern Lk Superior will diminish this
evening. Winds will continue to diminish to less than to 25 kts late
tonight and to 20 kts or less on Wed as high pressure settles
overhead. S winds up to 25-30 kts will be possible late Wed night
into Thu under the tightening pres gradient on the western flank of
hi pres departing to the e. Expect winds to diminish on Thu night
thru Fri as a flatter pres gradient dominates. Expect ne winds to
increase up to 25-30 kts on Fri night into Sat night under the
tightening pres gradient on the southern flank of hi pres building
into Ontario. Depending on if and how quickly the Ontario hi pres
builds toward the area on Sun, winds may diminish then.

Upper Michigan...
Lake Superior...
Lake Michigan...


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