Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 190746
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
246 AM EST Sun Nov 19 2017

.SHORT TERM...(Today and tonight)
Issued at 246 AM EST SUN NOV 19 2017

Upper air pattern consists of a 500 mb trough over the lower Great
Lakes this morning and a shortwave over northern MN and western ON
and a ridge over the western U.S. This shortwave quickly moves
through this morning and this shortwave and trough dig into the ern
U.S. by 12z Mon. Nam quickly moves some 850-500 mb q-vector
convergence out of the cwa this morning. Did not make too many
changes to the going forecast overall. Lake effect snow showers will
continue today and let up tonight as winds start to back and warm
air advection moves in.

.LONG TERM...(Sunday night through Saturday)
Issued at 328 PM EST SAT NOV 18 2017

Lake effect snow will be ongoing for the WNW wind snow belts Sunday
evening. High resolution guidance suggests the eventual formation of
a somewhat dominant LES band crossing the southern Keweenaw before
extending eastward to Grand Marais to Whitefish point. A subtle
700hPa trough shifting southeastward across the CWA during the
evening hours will likely enhance convergence into this band via
backing surface flow. Modest inversion heights and the lack of DGZ
growth should limit accumulations, but several inches of LES will be
possible late Sunday afternoon through Sunday night for the
aforementioned locations. Much of the remainder of Upper MI will
remain dry Sunday night.

LES will diminish and shift northward over Lake Superior amid warm
air advection and backing surface winds on Monday. Much of the area
will likely see sunshine for the first time in over a week,
producing temps slightly above normal.

Then, a somewhat stagnant pattern with persistent deep troughing
near and over Hudson Bay will result in primarily west to northwest
flow across the Upper Great Lakes into the weekend. A period of lake
effect snow with gusty northwest winds will take hold late Monday
night into Tuesday night. Moderate accumulations will be possible
for the NW-wind snow belts, primarily Tuesday afternoon into the
evening.

LES will wane through the day Wednesday as inversion heights lower.
A brief round of LES is then expected on Thanksgiving night behind a
trough that clips the area to the northwest. A clipper system will
then cross the region Friday night into Saturday, but indications at
this time are that the bulk of the precip will remain north of the
CWA.
&&

.AVIATION...(For the 06Z TAFS through 06Z Sunday night)
Issued at 1151 PM EST SAT NOV 18 2017

Increasingly colder air flowing across Lake Superior on nw winds
overnight will result in lake effect -shsn becoming more numerous,
affecting KIWD/KCMX more so than KSAW. On a prevailing basis,
conditions should hold in the MVFR category, but as is typical for
lake effect, conditions will be variable with some brief IFR
possible at KIWD/KCMX. Winds will also be gusty overnight, strongest
at KCMX where gusts may approach 30kt. Backing winds should allow
KIWD to break out to VFR late morning or early aftn as overlake wind
trajectory is lost. KSAW will also become VFR in the morning as
downwsloping increases. KCMX will likely remain MVFR with
-shsn/flurries at times into the evening hrs.
&&

.MARINE...(For the 4 AM Lake Superior forecast issuance)
Issued at 246 AM EST SUN NOV 19 2017

Northwest winds of 20 to 30 knots are expected through this evening.
South gales are possible Monday night before shifting to northwest
gales Tuesday into Tuesday night. Otherwise, winds are generally
expected to be in the 15 to 25 knot range.
&&

.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
None.
Lake Michigan...
None.
&&

$$

SHORT TERM...07
LONG TERM...Kluber
AVIATION...Rolfson
MARINE...07


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