Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 121811

Area Forecast Discussion
National Weather Service Marquette MI
111 PM EST Fri Jan 12 2018

.SHORT TERM...(Today and tonight)
Issued at 514 AM EST FRI JAN 12 2018

NNW wind LES and blowing snow early this morning will continue to
diminish today and become more northwesterly. Blowing snow will
linger longest north-central near Lake Superior, so extended the
Advisory for Marquette County until noon today.

NW wind LES ramps back up tonight with the passage of a shortwave.
Generally expecting 1-4" in these areas tonight, which shouldn`t
produce enough impacts to justify an advisory (but the day shift
will obviously need to give it a close look). Otherwise, back to the
cold tonight with lows mainly in the single digits above and below
zero and wind chill as low as 25 below zero over the interior W.

.LONG TERM...(Saturday through Thursday)
Issued at 514 AM EST FRI JAN 12 2018

High amplitude ridge remains parked across Northwest Canada/Eastern
Alaska, locking in the deep trough over the Great Lakes and Ohio
Valley regions. Ensemble guidance suggests this trough and ridge
will begin to relax by Wed/Thur of next week, transitioning the long-
wave pattern into a quasi-zonal flow. Which suggests an increased
frequency of systems sliding from west to east across the Great

Sat/Sun will remain very cold, with highs in the single digits above
zero to possibly low teens in a few places in the Southern CWFA. Low-
level flow will keep periods of LES impacting portions of U.P.
through Sat ngt; however, with a ridge of high pressure arriving
from the west expect flow to turn southwesterly briefly Sun and shut-
off the LES for a period of time. The next shortwave is progged to
dive into the Upper Midwest late Sun, with a robust 500mb vort
arriving over the Dakotas. Quick return flow moisture is progged
Mon, lifting into the Ohio Valley. This shortwave will strengthen
quickly Mon ngt as the vort max arrives, with substantial low-level
moisture becoming associated with the system.

For Tue/Wed, a more organize low pressure system will be over the
Central/Eastern U.P. setting the stage for northeast low-level flow,
and deep moisture. This suggests the potential for significant LES
across the favored Northeast snowbelt areas of specifically
Marquette County and Alger County. With another area of high
pressure sliding into the Upper Midwest early Tue, the gradient and
baroclinic zone will tighten over the Central U.P. and possibly
further enhance the LES.

Temps will begin to moderate late next week with flow turning
southwesterly and 500mb longwave becoming quasi-zonal.

.AVIATION...(For the 18Z TAFS through 18Z Saturday afternoon)
Issued at 111 PM EST FRI JAN 12 2018

Light to sometimes moderate lake effect snow will continue through
the period at KCMX and KIWD, while mostly ending at KSAW late today
as winds back more WNW. Though the LES has not been heavy, small
snowflake sizes have been effective at reducing visibility.
Therefore, LIFR conditions are expected at KCMX and KIWD at times
today. LES should lessen somewhat late this afternoon and evening
before a shortwave crossing the region tonight enhances LES through
Saturday morning.

.MARINE...(For the 4 AM Lake Superior forecast issuance)
Issued at 514 AM EST FRI JAN 12 2018

Main issue will be periods of heavy freezing spray through the
forecast period. Could see a few gale gusts over mainly the south
central part of Lake Superior today into tonight, then perhaps some
gales Sun night into Mon night.

Upper Michigan...
Lake Superior...
  Heavy Freezing Spray Warning until 6 AM EST Saturday for LSZ244-

Lake Michigan...


LONG TERM...Beachler
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