Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 192001

Area Forecast Discussion
National Weather Service Marquette MI
301 PM EST Fri Jan 19 2018

.SHORT TERM...(This evening through Saturday)
Issued at 301 PM EST FRI JAN 19 2018

Low pressure around 990mb tracking north of Lk Superior this aftn.
Have seen breezy conditions at times, especially near Lk Superior
and over eastern forecast area. Warm up has arrived over parts of
Upper Michigan with mid 40s observed over western Upper Michigan.
Temps have stayed in the low to mid 30s elsewhere. A lot of dry air
to overcome in low-levels but could be enough lift with the low for
some drizzle or flurries this aftn east, then this evening over much
of the forecast area as band of deeper moisture and steeper lapse
rates move through along sfc low pressure trough. Plenty of high
clouds regardless until late tonight so min temps tonight should be
in the mid 20s to lower 30s. Intervals of clouds and sunshine on
Saturday. Dwpnts will be on the rise, but think extensive low clouds
as some models show is too aggressive. Not as much wind on Saturday
and expect highs similar to today, mid 30s to lower 40s.

.LONG TERM...(Saturday through Thursday)
Issued at 447 AM EST FRI JAN 19 2018

...Impacts from potential winter storm may be delayed until later
Sun night into Tuesday...

Saturday into Sunday: The early portion of the extended forecast,
Saturday into much of Sunday looks fairly dry with models trending
slower with advance of system from the Central Plains. Actually, it
looks like high temperatures On Saturday will warm above normal with
mid to upper 30s most locations, except some lower 40s readings
possible south central. Sunday won`t be quite as warm (generally
lower to mid 30s) as winds shift northeast and clouds thicken ahead
of incoming Plains system.

Attention turns to the potential winter storm for Sunday night into
Tuesday. 00Z GFS and GEM model runs trending east and a bit slower
than 12z runs. They are now more in line with the 12z ECMWF
solution, which would track developing storm system from the Central
Plains late Sunday across northern Lower Mi Monday night. Latest 00z
ECMWF indicates even slower solution yet with dry easterly flow
around Ontario sfc high delaying pcpn arrival until at least late
Sun night. With model trend toward more eastward track across
northern Lower Mi/Mackinac Straits, this would favor snow as
predominant ptype with maybe some fzra/fzdz mixing in initially Sun
night/Mon morning as model soundings indicate dry mid-levels which
could disrupt ice nucleation within cloud layer. Models suggest
system would likely have plenty of moisture to work with as
southerly flow ahead of the system wide open to tapping Gulf of
Mexico moisture. Models are still indicating upwards of an inch of
qpf through the event into Tue morning, especially over higher
terrain areas favored by lake enhancement in northeast upslope flow.
With SLRs expected of 12-14/1 seems likely snowfall totals will
exceed a foot over the higher terrain of the far west (Gogebic and
Ontonagon) and Baraga and western Marquette counties of north
central U.P. Model uncertainty with this system will likely continue
for the next 24 hours until main shortwave associated with this
system moves onshore of southern CA late tonight/early Sat and can
be better sampled by RAOB and sfc observing networks. At this point,
will continue to mention the potential for widespread heavy snow
late Sunday night into Tuesday morning.

As system departs east late Tue and ridging moves behind it Tue
night into Wed, lake effect snow should taper off and become
confined to the Keweenaw and far eastern shoreline areas of cwa.
After a period of quieter wx on Thu, models suggest another system
developing over the Plains and moving into the Upper Great Lakes for
next weekend with the potential for more significant snowfall over
portions of Upper Mi.

.AVIATION...(For the 18Z TAFS through 18Z Saturday afternoon)
Issued at 100 PM EST FRI JAN 19 2018

VFR conditions will prevail at all sites with mid to upper level
clouds. Robust low-level jet will result in LLWS at all TAF sites
through early this evening.

.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 301 PM EST FRI JAN 19 2018

Northeast gales are expected across most of Lake Superior Monday
into Tuesday. Heavy freezing spray is expected Monday night through
Tuesday night.

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


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