Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 170959

Area Forecast Discussion
National Weather Service Marquette MI
459 AM EST Fri Nov 17 2017

.SHORT TERM...(Today and tonight)
Issued at 459 AM EST FRI NOV 17 2017


Pretty complicated in terms of ptype today into tonight. Narrow band
of snow/sleet/rain moving through the central U.P. early this
morning, but won`t last long enough to cause significant impacts.

Additional precip develops and becomes widespread later this morning
through the afternoon. As a nose of warm air aloft moves in, a mix
of rain, freezing rain, sleet, and snow will all be possible through
this evening. The E-central U.P. (roughly Menominee, Delta, Alger,
and Schoolcraft Counties) will see warmer SFC temps, so less
freezing precip expected there. Tonight, as deeper moisture exits,
upslope drizzle/freezing drizzle is possible over the N-Central and
W. Snowfall accumulations of up to 2 inches will be possible through
this evening (greatest over the higher terrain of the Keweenaw), but
most locations should see under an inch. Could see some light ice
accumulations over the W this morning, then across the interior W
this afternoon, and the higher terrain of N-central and W U.P.
tonight. Could certainly see some slippery travel conditions at
times today and tonight in areas that see freezing precip, but think
that impacts will not justify an advisory so will stick with the
Special Weather Statement.

.LONG TERM...(Saturday through Thursday)
Issued at 300 AM EST FRI NOV 17 2017

The upper level pattern through the extended forecast will remain
pretty similar with general western U.S. ridging and troughing over
the eastern U.S. Clippers diving southeastward out of Canada into
the Great Lakes will briefly amplify the eastern U.S. troughing
every couple of days. All in all no major storms will affect the
Upper Great Lakes through Thanksgiving week but there will be a
couple bouts of mainly nuisance northwesterly flow lake effect snow
with gusty winds on the Lake.

Beginning on Saturday...deepening surface low over the eastern
lakes will lift northeastward through Ontario into Quebec. Deeper
moisture will be east of the area and while cold advection will be
occurring through the day 85H temperatures will only be in the -5 to
-8 C range. Precipitation should be pretty minimal through the day
Saturday with the continuation of some drizzle/freezing drizzle. A
reinforcing surge of colder air will arrive Saturday night into
Sunday which should provide an uptick in northwest flow lake effect
snow showers but with inversion heights only around 5kft and limited
moisture...snow amounts will not get out of hand with only a few
inches expected.

Warm advection pattern quickly returns on Sunday night into Monday
ahead of the next clipper diving southeast out of Canada. As this
clipper moves through on Tuesday into Wednesday expect a similar
surge of cold air to Sunday with another uptick in lake effect snow
showers for northwest wind snowbelts. Once again amounts should
remain in check with only a few inches expected.

Thanksgiving looks pretty tranquil for the U.P. ahead of next
clipper that will arrive on Friday.

Temperatures in between clippers will average pretty close to their
late November normals with temperatures running a few degrees below
normal with each brief cold shot behind each clipper.

.AVIATION...(For the 06Z TAFS through 06Z Friday night)
Issued at 1214 AM EST FRI NOV 17 2017

Downslope wind at KIWD should allow VFR conditions to prevail into
the morning hrs, though there could be a very brief period of MVFR
or even IFR vis in -sn thru 07z as a thin line of -sn moves across
far western Upper MI. SSE Downsloping wind off the Huron Mtns should
also allow VFR conditions to develop and then prevail at KCMX into
the morning hrs. As with KIWD, there could be a very brief period of
MVFR or IFR vis in -sn overnight at KCMX. LLWS is also expected at
KIWD/KCMX as winds strengthen above low-level inversion. At KSAW,
upslope sse wind will likely maintain MVFR cigs overnight. A light
wintry mix of pcpn should develop this morning thru the aftn,
affecting all terminals. There may be some very light icing before
sfc temps rise above freezing. Increase in low-level moisture will
also lead to conditions falling to IFR at all terminals today. LIFR
conditions are possible as well by evening, especially at KSAW.
Finally, southerly winds will be gusty to around 30kt thru roughly
mid aftn.

.MARINE...(For the 4 AM Lake Superior forecast issuance)
Issued at 459 AM EST FRI NOV 17 2017

Gales are expected today over central and eastern Lake Superior and
a gale warning has been posted. Cold front to the south of the low
moves through tonight with winds diminishing below gales. However,
northwest winds increase to gales again late Sat into Sat night.
Winds diminish to 30 kts Sun-Mon but more gales are possible Tue
into Wed as active pattern continues.

Upper Michigan...
Lake Superior...
  Gale Warning until 4 PM EST this afternoon for LSZ244-245-

Lake Michigan...
  Gale Warning until 7 PM EST this evening for LMZ221-248-250.



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