Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 231149

Area Forecast Discussion
National Weather Service Marquette MI
649 AM EST Mon Jan 23 2017

.SHORT TERM...(Today and tonight)
Issued at 514 AM EST MON JAN 23 2017

WV imagery and RAP analysis indicated a broad mid/upper level trough
from southern Saskatchewan into the western Great Lakes. A weak
upstream shortwave trough extended from the ern Dakotas into wrn IA.
At the surface a very weak pressure gradient prevailed across the
region with a diffuse trough extending from srn Manitoba through ern
Upper Michigan. With light winds and abundant low level moisture
remaining over the area, widespread fog, locally dense, was observed
across the region.

Today, the stagnant weather pattern suggests that temps will remain
in the same relatively narrow range with highs in the mid to upper
30s. Morning fog should also gradually improve by afternoon leaving
a low overcast. Since no more than patchy dense fog is expected, an
SPS rather than dense fog advisory was issued to highlight any

Tonight, 700-300 mb qvector conv and deeper moisture associated with
the approaching shrtwv will be greatest over the ern cwa, where
chance pops for light pcpn are mentioned. Forecast min temps near
33F and soundings suggest potential for a mix of rain and snow.
Otherwise, areas of fog that again may be locally dense should
develop over the rest of the cwa as min temps drop into the lower

.LONG TERM...(Tuesday through Sunday)
Issued at 446 AM EST MON JAN 23 2017

Main stories in the long term are mid-week snow and colder air that
will bring the return of LES.

A shortwave will move south of the area Tue night and Wed, which
will bring snow to portions or all of the CWA. Exact track remains
uncertain, as a couple models are taking it farther south which
would mean parts or even much of the area would be dry (or possible
some drizzle/freezing drizzle). Current thinking is that 2-4 inches
of snow will fall 00Z Wed to 00Z Thu, with potential for higher and
lower amounts depending on track.

Major pattern change starts mid-week as the upper trough shifts E
across the country, settling over the eastern half of the CONUS by
the weekend. Colder air will promote LES in N-NW wind snowbelts
during this time, but potential for moderate to heavy LES will not
exist until the colder air (850mb temps down to -18C) move in. LES
may end on Mon as winds turn SW ahead of a potential low pressure

.AVIATION...(For the 12Z TAFS through 12Z Tuesday morning)
Issued at 649 AM EST MON JAN 23 2017

With lingering low level moisture over slowly melting snow pack and
light winds, expect some dense fog with LIFR to VLIFR conditions to
predominate until mid/late this morning. While there is likely to be
improvement in vsby into perhaps the MVFR category, low cigs in the
LIFR to IFR range will linger. Vsbys will probably fall into the
LIFR range this evening with the favorable conditions for fog
persisting in the presence of nocturnal cooling.

.MARINE...(For the 4 AM Lake Superior forecast issuance)
Issued at 514 AM EST MON JAN 23 2017

A relatively weak pressure gradient over the Upper Great Lakes in
the absence of any strong weather systems will continue to result in
winds under 20 kts over Lake Superior into Tue. Expect N to NW winds
to 25 kts late Wed through the end of the week as low pressure over
the central Plains moves toward eastern Canada and colder air
returns to the Lk Superior region.

Upper Michigan...
Lake Superior...
Lake Michigan...
  Dense Fog Advisory until 1 PM EST this afternoon for LMZ248-250.



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