Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 141748

Area Forecast Discussion
National Weather Service Marquette MI
1248 PM EST Sun Jan 14 2018

.SHORT TERM...(Today and tonight)
Issued at 454 AM EST SUN JAN 14 2018

...Moderate to heavy lake effect/enhanced snowfall potential tonight
downwind of Lake Michigan...

Winter storm warning issued for Delta County and Winter Weather
Advisory issued for Schoolcraft County.

Today: Fairly dry air will remain in place across much of the Upper
Peninsula throughout the day as a surface ridge slides through the
area. Mositure will steadily return from the west as winds shift to
the south on the back side of the high and ahead of an approaching
surface low and upper level shortwave. Again most locations will
stay dry; however, as the system forcing approaches and moisture
slowly increases, the far western U.P. may see some light snow slide
into the area by late afternoon. Still not expecting much more than
a half inch or so from near Ontonagon to Ironwood, with little if
any for locations east of there druing the day.

Tonight: This evening, the aforementioned shortwave is progged to
intensify as the associated surface low approaches from the west.
This will allow mositure to continue to flow into the area on
southerly flow. The system forcing will allow widespread light to
moderate snow to spread across much of the U.P. tonight from west to
east. Models are generally showing around 0.05 - 0.10 inches of QPF
for much of the area, which would equate to roughly 1 to 3 inches of
snow for most locations. Not really expecting too much in the way of
blowing snow as winds will generally be fairly light so overall
impact should be fairly limited. It will may make for a slippery
Monday morning commute, which would be the main reason for any
potential headline. Will defer to the day shift to add an advisory
if needed for portions of the central and western U.P. The locations
that would have the best chance of seeing heavier snowfall would be
over the eastern U.P. downwind of Lake Michigan. 850mb temperatures
are expected to be in the -15C to -17C range with at least some
component of southerly flow across Lake Michigan. Inversion heights
are progged to be around 10kft tonight and possibly even into Monday
with a significant portion of the moisture/forcing/instability in
the DGZ. This will increase snow to liquid ratios over those areas
along with higher QPF totals due to the increased fetch across Lake
Michigan. Totals tonight through Monday will likely approach or
exceed 10 inches for portions of Delta County and even for portions
of Southern Schoolcraft County near the Delta County line. The
better convergence signature looks to be fairly transient across
Schoolcraft County, which may keep the total a bit lower than Delta
County; therefore, Schoolcraft County was placed under a Winter
Weather Advisory. Still, as previously mentioned some portions of
Delta may see isolated warning totals. Delta County will likely see
a longer period where the convergence/snow band is focused, which
will lead to greater snowfall totals across at least the eastern
half of the county. The west half of the county, including Escanaba
and Gladstone and Rock, will see lower snowfall totals than the east
half. The longer focus over Delta County has led to the Winter Storm
Watch being upgraded to a Winter Storm Warning.

.LONG TERM...(Monday through Saturday)
Issued at 515 AM EST SUN JAN 14 2018

Attention is on Mon into Tue when moderate to potentially heavy lake
enhanced snow is expected.

An upper closed low accompanied by a more broad surface low will
move S of the area Sun night and Mon, then shift E Mon night. Lake
enhancements with southerly winds will favor S-central Upper MI for
snow Mainly Mon morning, potentially with another 1-3 inches of
accumulation there. Elsewhere, light synoptic forced snow is
expected Mon, except potentially over the far W where heavier lake
enhanced snow is possible depending on meso-low development and
placement. If better banding can get into the Ironwood area, some
significant snowfall amounts could result, but at this time it is
too uncertain to put that into the forecast.

For Mon night into Tue, as the low shifts E, meso-lows will not be
as much of an issue and the typical NE-N wind snow belts will see
moderate to potentially heavy snow. Generally have 6-8" Mon night
through Tue over western Ontonagon and Gogebic Counties, the higher
terrain near Lake Superior in Marquette County and a small portion
of the keweenaw, with lower amounts elsewhere. However, if winds
shift faster, these amounts could be higher.

No significant impacts expected after Tue. Will see a warmup with
highs around freezing Thu through the weekend.

.AVIATION...(For the 18Z TAFS through 18Z Monday afternoon)
Issued at 1247 PM EST SUN JAN 14 2018

MVFR ceilings will quickly move west to east across Upper MI this
afternoon into this evening, followed shortly after by IFR
visibilities, as a trough brings -SN to the area. There could be a
period of LIFR visibilities at KIWD this evening. Also, LIFR
visibilities will be possible at KCMX late this evening into Monday
morning due to lake enhancement from Lake Superior, but confidence
was too low to include a specific time in the TAF at this point.

.MARINE...(For the 4 AM Lake Superior forecast issuance)
Issued at 454 AM EST SUN JAN 14 2018

Closing out the 2017 shipping season with strong winds to 30 kts
tonight through Monday. Could see a few south gale gusts to 35 kts
over eastern portions of Lake Superior this afternoon into this
evening. Heavy freezing spray should be limited to early this
evening over east half, but otherwise expect only moderate freezing
spray through Monday evening. Could be more heavy freezing spray
later Monday night into Tuesday and again on Wednesday. Expect winds
of 20 to 30 kts for rest of the week with another chance of west
gales on Wed.

Upper Michigan...
  Winter Weather Advisory from 7 PM this evening to 1 PM EST
     Monday for MIZ014-085.

  Winter Storm Warning from 1 AM to 7 PM EST Monday for MIZ013.

Lake Superior...
Lake Michigan...


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