Area Forecast Discussion
Issued by NWS Gaylord, MI

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FXUS63 KAPX 160445

Area Forecast Discussion
National Weather Service Gaylord MI
1145 PM EST Mon Jan 15 2018

Issued at 1007 PM EST Mon Jan 15 2018

Vertically stacked low pressure center has reached southern Lake
Michigan late this evening. Widespread light synoptic snow is
gradually diminishing across our CWA...but 2 dominant Lake Huron
enhanced snow bands continue to impact portions of far northern
and NE Lower Michigan resulting in periods of heavy snowfall for
these areas. The snowbands have become transient as low level flow
steadily backs from the east to the NE as the surface low center
begins to move into southern Lower Michigan. Short term models
still drive the stacked low thru southern Lower Michigan overnight
and into far SE Ontario on Tuesday...which will allow for further
shifting of low level wind trajectories from NE overnight to
northerly on Tuesday. Also...latest base ref loop shows a steady
diminish in overall intensity within the snow bands. Thus...
combination of transient bands and diminishing intensities should
yield relatively minor new snow amounts overnight into Tuesday
(i.e. an additional inch or two...mainly across NE Lower
Michigan). Will maintain remaining advisories for our Lake Huron
shoreline counties until 1 am...but expect this headline will not
need to be extended given downward trends.


.NEAR TERM...(Tonight through Tuesday)
Issued at 340 PM EST Mon Jan 15 2018

...Diminishing snow tonight and Tuesday...

High Impact Weather Potential...Higher accumulations in lake
enhanced snow across NE lower Michigan.

Pattern Synopsis/Forecast...Composite analysis reveals a closed
short wave trough and a nearly vertically stacked low pressure
system over Wisconsin. Broad axis of modest mid level warm
advection (and weak-ish thermal deformation) wraps across Michigan
and back into Wisconsin and continues to produce categorical
light snow across the CWA. Better radar returns and a bit heavier
snowfall continues along a narrow axis from southern Wisconsin
across southern Michigan/northern Illinois and Indiana where
strong forcing along a much tighter low-mid level thermal
gradient resides. Snow accumulations across our area remain rather

Meanwhile...SE flow lake enhanced banding off Lake Huron continues
to be the main focus/problem. Another well defined and hefty lake
band is evident just offshore in northern Lake Huron that extends
northwestward across eastern upper MI and back out into Lake
Superior. Enhanced band is likely producing 1-2 inch per hour
snowfall rates as KCIU reported 1/4SM VSBYS for awhile as that
band moved through. Weaker multi-lake banding is also evident
down through NE lower Michigan with some topographic enhancement
evident in radar intensities.

Closed/stacked low will fill and slowly pivot through lower Michigan
before heading through the eastern Great Lakes region on Tuesday.
Broad axis of modest warm advection/deformation forcing/light
snowfall will continue to pivot through northern Michigan over the
next several hours...although weaken with time (already seeing a
weakening trend). Only minor accumulations anticipated going
forward from the synoptic part of this system.

Lake enhancement off Lake Huron is another story. SE low level mean
flow will back easterly through this evening...and on around into
the north by Tuesday morning. This will continue to focus better
snow showers up through NE lower Michigan this evening...particularly
from Cheboygan county down through Alpena county as that aforementioned
hefty lake band pivots down through the area. Banding is on the
move...which will curtail overall accumulations to some extent.
But along with gusty winds/blowing snow...advisory of course will
remain intact.

Tuesday...low pressure system will slowly exit east through the
eastern Great lakes while "wrap-around" deeper moisture continues
to pivot and gradually thin out in time. Northerly flow light lake
effect snows will persist through the day...but with just minor
(if any) accumulations.


.SHORT TERM...(Tuesday night through Thursday)
Issued at 300 PM EST Mon Jan 15 2018

...Moderating temperatures...

High Impact Weather Potential...Low.

Primary Forecast Concerns: None except for somewhat low wind chills

Transitional period with surface high pressure centered off to our
south and slowly rising heights aloft. This pattern will lead to
warm advection with mainly dry conditions and moderating
temperatures. In addition, a decent surface pressure gradient
between high pressure centered over the Tennessee Valley and low
pressure moving across north central Canada should lead to rather
brisk conditions late Tuesday night through Wednesday night. This is
expected to result in low wind chill temperatures in the single
digits below zero Tuesday night and the single digits above zero for
Wednesday into Wednesday night. Actual highs in the lower to middle
20s Tuesday and the upper 20s to middle 30s Thursday. Lows in the
single digits above zero Tuesday night and the middle teens to lower
20s Wednesday night.

.LONG TERM...(Thursday night through Monday)
Issued at 300 PM EST Mon Jan 15 2018

With a fairly quiet start to the extended period, the primary
concern turns towards a potential storm system as we head into early
next week. Confidence remains low just how strong the low gets, with
everything from 985mb to 1004mb showing up in guidance. The stronger
guidance seems a bit overdone, and I wouldn`t be surprised to see it
weaken a bit in the next few runs. Track is going to be another
factor to wrestle with. More northwestern tracks will bring rain on
the front end with snow behind it, while the more southern solutions
will bring all snow. North American guidance has been trending
further south over the past couple of runs, with the Euro staying
more consistent with it`s track to the northwest. This will be a
storm worth keeping an eye on over the next week.


.AVIATION...(For the 06Z TAFS through 06Z Tuesday night)
Issued at 1145 PM EST Mon Jan 15 2018

Bands of light to moderate Lake Huron enhanced snow will continue
to impact NE Lower Michigan (APN) into the overnight hours...periodically
dropping conditions to IFR. Low pressure will slowly track thru
southern Lower Michigan...eventually transitioning to northerly
flow light lake effect snow showers on Tuesday. NE winds AOB 10
kts will shift to the north on Tuesday.


Issued at 340 PM EST Mon Jan 15 2018

Gusty SE-E winds will back and diminish tonight. Small craft
advisory conditions will persist on Lake Michigan for much of the
night before subsiding on Tuesday.


MI...WINTER WEATHER ADVISORY until 1 AM EST Tuesday for MIZ017-018-
LM...SMALL CRAFT ADVISORY until 6 AM EST Tuesday for LMZ323-342-


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