Area Forecast Discussion
Issued by NWS Gaylord, MI

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FXUS63 KAPX 151606

Area Forecast Discussion
National Weather Service Gaylord MI
1106 AM EST Mon Jan 15 2018

Issued at 1106 AM EST Mon Jan 15 2018

Morning composite analysis reveals a closed short wave trough
and a nearly vertically stacked low pressure system over
Wisconsin. A broad axis of very modest mid level warm advection
(and some hints of thermal deformation) wraps up through Michigan
and back into Wisconsin and continues to produce categorical light
snow across the CWA this morning. Better radar returns/heavier
snowfall is occurring along a narrow axis from southern Wisconsin
into southern Michigan/northern Illinois and Indiana where a much
tighter low-mid level thermal gradient resides and is getting
squeezed. Snow accumulations across our area have been rather
light...under an inch (and in many cases well under an inch) since
it began. There are actually thin spots in the cloud cover with
some sun getting through.

Lake enhanced banding potential continues to be the main focus.
Hefty lake enhanced band has made it into eastern Wisconsin with
reports of around a foot. Nothing like that here thus far...but
APX radar clearly shows some lake banding migrating off Lake Huron
into parts NE lower MI coastline (Presque Isle/Alpena/Alcona) as
well as up into the Drummond Island/southeast Chippewa county

Rest of today/tonight...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 although weakening in time. I
wasn`t anticipating much in regard to snow accumulations...and
based on trends/ anticipating even less and have
trimmed accumulations down.

Lake enhancement off Lake Huron is another story. SE low level
mean flow in place now will back easterly later this afternoon
through this evening...and on around into the north by Tuesday
morning. Some heftier snow accumulations still look like a good
bet particularly across parts of Presque Isle and Alpena counties
where in excess of 6 inches is not out of the question (ARW high
res guidance suggests in excess of 8).

Combined with gusty winds/blowing snow...advisory of course will
remain intact and we will have monitor those areas for possible


.NEAR TERM...(Today through Tonight)
Issued at 255 AM EST Mon Jan 15 2018

...Snow overspreads the area...

High impact weather potential: Lake enhanced snow off northern Lake
Huron today into this this evening.

Pattern synopsis/forecast: Rather deep mid level low digging south
across northern Minnesota, with attendant (and not quite as
impressive) surface low detached a bit to the south across southeast
Minnesota. Large band of "warm" air advection driven light snow just
starting to make a push into our area , with the most significant
snow, at least from a synoptic scale perspective, off to our
southwest where forcing is maximized in northeast quadrant of 130+
knot upper level jet streak. Synoptic forcing/moisture overtopping a
still very unstable over-water thermal regime resulting in quite the
band of intense snow rotating northwest off northern Lake Michigan
into central Upper Michigan and northeast Wisconsin. Simple distance
preventing much of anything to be seen on local radars rotating
north off Lake Huron, although high resolution satellite and
Canadian observations indeed show some shallow lake processes
ongoing on the second largest Great Lake.

Despite deep amplification, large scale features remains somewhat
transient through tonight, with surface and mid level low pressure
expected to slide across southern Wisconsin into lower Michigan.

Primary forecast concerns/challenges: While widespread light snow is
expected through tonight, primary forecast emphasis is on Lake Huron
enhanced snowfall rotating into eastern upper and northeast lower

Details: Light snow will continue to spread across the remainder of
northern Michigan this morning, with periods of light snow expected
to continue into this evening. Simple lack off deeper moisture and
displacement of best upper jet dynamics to our south will keep snow
amounts limited for most...on the order of an inch or two. However,
Lake Huron enhanced snow remains the wild card, although backing
winds and simple pattern recognition definitely supports some
heavier snow shower rotating into southeast sections of eastern
upper Michigan this morning, and into northeast lower Michigan this
afternoon and evening. Snowfall rates should be rather impressive
(over an inch per hour at times), with H8 temperatures squarely in
the favored dendritic growth zone and enhanced omega within this
layer. While snowfall rates will be impressive, duration of these
intense snows will not be given steadily backing winds. And, that
lack of duration will definitely keep snow amounts in-check, on the
order of 2 to 5 inches, with locally higher amounts possible under
band pivot points. Borderline advisory criteria for sure, but given
those expected intense rates likely having significant impacts on
travel, will go ahead an issue an advisory for those favored areas.


.SHORT TERM...(Tuesday through Wednesday)
Issued at 255 AM EST Mon Jan 15 2018

...Lingering light lake effect diminishes...

High Impact Weather Potential: Lingering NNW flow light lake effect
snow showers may result in additional minor accumulation in some
locations on Tuesday before diminishing.

Pattern Forecast: By Tuesday morning, Monday`s area of low pressure
is expected to be centered across northern NY/southeast Ontario with
associated elongated mid level trough axis draped northeast to
southwest over the western Great Lakes. North-northwest flow on the
back side of the departing system will likely keep lingering light
lake effect snow going, although anemic synoptic support/moisture
should preclude much more than minor amounts of new snow
accumulation. Snow showers diminish Tuesday night into early
Wednesday as winds gradually shift west-southwest in associated warm
air advection ahead of the next moisture-started wave set to drop
across the area during the day Wednesday.

Primary Forecast Concerns/Challenges: Lingering LES Tuesday.
Moisture-starved wave arrives Wednesday with a brief pocket of light
snow possible across eastern upper.

Primarily north flow is expected across the bulk of northern
Michigan by Tuesday morning with any synoptically aided lingering
snow showers across parts of northeast lower continuing to depart by
midday. Tuesday afternoon, developing lake induced snow showers
(mainly light) are expected to scrape parts of Benzie and Manistee
counties off and on throughout the day along with the immediate Lake
Huron shoreline of far northeast lower...primarily parts of Presque
Isle, Alpena and Alcona counties.

Flow gradually backs more north-northwesterly by Tuesday evening
aiding to press lingering snow showers inland across sections of NW
lower...primarily near and west of the GTV Bay region before
shifting toward the US-131 corridor after midnight Tuesday. All in
all, new amounts likely an inch of less for locations that see
lingering snow showers before activity diminishes early Wednesday.

The next wave will be quick to approach far northern reaches of the
forecast area by midday Wednesday...perhaps accompanied by a pocket
of light snow showers. Anemic moisture and synoptic support will
limit the overall coverage of snow and resultant snow amounts across
eastern upper before precipitation diminishes as it presses
southeastward across northern Lake Huron Wednesday afternoon.

A moderating temperature trend is anticipated on Wednesday with
highs topping out in the low-mid 20s area-wide with even warmer
temperatures expected beyond midweek.

.LONG TERM...(Wednesday night through Sunday)
Issued at 255 AM EST Mon Jan 15 2018

High impact weather potential: Minimal.

High pressure across much of the eastern CONUS will bring moderating
temperatures to northern Michigan through much of the extended
forecast period. Increasing confidence in high temperatures upwards
of 15 degrees above normal from Thursday through at least Saturday.
Quiet weather is expected through much of the period, with the next
widespread precipitation chances tied to a system ejecting out of
the southern Plains late this weekend. Plenty of uncertainty with
this system with respect to track, strength and predominant p-type
locally, but remains worth watching in the coming days.


.AVIATION...(For the 12Z TAFS through 12Z Tuesday morning)
Issued at 609 AM EST Mon Jan 15 2018

Large area of light snow will continue across the taf sites into
this evening. Mostly IFR/low end MVFR conditions expected,
although snow amounts look limited. One exception to this will be
at KAPN where lake enhancement will increase snowfall rates later
today into this evening, with several inches of accumulation
expected by late tonight. Snow-to-liquid ratios will remain
elevated, especially at KAPN, where they should average around 20
to 1. Winds will steadily back through the period, becoming
northeast overnight. At this time, it appears wind gusts will not
support much blowing and drifting snow.


Issued at 255 AM EST Mon Jan 15 2018

Low pressure passing across the area today and tonight will
bring small craft producing gusty east winds to Lake Michigan.


MI...WINTER WEATHER ADVISORY until 7 PM EST this evening for MIZ008-
     WINTER WEATHER ADVISORY until 1 AM EST Tuesday for MIZ018-024-
LM...SMALL CRAFT ADVISORY until 6 AM EST Tuesday for LMZ323-342-


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