Area Forecast Discussion
Issued by NWS Gaylord, MI

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FXUS63 KAPX 171746
AFDAPX

Area Forecast Discussion
National Weather Service Gaylord MI
1246 PM EST Wed Jan 17 2018

.UPDATE...
Issued at 1100 AM EST Wed Jan 17 2018

Morning composite analysis reveals subtle short wave ridging
pressing into the western Great Lakes. Surface high pressure has
drifted into the lower Mississippi River Valley with low pressure
over northern Ontario/Hudson Bay region. In between these two
systems...wedge of warmer low-mid level air is wedging across the
northern plains into the western Great Lakes with a smaller batch
of warm advection forced enhanced cloud cover and radar returns
rolling through northern Michigan. A little bit of light snow/
flurries has been reported (DRM/PZQ) but nothing substantial.

Meanwhile...with the tightening P-gradient...gusty W/SW winds
continue to ramp up across northern Michigan this morning...likely
with some blowing/drifting snow occurring across the CWA. CVX
reported 5SM HZ this last hour...likely blowing snow.

Rest of today...warmer (and fairly dry) air will continue to
wedge through the region through early evening...although warm
advection forcing wanes/kicks on eastward by early afternoon as
flow becomes more parallel to the thermal gradient. So...I still
anticipate an end to the flurries and gradual thinning to the
mid/high cloud cover that`s out there now. That said...guidance/
forecast soundings hang onto shallow cold air across the region
as temp inversion tightens aloft. This could keep some shallow
lake clouds around and/or manifest itself as an increasing stratus
layer later tonight into Thursday as better low level moisture/
higher dewpoint air begins to spread into the western Great
Lakes. Will see...but for now I will maintain a decreasing cloud
cover forecast through the afternoon and this evening.

Finally...patchy blowing/drifting snow will persist through the
afternoon. Don`t think it will be a major problem...but areas
along the Lake Michigan shoreline will likely see some reductions
of VSBY through the day...particularly in the tip of the mitt and
Mackinac county with snow blowing off the ice. Will continue to
monitor OBS/webcams.

&&

.NEAR TERM...(Today through Tonight)
Issued at 306 AM EST Wed Jan 17 2018

...Winds on the increase...

High impact weather potential: Nothing.

Pattern synopsis/forecast: Early morning analysis shows positively
tilted trough axis slowly pinwheeling east out of the region as mid
level ridge axis builds into the High Plains. Subtle shortwave
trough dropping southeast across northeast Ontario, with attendant
weak cold front increasing the pressure gradient across the northern
Lakes between it and high pressure dropping through the southern
Plains. Winds have quickly backed overnight, punting lake effect
snow showers into the traditional snowbelts, although limited
convective depth and non-existent synoptic support has kept them
fairly disorganized. Clear skies across much of the interior and a
quick decoupling of winds allowed temperatures to tank during the
evening, with readings by midnight well below zero in several
locations.

Warm (but dry) advection processes really begin to ramp up today in
increasingly southwest flow wind environment as strong high pressure
slowly rotates into the western Tennessee Valley by evening. This
will put an end to lake processes and begin a milder weather regime
to finish out this week.

Primary forecast concerns/challenges: Not much, with primary focus
on those increasingly gusty southwest winds and attendant wind
chills.

Details: Light lake effect snow showers expected to come to an end
this morning as strong warm air advection greatly limits over-water
instability. Any snow accumulations will be minimal. Warming into
the cloud layer will also help scatter out some of the lake induced
overcast, resulting in at least partly cloudy skies by later this
afternoon all areas. Winds will most definitely be on the increase
as pressure gradient continues to increase, with wind gusts by this
afternoon easily topping 25 mph, with some of the higher elevation
areas and areas near Lake Michigan going over 30 mph at times. Per
the usual, initial surge of strongest warm air advection will be
just off the deck, but still expect highs several degrees warmer
than those experienced yesterday, with readings largely in the 20s.
Unfortunately, those winds will definitely add a bit of chill, with
wind chill readings mostly in the single digits. Those gusty winds
will also produce a bit of blowing snow, especially in those favored
exposed areas.

Really no change tonight as gusty southwest winds continue
(especially so this evening) within a dry environment. Those winds
should keep temperatures from falling too much, with readings only
dropping back into the teens and lower 20s. Once again, wind chill
readings will be several degrees colder, staying mostly in the
single digits.

&&

.SHORT TERM...(Thursday through Friday)
Issued at 306 AM EST Wed Jan 17 2018

...Moderating temperatures...

High Impact Weather Potential: Minimal.

Pattern Forecast: Primary feature to note through the short term
forecast period is a well-defined, but moisture starved wave is
expected to race across the northern Great Lakes during the day
Thursday. Weak surface reflection and associated low chances for
light/scattered precip are expected to accompany the wave before it
exits the region by Thursday evening. Otherwise, heights rise Friday
with high pressure nosing into the Great White North from the south
bringing temperatures some 10-15 degrees above normal.

Primary Forecast Concerns/Challenges: Low threat for snow showers
during the day Thursday.

Little in the way of sensible weather is expected through the
forecast period, with the one exception revolving around the
Thursday time frame as a moisture starved wave is expected to barrel
its way from Manitoba into the northern Great Lakes. Forecast
soundings suggest little in the way of appreciable moisture through
the column lending little support for widespread precip. However
there does remain a brief window for scattered snow shower
development across the Tip of the Mitt into eastern upper Thursday
afternoon, but passing with little impact. High temps Thursday
rising another 5 or so degrees over Wednesday...topping out in the
upper 20s to low 30s area-wide.

Primarily dry conditions under partly to mostly cloudy skies are
expected Friday with temperatures warming to 10-15 degrees above
normal...varying from the low-mid 30s across eastern upper to the
upper 30s-40 degrees for most of northern lower.

.LONG TERM...(Friday night through Tuesday)
Issued at 306 AM EST Wed Jan 17 2018

High impact weather potential: Watching the potential for a storm
system crossing the area late this weekend into early next week,
although timing and p-type remain uncertain.

Primary focus through the extended period continues to revolve
around the late weekend - early next week timeframe as guidance
remains consistent with the idea of a wave ejecting out of the Four-
Corners region with cyclogenesis lee of the Rockies by Sunday
morning. This wave and strengthening area of low pressure is
expected to trek northeastward toward the western Great Lakes late
in the day Sunday into Monday. Confidence remains low in the overall
track and strength of this system...ultimately affecting whether
northern Michigan experiences unseasonably mild temperatures and
rain or greater impacts from a wintry mix or wet accumulating
snowfall. Definitely a system worth monitoring over the next week.

&&

.AVIATION...(For the 18Z TAFS through 18Z Thursday afternoon)
Issued at 1246 PM EST Wed Jan 17 2018

Batch of mid and high cloud cover across northern Michigan will
thin out through the afternoon...with VFR conditions persisting.
That said...gusty W/SW winds through the afternoon may result in
some brief VSBY reductions due to blowing snow. But overall low
impacts anticipated.

Surface winds diminish some tonight but remain strong off the
surface. Thus...LLWS may become an issue for a time. Late
overnight into Thursday...with shallow cold air and increasing
low level moisture...guidance/forecast soundings suggest lake
induced stratus may develop/overspread northern lower Michigan.
Will see...but have tentatively lowered CIGs to MVFR for Thursday.


&&

.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...NONE.
LM...NONE.
LS...NONE.
&&

$$

UPDATE...BA
NEAR TERM...MSB
SHORT TERM...MJG
LONG TERM...MJG
AVIATION...BA



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