Area Forecast Discussion
Issued by NWS Gaylord, MI

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FXUS63 KAPX 032026

Area Forecast Discussion
National Weather Service Gaylord MI
326 PM EST Sat Dec 3 2016

.NEAR TERM...(Tonight and Sunday)
Issued at 324 PM EST Sat Dec 3 2016

High impact weather potential: A wet synoptic snow developing Sunday

Pattern synopsis and forecast:

Shallow mid level ridging and sfc high pressure were drifting
through the western Great Lakes this afternoon, with 1000-850mb low
level winds weakening with time out of the west. Still have light
lake effect rain and snow showers drifting into eastern upper and NW
lower with sufficiently cold air over the warmer lake waters (-7C to
-8C). Upper level troughing was noted upstream across the Dakotas
with an anomalously deep closed upper circulation over the Baja
peninsula of Mexico. Energy ejected out of this closed low has
crossed into the south central plains, while strengthening southerly
winds were tapping Gulf moisture. Strong low to mid level WAA and
impressive upper divergence in right entrance zone of a 140+ jet was
resulting in widespread rains from Texas to Alabama. Weaker
reflectivities were associated with the Dakotas trough, with light
snows and rain in NE/K, working into Iowa. Forcing was weakish low
to mid level WAA and DPVA, while the deeper Gulf moisture was just
starting to get pulled into this system.

Low level winds continue to weaken by late afternoon with speeds in
the 1000-850mb layer dipping to 5kts or less early this evening. The
light rain and snow off the lakes will pretty much stop moving
inland and remain out over the Lakes. Continued overlake instability
and this weak flow will likely lead to a mesolow over nrn Lake
Michigan, with periodic lake effect likely in and around Beaver
Island. Kind of unsure about the cloud situation tonight, but
moisture seen off the 12Z APX sounding was deep, and without any dry
air advection, along with the presence of a persistent inversion
aloft, and no mixing, gotta believe skies will be more cloudy than
not. We will also have the initial higher level clouds advecting
into nrn Michigan ahead of the Dakotas upper trough and a developing
warm front. The upper trough will become more negatively tilted as
it makes it into the western Great Lakes Sunday. The deeper Gulf
moisture will gradually surge north ahead of the trough over this
time, while forcing strengthens, mainly DPVA and developing upper
divergence in a secondary jetlet. This leads to moderate to strong
overall deep layer -divQ. PWATS increase to around 0.50" and
temperatures will be in the lower to middle 30s as precipitation
expands across the western Great Lakes and nrn Michigan Sunday
afternoon. FCST soundings show some evaporational cooling of the
BL/wetbulbing with the onset of precipitation, which may briefly
start as rain or rain/snow mix, but quickly become all snow. There
are some hints that srn areas of the CWA, south of M-72, can see
some higher snow ratios with some of the max lift hitting the DGZ.

Taking all into consideration, can see a general 2-3" of wet snow
across the region, with roads becoming slippery into the afternoon.
Will not issue a winter weather advisory, but will add some
additional verbiage in the HWOAPX.


.SHORT TERM...(Sunday night through Tuesday)
Issued at 324 PM EST Sat Dec 3 2016

...More light snow Sunday night...

The short wave moving across the region will lead to mainly light
snow into early Sunday night (perhaps mixed with rain near the
lakeshore). Expect to see another inch or two of accumulation. Could
see a little enhancement in the evening across eastern upper with
the southerly mean low level flow. It now looks cold enough for the
chance for a little west southwest flow lake effect Monday morning.
Ridging/warm air advection should then put an end to any lingering
activity Monday afternoon. It should be too warm for lake effect
Monday night. Low pressure likely sliding by to our southeast will
then bring a chance for rain or snow Tuesday (especially southeast
zones) but model consensus is for a weaker/farther southeast
solution. Temperatures will remain at least a few degrees above
average through the short term. Highs in the upper 30s to lower 40s.
Lows in the upper 20s to lower 30s.


.LONG TERM...(Tuesday night through Saturday)
Issued at 324 PM EST Sat Dec 3 2016

A pair of surface lows continue to skirt the region going into mid-
week, with a deep occluding low to our NW and another not quite as
deep but with much more moisture to our SE. The SE system had been
progged to track further north and affect us, but has remained to
our SE for a few runs now. I would not be surprised to see a bit of
a northward adjustment in the next few days as guidance can be a bit
aggressive in bringing the cold air south. Just how far is the
question, but our SE counties getting clipped is not out of the
realm of possibility as some guidance is already near there. Lake
effect will pick up as we get into the late week timeframe, with the
magnitude of the cold air aloft increasing into the weekend. The
persistence of NW flow over a few day period could bring some decent
accumulations to favored snow belts. Current model soundings show a
few locations with max omega inside the DGZ which could further
enhance accumulations, especially over the weekend. Will see if that
continues to hold in the coming days to get a better feel for
possible amounts.


.AVIATION...(For the 12Z TAFS through 12Z Sunday morning)
Issued at 626 AM EST Sat Dec 3 2016

MVFR/low end VFR conditions to persist through this taf period in
weak lake effect regime. No vis restriction expected. Light winds
through the duration.


Issued at 324 PM EST Sat Dec 3 2016

Lake effect showers will continue into tomorrow morning as high
pressure crosses the Great Lakes. Light winds become light southerly
Sunday as a warm front approaches and as rain and snow spread across
all of the nearshore waters. After the warm front passes late Sunday
night, winds shift out of the SW then west, and briefly increase to
possible low end advisory levels. Winds turn back southerly Monday
as low pressure lifts into srn Canada.

Looking ahead, this low pressure deepens and a cold front will cross
Wednesday. Winds increase through Friday out of the WNW/NW with much
colder air arriving and fairly widespread lake effect snows
developing. Not sure how strong winds will be, but there will be a
high chance for headlines.




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