Area Forecast Discussion
Issued by NWS Gaylord, MI

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FXUS63 KAPX 121725
AFDAPX

Area Forecast Discussion
National Weather Service Gaylord MI
1225 PM EST Thu Jan 12 2017

.UPDATE...
Issued at 1025 AM EST Thu Jan 12 2017

Short wave is sliding eastward out of Wisconsin and into Lower
Michigan this morning ahead of the upper level trough axis. A
couple of areas of enhanced 700-500 mb omega are impacting our
area...a stronger area to our south over Southern Lower Michigan...
Northern Indiana and NW Ohio...and a weaker area moving into
portions of Northern Lower Michigan. Resulting areas of precip are
following suit. Southern area of precip is more robust...with
weaker returns developing over Northern Lower Michigan. Precip
type across our entire CWA is all frozen...but obs over far
Southern Lower Michigan indicates mixed precip well south of our
area within the still rather tight thermal gradient. Short wave
will continue to slide east out of and away from Michigan this
afternoon...followed by the arrival of a rather dry airmass later
this afternoon and tonight. Expect light snow will continue to
impact mainly Northern Lower Michigan into early afternoon and
will then diminish from west to east as the wave pulls away. Most
locations will only see another inch or so of new snow from this
feature. With ongoing CAA...especially behind this wave...temps
will only warm a few degrees today...with highs ranging form the
lower 20s in Eastern Upper Michigan to the Upper 20s near Saginaw
Bay.

&&

.NEAR TERM...(Today)
Issued at 354 AM EST Thu Jan 12 2017

High impact weather potential: Less than what has been the usual.
minor/light accumulations across nrn lower today and more
minor/light accumulations of wind blow lake effect snows across
Chippewa county.

Pattern synopsis and forecast:

Nrn Michigan between the two main weather systems. One...A frontal
boundary stretches from Oklahoma up through the far eastern Great
Lakes, and the other a sharper upper level trough and low pressure
in srn Manitoba. The front has pockets of upper divergence and the
low to mid level warm/moist advection along it, while the upper
trough is more PVA driven with some semblance of upper divergence.
In between lies nrn Michigan, not the center of attention, with the
last of the fgen driven band of intense snows all but gone. We do
see some additional returns on radar upstream, associated with
weaker energy moving through the WSW flow aloft.

This weaker energy does drift across the region today with weak
forcing for minor snows to string out across mainly nrn lower
Michigan. These light snows will be enhanced to some degree by H8
temps in the -10C to -12C range in westerly flow. This would result
in snowfall maybe a couple of inches along the NW lower shore, with
little in the way of inland penetration of the better amounts due to
pretty light flow. This is something to watch though, as weak flow
events can sometimes be sneaky. Winds are really moving around over
time however, and the deeper moisture associated with the weak
shortwave energy is moving pretty fast.

Much drier air moves in across the region late this afternoon and
into tonight, but the aforementioned sharp upper level trough does
swing down into eastern Lake Superior and throws colder air in from
the WNW. Lake effect parameters are not impressive with inversion
heights only hitting 5kft for a few hours this evening, but lift
does appear to be in the DGZ. Again, maybe a couple of inches, but
if fluffier snows fall, that can stack up a bit more.

Highs in the low to mid 20s today with lows in the single digits
inland and teens coasts.

&&

.SHORT TERM...(Tonight through Saturday)
Issued at 354 AM EST Thu Jan 12 2017

...Cold with diminishing lake effect...

High Impact Weather Potential...Minimal.

Pattern Synopsis/Forecast...Flow aloft turns mostly zonal Friday
into the weekend as an Arctic high builds over the Great Lakes. A
return to frigid conditions is expected through Friday night as the
center of the high passes overhead. This will lead to continued lake
effect snow through Friday afternoon until WAA develops Friday
evening and begins to warm the low levels. A shortwave will move
across the Upper Midwest late Friday night into Saturday while a
surface trough brushes across eastern Upper, bringing a chance of
light snow to northern Michigan. There may be a bit of lake
enhancement that comes into play along Lake Michigan during the day
as SSW winds veer WNW with the trough passage. This would come to an
end by evening, however, as another high builds into the region
Saturday night.

Primary Forecast Concerns...Friday`s forecast concerns will revolve
around the continuing lake effect potential and how quickly it shuts
off. Inversion heights will be falling through the day from around
4500 ft initially. Generally weak low level omega will be present
through the day, diminishing by late afternoon. Additionally,
moisture will be limited to below 800mb, and even then it won`t be
quite near saturation. All this to say the lake effect will present
only minimal impacts with an inch or less of additional accumulation
during the day in the Straits.

Late Friday night into Saturday morning is trending snowier across
the southern portion of the forecast area. The 12.00Z NAM/GFS came
in with much more QPF than their 18Z runs, better in line with the
ECMWF. Yet to be resolved are timing differences and placement of
the heaviest QPF. The Canadian is fastest, followed by the GFS,
ECMWF, and then the NAM. The Canadian and ECMWF place the bulk of the
QPF downstate, whereas the NAM and GFS favor a more northward
solution. For now have discounted the quick Canadian and slow NAM,
taking more of a GFS/ECMWF blend for timing. But have gone with a
general model blend for QPF placement, with the greatest snowfall
expected across our southwestern counties. Not talking a lot of
snowfall, though...looking like around an inch at this time.

.LONG TERM...(Saturday night through Wednesday)
Issued at 354 AM EST Thu Jan 12 2017

.High Impact Weather Potential...A mixed precipitation event is
looking increasingly likely across northern Lower Monday afternoon
into Monday night.

A warming trend will develop Sunday through the start of the work
week as high pressure pushes off to the east. The high will provide
fair weather and even allow for some sunshine across the area on
Sunday. Heading into Monday, a potent winter system developing over
the Central Plains will lift into the Midwest, with precipitation
associated with strong WAA overspreads northern Michigan Monday
morning. Models are surprisingly in pretty good agreement for being
this far out. Thermal profiles will be very important in determining
ptype here, and with a strong southerly surge of warmer air coming
into play, am expecting the possibility for another mixed precip
event across northern Lower. Max 0-3km layer wet bulb temps will
steadily rise Monday into Monday night, with partial to complete
melting aloft likely over northern Lower during the day and complete
melting Monday night. For now, being several periods out, have a
rain/snow mix in the grids but a period of ZR/IP is looking
increasingly likely beyond Monday morning at least across northern
Lower and perhaps even eastern Upper by Tuesday morning. The bulk of
the precip looks to exit the area before Tuesday night with quieter
weather on Wednesday.AVIATION...(For the 06Z TAFS through 06Z Thursday night)
Issued at 1051 PM EST Wed Jan 11 2017

Low pressure sliding through SE lower Michigan will continue to
bring heavier snow to northern lower Michigan into the early
overnight hours, winding down overnight into Thursday morning.
IFR conditions with periods of moderate to briefly heavy snow can
be expected at various times at the terminal sites.

Improvement late overnight into Thursday morning and there will be
window of MVFR and possible VFR conditions Thursday morning. But
another round of lighter snow rolls through the region later in
the morning through Thursday afternoon bringing a return of MVFR
and possible IFR conditions through the afternoon. Improvement
Thursday night.

&&

.AVIATION...(For the 18Z TAFS through 18Z Friday afternoon)
Issued at 1225 PM EST Thu Jan 12 2017

Area of light snow will exit east out of Northern Lower Michigan
this afternoon...leaving some MVFR clouds as well as some mid
clouds that will drift in and out of the area tonight into
Friday. W/NW winds will strengthen this evening...with gusts of 20
to 30 kts expected thru the night. Winds will diminish toward
daybreak Friday and switch to the north.

&&

.MARINE...
Issued at 354 AM EST Thu Jan 12 2017

North winds have weakened over the last several hours with the
arrival of higher pressure, and advisories have ended. A cold front
rips through here through late this afternoon and evening and the
gradient tightens up substantially for gales to develop across
portions of nrn Lake Michigan/Straits and across Whitefish Bay.
Those have been issued already. These winds die down by Friday with
higher pressure settling in for the weekend.

&&

.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...SMALL CRAFT ADVISORY from 4 PM this afternoon to 4 AM EST Friday
     for LHZ349.
     GALE WARNING from 4 PM this afternoon to 4 AM EST Friday for
     LHZ345>348.
LM...SMALL CRAFT ADVISORY from 4 PM this afternoon to 4 AM EST Friday
     for LMZ323-341-345-346.
     GALE WARNING from 4 PM this afternoon to 4 AM EST Friday for
     LMZ342-344.
LS...SMALL CRAFT ADVISORY from 4 PM this afternoon to 4 AM EST Friday
     for LSZ322.
     GALE WARNING from 4 PM this afternoon to 4 AM EST Friday for
     LSZ321.
&&

$$

UPDATE...MLR
NEAR TERM...SMD
SHORT TERM...MEK
LONG TERM...MEK
AVIATION...MLR
MARINE...SMD



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