Area Forecast Discussion
Issued by NWS Gaylord, MI

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FXUS63 KAPX 141538

Area Forecast Discussion
National Weather Service Gaylord MI
1038 AM EST Tue Feb 14 2017

Issued at 1029 AM EST Tue Feb 14 2017

...Slippery roads and blowing/drifting snow later today...

A fairly compact but potent Alberta Clipper similar to the system
Sunday will bring another short lived round of active weather
later today into early tonight. This will lead to deteriorating
condtions from north to south this afternoon. Snow may mix with
or start out as a little rain. Colder air will advect in later
this afternoon changing any mix into all snow. In addition, winds
will pick up and become gusty with 35 to 40 mph gusts possible.
This will lead to blowing and drifting snow. Lastly, as
temperatures drop late today into this evening, roads will likely
freeze and become icy. All this adds up to the potential for a
fairly high impact event. Therefore, have issued winter weather
advisories for all counties in the forecast area except for the
far southeast where little snow is expected to fall.


.NEAR TERM...(Today and Tonight)
Issued at 249 AM EST Tue Feb 14 2017

...Accumulating snow redevelops today and tonight...

High Impact Weather Potential...Accumulating snow and blowing
snow...especially tonight.

Pattern Synopsis/Forecast...Upstream cold front has reached our NW
CWA border early this morning...marked by increasing mid level
returns per latest KAPX base ref loop along and ahead of this
boundary. At this precip is actually reaching the ground
per regional obs. Temps are holding mainly in the 30s early this
morning across most of our CWA thanks to a narrow thermal ridge
ahead of the front. Initial cold front will slide thru Michigan this
morning...with a stronger secondary cold front sweeping thru the our
CWA tonight. Small chances of mainly synoptically driven precip
today will evolve into more of a lake enhanced snow shower event
tonight as colder air arrives and activates the lakes. Wind speeds
also increase with the secondary cold front...producing areas of
blowing/drifting snow.

Primary Forecast Concerns...Main forecast concerns are POPS and
precip type as these two cold front push thru our CWA today and well as potential for accumulating snow over the next
24 hours. NAM BUFR soundings appears to be too cold as low levels
with the initial cold front today...suggesting precip will be all
snow across our entire CWA throughout the entire day. CAA with this
first front will be relatively weak...and still expect temps to hold
steady or slightly warm into the mid to upper 30s for afternoon
highs. This may lend to the idea of some rain mixing with the
snow...especially in our SE CWA where CAA will occur latest and
precip may actually be primarily rain during early to mid afternoon.
Mixed precip and temps in the 30s will limit snow accumulations to 1
to 2 inches across Eastern Upper Michigan and around an inch or less
for Northern Lower Michigan. Precip will switch over to all snow
from NW to SE this evening. Stronger CAA will begin with passage of
the secondary stronger cold winds shift to the NW. This
will target our typical snowbelt areas for highest snow
accumulations. Also...inversion heights just up to over 10 kft later
this evening...which could translate to a few hours of heavier
snowfall. These areas will see an additional 2 to 4 inches tonight
with some localized higher amounts possible...along with
blowing/drifting snow as wind speeds strengthen to 20 to 30 kts
(especially along the Lake Michigan shoreline). Some locations may
reach advisory criteria snowfall/blowing snow later tonight. Still
some questions regarding timing and amount of cold air behind the
secondary front...thus will hold off on issuing any headlines for


.SHORT TERM...(Wednesday through Thursday night)
Issued at 249 AM EST Tue Feb 14 2017

...Wintry Weather Continues Wednesday...

High impact weather potential: Lake effect snow and gusty winds
continue. Combination of falling snow and blowing/drifting expected
to continue to result in hazardous travel across sections of
northwest Lower/eastern Upper MI.

Pattern Forecast: Longwave upper-level ridging continues to dominate
the Pac NW into western Canada, forcing shortwave energy down the
eastern flank of the ridge tonight. This feature will continue to
deepen as it crosses the Great Lakes region tonight through
Wednesday, temporarily bringing another shot of cold air into
northern Michigan midweek. Temperatures then moderate to well above
normal toward the end of the week and especially this weekend as
aforementioned upstream ridge axis treks eastward. ~994mb surface
low associated with the deepening wave aloft will track from central
to southeastern Ontario, swinging an initial cold front through
northern Michigan this morning and a secondary, more robust, front
Tuesday night. This will allow for lake effect snow showers to
target north-northwesterly flow locations through the day Wednesday
before surface ridging/WAA pokes into the area on Thursday...
effectively shutting off lake processes.

Primary Forecast Concerns: Continuing lake effect snow on Wednesday
will garner the most attention through the short term forecast
period, although likely less robust than Tuesday night as deep layer
moisture begins to wane during the morning hours. In addition, what
were once non-existent subsidence inversion heights Tuesday night
gradually fall to around 4,500-5000 ft throughout the day. Fully
expect snow showers to continue across the majority of northwest
Lower, but more so in northern Michigan`s "traditional" multi-band
set up. With a 330-340 degree wind continuing through the day, the
primary locations of interest continue to be along and west of US-
131, downwind of Grand Traverse Bay, and western Chippewa/Mackinac
counties. Additional snow accumulation in the aforementioned areas
on the order of a couple of inches with the highest amounts focused
from Cadillac to Kalkaska...lesser amounts elsewhere. Snow showers
continue Wednesday night, but with gradually waning intensity and
coverage. This thought really amplifies early Thursday morning as
surface ridging/WAA noses in from the west and cold air aloft
retreats back to the north.

.LONG TERM...(Friday through Monday)
Issued at 249 AM EST Tue Feb 14 2017

High impact weather potential: None.

A fairly formidable baroclinic zone is draped across northern
Michigan Thursday night into Friday as WAA continues to shunt cold
air aloft back into Canada. GFS continues (and to an extent the
ECMWF) to pump out a narrow band of light QPF along this gradient
during the day on Friday. With awfully dry air overhead come that
time, I remain hesitant to include it much further than mentioning
it here, but worth watching as we get toward the end of the week for
perhaps a little light/scattered precip as unseasonably mild air
works its way into the region

High temperatures begin their ascent Friday...and more so over the
weekend into early next week. No reason to alter the inherited dry
forecast through the weekend as the next threat of precip doesn`t
look to arrive until early next week...likely in the form of liquid
rather than snow/frozen.


.AVIATION...(For the 12Z TAFS through 12Z Wednesday morning)
Issued at 621 AM EST Tue Feb 14 2017

Passage of two cold front will gradually increase chances of snow
showers today and especially tonight as sufficiently cold air
arrives to produce lake enhanced snow showers. Conditions will
deteriorate to MVFR/IFR within some of the heavier snow showers.
Winds will shift to the west today and then to the NW tonight...
gradually strengthening to gusts as high as 30 kts by tonight.


Issued at 249 AM EST Tue Feb 14 2017

Winds and waves will strengthen to marginally gale warning criteria
tonight for much of our nearshore areas of Northern Lakes Michigan
and Huron. Expect SCA criteria winds and waves will linger into
Wednesday as well. Chances of snow will gradually increase today
with the passage of a weak cold front...and especially tonight as a
stronger secondary cold front sweeps thru our region...serving to
activate the lakes and produce lake effect snow showers.


MI...WINTER WEATHER ADVISORY from 5 PM this afternoon to 5 AM EST
     Wednesday for MIZ016>029-031>034.
     WINTER WEATHER ADVISORY until 1 AM EST Wednesday for MIZ008-015.
LH...GALE WARNING from 7 PM this evening to 7 AM EST Wednesday for
     SMALL CRAFT ADVISORY until 7 PM EST Wednesday for LHZ345-346.
LM...GALE WARNING from 7 PM this evening to 7 AM EST Wednesday for
     SMALL CRAFT ADVISORY until 7 PM EST Wednesday for LMZ341.


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