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000
FXUS63 KAPX 230852
AFDAPX

Area Forecast Discussion
National Weather Service Gaylord MI
352 AM EST Wed Jan 23 2019

.NEAR TERM...(Tonight)
Issued at 352 AM EST Wed Jan 23 2019

...Long Fused Snow Event Continues...

High Impact Weather Potential: Another round of accumulating snow
today, transitioning to lake effect snow tonight.

Pattern Synopsis/Forecast: Overnight composite analysis reveals a
well defined short-wave pressing into the Iowa/Arkansas area.
Attendant surface low is over Arkansas with an inverted surface
trough stretching up through the western Great Lakes, connecting
to a weaker surface low over southern Ontario. Satellite imagery
shows a nice moisture plume/warm conveyor belt extending from the
western Gulf up into the lower Great Lakes along with a widespread
area of precipitation that extends up through the Midwest and
across the southern half of lower Michigan along a limiting
streamline. Further west, well defined deformation axis is
emerging across Iowa and into Wisconsin along the northern side of
the wave, and one can already see the next wave of heavier
snowfall pivoting into the region.

Aforementioned short wave over Iowa/Arkansas expected to open
and lift into the western Great Lakes through this morning and
cross through northern Michigan this afternoon into the evening.
Emerging deformation axis and attendant axis of heavier snowfall
still looking to slide up through northern lower/eastern upper
Michigan through the day bringing another round of heavier
snowfall to the entire CWA. Precip may get a bit mixy across the
far SE counties this afternoon and surface temps warm to above
freezing and warm nose aloft just skirts into the Saginaw Bay
area.

Transition to NNW lake effect snow unfolds quickly tonight with
passage of the low and cold air spilling back into the region.
Lake effect snows continue into Thursday.

Primary Forecast Concerns: Headline management/decisions for the
duration of the event.

Ongoing overnight lull in snowfall really put the brakes on
storm total accumulations with most locations probably under or
even well under an inch of snow since late last evening. As
mentioned above, there will be another round of heavier snow
sliding up through the region today. But barring any goofy f-gen
banded heavy snow that might develop, I anticipate another broad
3 to maybe 5 inches of new accumulation across the CWA with the
higher amounts through the tip of the mitt counties into eastern
upper Michigan. This keeps most areas tucked under warning
criteria for the event (western Mackinac`s beefier snow amounts
yesterday I`m chalking up to localized lake enhancement).
Furthermore, with the lack of strong winds or any other auxiliary
impacts, my inclination is to downgrade the winter storm warnings
back to advisories.

All that said, changing/downgrading headlines in the middle of an
event can lend itself to confusion particularly since there will
be another period of heavier snow today. So...at this juncture we
plan to keep headlines intact as is at this point and see how
things play out.

&&

.SHORT TERM...(Thursday through Friday)
Issued at 352 AM EST Wed Jan 23 2019

...Several chances for snow with temperatures falling well below
normal Friday...

High Impact Weather Potential: Wintry travel and cold to end the
work week.

Primary Forecast Concerns/Challenges: Temperatures and snowfall
through the period.

Pattern Synopsis/Forecast...A weak feature dropping across the Great
Lakes Thursday will slowly exit east of the region Friday afternoon,
while an upper trough and extremely cold pool aloft dig into the
Great Lakes region Friday.

850/700mb and 500/300mb qvectors show significant forcing associated
with surface and upper level features pushing through the Great
Lakes Thursday, while models show sufficient moisture for pcpn
across much of the forecast area through the period.

Pcpn early Thursday will largely be driven by lake processes as
model soundings show limited mid and upper lvl mstr across much of
nrn Michigan thru the morning. However mstr does quickly increase
rapidly by 18z Thursday in mid and upper levels in advance of the
digging 500mb trough. Expect a good shot of accumulating snows
across much of nrn Michigan into Thursday evening, as vertical
temperature profiles show sufficient mstr extending up through the
-12c to -15c isotherm. Expect the highest snowfall amounts thru
Thursday evening to be located over the wrn Lakes, as synoptic snows
combine with northwesterly flow lake snows off Lake Michigan and
Lake Superior.

A transition to mainly lake snow will quickly develop Thursday night
and Friday, as synoptic support diminishes on the backside of the
exiting surface feature and over water instability increases quickly
with 850mb temps falling to around -24c. Model soundings show 925-
850mb winds continue northwest early Friday morning with a low lvl
inversion around 7k ft. 925-850mb winds will tend more westerly
Friday afternoon, continuing lake effect snows within favored Lake
Michigan snow belts through Friday evening.

&&

.LONG TERM...(Friday night through Tuesday)
Issued at 352 AM EST Wed Jan 23 2019

A couple of systems passing through the Great Lakes will continue a
very cold and wintry pattern across northern Michigan through the
weekend and to begin the upcoming work week. A deep upper trough and
cold pool aloft will remain anchored over the eastern third of the
country and Great Lakes through the weekend. 850mb temps in this
pattern will be around -24c, generating temps well below normal with
day time highs struggling to warm through the single digits.


&&

.AVIATION...(For the 06Z TAFS through 06Z Wednesday night)
Issued at 1145 PM EST Tue Jan 22 2019

Low pressure will lift NE thru Missouri and Illinois tonight and
thru Lower Michigan on Wednesday. Deep moisture and strong lift
associated with this system will continue to produce widespread
synoptic snow across all of Lower Michigan thru Wednesday. Appears
the heaviest and most persistent snow will likely occur on
Wednesday as the surface low center slides thru Lower Michigan.
Overall conditions will remain mostly IFR thru the 24 hr forecast
period. Southerly winds under 10 kts tonight will become NE and
eventually NW on Wednesday as the surface low tracks just south of
our area.


&&

.MARINE...
Issued at 352 AM EST Wed Jan 23 2019

Gustier northerly winds develop through the day leading to small
craft advisory winds/waves. Another lull anticipated tonight
followed by stronger winds again Thursday and Thursday night.

&&

.APX WATCHES/WARNINGS/ADVISORIES...
MI...WINTER WEATHER ADVISORY until 7 PM EST this evening for MIZ008-
     015-020-025>035.
     WINTER STORM WARNING until 7 PM EST this evening for MIZ016>019-
     021>024.
     WINTER WEATHER ADVISORY until noon EST today for MIZ036-041-042.
LH...NONE.
LM...NONE.
&&

$$

NEAR TERM...BA
SHORT TERM...SR
LONG TERM...SR
AVIATION...MR
MARINE...BA