National Weather Service - Area Forecast Discussion

000
FXUS63 KAPX 221949
AFDAPX

Area Forecast Discussion
National Weather Service Gaylord MI
249 PM EST Fri Feb 22 2019

.NEAR TERM...(Through Tonight)
Issued at 243 PM EST Fri Feb 22 2019

...The calm before the weekend storm...

High Impact Weather Potential...None.

Pattern Synopsis/Forecast...Strong high pressure remains centered
from the Northern Plains thru the Mid Mississippi Valley eastward
thru the Great Lakes late this afternoon. Majority of the residual
low level moisture/clouds have mixed into a sct/bkn SC deck...with a
good amount of sunshine gracing our CWA attm. A look upstream via IR
satellite and surface obs shows the leading edge of a mid cloud
shield reaching into Western Wisconsin well in advance of developing
low pressure to the lee of the Central Rockies. This mid cloud
shield will begin to move into our CWA late tonight. Until then...
partly to mostly clear skies will prevail...with overnight lows
dropping into the upper teens to lower 20s.

&&

.SHORT TERM...(Saturday through Monday)
Issued at 243 PM EST Fri Feb 22 2019

High Impact Weather Potential: Freezing rain concerns Saturday
through Saturday evening. Snow and strong winds on Sunday leading to
potentially dangerous travel, low visibility and isolated power
outages.

Pattern Synopsis/Forecast: By Saturday morning, mid-level ridging is
expected to be encompassing the eastern two-thirds of the CONUS with
well-defined, potent shortwave troughing evident across the Four-
Corners region. This wave will become the center of attention
through the weekend as it becomes negatively tilted and cuts off
across the midsection of the country. Attendant strengthening low
pressure (bombing out from roughly 997 mb to 970-975 mb) is
expected to trek across the Plains through the northern Great
Lakes, bringing a messy wintry mix of snow, freezing rain and rain
to the area, along with very strong westerly winds behind low
pressure`s passage during the day Sunday into Sunday evening.

Primary Forecast Concerns/Challenges: Temperature trends Saturday
through Saturday night, leading to a challenging messy wintry mix
forecast. Cooler temperatures arriving Sunday leading to a
transition to all snow, along with increasingly strong westerly
winds leading to low visibility and perhaps some sporadic power
outages.

By Saturday morning, aforementioned low pressure is expected to be
situated across the TX/OK panhandles with isentropically driven snow
showers possible across eastern upper/Straits as early as Saturday
morning. However, the main surge of moisture across the remainder of
northern Michigan holds off until Saturday afternoon and evening as
low pressure deepens while trekking northeastward into the mid-
Mississippi valley. Latest trends suggest by the time deeper
moisture arrives from southwest to northeast across northern lower
Saturday afternoon into Saturday evening that a pronounced warm nose
aloft will allow much of the intial precip to fall in the form of
freezing rain/drizzle...perhaps mixed with a bit of snow across
parts of northeast lower and the Tip of the Mitt. Temperature trends
late Saturday afternoon into Saturday evening will largely play
role in precip-type through that time frame as warm air advection
intensifies. Think that temperatures will slowly climb above
freezing from south to north Sunday evening into the overnight
hours...perhaps even clipping the 40 degree mark along and south
of M-72 overnight. This should allow precipitation to transition
to all rain and bring an end to the icing threat across much of
the forecast area. Do have some concerns that temperatures across
eastern upper struggle to rise given an easterly wind out of
Canada, but there`s enough support that suggests precipitation
transitions to mainly rain for a period of time overnight across
that area as well. Ice accumulation Saturday afternoon through
Saturday night ranging from a glaze to a tenth of an inch across
much of northern lower...perhaps a bit higher across far northwest
lower/Tip of the Mitt before precipitation transitions to all
rain. A little higher in eastern upper where 0.10-0.20 inches is
possible.

Cooler temperatures expected to arrive on the backside of low
pressure as it moves off to the northeast by early Sunday morning.
Initial temperatures around sunrise Sunday in the mid-30s are
expected to steadily fall throughout the day allowing precipitation
to transition to all snow. Forecast soundings continue to suggest
that potentially heavy snowfall may occur, especially across
northwest lower and parts of eastern upper downwind of Lake Superior
and Michigan. Inversion heights progged near 10 kft with omega
pegged squarely in the DGZ, along with plenty of synoptic
moisture/support through the column and unidirectional west-
northwesterly winds through the boundary layer should yield
potentially locally heavy lake effect/enhanced snowfall. Do have
some concern that increasingly strong wind gusts may lessen dendrite
size and limit overall accumulation, all while supplying a greater
reduction to visibility. 24-hour accumulation Sunday through Sunday
night expected to range from 1-4 inches across the snow belts of
northwest lower/eastern upper (highest in parts of Chippewa,
Charlevoix, Antrim, Otsego, and Kalkaska counties)...tapering to
less than an inch east of M-33 in northeast lower. Do expect such
strong winds to carry snow further into north-central lower,
including into parts of Montmorency, Oscoda and Ogemaw counties.

Accompanying the increasing snow chances will be very strong winds
across all of northern Michigan with WNW gusts ranging from 40-50
mph from Sunday morning through Sunday evening...perhaps even a
touch higher near the Lake Michigan and Superior coast lines. This
is expected to be the most impactful time frame across northern
Michigan given falling/blowing snow leading to severely reduced
visibilities, along with isolated power outages.

Have issued a Winter Storm Watch for the entire forecast area
starting 21z/Saturday through Sunday night/Monday morning to
encompass the initial light snow/freezing rain threat
(transitioning to rain overnight into early Sunday) before
becoming all snow during the day Sunday, along with increasingly
strong winds and blowing snow leading to potentially dangerous
travel in spots (reduced visibilities, snow-covered/drifting on
roads) and isolated power outages.

&&

.LONG TERM...(Monday night through Friday)
Issued at 243 PM EST Fri Feb 22 2019

High Impact Weather Potential: Minimal for now.

Relatively tranquil weather returns early next week, although some
lingering light lake effect may continue at times down wind of Lake
Michigan/Superior Monday through Monday night. Some signals of
another wave moving across the area during the day Wednesday with
accompanying light snow, although confidence is rather low in that
at this point. Looking beyond that, another impactful storm system
is possible late next week into next weekend as energy ejects lee of
the Rockies toward the Great Lakes. Worth monitoring over the next
week as details become more clear.

&&

.AVIATION...(For the 18Z TAFS through 18Z Saturday afternoon)
Issued at 1200 PM EST Fri Feb 22 2019

Strong high pressure will remain overhead thru tonight and will
then shift east of Michigan as a strengthening storm system begins
to approach the Great Lakes region. Solid VFR conditions are
expected at all TAF sites thru the forecast period now that
residual low clouds have dissipated. Mainly mid clouds will
increase on Saturday ahead of that next system. Light/variable
winds this afternoon and tonight will become easterly at around 10
kts Saturday morning...and are expected to strengthen later
Saturday.


&&

.APX WATCHES/WARNINGS/ADVISORIES...
MI...WINTER STORM WATCH from Saturday afternoon through Monday
morning for MIZ008-015>023-025>028-031>033.

WINTER STORM WATCH from Saturday afternoon through late Sunday
night for MIZ024-029-030-034>036-041-042.

&&

$$

NEAR TERM...MR
SHORT TERM...MG
LONG TERM...MG
AVIATION...MR

NWS APX Office Area Forecast Discussion