FXUS63 KAPX 071820

Area Forecast Discussion
National Weather Service Gaylord MI
120 PM EST Tue Feb 7 2023

Issued at 1145 AM EST Tue Feb 7 2023

Afternoon forecast Update...Niblets entering the region should keep
things from being totally quiet across the region today...with
lingering drizzly crud likely...especially over regions that see
upsloping (i.e., interior higher terrain of northern Lower). With
falling temperatures aloft...could start to see a little more of a
lake component over the EUP at least, potentially...though chance is
pretty small. Additionally...expect things will be largely rain as
temps remain above freezing this afternoon with the front moving
through attm...and temps already starting to fall across the western
portions of the CWA as of 16z behind the front. Some guidance
soundings suggest there could be a bit of a dry layer toward the
surface later this afternoon...may have to keep an eye on
evaporative cooling processes given the crummy low stratus
overhead...but not sure if precip will be intense enough to do much.
Otherwise...does appear that despite temps aloft falling...some
areas may still see cloud tops warmer than the typical ice
nucleation temps going into this evening...so as surface temps fall
back below freezing with time...not out of the question there could
be some freezing drizzle potential...not to mention the potential
for things to slick back up after dark.

UPDATE Issued at 1031 AM EST Tue Feb 7 2023

Trough axis extends from Hudson Bay around to the Desert SW...with a
handful of pretty little swirlies in the flow per water vapor
satellite. A couple weaker ones just ahead of the main trough
axis...with one over the western UP as of 14z, and another just to
our west in S. WI. More potent niblets just behind them...and that
terminus of the trough axis in the Desert SW looks pretty potent as
well. SW-NE oriented 120+kt upper level jet axis from AZ into
southern MI. Ridging over the western US as well...also positively
tilted. Moisture plume and strong LLJ on their way out attm...with
back edge of the precip making its way across the CWA as I write.
Another bit of cold air over central Canada behind a cold front
draped from surface low over the western edge of Hudson Bay...which
has a surface trough connecting it to an occluded surface low over
northern Lake Michigan attm. Cold front extends south into the
Southern Plains. High pressure over the East Coast...and attempting
to hold on in the Western CONUS as well.


.NEAR TERM...(Today through Tonight)
Issued at 258 AM EST Tue Feb 7 2023

...Wintry mix of precip today into this evening...

High Impact Weather Potential...Wintry mix of precip will lead to
hazardous driving conditions across Eastern Upper and Northern
Lower Michigan this morning.

Upstream cold front stretches from low pressure centered over NW
Ontario thru Minnesota and Iowa into NW Missouri and the Southern
Plains early this morning. Shower activity developing ahead of this
boundary is moving NE out of Wisconsin and into our western CWA
attm...featuring a mixture of rain..freezing rain and snow. A few
isold hits of lightning were embedded within some of the heavier
shower activity while it was over Wisconsin...but this has since
come to an end as it moves into our CWA. Surface temps are quickly
warming thru the 30s across most of NW Lower Michigan thanks to WAA
in progress.

Temps will continue to rise to and above freezing this morning as
WAA continues along with the arrival of this area of precip. Latest
near term model soundings suggest precip type across most of
Northern Lower Michigan will initially begin as a period of freezing
rain during the onset before temps sufficiently warm for precip to
become plain rain. Also...road temps at this time of year are
definitely below freezing...which will likely lead to freezing rain
on road surfaces despite air temps warming above freezing. Precip
type across Eastern Upper Michigan will begin as snow and then
eventually switch over to rain early this morning. All precip will
diminish to patchy drizzle this morning and then switch to scattered
light snow showers this afternoon before coming to an end this
evening as low level drying takes place and subsidence strengthens
with the arrival of weak low level ridging.

Still expect an inch or two of snow across Eastern Upper Michigan
this morning...with generally less than a tenth of an inch of ice
accumulations across much of Northern Lower Michigan. Will certainly
keep all Winter Wx Advisory headlines in tact during the morning
hours as the above scenario plays out and likely leads to some
hazardous travel across our CWA. Temps will continue to warm into
the upper 30s to near 40 degrees this morning...and then fall into
the lower 30s by early evening as CAA commences. Low temps tonight
will drop into the upper teens across Eastern Upper Michigan and
into the low to mid 20s across Northern Lower Michigan.


.SHORT TERM...(Wednesday through Thursday)
Issued at 258 AM EST Tue Feb 7 2023

...Messy wintry mix on the way...

High Impact Weather Potential: Storm system for Thursday set to
bring accumulating wintry mix and heavy wet snow.

Synopsis/Forecast: A wavy progressive pattern dominates the pattern
across the CONUS through much of the week. Abnormally strong
shortwave ridging briefly builds across the Great Lakes for
Wednesday bringing quiet weather, followed by a surge of moisture
ahead of a compact negatively tilted shortwave that moves across the
area Thursday, set to bring a mixed bag of precipitation types with
quite a bit of QPF.

Forecast Details: Wednesday will be a quiet day with a lack of
sensible weather thanks to abnormally strong 500mg  heights moving
briefly moving across the region, abundant dry air and weak
subsidence within the upper level jet cutting through the upper Ohio
Valley. 850mb temperatures will warm to about 2 or 3C through the
day (+1-2 St. Dev above normal for early Feb). Thanks to all this
expect sunny skies for most of the day, with afternoon highs in the
upper 30s (at least) in the south to mid 30s in the north. High
level clouds move in from the south in the late afternoon, well out
ahead of the surface warm front pushing north into the Ohio Valley.
They will continue to thicken and lower overnight as we continue to
slowly saturate.

Attention then turns to the system rapidly moving into the region.
The previously weaker/southeastern Canadian has jumped on board with
the rest of the guidance suite in keeping the parent shortwave sharp
and relatively deep as it takes on a negative tilt as it lifts from
the southern Plains early Wednesday night to around central Illinois
by Thursday morning. Am concerned that the shortwave will be
dampened at bit as it runs into the anomalous ridging to its east,
but the wave is being supported by the right entrance of the upper
level jet arcing over the Great Lakes...so maybe the wave will
remain compact and strong as it moves toward and over our region.
Either way an impressive plume of moisture moves into Michigan late
Wednesday night into much of Thursday. We saturate top-down late
Wednesday night, with light precipitation moving into areas along
and south of the M-55 corridor in the wee hours of the morning.  The
associated strengthening surface low looks to move toward Chicago by
Thursday morning...supported by great dynamic lift ahead of the
wave. Precipitation looks to continue, heaviest through the daylight
hours, through the day into the overnight hours.

P-types and amounts:

Precipitation looks to start as light freezing rain showers south of
M-55 late overnight. The warm nose should be sufficient enough (2 to
3 kft with a maximum temperature of 3 to 4C) to support full melting
of any flakes, with a shallow cold dome at the surface. This holds
true up to about the M-32 corridor, with freezing rain (or rain in
the slightly warmer spots) expected through the morning.
Temperatures remain cool enough for flakes to mix in or dominate
near the tip of the mitt and north of the bridge. Then the column
cools through mid-day, enough to transition stuff over to snow for
the south. This transition may happen earlier than mid-day for areas
south of the bridge, but confidence in precip type and change-over
timing is low at this point. Overall 0.10-0.15" of ice look at least
plausible for some areas south of M-32 in the higher terrain, with a
sharp gradient to 4 to 6" of snow the further north one goes into
the tip of the mitt and eastern upper. It should be noted (as by
previous shifts) that this will be a very heavy and wet snow.

Snow looks to continue Thursday night into Friday morning as colder
air wraps back in behind the sytem with support and another corridor
of moisture ahead of the next wave moving in from the northwest.

.LONG TERM...(Thursday night through Monday)
Issued at 258 AM EST Tue Feb 7 2023

...Snow Friday, mild and quiet heading through weekend...

High Impact Weather Potential: Minimal for now.

Another wave shoots up the Ohio Valley Friday, with its surface low
scraping by to our south, although it is much weaker and further
southeast than previously. We may not get any synoptic snow out of
this, but we may have enough cold air moving across the lakes for NW-
flow lake effect Friday. This looks to be followed by a quieter and
mostly dry weekend as surface ridging slides overhead. Another
baroclinic zone sagging into the region along with southerly flow on
the backside of the sfc ridging will bring more mixed precipitation
chances early next week. Highs will be above normal late in the
weekend into early next week.


.AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon)
Issued at 119 PM EST Tue Feb 7 2023

Already seeing some breaks in the clouds across WI behind a front
this afternoon. Expect these will continue to spread into northern
Michigan this afternoon...though westerly winds will support some
continued misty/drizzly junk over interior northern Lower that may
keep visbys down toward MVFR or lower...as cigs remain largely
around or below 2000ft. Best chances for this would be at KPLN,
KTVC, and may eke into KAPN. Some concern it could try to linger
over KCIU...but less certainty there...though there is mention of a
little drizzle there yet this afternoon. Not out of the question
some of this could tick up again at times overnight, with some
concern for freezing drizzle...though things should largely quiet
down overall. Winds should remain gusty through the afternoon but
begin to diminish with time going into tonight, shifting from
westish to more southwest overnight into Wednesday. Do have some
concerns for fog development in spots tonight, which could lower
visbys and ceilings as well.


Issued at 258 AM EST Tue Feb 7 2023

Winds and waves will continue to reach gale warning criteria along
most of our nearshore areas thru today. Conditions will drop to SCA
later this afternoon and evening...and then diminish below headline
criteria later tonight. Wintry mix of precip will impact all of our
nearshore areas today into this evening as a cold front sweeps thru
our region. A stronger system will impact our region late Wednesday
night thru Thursday...bringing more chances of mixed precip to
Northern Michigan along with gusty winds.


LH...Small Craft Advisory until 11 PM EST this evening for LHZ345>348.
     Gale Warning until 4 PM EST this afternoon for LHZ349.
LM...Small Craft Advisory until 10 PM EST this evening for LMZ323-341-
LS...Small Craft Advisory until 10 PM EST this evening for LSZ321-322.



NWS APX Office Area Forecast Discussion