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FXUS63 KAPX 272045
AFDAPX

Area Forecast Discussion
National Weather Service Gaylord MI
345 PM EST Sat Feb 27 2021

.NEAR TERM...(Through Sunday)
Issued at 345 PM EST Sat Feb 27 2021

...Quiet night, precip returns Sunday...

High Impact Weather Potential: Minimal. Spotty light wintry mixed
precipitation possible Sunday morning, and some accumulating snow
in the U.P.

Pattern Synopsis/Forecast: Afternoon composite analysis reveals a
sharp cold front draped across southern Ontario and across Lake
Superior, making headway toward the north shore of the U.P.
Low level convergence axis noted across interior eastern Upper MI
with a narrow band of Cu that has popped...reminiscent of summertime
lake breeze convergence. Further south, we cleared out nicely
again across northern Lower Michigan with temperatures solidly in
the 40s in most areas.

Well upstream, a well defined mid level circulation is evident
over eastern Wyoming along with developing low pressure down the
front range of the Rockies. Closed mid level wave will open up and
progress across the northern plains tonight and through the
northern Great Lakes on Sunday. This will drive a stronger area of
surface low pressure through the northern Great Lakes during the
day Sunday with the SREF consensus track taking the surface low
across the Straits around early to mid afternoon. Strong warm
advection forcing ahead of the system drives precip northward
through the region through midday Sunday, followed by a period of
deformation "wrap-around" precip swinging back through Sunday
afternoon/evening as the system departs.

Primary Forecast Concerns: Precip type and snow accumulations.

Details: Not much to worry about for the bulk of tonight. As
mentioned, sharp cold front continues to sag down through Lake
Superior and likely to stall out across the U.P. tonight. Nothing
(precip-wise) anticipated along the boundary other than some lower
cloud cover sagging into that area. South of the bridge, mainly
clear skies will be the rule through much of the night. A decent
set-up for radiational cooling although that will be curtailed by
an increasing pressure gradient and some wind aloft keeping things
mixed through the night. Nonetheless, I have lowered temps down
several degrees for some of our cold spots (GOV, etc) where sfc
decoupling is most likely.

Meanwhile, aforementioned system will be tracking into the
western Great Lakes early Sunday morning driving a band of strong
low-mid level warm advection forcing northward into the region.
Across northern Lower Michigan, initial dry air in place will take
a little time to overcome. But with cold surface conditions to
start and a wedge of warm (>0C) air aloft spreading into northern
Michigan, some spotty low QPF freezing rain is a possibility
across northern Lower Michigan Sunday morning. Given the low
QPF/spotty nature of the precip, I Don`t think we will need a
winter weather advisory headline at this juncture. But will see
how it goes.

Precip will become a bit more showery and widespread heading into
the afternoon as stronger upper jet/synoptic forcing arrives,
working in conjunction with steeper lapse rates aloft. But
temperatures across northern Lower Michigan should be well above
freezing at that juncture with just rain anticipated.

Across the U.P. and further into the colder air, it will take a
bit longer for precip to arrive, early afternoon or so and may
initially begin with some rain or rain/snow mix. Precip
transitions back to mainly snow through the afternoon as colder
air wraps back into the region with an inch or two of accumulation
anticipated through early evening.

&&

.SHORT TERM...(Sunday night through Tuesday)
Issued at 345 PM EST Sat Feb 27 2021

High Impact Weather Potential: Moderate...LES and cold Sunday night-
Monday

Pattern Synopsis/Forecast:

Surface cold front should be exiting the region stage right as
deepening surface low departs the area to the northeast Sunday
evening. Attention then turns to approaching anomalously strong
shortwave troughing dropping in from the northwest with a chilly
start to meteorological spring for Michigan on Monday (March 1). As
temperatures fall aloft and at the surface late Sunday night...will
look for northwest flow lake effect and/or enhancement to kick up,
especially as some synoptic moisture swings through ahead of that
shortwave early Monday. Will feel quite wintry Monday with gusty
winds ramping up between departing surface low to our east...and
arctic high to our west. Subsidence and high pressure attempt to
take control of the region Monday night...which could lead to a
quite cold night (below normal, even for Pellston by this time).
Ridging building into the upper Midwest Monday night into Tuesday
will be a harbinger of milder air for the middle of the week.

Primary Forecast Concerns: lake effect/enhanced snow Sunday night
into Monday...gusty winds and cold temps Monday into Monday
night...gusty winds (and precip chances?) Tuesday.

Looks like there could be a bit of wraparound moisture on the
backside of the departing system Sunday night that could linger
synoptic snow chances into the evening...especially across E. Upper
and perhaps the Tip of the Mitt. With northwest flow CAA, temps
aloft will fall through the night...and become sufficient for
overlake instability by 6z. Steepening mid-level lapse rates with
CAA aloft could lead to potential for some added oomph to lake
effect/enhancement Sunday night through Monday. Though LES may start
to kick up as early as Sunday night...will look for snow to pick up
in intensity and become a little more widespread, perhaps, Monday
morning as some Pacific-based moisture moves in along/ahead of the
main shortwave. LES should dwindle through the day as subsidence
begins to take hold of the region...and surface high pressure
approaches the area.

Will likely see winds stay on the stronger side through Monday as we
sit between deep surface low to our northeast...and strong, cold,
surface high to our west once that potent shortwave moves through.
Once shortwave begins to depart eastward Monday night...and surface
high pressure builds in...will start to see pressure gradient ease a
bit and winds should begin to lighten...for a time, anyway. Winds
look to again pick up Tuesday as northern stream system well to our
north should intensify the pressure gradient again, though this
time, it should be on the northwest quadrant of high pressure...so
we`d be in a return flow situation (i.e., southwesterly winds and
therefore, milder flow).

Still looking for minimal temperature rebound through the day Monday
as the surface cold front passes through. Would not be surprised to
see highs occur either during the overnight or early in the day
(except for perhaps the southern tier of counties along the M-55
corridor...perhaps...) and temps in the teens by suppertime. With
high pressure and overall subsidence moving into the region Monday
night...will have to keep an eye on cloud cover trends to determine
just how cold lows can go. Despite mitigating factor of potential
cloud cover off the lakes...would still expect lows to be chilly,
given the anomalous troughing in the vicinity. Current MOS guidance
indicates lows in the single digits across much of the CWA...and
model guidance otherwise continues to stay in reasonable agreement
on the cold air...so see no reason attm to make any huge changes to
min Ts for Monday night.

As briefly mentioned above regarding Tuesday...will likely see
southwesterly winds kick up on the backside of high pressure as
northern stream troughing scootches by well to our northwest. Looks
like a semi-longitudinally-oriented warm front should be moving
through the upper Midwest or just to our north on Tuesday as milder
air is advected into the region, bringing temperatures back up into
the normal (or perhaps above normal) range. Some synoptic moisture
is noted in guidance over the Tip of the Mitt and Eastern Upper with
the warm front passage Tuesday morning...though model derived
soundings indicate that the moisture will have a hard time
overcoming mid and low level dry air (makes sense given that we`ll
be in the right exit quadrant of the jet...typically more favored
for subsidence). Will keep things dry for now.

&&

.LONG TERM...(Tuesday night through Saturday)
Issued at 345 PM EST Sat Feb 27 2021

High Impact Weather Potential: Minimal...

Generally zonal flow looks to be in place across the northern CONUS
Tuesday night into Wednesday...though some subtle differences in the
upper level pattern are noted here and there. Cutoff low in the
southwestern US will begin to move eastward as upstream flow over
the Pacific amplifies...with a trough digging off the coast of
western North America that should begin to kick the cutoff low
eastward through the period. ATTM...cutoff low looks to stay to our
south...but ridging already in place north of the cutoff low will
further amplify...causing troughing to redevelop across the Great
Lakes region through the latter half of the week. Will continue to
monitor this in the coming days...as things are still struggling to
come into alignment.

&&

.AVIATION...(For the 18Z TAFS through 18Z Sunday afternoon)
Issued at 225 PM EST Sat Feb 27 2021

Cleared out nicely once again across northern Lower Michigan with
solid VFR weather for this afternoon and through tonight as well.
Some W/SW gustiness out there this afternoon. Winds will diminish
as we head into this evening.

Another weather system will eject E/NE out of the central Rockies
tonight and drive an area of low pressure through the northern
lakes region on Sunday. System will bring a brief wintry mix to
northern Lower Michigan Sunday morning, although I`m not
anticipating much impact. More substantial precip arrives Sunday
afternoon across northern Lower Michigan, but should be all rain
at that juncture with temps warming through the upper 30s to lower
40s. But lower CIGs will bring MVFR weather back to the region.


&&

.MARINE...
Issued at 345 PM EST Sat Feb 27 2021

Strong low pressure system expected to track through the northern
lakes region on Sunday. Small craft advisories will likely be
needed for some marine zones for Sunday. But the bigger impact
will come Sunday night into Monday behind the system as gusty
northwest winds develop across the region. Could see a few hours
of gale force gusts on northern Lake Michigan late Sunday
afternooninto the evening. But a longer period of gale force
gusts is anticipated on northern Lake Huron Sunday night and
continuing through Monday. Plan to hoist a gale watch for some
nearshore zones of northern Lake Huron, coincident with the gale
watch already in place in the open waters.

&&

.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...GALE WATCH from Sunday evening through late Sunday night for
     LHZ347-348.
LM...NONE.
LS...NONE.
&&

$$

NEAR TERM...BA
SHORT TERM...FEF
LONG TERM...FEF
AVIATION...BA
MARINE...BA

NWS APX Office Area Forecast Discussion