717 
FXUS63 KMQT 042209
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
509 PM EST Tue Jan 4 2022

.SHORT TERM...(This evening through Wednesday)
Issued at 427 PM EST TUE JAN 4 2022

...Hazardous driving conditions expected on Wednesday...

Overall, forecast remains on track for this upcoming system/lake-
enhanced event; therefore, no changes made to the headlines for
this latest forecast update. 

There is good consistency amongst the models in terms of not only
the track of the low, which is to cut across northern Lake
Michigan tomorrow, but also seeing lots of agreement on an
embedded heavy snow band initially developing out across the
western and central portions of Lake Superior dropping
south-southeastward tomorrow morning across at least the western
two-thirds of the U.P. The combination of ample atmospheric
moisture, favored NErly flow off of Lake Superior, and this
frontogenetical band trekking through will create the potential
for 1 to 2+ inch per hour snow rates within this heavy band. In
terms of timing, it looks to occur right in the heart of the
morning commute, so even if the roads initially don't seem very
poor, they could rapidly deteriorate within this band, especially
if traveling within the higher terrain areas (of the warned
counties) simultaneously. Snow will continue falling throughout
the day, with everyone in the U.P. picking up at least a couple of
inches before the day is done. On the Lake Michigan side, winds
out of the S to SE out ahead of the low's center tonight will
allow for lake-enhancement snow into portions of the eastern U.P.,
particularly near the Garden Peninsula, but will be relatively
short-lived as the winds back with the lowpa. 

Speaking of lowpa, the winds will pick up as the day progresses,
especially near and along Lake Superior, creating blowing snow.
These winds coupled with falling temps throughout the day will
also create chilly wind chills, with single digit wind chills
appearing by day's end, and even sub-zero wind chills in the west.
Lows tonight will be in the teens and 20s, and highs tomorrow will
occur early in the day, especially across the west half, with
widespread 20s expected, perhaps near 30 degrees along the
lakeshores, but again, following that non-diurnal temp curve.

Bottom line: don't focus on the snow amounts when it comes to
anticipating impacts. The primary concerns for this forecast
period revolve around the hazardous driving conditions expected,
especially if finding oneself within an area of heavy snow
falling. The snow will fall quickly in a short amount of time,
reducing visibilities in addition to quickly accumulating on 
roads, and will become even more treacherous by the afternoon when
blowing snow picks up.

.LONG TERM...(Wednesday night through Tuesday)
Issued at 448 PM EST TUE JAN 4 2022

The primary weather hazards early in the extended are below normal 
temperatures allowing for locally heavy lake effect and lake 
enhancement to persist into Friday. Warm air advection late Friday 
into Saturday results in a period of light snow as temps briefly 
warm above normal ahead of Sunday's arctic cold front. ECMWF EFI 
guidance is already pointing to a potentially extreme arctic blast 
from late Sunday into early Tuesday. 

Starting at 00z Thursday, lake enhanced snow will be ongoing with 
the heaviest snowfall expected where northeasterly upslope is 
maximized. Low level flow weakens and backs more northerly across 
western Lake Superior by Thursday evening. Winds weaken and continue 
to back northwesterly Thursday night with southwesterly winds 
spreading over the lake on Friday, effectively ending LES potential. 
A more detailed looks shows two distinct 500 mb lows that pivot 
across the region with the first low moving away at 00Z Thursday 
while the next one approaches. While weaker than the first, this 
secondary episode of synoptic scale supports ongoing LES via the 
seeder-feeder process. Slightly cooler air behind the second system 
allows inversion heights to gradually increase from ~4kft at 00Z 
Thursday to >5kft at 00Z Friday. Even though the increase is small, 
it could represent one last hurrah of snowfall before WAA kicks in 
Friday morning. 

WAA begins in earnest Friday night and frontogenesis may lead to 
some light snow across the CWA. WAA continues through Saturday, but 
a low-level inversion limits our warm-up to the 20s. The warmest 
locations downwind of Lake MI could approach the freezing mark. 
However, the warm-up will be brief as the next arctic cold front 
rapidly pushes southeast across our CWA late Saturday night into 
Sunday. Deterministic 12z guidance indicates a bubble of -33C 850 mb 
temperatures tracking southeast across Ontario Sunday night 
suggesting lake-850 mb delta-T values increasing to near or above 
35C. There could be substantial LES early next week for NW wind snow 
belts even though the DGZ is below the ground/lake surface. 
Potentially extreme cold and wind chill hazards are also a distinct 
possibility.
&&

.AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon)
Issued at 1252 PM EST TUE JAN 4 2022

Snow is on its way, impacting all three terminals tonight into
tomorrow. Currently, KCMX and KSAW are wavering between IFR and 
MVFR, but once the snow sets in, low-end MVFR is expected to be 
the max, with IFR expected to dominate, and likely that LIFR will 
make an appearance. Have gone with a bit more broadbrush approach 
to this TAF issuance, but less than 1SM is expected; just a matter
of refining those details in subsequent TAF issuances. SErly 
winds to start will back to the NE for the latter portions of this
TAF period.
&&

.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 501 PM EST TUE JAN 4 2022

Gales early tonight will turn into NErly storm-force gusts by the
pre-dawn hours as a low pressure system traverses past. These
storm-force gusts will drop back down into gales by late tomorrow,
with winds continuing to back to the N-NE. Gusts will remain above
25 knots late tomorrow night into early Thursday, trending
downward by day's end. Less than 25 knots is expected to end out
the week, with Srly to SWrly winds exceeding 25 knots later on
Saturday and remaining elevated through the weekend into early
next week but from primarily out of the NW.

In addition to the winds, marine interests should also be aware of
the heavy freezing spray expected tonight into early Thursday.

&&

.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
  Winter Storm Warning from 1 AM to 7 PM EST Wednesday for MIZ004-
     005-084.

  Winter Weather Advisory from 1 AM EST /midnight CST/ to 7 PM EST 
     /6 PM CST/ Wednesday for MIZ006-007-010-011-014-085.

  Winter Storm Warning from 10 PM EST /9 PM CST/ this evening to 7 
     PM EST /6 PM CST/ Wednesday for MIZ001>003-009.

  Lakeshore Flood Advisory from 4 AM EST /3 AM CST/ Wednesday to 1 
     AM EST /midnight CST/ Thursday for MIZ001>003-009.

  Lakeshore Flood Advisory from 7 AM Wednesday to 4 AM EST 
     Thursday for MIZ004>007.

Lake Superior...
  Heavy Freezing Spray Warning from 4 PM Wednesday to 10 AM EST 
     Thursday for LSZ267.

  Gale Warning from 7 AM to 9 PM EST Wednesday for LSZ267.

  Heavy Freezing Spray Warning from 1 AM Wednesday to 10 AM EST 
     Thursday for LSZ266.

  Gale Warning from 3 AM to 10 PM EST Wednesday for LSZ266.

  Gale Warning from 5 AM to 9 PM EST Wednesday for LSZ265.

  Heavy Freezing Spray Warning from 10 PM this evening to 10 AM 
     EST Thursday for LSZ263-264.

  Storm Warning until 1 PM EST /noon CST/ Wednesday for LSZ162-263-
     264.

  Gale Warning from 7 AM to 7 PM EST Wednesday for LSZ249>251.

  Gale Warning from 5 AM to 1 PM EST Wednesday for LSZ248.

  Gale Warning from 1 AM EST /midnight CST/ to 9 PM EST /8 PM CST/ 
     Wednesday for LSZ241>245.

  Gale Warning from 1 AM to 1 PM EST Wednesday for LSZ246-247.

  Gale Warning from 1 AM EST /midnight CST/ to 7 PM EST /6 PM CST/ 
     Wednesday for LSZ240.

  Heavy Freezing Spray Warning from 10 PM EST /9 PM CST/ this 
     evening to 7 AM EST /6 AM CST/ Thursday for LSZ162.

Lake Michigan...
None.
&&

$$

SHORT TERM...lg
LONG TERM...EK
AVIATION...lg
MARINE...lg