National Weather Service Raw Text Product

850 
FXUS63 KMQT 221921
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
221 PM EST Thu Dec 22 2022

.SHORT TERM...(Through Tonight) 
Issued at 220 PM EST THU DEC 22 2022

Key Messages:
-Lake-enhanced system snow bringing 2-5 inches of snow through 
tonight
-Road conditions are slick, but still driveable if absolutely 
necessary

Winter Weather Advisory-level snow continues for the Upper Peninsula 
as a weak, broad surface low passes through the region ahead of a 
deepening, negatively tilting 500mb trough. 850 mb warm advection 
will decrease through the day as the low passes and winds aloft 
begin turning to be out of the north. Snow today is mostly system 
snow however it is lake enhanced from Lake Michigan with southerlies 
ahead of the low and Lake Superior with northerlies behind the low. 
The 850mb temperatures ahead of the low are in the 
-8 to -10 C range while behind the low the temps aloft are easily 
into the negative teens and 20s C. As far as the snow:liquid 
forecast, a fairly deep dendritic growth zone will support higher 
ratios but those will be kept in check by strong winds and wind 
shear tearing apart some flakes, so mostly forecasting around 15:1, 
though 10:1 was been observed at the office in Negaunee Township 
this morning and that has increased throughout the day. With those 
snow ratios in mind, most of the UP will see an additional 3 inches 
(give or take an inch or 2) leading up to the warnings late tonight. 
With multiple observations and reports of slick roads thus far, 
travel is not necessarily advised, but it is still possible for now.

.LONG TERM...(Tonight through Wednesday) 
Issued at 414 AM EST THU DEC 22 2022

Strong storm occurring with a closed 500 mb low in central Minnesota 
00z Fri. This low heads southeast to northeast Indiana 12z Fri and 
causes the 500 mb trough to become negatively tilted Thu night over 
the Great Lakes region. The 500 mb low then heads northeast to north 
of Lake Ontario 00z Sat and then to near James Bay by 00z Sun. This 
will keep the area under upper level troughing through this forecast 
period. Part one of the storm is ongoing and will continue until 06z 
tonight. Extended advisories until 06z and chose that end time to 
when the wind picks up. After 06z tonight to 00z Sunday with the 
strongest winds, blizzard conditions will occur went with blizzard 
warnings near Lake Superior and winter storm warnings elsewhere. 
Tied the winter storm warnings to where lesser amounts of snow will 
be seen, but the snow that does fall and has fallen with event one 
will cause blizzard conditions anyway, just might not have the 
amounts, but the visibilities will still be very low. With Southern 
Schoolcraft County, the strong wind will push the lake enhanced snow 
further inland than usual and this will make it all the way down to 
U.S. Highway 2, so thought blizzard warning appropriate there. These 
are the changes made to the going forecast.

In the extended, GFS and ECMWF show a 500 mb ridge in the western 
U.S. and a trough in the eastern half of the U.S. in a highly 
amplified pattern 12z Sun. The ridge moves into the Rockies 12z Mon. 
Pattern starts to de-amplify 12z Tue with the ridge beginning to be 
flattened over the Rockies as a shortwave moves into the northern 
Rockies. Pattern becomes a mess 12z Wed with weak upper troughing 
remaining over the upper Great Lakes and a ridge in the southern 
Plains. Troughing moves into the northern plains 12z Thu. 
Temperatures start out below normal and then a warming trend takes 
place with temperatures near normal on Tue going above normal for 
Wed and Thu.
&&

.AVIATION...(For the 18Z TAFS through 18Z Friday afternoon)
Issued at 104 PM EST THU DEC 22 2022

IFR conditions will be the dominant category at all TAF sites for 
this TAF period minus IWD, which has been VFR in a dry slot all 
morning and will start the TAF period MVFR. Eventually, lake effect 
snow, gusty NW winds, and blowing snow will drive the aviation 
impacts in the forecast at all sites. With all 3 TAF sites within a 
Blizzard Warning after 06Z tonight, occasional whiteout conditions 
are possible, though exact periods of airport minimums will be 
difficult to pinpoint until it happens in real time. Some wind shear 
is also present in the SAW TAF as rapidly changing wind speeds with 
height in the vicinity of the TAF do reach LLWS criteria.
&&

.MARINE...(For the 4 AM Lake Superior forecast issuance)
Issued at 414 AM EST THU DEC 22 2022

Major storm force wind event will continue on Lake Superior for this 
forecast. Winds increase tonight quickly and kept the storm warning 
time the same. The wind does get up earlier in the far west to gale, 
but with storm warning out, a gale warning before that would be 
implied. To remove confusion, kept the start time the same but went 
storm when gales would start. The wind stays at 15 to 30 knots today 
before increasing to north gales tonight to 45 knots and then storm 
force winds to 60 knots through Saturday. The strong gale to 45 
knots drops off then by Sunday night. In addition to the winds, 
strong northerly winds will usher in cold air and a heavy freezing 
spray hazard and wind-driven waves in the eastern half could exceed 
25 feet Saturday.

Marine interests with passage plans through Lake Superior tonight 
through Monday should make the appropriate plans now to avoid these 
conditions.
&&

.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
  Winter Weather Advisory until 1 AM EST Friday for MIZ001>007-
     009>014-084-085.

  Blizzard Warning from 1 AM Friday to 7 PM EST Saturday for 
     MIZ001>003-005>007-009-014-085.

  Winter Storm Warning from 1 AM Friday to 7 PM EST Saturday for 
     MIZ004-010>013-084.

Lake Superior...
  Storm Warning from 1 AM Friday to 1 AM EST Sunday for LSZ162-
     240>251-263>267.

  Heavy Freezing Spray Warning from 1 AM Friday to 1 AM EST Sunday 
     for LSZ162-240>251-263>267.

Lake Michigan...
  Storm Warning from 1 AM to 7 PM EST Friday for LMZ221-248-250.

  Heavy Freezing Spray Warning from 1 AM Friday to 7 AM EST 
     Saturday for LMZ221-248-250.

&&

$$

SHORT TERM...GS
LONG TERM...07
AVIATION...GS
MARINE...07