705
FXUS63 KMQT 211858
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
258 PM EDT Fri Mar 21 2025

.KEY MESSAGES...

- Rain showers will turn to snow showers behind a sharp cold
  front from about 5-9 pm this evening as temperatures plummet
  below freezing. Accumulations will be light but slippery spots
  on untreated roads cannot be ruled out.

- Lake effect snow showers continue tonight in the north to
  northwest wind belts with wind chills plummeting to 0 to 10
  below by Saturday morning. 1-3 inches of snow is expected with
  locally higher amounts over the eastern UP.

- Another system brings several inches of wet accumulating snow
  Sunday into Monday.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 257 PM EDT Fri Mar 21 2025

Early afternoon water vapor imagery shows a positively tilted trough
extending from northern Ontario southwestward through the northern
and central Plains. Warm temps on southwesterly flow are boosting
temps into the 40s locally. A few high-based showers/virga are
showing up on area radars this afternoon. A cold front associated
with the approaching trough will push through the CWA from NW to SE
roughly 5-9 pm this evening. Good low-level frontogenesis signature
will result in a band of precipitation developing along and just
behind the front, with rain quickly turning to snow. Better low-
level instability doesn`t coincide with the better forcing, and
frontal precip should end before temps get too cold, so do not
expect a classic snow squall/flash freeze setup. However,
temperatures continuing to plummet behind the front along with lake
effect snow showers developing over the N/NW wind belts does raise
some concern for some slippery travel on untreated surfaces later
this evening. The cold air associated with this trough is legit,
with 850 mb temps falling below -20C over Lake Superior by 12Z Sat,
which represent standardized anomalies of -2 to -3 sigma. Combined
with northerly winds gusting to 20-30 mph, this will produce wind
chills down to 0 to 10 below late tonight/early Saturday morning.

&&

.LONG TERM /SATURDAY THROUGH THURSDAY/...
Issued at 256 PM EDT Fri Mar 21 2025

Upper air pattern consists of a 500 mb trough over the lower Great
Lakes with another over the northern Rockies 12z Sat. Troughing
moves into the northern plains 00z Sun which moves into the area
Sun. A closed low develops over northern Wisconsin by 00z Mon and
then heads to near Georgian Bay 00z Tue according to the NAM. Two
systems will affect the area. The first system will be moving out
Saturday morning with lingering lake effect and then it dries out
into Saturday evening. The next system looks interesting for the
area Saturday night into Sunday night. Confidence is still too low
for a watch at this time, but there are a couple places that are
scattered around that could see warning criteria for snowfall
amounts. Most places though look like advisory amounts at this time.
This will be mentioned in the mqt product. Does look like a
little freezing rain starts off across the west later Saturday night
into Sunday morning.

In the extended, the GFS and ECMWF show a 500 mb ridge in the
western U.S. and a broad trough across the eastern half of the U.S.
12z Tue. The ridge moves into the Rockies 12z Wed. Differences
between the ECMWF and GFS show up 12z Thu with the GFS keeping the
ridge over the Rockies while the ECMWF brings the trough into the
plains. Troughing remains then 12z Fri into the western U.S.
Temperatures look to remain near normal for this forecast period.

&&

.AVIATION /18Z TAFS THROUGH 18Z SATURDAY/...
Issued at 140 PM EDT Fri Mar 21 2025

Strong cold front crossing the UP from NW to SE will
bring lower ceilings, rain showers turning to snow showers, and
gusty northwest to north winds to 25 kt late afternoon into tonight.
Predominant ceiling category in the wake of the front looks to be
MVFR at SAW and borderline MVFR/VFR at CMX/IWD. A band of rain
showers turning to snow showers will be most pronounced at SAW from
21-23Z, with lake effect snow showers continuing at times into at
least the first part of the night. This could drop vsby to IFR at
times, although confidence was not high enough to include in the
TAFs at this time. The snow showers should diminish late tonight
into Saturday morning.

&&

.MARINE...
Issued at 256 PM EDT Fri Mar 21 2025

We get close to gales at times this forecast period, but the areas
are pretty spotty and brief. One such time period is tonight where a
few north gale gusts to 35 knots are possible between Isle Royale
and the Keweenaw north of Copper Harbor. Winds then drop below 20
knots by Saturday afternoon into Saturday evening. There will also
be some heavy freezing spray tonight into Saturday morning. Winds
then increase to 20 to 30 knots on Sunday from the southeast and
then switch to the north Sunday night. Northerly winds settle below
20 kts Monday night through Tuesday.

&&

.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
  Heavy Freezing Spray Warning from 11 PM EDT /10 PM CDT/ this
     evening to 8 AM EDT /7 AM CDT/ Saturday for LSZ241-242-
     263.

  Heavy Freezing Spray Warning from 10 PM this evening to 9 AM
     EDT Saturday for LSZ243-244-264.

  Heavy Freezing Spray Warning from 11 PM this evening to 11 AM
     EDT Saturday for LSZ245-248>251-265>267.

Lake Michigan...
None.

&&

$$

SHORT TERM...Thompson
LONG TERM...07
AVIATION...Thompson
MARINE...07