778
FXUS63 KMQT 020801
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
401 AM EDT Wed Apr 2 2025

.KEY MESSAGES...

- Winter Weather Advisories remain in effect for the south-
  central UP and the Keweenaw for multiple inches of
  accumulating wet snow and potential for impactful wintry mix.

- Wind Advisories have been issued for portions of the eastern
  UP for afternoon wind gusts in excess of 45 mph.

- East to southeast gales of 45 knots to storm force winds up to
  at least 50 knots are expected today across Lake Superior.
  Southeasterly gales up to 40 knots are also expected over the
  Lake Michigan nearshores until this evening.

- West gales of 35 to possible even 45 knots expected over
  mainly central and eastern Lake Superior late tonight into
  Thursday behind the center of the low. Gales look to end by
  late in the afternoon as high pressure builds in.

- Warming temperatures and the high April sun angle will lead to
  rapidly melting snow and ice during the daylight hours late
  this week into early this weekend.

&&

.SHORT TERM /THROUGH THIS AFTERNOON/...
Issued at 336 AM EDT Wed Apr 2 2025

RAP analysis shows a high 980s mb low pressure straddling the OK/KS
line at 07Z this morning, with GOES-16 water vapor imagery showing
isentropically-forced showers extending well to the north and east
of this system. KMNM METARs have shown precipitation for a couple of
hours now, but further to the north, light radar returns do give the
indication that showers are trying to form, but are battling low
level dry air with dew point depressions around 5-10 degrees still.
Forecast PoPs for this morning have been trimmed back as a result,
especially as 00Z CAMs show this first push of shower activity
"fizzling out" by 12Z for most of the UP. The cloud cover is well
established now though, which is a bit of a bummer as NPS Isle
Royale webcams showed a decent amount of auroral activity. The cloud
cover will also keep low temperatures mainly in the 20s this
morning, significantly warmer than last night`s lows.

The main push of precipitation ahead of this low will arrive
throughout the later morning hours through the afternoon as the GEFS
shows the low pressure just south of Duluth in the mid 980s mb by
00Z Thursday. While atmospheric profiles should keep the initial
precipitation types as snow, a warm nose quickly develops on
soundings, which creates a complex precipitation type forecast, with
freezing rain and sleet mixing in for the early afternoon before a
push to all rain for most by 00Z as the surface warm front arrives.
The HREF FRAM 50th percentile does show a core of values around 0.1"
of ice accumulation for the spine of the Keweenaw and for the
central UP, but with actual surface temperatures warming to above
freezing, less confidence exists in lasting impacts from freezing
rain with this system, and a similar phenomena to the previous
system could occur where sleet mixing in with the freezing rain
could leave a textured surface, giving more traction to otherwise
iced-over surfaces. Still, expect some slick conditions on elevated
and/or untreated surfaces with this system. Snow totals have trended
downwards, both because of reduced snow ratios as the UP will be in
the warm sector and due to aforementioned precip type concerns, but
the south-central remain 40-70% likely to get 2+ inches of wet snow
today. Elsewhere, around 50% chances of exceeding an inch. One other
factor of consideration will be the winds, as low level winds will
be elevated with this system. The HREF shows 925mb winds of 50 kts
this afternoon over the eastern third and over the Keweenaw, and
even assuming some frictional loss of winds, probabilities of
breaking 45 mph gusts at the surface are over 70% per the HREF this
afternoon. Therefore, a Wind Advisory has been issued for Alger,
northern Schoolcraft, and Luce Counties with gusty wind verbiage
added to existing Winter Weather Advisories.

&&

.LONG TERM /TONIGHT THROUGH TUESDAY/...
Issued at 359 AM EDT Wed Apr 2 2025

As the warm front of the low leaves the area early this evening,
wrap around moisture from the comma-head of the low will fire up
rain and snow showers over the west-northwest wind snow belts
tonight into Thursday morning from west to east. Given the strong
pressure rises immediately behind the low, expect strong westerly
winds up to 35 mph to develop over the U.P. by Thursday morning as
pressure rises as great as 6mb in 3 hours occur over us (highest
gusts expected in the Keweenaw). With cloud cover helping to
insulate the area tonight, expect low temperatures to only get down
to around freezing. Thus, any snowfall we do see across the area
tonight through Thursday (mainly the west to northwest wind snow
belts) should be light, wet, and less than an inch in accumulation.
As the low lifts into northern Ontario Thursday morning, expect the
last of the precipitation to end by the late morning to early
afternoon as high pressure ridging moves in behind the low. With the
decreasing cloud cover throughout the day, expect highs on Thursday
to get into the upper 30s to mid 40s.

The rest of the extended period looks fairly quiet, with
temperatures being close if not a little above normal Friday and
Saturday as high pressure ridging persists over the region. With
high temperatures getting into the 40s and possibly 50s in the south
central, in addition to the high April sun angle, we could see
significant snow and ice melt across the region late this week into
this weekend. Therefore, watch out for rapidly melting ice and snow
over the area, especially over the lakes and rivers.

Expect temperatures to trend cooler late this weekend into early
next week as a cold front pushes through the area. This cold front
could bring light lake effect snowfall across the north-northwest
wind snow belts. However, given the high sun angle and marginal
delta-Ts, thinking accumulations will be rather light. There is also
a shortwave low lifting from the Plains into the Lower Midwest that
could bring some upslope precipitation Saturday as well. However,
confidence in this is very low (20% or less) as the low looks to
miss our area well to the south at this time. Behind the cold front
early next week, expect high temperatures to be well below normal as
a building high over the Plains keeps cycling polar air over us
until the middle of next week.

&&

.AVIATION /06Z TAFS THROUGH 06Z THURSDAY/...
Issued at 1208 AM EDT Wed Apr 2 2025

Conditions deteriorate as a system brings strong winds, low ceilings,
mixed precipitation and low level wind shear to all terminals.
Strong southeasterly winds of 25kts develop tonight and peak at 30-
40kts during the day Wednesday, highest at KCMX. First wave of snow
will build in tonight lifting northeastward, although this may have
trouble overcoming dry air currently over the region. A second wave
follows by morning, which will shift to rain in the afternoon as it
continues to lift through the region. Models continue to include
signals for freezing rain or sleet before the transition to rain.
Greatest confidence is for this to occur at KCMX/KSAW. Ceilings/vis
will fall to MVFR and then IFR as precip continues through the day.
LIFR ceilings can`t be ruled out at KCMX/KSAW by afternoon and all
terminals by evening.

&&

.MARINE...
Issued at 359 AM EDT Wed Apr 2 2025

East to southeast winds continue building today as a low approaches
from the Central Plains, eventually getting up to gales of 45 knots
to storm force winds of 50 knots this afternoon and evening (HREF
shows even a 50% chance for winds up to 55 knots near Whitefish Bay
this evening). Once the low moves into the lake, expect the winds to
weaken for a short time as the low`s center moves through.
Afterwards though, expect the winds to increase from the west behind
the low late tonight into Thursday as strong pressure rises move
into the Upper Great Lakes; expect westerly gales of 35 to possibly
even 45 knots across mainly the central and eastern lake late
tonight into Thursday behind the low. As high pressure quickly
builds in behind the low Thursday and Thursday night, expect the
winds to begin dying down Thursday afternoon, weakening to 20 knots
or less by midnight Thursday night. The lighter winds look to
continue through Friday and Saturday as high pressure dominates the
Upper Great Lakes and a shortwave low misses us well to the south.
However, we could see a return to northwest to north-northwest winds
of 20 to 25 knots late this weekend into early next week as a cold
front pushes through the region.

&&

.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
  Winter Weather Advisory until 8 PM EDT this evening for MIZ001-
     003.

  Wind Advisory from 2 PM this afternoon to 10 PM EDT this
     evening for MIZ006-007-085.

  Winter Weather Advisory until 2 PM EDT /1 PM CDT/ this
     afternoon for MIZ010>013.

  Winter Weather Advisory from 8 AM this morning to 5 PM EDT
     this afternoon for MIZ014.

Lake Superior...
  Gale Warning until 8 PM EDT /7 PM CDT/ this evening for LSZ162-
     243-247>250-263.

  Gale Warning from 2 AM EDT /1 AM CDT/ to 2 PM EDT /1 PM CDT/
     Thursday for LSZ241>244-263-264.

  Gale Warning until 8 PM EDT this evening for LSZ244>246-265.

  Gale Warning until 11 PM EDT this evening for LSZ251.

  Gale Warning until 11 AM EDT this morning for LSZ264-266-267.

  Storm Warning from 11 AM this morning to 5 PM EDT this
     afternoon for LSZ264-266-267.

  Gale Warning from 5 AM to 2 PM EDT Thursday for LSZ265.

  Gale Warning from 5 AM to 5 PM EDT Thursday for LSZ266.

  Gale Warning from 8 AM to 5 PM EDT Thursday for LSZ267.

Lake Michigan...
  Gale Warning until 8 PM EDT this evening for LMZ221-248-250.

&&

$$

SHORT TERM...GS
LONG TERM...TAP
AVIATION...JTP
MARINE...TAP