727
FXUS63 KMQT 071902
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
302 PM EDT Mon Apr 7 2025

.KEY MESSAGES...

- Lake effect snow showers will continue this evening and tonight,
although coverage should decrease. An inch or so of additional
accumulation will be possible, mainly east of Marquette.

- High pressure dominates the forecast Tuesday into the weekend,
though a system passing south of the region late Wednesday/Thursday
will introduce 15-25% chance for rain/snow showers.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 116 PM EDT Mon Apr 7 2025

Broad mid-upper level cyclonic flow emanating out of a upper level
low in northern Quebec continued today. With a few different
shortwaves embedded within this flow, 850mb temps over Lake Superior
estimated at -16 or -17C per SPC mesoanalysis, and lake surface
temps ~2C per GLERL analysis, lake effect cloud cover and snow
showers pressing south into Upper Michigan have been the main
feature for today. Webcams across the area show some snow
accumulation on roadways here and there, but with road temperatures
warming into the low to mid 30s across the area this morning,
impacts are likely minimal save for rapid visibility reductions in
the stronger showers. Temperatures have plateaued in the 20s across
the region and northerly flow has been gusting near 20-25 kts in
many locations, particularly across the northern half of the forecast
area. Higher gusts near 30 kts have been noted near Lake Superior
and in the Keweenaw.

A surface high over northern Manitoba is expected to inch eastward
into northwestern Ontario tonight. Upstream associated ridging, dry
air, and calmer winds will press into Upper Michigan from west to
east late this afternoon and evening thanks to the high`s migration.
Despite this though, model soundings continue to highlight saturated
boundary layer with DGZ access to heights of ~6-7k feet. Given this,
suspect scattered to numerous lake effect snow showers will continue
into the evening for the traditional north to northwest wind snow
belts. Overnight, the dry air should have more of an effect,
resulting in lowering inversion heights and inverted v soundings.
While this will help clear skies and diminish most shower activity
for most, upslope flow aided by low level convergence should allow
scattered showers to persist into the southern parts of the Spine,
Michigamme Highlands, and in and around Munising. Additional snow
accumulation of an inch or so are expected in the strongest showers.

Cold air over the region and the dry airmass will help overnight
lows dip into the single digits above and teens. Most effective
radiational cooling, and thus, the coldest conditions are expected
outside of the snow belts thanks to clearing skies.

&&

.LONG TERM /TUESDAY THROUGH MONDAY/...
Issued at 302 PM EDT Mon Apr 7 2025

General pattern aloft is highly meridional as deeply anomalous
cutoff lows over eastern Canada and the Gulf of Alaska are separated
by a tall ridge that extends from WY/MT all the way to northern
Nunavut. As the eastern Canada cutoff low continues to wobble, a
shortwave from the Gulf of Alaska low will transit through the
Rockies early this week, but passing south of the central Canada
ridge will force the resulting surface feature too far south for
much affects for the UP. Ridging looks to dominate the central CONUS
next weekend, but agreement is good for this time range on a more
substantial shortwave from the Gulf of Alaska trough making landfall
this weekend and progressing into the Northern Plains by Monday.
Generally speaking, this type of pattern looks to be dominated by
high pressure over the central CONUS with brief interruptions by
shortwave lows (think Clippers, etc).

Chilly NW flow will keep in a chance for lake effect snow showers
across the eastern UP through Tuesday afternoon, though rather dry
lower levels apparent in model soundings should limit accumulations
to below an inch before snow showers taper off by Tuesday evening.
Otherwise, expect gradually clearing skies and decreasing winds,
while temperatures climb up into the upper 20s to lower 30s. 1020s
mb high pressure then keeps the weather quiet for Tuesday night.
Initially clearer skies and light winds under the high pressure will
allow for an efficient radiational cooling night Tuesday night, with
NBM lows Wednesday morning in the teens and potentially even single
digits for much of the area.

A clipper low passing from the Plains to the Great Lakes in the
midweek is expected to remain too far south for significant impacts
to the UP, but we do get clipped by some precipitation Wednesday
into Thursday, so will allow for those 20-30% chance PoPs to remain.
Soundings are cool enough for any precipitation to be mainly snow,
with amounts again looking to stay below an inch. Expansive high
pressure returns to give pleasant weather Friday into the weekend,
with NBM highs in the 60s in the interior west by Sunday. Spread
then remains high on the surface features into the following week,
but there`s some signal beginning in a low pressure passing to the
north of the UP sometime in the Days 6+ period. Whatever does fall
is pretty likely to be rain at this point, with LREF chances of 6-
hourly accumulating snowfall at 25% or less throughout the end of
this week into the next.

&&

.AVIATION /18Z TAFS THROUGH 18Z TUESDAY/...
Issued at 116 PM EDT Mon Apr 7 2025

Lake effect cloud cover and snow showers look to hold on longer than
previously forecast given the continued saturated boundary layer.
While incoming dry air and ridging will help to diminish activity in
the period, MVFR ceilings, IFR visibilities, and gusty northerly
winds are likely to persist into the afternoon and evening,
particularly at KCMX and KSAW. Overnight, main focus for showers
shifts south of KCMX and east of KSAW, but prob30s were included
given the scattered nature of showers into these areas. Otherwise,
expect a trend toward VFR at all sites and lighter winds overnight.

&&

.MARINE...
Issued at 302 PM EDT Mon Apr 7 2025

Northerly winds remain elevated across the eastern half of the lake
this afternoon, with gusts up to 25-30kts more common. Winds fall to
below 20 kt in the west this evening, but northwest gusts to 25 kt
hang on in the east half until falling below 20 kt Tuesday morning.
Waves up to 6-10ft will remain possible across the eastern half of
the lake through tonight, while to the west, waves fall below 4ft
through the evening. Waves finally fall below 4ft in the east
Tuesday afternoon. Light to moderate freezing spray is expected to
persist tonight, ending Tuesday morning.

Under primarily high pressure, winds will remain light and variable
the remainder of the work week and into the weekend.

&&

.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
None.
Lake Michigan...
None.

&&

$$

SHORT TERM...JTP
LONG TERM...LC
AVIATION...JTP
MARINE...LC