826
FXUS63 KMQT 200528
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
128 AM EDT Sun Apr 20 2025

.KEY MESSAGES...

- A wintry mix of precipitation Sunday night through Monday
  night could lead to some slick roads on the Monday morning
  commute, but chances of 1+ inch of snow are only 15-30% in the
  high terrain of the western UP.

- Rain and snowmelt will continue to lead to rises on area
  rivers and possible minor flooding on typically flood-prone
  rivers.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 135 PM EDT Sat Apr 19 2025

Upper air pattern consists of a 500 mb trough in the southern and
central Rockies and a trough in the northern plains and upper Great
Lakes. This northern trough moves out tonight with the southern
trough moving into the southern plains by 12z Sun. Showers have
popped up this afternoon with the shortwave trough and also some
diurnal heating, but drier air is slowly coming into the area and
this will bring an end to the rain and snow showers by evening. Did
not make too many changes to the going forecast except to put some
pops into the area this afternoon.

&&

.LONG TERM /SUNDAY THROUGH SATURDAY/...
Issued at 352 PM EDT Sat Apr 19 2025

Ridging aloft remains over the Upper Great Lakes Sunday morning, but
just upstream over the Plains, troughing is in the process of
negatively tilting, supporting a surface low that will provide
unsettled weather Sunday night through Monday night. Relief from
that system will only be brief as troughing sliding northwest
to southeast through British Columbia Sunday itself acquires a
negative tilt as it rides the international border through
Tuesday. With the high number of features in a short period of
time, ensembles fall to chaos fairly quickly, but broad ridging
is generally expected to take root over the central CONUS,
meaning high pressure and dry weather would be expected for the
most part, but occasional disturbances may provide periodic
breaks in the long term, such as the UP being on the northern
periphery of a system passing along the Lower Great Lakes late
this week.

Beginning Sunday, 12Z GEFS mean shows 1032 mb high pressure centered
in the Lake Huron vicinity still providing dry conditions for the
UP. RHs look to fall to near 30 percent with winds of around 10 mph
gusting to near 15 mph out of the south to southeast, mitigating
fire weather concerns somewhat. CAMs show a lake breeze forming
along Lake Superior, but with the persistent flow nearly
perpendicular to the shoreline, inland penetration of such a lake
breeze will not be particularly far. Expect high temperatures
to climb to about 50.

Around 00Z Monday, chances of precipitation begin to climb ahead of
deepening low pressure passing from the Iowa/Missouri area to
Wisconsin by 12Z Monday and then into northeast Ontario by 06Z
Tuesday. Recent trends in the model guidance has been warmer with
this system, and while chances of at least some snowflakes flying
are around 40-60 percent across the western half, chances of even an
inch of snow accumulation have fallen to 15-30 percent for the high
terrain of the west. Snow accumulation is made even harder by ground
temperatures have been warming significantly lately and with 50s air
temperatures the preceding day, snow will probably struggle to
accumulate except on elevated surfaces or typical places where cold
air settles. The ground temperature will also make it hard for
freezing rain to accumulate, despite supportive sounding profiles
for brief accumulating freezing rain for inland Marquette County
around 12Z Monday. Still, a few slick spots can be expected on the
Monday morning commute, but with the forecast being a moving target
with sensitive precipitation types, a SPS in real time might be the
proper headline assuming no changes in the forecast. As the system
passes on Monday, total QPF 25th-75th percentile ranges are about a
third of an inch to over 0.75 inches, which the rainfall and
enhanced melting of snowpack will put additional stresses on rising
rivers. Precipitation looks to end from southwest to northeast
throughout Monday night.

While ridging in the wake of the low will provide some break in the
precipitation, such a break will be shortlived as a weak low
pressure looks to come out of the Northern Plains Tuesday, though
chances of precip and precipitation totals look to be less than this
current system as the low pressure battles the ridging and actually
looks to split into a weaker lobe passing through the Great Lakes
region and another only slightly stronger system pushing through
northern Ontario. Either way, impacts look to be pretty low, even
the 90th percentile looks to be around a quarter inch of
precipitation.

High pressure then looks most likely to take root over much of
central North America moving forward. There are some indications of
a low pressure passing from the Southern Plains to the Lower Great
Lakes that the UP might be on the northern periphery of for the late
Thursday into the weekend timeframe, but PoPs are 50% or less for
all but the furthest southern extent of the UP Wednesday and beyond.
Wednesday in particular looks to be the warmest day of the forecast,
with NBM high temperatures climbing to the mid-60s for the Iron
Mountain region, but the rest of the forecast does frequently put
high 50s to low 60s in the forecast away from the Great Lakes going
forward, with low temperatures remaining above freezing except for
the typical cold spots.

&&

.AVIATION /06Z TAFS THROUGH 06Z MONDAY/...
Issued at 126 AM EDT Sun Apr 20 2025

VFR conditions are anticipated at CMX and IWD for most of the TAF
period. Given the recent precipitation and clearing skies, fog has
developed at SAW causing IFR conditions. This fog will persist until
sunrise, after which it will begin to abate. There is a 30% chance
the fog may thicken up at bit a SAW resulting in brief periods of
LIFR conditions. VFR conditions will return to SAW by late morning.
Clouds will begin to thicken up across the area this evening as
a system approaches from the south. Rain showers will start to
move in after 03Z with with MVFR conditions expected to develop
at all terminals.

&&

.MARINE...
Issued at 352 PM EDT Sat Apr 19 2025

High pressure over the Great Lakes will keep wind gusts below 20 kt
through Sunday evening. Sunday night into Monday morning, a low
pressure passing through the Upper Great Lakes will cause easterly
and northeasterly wind gusts to increase to 25-30 kt by Monday
morning, becoming northerly around 25 kt Monday evening, and falling
below 20 kt Tuesday morning`s winds become northwesterly.
Chances for a few gale force gusts to 35 knots are about 20
percent. The remainder of the forecast looks to be sub-20 kt as
either high pressure or weak low pressures pass by the area.
Expect waves of 4-8 ft Monday morning through Tuesday afternoon.

&&

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

&&

$$

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