NWS Marquette, MI wrote its last area forecast discussion before the first event at Apr 12, 5:41 AM CST, 3 hours 19 minutes earlier. Its key messages:
Area forecast discussion, Apr 12, 5:41 AM CST, 3 hours 19 minutes before
Area Forecast Discussion
National Weather Service Marquette MI
741 AM EDT Sun Apr 12 2026
.KEY MESSAGES...
- Active weather returns continues through much of at least the
first half of next week as several periods of showers and
thunderstorms are poised to move through the region.
- A prolonged period of well above freezing temperatures and
higher dewpoints will bring increased snowmelt. This, combined
with periods of potential heavy rain and thunderstorms, will
accelerate river rises and lead to ponding of water in areas
with poor drainage. A Flood Watch remains in place for all of
Upper Michigan through Wednesday morning.
&&
.DISCUSSION...
Issued at 341 AM EDT Sun Apr 12 2026
Early morning remote sensing tools reveal widespread rain across the
Northern Great Lakes region as strong WAA/isentropic ascent occurs
ahead of developing low pressure system currently organizing in the
High Plains. A few non-severe thunderstorms are noted across north-
central WI on the nose of a ~55kt LLJ, but given meager elevated
instability nothing more than a few rumbles of thunder and localized
pockets of heavier rain are expected from them. Through the rest of
the day, showers and embedded thunderstorms continue lifting through
the UP much of the morning and afternoon, tallying additional
rainfall totals upwards of 0.5-1", greatest south-central and east,
and locally greater amounts between 1-1.5" where thunderstorms and
heavier rain showers linger the longest. Precip largely wraps up
from west to east this afternoon/evening as the parent shortwave and
sfc pressure reflection lift north of Lake Superior. Today's
temperature forecast is a bit uncertain. There will likely be a
large gradient across the UP from east to west, with the east half
being much cooler, potentially 15-20 degrees cooler than the WI/UP
stateline. The NBM soars daytime highs into the mid to upper 60s
across the west and 50s east. Have opted to kick temps down a tad
given widespread rain and cloud clover, especially across the east
half where cool S-SW flow off Lake Michigan will mute sfc temps
despite 850 temps pushing 10-13C. Tonight, some additional light
showers may be seen as the system's cold front pushes west to east
late into Monday morning. Low temps fall into the 40s, though the
some areas of the south-central may remain above 50 overnight!
Monday starts off fairly quiet with a brief period of zonal flow
overhead and sfc high pressure nosing south across northwestern
Ontario, however, troughing emanating out of the Rockies once again
sends another surge of moisture into the UP Monday PM, kicking off
another round of widespread showers and thunderstorms. Latest
ensemble suites and NBM suggest a 50-70% chance for an additional
0.5" of widespread rainfall by Tuesday morning, though suspect
locally higher amounts will be possible given PWATs pushing 1" and
thunderstorm activity. Both SPC and WPC have the UP in a Marginal
Risk (level 1 of 5) for severe thunderstorm and flash flood
potential, respectively.
Looking into the mid to late week, global models and ensembles are
in decent agreement on a continued active period with southwest flow
aloft translating embedded shortwaves through the Great Lakes,
mostly notably a stronger wave late Wednesday into Thursday.
Continued SW flow will hold a warmer than normal temperature trend
through the coming workweek.
For additional information specifically on flooding concerns due to
the combination of rain and snowmelt, please see the Hydrology
section below.
&&
.AVIATION /12Z TAFS THROUGH 12Z MONDAY/...
Issued at 741 AM EDT Sun Apr 12 2026
IFR/LIFR has settled in at CMX and SAW this morning courtesy of
overnight and early morning rainfall, while IWD hovers at MVFR
still. A drop to IFR is expected there by mid morning. After this
first batch of rain moves eastward out of the UP over the next few
hours, there will still be lingering chances for more scattered
showers and storms this afternoon and evening. Given the uncertainty
in location and timing, have handled this primarily with PROB30
groups. A slow improvement to VFR is expected into the late
afternoon and evening (though SAW should miss out on this), then
ceilings drop down again to MVFR/IFR overnight with fog also
possible again mainly at CMX. Meanwhile, LLWS will continue to be
an impact as LLJ moves overhead this morning, accompanied by gusty
south winds at the surface.
&&
.MARINE...
Issued at 341 AM EDT Sun Apr 12 2026
South-southeat wind gusts will be on the rise this morning as a low
pressure lifts north of Lake Superior today. Gusts are expected to
peak during the early afternoon between 30-35 kts across the east
half of the lake. Gales >35 kts are not expected (<20% chance),
though cannot rule out an isolated gale. Significant wave heights
peak between 5-10 ft largely across the northern tier of the lake,
falling tonight as winds diminish below 25 kts lake wide. A few
strong showers and thunderstorms are possible tonight.
After a quick reprieve from the active weather during the day on
Monday, another shortwave low moves over the Upper Great Lakes
Monday night through Tuesday. Besides additional showers and
thunderstorms potentially moving across Lake Superior, expect winds
to back to the northeast to around 20 knots Monday night before
weakening Tuesday. After another quick reprieve Tuesday night, a low
pressure system could potentially move over Lake Superior on
Wednesday. While this system could bring additional rain showers and
thunderstorms to the lake, winds as of right now are still currently
slated to remain at 20 knots or less before and after the low's
passage. Weak high pressure ridging building in on Thursday looks to
keep the winds and weather quiet over the lake as we begin heading
towards the end of next week.
&&
.HYDROLOGY...
Issued at 341 AM EDT Sun Apr 12 2026
The slow snow melt seen over the past few days gives way to
accelerated melting through Wednesday morning as the latest NOHRSC
analysis shows the remaining snowpack ripe for melting (snowpack
temperature at freezing). In addition, with temperatures, dewpoints,
winds, and heavy rainfall chances increasing, expect potentially
significant river rises early next week given the expected rainfall
and favorable melting conditions.
With a robust Gulf connection supplying very warm, moist air to the
Great Lakes region early next week, expect temperatures to warm up
generally into the 50s and 60s, save for maybe the northern Keweenaw
after Sunday. Temperatures are expected to remain above freezing
through the entire coming work week.
Today and Monday are the focus of highest temperatures, with
forecasts ranging 10 to 20 degrees above normal (Normal Highs: 40s
to low 50s, Normal Lows: 20s to 32) as parts of the U.P. get placed
underneath the warm sector. The going forecast has highs in the 50s
and 60s, warmest in the interior west today and in the south-central
on Monday. There is a 30-60% chance of exceeding 70 near the WI/MI
state line on today and Monday. Lows are expected in the 40s to mid
50s tonight and mid 30s to mid 40s Monday night (15 to 30 degrees
above normal). During this period dewpoint temperatures soar into
the 50s tonight, remaining elevated into Monday night even after the
cold front of a shortwave low passes. Gusty south to southwesterly
winds will support heat transfer near the surface today, increasing
snow melt efficiency.
Periods of showers and thunderstorms are anticipated this weekend
into the coming workweek. the ongoing precip event will bring an
additional 0.25 to 1.25" by Monday morning (least west, greatest s-
central and east, locally high amounts in thunderstorms. A second
round of showers and thunderstorms moves through Monday night into
Tuesday as shortwave low moves through the Upper Great Lakes. Mean
rainfall amounts predicted with this shortwave's passage are between
0.5 to 1 inch of rain with stronger showers/storms reaching up to
1.25 to 1.5 inches of rainfall (as seen via NBM90th percentile).
Additional precipitation is anticipated into mid next week as one
final low pressure system is expected to move through Lake Superior
on Wednesday.
All these factors lead to accelerated rate of snowmelt and
increasing likelihood of ponding of water on low-lying/poor drainage
areas as well as minor river flooding. A Flood Watch remains in
effect for the entire U.P. tonight through Wednesday morning to
account for these concerns. Moderate river flooding remains possible
on the Paint River near Crystal Falls and the Sturgeon River near
Alston (now up to a 45-60% chance in these locations); see the
latest River Flood Statements for additional information. In
addition, chances for at least Minor river flooding are increasing
for areas such as the Black River at Bessemer, the Chocolay River at
Harvey, the Middle Branch of the Escanaba River at Humboldt, the
Eastern Branch of the Escanaba River at Gwinn, the Sturgeon River
near Nahma Junction, and the Tahquamenon River near Paradise (now up
to a range of 30-60%, save for near 90% at Gwinn, near Nahma
Junction, and near Paradise). Those living near and planning to
recreate around the rivers and low-lying areas of the U.P. early
next week should keep up with the forecast and river levels as the
snowmelt and rainfall amounts will determine flooding potential.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
Flood Watch through Wednesday morning for MIZ001>007-009>014-
084-085.
Lake Superior...
None.
Lake Michigan...
None.
&&
DISCUSSION...BW
AVIATION...LC
MARINE...BW/TAP
HYDROLOGY...