393
FXUS63 KMQT 111932
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
332 PM EDT Sat May 11 2024

.KEY MESSAGES...

- Light rain showers end from west to east this morning.
- Could flirt with borderline fire weather conditions near the
  Wisconsin border late this afternoon as min RHs dip to around
  30%, northwest winds could gust up to 20 mph at times, and
  high temperatures could get to the low to mid 60s.
- Scattered thunderstorms to develop Sunday afternoon,
  especially south central. There is a low chance (2%), for
  marginally severe hail and/or wind.
- Dry weather returns by Monday, continuing through Wednesday
  afternoon.

&&

.SHORT TERM /THROUGH THIS AFTERNOON/...
Issued at 240 AM EDT Sat May 11 2024

With some breaks in the clouds, some of us were able to see the
Aurora Borealis over us this past evening into very early this
morning from time to time, including us at the forecast office here
in Negaunee Township. As the low pressure now over northern Lake
Michigan continues to spin away from the area today and high
pressure ridging moves in from the northwest, skies clear out and
the light rain showers cease. The rain showers are looking to be
limited to the far eastern U.P. (Chippewa and Mackinac counties) by
the early afternoon hours as the ridging builds in. However, a few
upslope sprinkles from the modest northwest flow could be seen over
the highlands of the Keweenaw and the north central U.P. from time
to time until the middle of this afternoon. In addition, the Euro is
wanting to bring some sprinkles over the south central this evening.
However, with hires model soundings showing an inversion up to 4-5
kft by the mid afternoon hours over the south central, any rain
droplets hitting the ground seems very doubtful (90+% of being
precip-free this afternoon). With mostly sunny skies across the U.P.
by the mid-afternoon hours and slight warm air advection occurring
throughout the day, thinking the high temperatures will be in the
low to mid 60s over the interior west half and the 50s in the east
and along the lakeshores. While winds aren`t expected to be all that
impressive today, we could see some northwesterly gusts up to 20 mph
in the interior areas by the afternoon hours today. With min RHs
looking to get down to around 30% near the Wisconsin border, we may
flirt with borderline fire weather concerns late this afternoon in
the interior west.

&&

.LONG TERM /SUNDAY NIGHT THROUGH SATURDAY/...
Issued at 331 PM EDT Sat May 11 2024

A couple cold fronts will press through the Upper Great Lakes Sunday
evening, allowing a cool to seasonable airmass to break into the
region through at least mid-week. Ahead of the initial cold front on
Sunday, afternoon shower and thunderstorm development may occur if
we`re able to destabilize enough following the Sunday morning
isentropically/warm frontally forced showers. By 0z Sunday and the
start of this forecast period, the cold front looks to be draped
across the central UP with the aforementioned shower/thunderstorm
region out ahead stretching from Menominee County northeastward
into the eastern UP. The environment at this point should be less
conducive for any new convective development given the quickly
waning influence of the day`s diurnal heating. However, if a strong
or severe storm does develop earlier, guidance suggests enough deep
layer shear could sustain updrafts into the evening hours. However,
the window will be short lived given the cold front`s fast eastward
progression. By 3z, CAMS all suggest convective activity should be
outside of the forecast area.

Behind the cold front, a dry airmass will press into the region
while a secondary cold front moves through after midnight Sunday
night. This, in addition to surface ridging building over the area,
will sustain a dry couple of days for the forecast area. The daytime
high temperature gradient Monday and Tuesday should stretch from
near 50F by Lake Superior to the low-mid 60s across the south-
central. On Wednesday, more widespread 60s are expected, with most
areas outside of the immediate lakeshores and Keweenaw looking to
climb into the low-mid 60s. Overnight lows should be mostly in the
30s, with chances for sub-freezing temperatures in the interior-
central spots (20-30% chance). Fire weather concerns should be
mitigated by the near to slightly cooler then normal conditions and
light winds these days. But daytime mixing into a dry airmass aloft
may support RH values nearing 30% for some interior central and west
locations.

Mid-level ridging shifts through the region on Wednesday followed by
a shortwave pressing through Minnesota/western Ontario Wednesday
night. Consensus among the 12z deterministic guidance suite has this
pressing into our forecast area Thursday, supporting another round
of showers through the day. This contrasts some with the GEFS, EC,
and GEPS ensemble systems, where some members suggest precip could
start Wednesday night.

&&

.AVIATION /18Z TAFS THROUGH 18Z SUNDAY/...
Issued at 149 PM EDT Sat May 11 2024

VFR conditions will prevail thru this fcst period at IWD/CMX/SAW. As
low pres drops into far northern Ontario tonight, a low-level jet
will develop into Upper MI late tonight into Sun morning, resulting
in 2-6hrs of LLWS at all terminals, lasting longest at IWD. The low-
level jet will also generate sct -shra, but confidence in a shra
passing over any of the terminals is low. Not expecting conditions
to drop out of VFR if a shra does occur. More shra/possible tsra
will develop Sun aftn across central Upper MI, possibly affecting
SAW.

&&

.MARINE...
Issued at 331 PM EDT Sat May 11 2024

Winds are mainly expected to remain below 20 kts through the
entire forecast period, with some exceptions.

A warm front will lift through the lake late tonight and early
Sunday. Ahead of and behind the front, some isolated 20-25 kt wind
gusts will be possible. The stronger pressure gradient will be
Sunday across the east half and behind the warm front; however, the
increasingly stable airmass over the lake should work against mixing
the stronger southerly winds to the surface. Given the environment,
higher reporting platforms would be more likely to observed these
stronger winds then the surface buoys. A cold front will press from
west to east through Lake Superior through the day as well. A shower
or thunderstorm can`t be ruled out by afternoon across the east
half, but with the focus for convection being over Upper Michigan
and not Minnesota, the probability is low (20-30%). Behind the
front, high pressure will settle over the lake, supporting a few
days of mostly 20kts or less over the lake through at least midweek.

&&

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

&&

$$

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