822
FXUS63 KMQT 110640
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
240 AM 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 Monday thru 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 /SATURDAY NIGHT THROUGH FRIDAY/...
Issued at 442 PM EDT Fri May 10 2024

Current ridging over western N America will force a couple of
shortwaves to dive se into eastern N America over the next several
days. The first drops into the Great Lakes region tonight/Sat. The
second wave won`t drop as far s due to the upstream ridge losing
some amplitude. It will pass across northern Ontario Sun/Mon.
Thereafter, mid-level troffing developing into western
Canada/northern U.S. Rockies early next week will shift downstream
thru the week. There is and has been considerable model spread on
the evolution of this trof, amplitude of the upstream ridge forcing
the trof, and the progression of shortwaves around that ridge into
the trof. Early on in the fcst period, a couple of periods of pcpn
are expected, the first with the shortwave dropping thru the Great
Lakes region tonight/Sat and the second with the shortwave reaching
northern Ontario on Sun. A dry period will follow Mon/Tue and likely
thru Wed aftn. Approaching mid-level trof will bring shra back to
Upper MI Thu/Fri. Whether it ends up being sct or widespread pcpn
will depend on the highly uncertain evolution of the trof. As for
temps, readings most days thru the middle of next week will be
around normal, then there is more uncertainty late week depending on
rain coverage/potential sfc low developing into the Great Lakes
region. Warmest day will be on Sun. Closer to Lake Superior, it will
be on the cool side for at least Mon/Tue as high pres ridging
building southward into the Great Lakes brings a gradient onshore
wind component.

Beginning Sat night/Sun, shortwave over the NW Territories tonight
will reach northern Ontario Sun morning. In response, a 30-40kt low-
level jet develops, leading to a good push of waa/isentropic ascent
and theta-e advection into Upper MI late Sat night/Sun morning. As a
result, sct -shra should develop into roughly the w half of Upper MI
overnight Sat night, spreading eastward Sun morning. After this
initial waa/isentropic ascent pcpn moves across the area, attention
on Sun aftn turns to lake breeze aided cold front that moves across
the area. Timing of this feature will be coincident with peak
heating Sun aftn across the central, s central in particular. The
NAM/GFS have MLCAPE increasing to 500-1000j/kg, though the NAM peaks
at around 1500j/kg. The CMC RDPS and ECMWF are less than 500j/kg.
With consensus deep layer shear of 30-40kt, an isolated svr storm is
a possibility if the higher MLCAPE materializes. That will depend on
how much cloud cover and even shra from earlier in the day linger
into the aftn. Expect highs on Sun in the mid 60s to mid 70s for
much of the area, though it will turn cooler closer to Lake
Superior once winds shift off of the lake.

Shra/tsra will exit the s and e Sun evening. A secondary cold front
will pass uneventfully during the night, setting up dry days on
Mon/Tue as sfc high pres builds s into the western Great Lakes. Will
be cool near Lake Superior on Mon/Tue, especially e half, under
gradient northerly winds due to high pres ridge building s into the
area. Expect 40s F to be the rule. Temps both days will range up to
the low/mid 60s well inland w half. There is plenty of dry avbl to
mix down, especially on Tue. RH may fall blo 30pct interior w, but
winds will be lighter in that area than over the rest of the U.P.
to limit fire weather concerns.

The 12z medium range model runs not did show any trend toward
agreement with the approaching mid-level trof mid and late week.
Agreement is there for dry weather to linger thru Wed aftn.
Lingering dry air aloft is avbl to mix down, so it cloud be another
day with RH under 30pct in the interior. Thereafter, fcst will
reflect broad brush mostly 30-40pct chc shra for Thu/Fri.

&&

.AVIATION /06Z TAFS THROUGH 06Z SUNDAY/...
Issued at 110 AM EDT Sat May 11 2024

Wraparound moisture from low pressure deepening over northern Lake
Mi will continue scattered showers overnight mainly into central
Upper Mi. SAW will be most impacted from this system seeing VFR
conditions lower to MVFR in these showers and perhaps briefly to IFR
overnight before quickly improving back to MVFR late Saturday
morning and to VFR Saturday afternoon as high pressure builds back
in from the west.  Expect VFR conditions to mostly prevail at IWD
and CMX.

&&

.MARINE...
Issued at 442 PM EDT Fri May 10 2024

Expect winds mostly under 20kt thru Wed. However, there are a couple
of periods where winds will be a little stronger. Approaching cold
front Sat night will result in increasing southerly winds. Across
mainly the e half of Lake Superior, gusts up to around 25kt are
possible by Sun morning, but these stronger winds would be at the
high obs platforms due to the stability within the chilly marine
layer. Then on Mon, high pres ridge building s into the western
Great Lakes may support higher nw wind gusts to 25kt over far
eastern Lake Superior.

&&

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

&&

$$

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