433
FXUS63 KMQT 092012
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
412 PM EDT Sun Mar 9 2025

.KEY MESSAGES...

- Strong winds of 30 or 40 mph this afternoon across western and
  central Upper Michigan and near Lake Superior will weaken this
  evening. Strong winds, up to 50 mph will be possible in the
  Keweenaw Peninsula.

- Northwest winds up to 40 mph will be possible Monday night
  into Tuesday, mainly in the Keweenaw and by Lake Superior.

- Mainly warmer than normal temperatures are expected through
  this week. This will lead to melting snowpack and increasingly
  dangerous ice conditions on lakes and rivers.

&&

.UPDATE...
Issued at 303 PM EDT Sun Mar 9 2025

Winds have been exceeding guidance in Houghton and Keweenaw
counties the past few hours, with frequent 40 mph gusts being
observed. KCMX has gusted a couple times over 45 mph as well.
Given these stronger winds should continue until sunset, issued
a Wind Advisory for Houghton and Keweenaw County through 0z.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 125 PM EDT Sun Mar 9 2025

Clear skies have spread eastward through the day as a weak shortwave
sent a swath of light snow through the Keweenaw and parts of eastern
Upper Michigan. Radar returns have been deceptive thanks to a dry
lower atmopshere and the warming trend in temperatures. Webcams here
and there showed some flakes, but overall, little or no accumulation
is likely to have occured. Across the west, temperatures have sored
into the mid to upper 40s so far, whereas moderating overlake
southwesterly flow and cloud cover has kept the east in the 30s.
Gusty south-southwesterly to southwesterly winds have started, with
multiple sites in the west and Keweenaw having already observed wind
gusts of 20-35 mph.

As we progress through the remainder of the afternoon, strong winds
will continue as surface heating supports continued mixing. The
source of the winds, a 35-45 kt 925-850mb low level jet, will press
eastward this afternoon, which will allow the stronger wind
potential to also shift east through the afternoon as skies clear
behind the outgoing wave. Thanks to the terrain, localized adiabatic
processes may further accelerate winds near Lake Superior, northeast
facing slopes of the west, and across the Keweenaw. Highest winds,
upwards of 40 mph, still look to focus in these downsloping areas
and across the higher terrain regions of the Michigamme Highlands
and Keweenaw Peninusla. Winds are expected to relax as the sun sets.
Temperatures this afternoon are likely to climb into the low 50s for
most of the west half whereas the Keweenaw and east are likely to
top out in the mid-upper 40s.

Tonight, surface ridging will sit over the region while the airmass
at 850mb sits around -1C. This should support a mild night with lows
mostly in the 20s under partly cloudy skies. Model soundings
highlight a low level inversion, that might work to trap low level
moisture near the surface in the interior portions of
central/western Upper Michigan. This may support some patchy fog.
Upstream, the next system will continue inching toward the forecast
area and early morning, cloud cover may fill into region.

&&

.LONG TERM /MONDAY THROUGH SUNDAY/...
Issued at 411 PM EDT Sun Mar 9 2025

A shortwave making landfall over the PAC NW this evening quickly
tracks E to the N Rockies by Mon morning. Mon night into Tue, the
shortwave pivots E over Upper MI/Lake Superior. This sends an
Alberta Clipper over the N shores of Lake Superior Mon night. WAA in
SW flow leads to another breezy afternoon with gusts up to 20-30
mph, especially in downslope flow areas. Temps are expected well
above normal with highs in the upper 40s to upper 50s, warmest near
WI/MI where some 60s are possible (~65% chance)! Precip associated
with the approaching system remain N of Lake Superior during the
day, but a strong cold front on the back side of the low presses SE
into Tue morning. This brings a round of light rain/snow to the W
Mon night which quickly changes over to snow as cold air surges in
behind the front. With 850mb temps reaching around -15C by Tue
morning and cyclonic flow aloft, some trailing isolated to scattered
light snow showers are expected over the NW wind snow belts. Snow
showers diminish from W to E by the afternoon as high pressure from
the Canadian Prairie descends SE over the Great Lakes. Snow
accumulations are expected to mainly hold below 0.5". The other
impact to watch for is gusty NW winds to 25-35 mph along and behind
the cold front. Latest EPS probabilities of gusts exceeding 40 mph
are around 25% in the west and 30-60% elsewhere, highest by the
eastern Lake Superior shores and in the Keweenaw. This could lead to
some patchy blowing snow in the Keweenaw.

Drier weather is likely to continue Tue night through Thu night (85%
chance) as the high pressure passes overhead Tue night and a weak
clipper system remains to the N Wed night. Meanwhile, ridging over
the N Rockies on Wed pushes off over the Plains on Thu and troughing
deepens over the W coast. This increases WAA from SW flow and
results in another warming trend to well above normal temps by the
weekend. The 3/9 0Z LREF probabilities of temps exceeding 55F Fri
and Sat is between 15-30% with the NBM showing 40-60% chances on Fri
and ~40% on Sat. Another mild factor to watch for is Tds as there is
a 30-60% chance across much of the UP for Tds +45F over the weekend.
This warm weather will continue to melt snowpack and weaken ice on
lakes and rivers, leading to dangerous conditions! No ice is safe,
be prepared for rapidly deteriorating ice conditions and to change
outdoor plans accordingly.

The deep trough swinging off the Rockies on Fri develops a strong CO
low which is expected to lift NE over the Midwest on Sat. While
there still remains some spread in the sfc low tracks among the
ensembles, there is pretty great agreement in the track likely
remaining W of Upper MI. This keeps the CWA within the warm sector
of the low and results in widespread chances for rain Fri through
Sat. Warm and moist air surges N into the region ahead of the
system, highlighted by the NAEFS showing mean WV transport in the 90-
99th climatological percentile. NBM probabilities of SBCAPE above
500J/kg are around 25% Fri afternoon/evening which would infer some
heavier convective showers embedded within are possible and a few
rumbles of thunder can`t be ruled out. This in tandem with the
melting snowpack could lead to some ponding on roadways as well.
Wrap around colder air favors some trailing LES behind the system
into Mon, but heavy snow is unlikely as probabilities of 3"/24hr are
below 10% and 1"/24hr probabilities are capped at 50%.

&&

.AVIATION /18Z TAFS THROUGH 18Z MONDAY/...
Issued at 125 PM EDT Sun Mar 9 2025

VFR conditions are expected to prevail at all TAF sites in this
period. Strong southwesterly winds near 30kts at all sites and some
potential for low level wind shear at KCMX/KSAW will continue this
afternoon, but winds should lighten and low level wind shear slacken
this evening. Some fog/mist may develop at KSAW overnight, but
guidance has really trended back this potential.

&&

.MARINE...
Issued at 411 PM EDT Sun Mar 9 2025

West 20-30 kt winds across the lake this afternoon settle below 20
kts in the west this evening and before midnight in the east. Winds
remain below 20 kts as they back south for Monday. While some gusts
increase up to 25-30 kts in the far east late Monday afternoon and
evening, winds generally hold below 20 kts during the day as a more
stable airmass resides over the cold waters.

A clipper system passing over the northern shores of Lake Superior
Monday evening sends a cold front southeast across the lake Monday
night. South winds quickly increase and veer northwest at 30-40 kts
behind the front. Some gusts up to 45 kts are possible over the
north central and east half of the lake. (50% chance) Hoisted a Gale
Watch for most of the lake starting at 11 PM EDT Monday and ending
at 11 AM Tuesday. Gales fall off Tuesday morning from west to east,
gradually back west through the day, and settle below 20 kts by
Tuesday evening. Winds back south for Wednesday increasing up to 20
kts over the east half of the lake, but winds are expected to remain
20 kts or less through Thursday night with warm stable air over the
lake. The next chances (25-50%) for gales hold off until
Saturday/Sunday with a strong Colorado low lifting northeast over
the Midwest.

&&

.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
  Wind Advisory until 8 PM EDT this evening for MIZ001-003.

Lake Superior...
  Gale Watch from Monday evening through late Monday night for
     LSZ162.

  Gale Watch from late Monday night through Tuesday morning for
     LSZ241-242-245-246-248-263-265.

  Gale Watch from late Monday night through Tuesday morning for
     LSZ243-244-249-250-264-266.

  Gale Watch from late Monday night through Tuesday morning for
     LSZ251-267.

Lake Michigan...
None.

&&

$$

UPDATE...JTP
SHORT TERM...JTP
LONG TERM...Jablonski
AVIATION...JTP
MARINE...Jablonski