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000
FXUS63 KMQT 172126
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
526 PM EDT Wed Apr 17 2024

.KEY MESSAGES...

-Rounds of light to moderate rainfall continue through the
 evening with deep, though gradually weakening, low pressure
 moving across the Great Lakes.
-Additional rainfall totals of a quarter to half inch are likely
 the before rain wraps up into tonight, highest across the
 eastern UP.
-Cooler temps Friday and Saturday with low (30%) chances for
 light diurnal showers Thursday afternoon/evening and perhaps a
 light lake effect rain/snow mix for Friday/Saturday.
-Localized fire wx concerns could resurface again Friday into
 Saturday with more widespread concerns emerging by Sunday and
 Monday as a drier airmass moves in with breezy W to NW winds.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 255 PM EDT Wed Apr 17 2024

Deep 1000mb surface low pressure analyzed over central WI will
continue to move ENE into the UP this afternoon with a negatively
tilting upper trough pivoting through the Great Lakes. Bands of
light to moderately heavy rainfall continue to move through the
area, with one round currently tracking into the northern UP. Water
vapor imagery reveals a narrow dry slot curling in behind this,
ahead of another area of lighter showers already moving into
northern WI. These should quickly move through the UP into the late
afternoon and evening. Radar estimated QPF across the UP is
generally up to a quarter to half inch in the heaviest of showers
with this batch moving through right now, which matches up fairly
well with various surface observations. With ongoing convection and
the next additional round of light rain (estimated QPF up to a
quarter inch courtesy of the GRB radar in the most persistent
showers), would not be surprised by another quarter to half inch the
rest of today into the evening - mainly across the Keweenaw and
eastern UP.

Meanwhile, winds remain gusty particulary across the Keweenaw and
eastern UP this afternoon, where gusts up to 35 to 40 mph remain
common. Stronger gusts to 45mph are still occurring closer to the
Lake Michigan shoreline. Still, winds are slowly decreasing as the
surface low is weakening, so although windy conditions continue into
the late afternoon and evening, we should be falling below wind
advisory criteria over the next few hours.

Tonight, showers lift northward over Lake Superior after midnight as
pressure rises behind the departing surface low and drier midlevel
air works in. Lower level moisture should keep in low cloud cover
and perhaps some patchy fog - but will note a narrow core of
stronger winds aloft behind the departing low that could produce a
brief window for breezy conditions mainly across the western UP the
first half of the night. That could limit our potential for patchy
fog.

&&

.LONG TERM /THURSDAY THROUGH WEDNESDAY/...
Issued at 525 PM EDT Wed Apr 17 2024

Overall, the extended period is characterized by mostly quiet
weather save for a few low-end chances for light precip (mainly
rain). Cold air advection behind Thursday night`s cold front passage
leads to deep mixing within westerly flow that is favorable for
strong winds on the Keweenaw. Model soundings dry out on Saturday
and stay dry through early next week while still advertising deep
mixing leading to a return of fire wx concerns. Temps for the entire
extended period should average near to above-normal, but Fri thru
Sat night will be chilly before moderating ahead of a system
tracking across the region Monday night or Tuesday.

Starting with Thursday morning, the area should be dry and in-
between features of interest. A modest cold front moves through late
on Thursday with cold air advection aloft decreasing stability
throughout the day. By afternoon/evening model soundings advertise
potential for diurnal showers developing with equilibrium levels
around ~10kft. Not expecting much in the way of precipitation with
this but isolated afternoon showers seem like a good bet. A drier
post-frontal air mass ends rain chances and should also allow for
clearing skies. This should allow low temps to dip to near the
freezing mark.

Friday into Saturday appears to be the most active period of
weather as the upper level low moves overhead. Almost due west
winds are expected on Friday which raises concerns about 1)
strong gusts on the Keweenaw and 2) fire wx potential with
temperatures/winds possibly exceeding guidance elsewhere within
a very deeply mixed boundary layer (perhaps up to ~9 kft at
IMT/MNM/ESC). The primary limiting factor appears to be
sufficient low level moisture for a robust cumulus field,
possibly including another shot at diurnal showers. Away from
Lake Superior, a 5kft deep inverted-v suggests rain drops will
struggle to reach the ground without a fairly robust shower.
Closer to Lake Superior, isolated to scattered showers are
expected by Friday night as deeper synoptic moisture moves into
the area. With wet bulb temps around freezing there`s a good
chance for snow to mix in if not completely change-over,
especially at higher elevations of the traditional WNW to NW
wind snow belts. Potential for lake enhanced showers continues
into Saturday morning (west) and afternoon (east) before
synoptic moisture departs to our east. QPF amounts stay light so
snowfall is unlikely to cause impacts. Drying appears to occur
late enough in the day for fire wx concerns to be delayed until
Sunday, but it`s something to keep an eye on especially south-
central where winds are downsloping.

Successively warmer days brings above normal temps back to the UP
for Sunday into Monday. Deep mixing continues except by Sunday we`ll
be mixing into a mid-level dry layer that is more favorable for fire
wx concerns. Winds could get gusty both Sunday and Monday afternoon,
but the wind fields appear slightly stronger on Sunday with gusts of
20 to 25 mph currently forecast. Models indicate the next wnw flow
shortwave will move through Mon night into Tue bringing the next
chance of rain showers. Given its west-northwest trajectory suspect
moisture inflow ahead of this shortwave will be somewhat limited so
only expect light rain showers at this time Mon night into Tue. It`s
worth noting that recent model guidance has trended toward a better
organized low pressure that may be capable of moderate precip
amounts, but ensembles indicate chances are still low around ~25%.
Models and ensembles advertise drier and somewhat cooler conditions
behind this shortwave into the middle of next week.

&&

.AVIATION /18Z TAFS THROUGH 18Z THURSDAY/...
Issued at 139 PM EDT Wed Apr 17 2024

Rounds of light to moderately heavy rain showers continue this
afternoon and through the evening with deep low pressure moving
through the Great Lakes. Ceilings are dropping to IFR, and MVFR/IFR
visibility is common where showers are occurring. A brief break in
rain showers behind the batch currently moving into the northern UP
will quickly be followed up by another, lighter round this evening,
with IFR or LIFR visiblity possible. Ceilings continue to lower to
LIFR into the evening hours, and while rain showers finally end by
06Z, lingering lower level moisture and decreasing winds may keep in
patchy fog overnight. A gradual improvement to MVFR is expected the
second half of the night as the low pulls away and drier air begins
to work in, then ceilings lift to VFR late tomorrow morning into the
afternoon. Otherwise, expect gusty winds up to 20 to 30 knots
through the afternoon, then wind gusts to around 20 knots are
possible into the night.

&&

.MARINE...
Issued at 525 PM EDT Wed Apr 17 2024

East-southeast gales of 35 to 40 kts persist across much of north-
central and eastern Lake Superior late this afternoon. Gales subside
this evening as the weakening low pressure moves into eastern Upper
Mi later this evening. Generally stable conditions persist over the
lake tonight into early Friday morning with WSW winds gusting up to
25 kts. A cold front moves across the lake late Thu into Thu night
with decreasing stability supporting increasing up to near gale
force, especially north of the Keweenaw Peninsula. Another
front/trough crosses the lake late on Friday shifting winds west-
northwesterly with a few gale force gusts to 35 kts possible Friday
night and Saturday before subsiding by the afternoon or evening.
Otherwise winds back westerly and subside to 15 to 25 kts across the
lake Sat night thru Monday.

&&

.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
  Gale Warning until 8 PM EDT this evening for LSZ243>246-250-
     251-264>267.

  Small Craft Advisory until 8 AM EDT Thursday for LSZ244>246.

  Small Craft Advisory until 8 AM EDT Thursday for LSZ247-248.

  Small Craft Advisory until 8 PM EDT this evening for LSZ249.

  Small Craft Advisory from 5 AM to 11 AM EDT Thursday for
     LSZ250.

  Small Craft Advisory from 8 AM to 2 PM EDT Thursday for LSZ251.

Lake Michigan...
  Gale Warning until 8 PM EDT this evening for LMZ248.

&&

$$

SHORT TERM...LC
LONG TERM...EK
AVIATION...LC
MARINE...EK