901
FXUS63 KMQT 240004
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
704 PM EST Sat Nov 23 2024

.KEY MESSAGES...

- Active weather with periodic chances for accumulating snow return
  next week. Temperatures will begin to trend below normal for this
  time of year.

&&

.SHORT TERM /THROUGH SUNDAY NIGHT/...
Issued at 218 PM EST Sat Nov 23 2024

Water vapor imagery and RAP analysis show a low amplitude mid-level
ridge across the central U.S. and a mid-level low over the NE U.S.
To the n, another mid-level low is centered in nw Ontario. A
shortwave extends from that low into northern and eastern Lake
Superior. KMQT radar and visible satellite show nw flow lake effect
rain and snow showers across much of the fcst area. Latest RAP
analysis indicates temps at the base of inversion at 850-800mb are
at -7C to -9C, marginal for the ongoing light lake effect pcpn. The
aforementioned shortwave could be providing weak enhancement to the
lake effect showers.

With caa lowering 850mb temps down to -8 to -10C through this
evening, expect nw flow lake effect pcpn to continue, especially
east where the colder 850 mb temps will be and where the longer
fetch will be across northern and eastern Lake Superior. However,
with inversions heights only at 4-5kft, and even a little lower over
the western fcst area, expect any lake effect pcpn to be light
through this evening. Ridging building in from the west, especially
late tonight, should taper or end lake effect showers for all areas
except maybe the far eastern cwa. Min temps tonight under partly to
mostly cloudy skies will be generally in the mid to upper 20s inland
to around 30F near the Lake Superior shore.

&&

.LONG TERM /SUNDAY THROUGH SATURDAY/...
Issued at 443 PM EST Sat Nov 23 2024

Starting Sunday, a mid level ridge moves east into the Great Lakes.
That said, the cloud cover is still expected during the day with
troughing building in from the west. Highs on Sunday are forecasted
in the mid 30s to low 40s.

The dry period then ends Sunday night into Monday as a clipper low
approaches from the Canadian Provinces, phasing with a Colorado low
that lifts into the Great Lakes on Monday. Isentropic ascent looks
to kick off some showers Sunday night from the south, which expand
northeast across the UP through Monday as the features phase
together and the mid level trough begins swinging through the
region. Where there still is some uncertainty in the forecast is the
sfc low track. The NAM and much of the high resolution model
guidance are in "camp one" where the Colorado low takes a more
northerly track over southeastern WI and over northern/central Lower
MI. This track which would bring a warmer airmass to our CWA and
start precip earlier in the CWA. This solution also would imply a
brief period where a wintry mix of rain/snow/sleet, most likely in
the interior central UP (near Iron Mountain). Some freezing rain is
also possible Sunday night over that region with a marginal warm
nose above 5kft. Ice accumulations would likely be sparse at best,
around a trace early Sunday night. Otherwise, snow is expected north
and west of the wintry mix area and mainly rain showers with some
snow mixing in later in the day near Lake MI. "Camp two", being the
rest of the guidance such as the GFS and ECMWF, take the sfc low
over southern Lower MI. This would result in less wintry mix, which
would be mostly rain and snow) and more snow overall in the CWA with
a cooler airmass overhead. Either solution looks to result in some
light snow accumulations over the north half of the UP and possibly
some slippery road conditions going into Monday.

Monday night through Tuesday, the mid level trough pivots over the
Upper Great Lakes. This is the beginning of troughing period over the
Great Lakes, yielding cold northwest to north flow that is expected
the rest of the extended forecast. 850 mb temps diminish from around
-7C Monday night to around -13C by the end of next week, sufficient
for LES (especially with Lake Superior being warmer than normal for
this time of year with average sfc temps ~8C). Several inches of
snow are likely over the course of next week, especially over the
east where some pre treatment from Lake Nipigon is expected.
Currently, Wednesday and Thursday look to bring the least amount of
precip with weak sfc ridging passing through briefly. Temps trend
toward below normal for Thanksgiving weekend.

&&

.AVIATION /00Z TAFS THROUGH 00Z MONDAY/...
Issued at 703 PM EST Sat Nov 23 2024

Persistent MVFR cigs will continue at IWD and CMX through the night
as low level moisture remains trapped under an inversion. Some
fluctuation to VFR at SAW is occurring, but expect MVFR to be
predominant at SAW as well through the night.  No wind impacts,
light and variable.

&&

.MARINE...
Issued at 443 PM EST Sat Nov 23 2024

Northwest winds of 20-25 kts over the east half of the lake this
afternoon diminish this evening, falling below 20 kts across the
lake. Winds veer northeast for Sunday then east Sunday night as
broad ridging moves through the Upper Great Lakes. While a few gusts
up to 20 kts are possible over the western third of the lake late
Sunday (~20% chance), winds are expected to hold mainly below 20 kts
until Monday night when a Colorado low moves through the Great
Lakes. This Colorado low phases with another low approaching from
the Canadian Provinces on Monday resulting in an uptick in northwest
winds of 20-25 kts Monday night through Tuesday. Strongest winds up
to 30 kt are possible on Tuesday, mainly over the waters south of
the Keweenaw (~50% chance). Winds then weaken to 20 kts or less
again Tuesday evening as the now phased low pulls away towards the
Atlantic. With weak impulses from the north moving through the area
much of next week, expect the light northwest to north winds mainly
less than 20 kts to continue until late next week.

&&

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

&&

$$

SHORT TERM...Voss
LONG TERM...Jablonski
AVIATION...TDUD
MARINE...Jablonski