Area Forecast Discussion
Issued by NWS Marquette, MI

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000
FXUS63 KMQT 160209
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
1009 PM EDT Fri Mar 15 2024

.KEY MESSAGES...

- Dry weather gives way to a brief round of light rain showers
  overnight as a cold front moves through. Some snow may mix in
  at times.
- A prolonged gale event on Lake Superior starts tonight and
  lasts into Sunday night.
- Southwest winds turn gusty overnight, particularly across the
  Keweenaw.
- Below-normal temperatures, continued blustery conditions into
  early next week and accumulating lake-effect snow potential
  are expected Saturday night into Monday.

&&

.UPDATE...
Issued at 1007 PM EDT Fri Mar 15 2024

Water vapor imagery and RAP analysis show a vigorous shortwave
dropping se into northern Ontario. Associated 995mb sfc low has
moved out of Manitoba into northern Ontario and is located to the nw
of Pickle Lake. Most of the pcpn associated with this system is
occurring to the n of the International Border, but some -ra has
developed southward into far northern MN this evening. Closer to
home, clouds are thickening, and temps range from the mid 30s to mid
40s.

Fcst appears to be in good shape with respect to pcpn chance
tonight. For most locations, pcpn chc will only last 1-3hrs with
pops ranging from 20-30pct far w to s central to 50-60pct Keweenaw
and to around 80pct e where best chc of column saturation occurs.

As for winds, even though a ~50kt low-level jet will translate
across the area just ahead of cold front, fcst soundings show
stability will work to limit mixing to higher winds overnight.
Strongly considered dropping wind advy for the Keweenaw, but there
is a small window (1-2hrs) just after fropa with the wind shift to a
more favorable w direction where gusts may still reach 45mph. That
said, with very weak caa, stability will still be an issue. Pres
rise/fall couplet is not particularly sharp either for an
isallobaric boost. Wind advy valid time was trimmed back to the
immediate postfrontal period from 07z-12z.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 226 PM EDT Fri Mar 15 2024

Skies are staying sunny across most of the area so far this
afternoon with weak ridging extending from a surface high sprawled
out over the Plains. A deepening surface low is analyzed over
Manitoba, resulting in a turn over to southerly flow over the Great
Lakes. This is helping to keep temperatures quite mild, with most of
hte area well into the 40s already. Expect temperatures to top out
in the upper 40s to lower 50s across most of the area today. Mid and
high level clouds should start to spread into the western UP closer
to sunset.

The surface low continues to track eastward through northern Ontario
tonight, with a trailing cold front extending southward through the
Great Lakes. SW winds pick up ahead of it, gusting to 20 to 30 mph
overnight. Stronger gusts around and even in excess of 40 mph are
possible across the Keweenaw for several hours. This will likely
necessitate the issuance of a wind advisory overnight. The passing
front will also touch off a round of rain showers, beginning by
midnight in the western UP and quickly exiting east into the pre-
dawn hours. Some snow may also mix in at times in the typically
cooler spots, but with most of the area hovering in the mid and
upper 30s for most of the  night, significant snow accumulations are
not expected. Behind the front, chilly WNW flow will result in the
development of light lake effect snow showers by Saturday morning.

&&

.LONG TERM /SATURDAY THROUGH FRIDAY/...
Issued at 348 PM EDT Fri Mar 15 2024

Well, Winter is finally deciding to show up a little now that we`ve
entered into Meteorological Spring! Normal to below normal
temperatures dominate the extended period as we see generally light
lake-effect snowfall across the northwest to north snow belts this
weekend through early next week. Additional snow chances are also
possible late next week too as the troughing pattern remains over
the Northeast and Upper Midwest. Additional details to the forecast
follow below.

The cold front of the shortwave digging through northern Ontario
drops across the U.P. Saturday from northwest to southeast
throughout the day. As this occurs, we should see snow showers
beginning over the western U.P. across the northwest snow belts and
precipitation showers (mainly rain in the morning) over the eastern
U.P. transition to pure lake-effect snow by the late afternoon
hours. While the cold air advection (CAA) and lake-effect cloud
cover will keep our region fairly insulated and cool Saturday, we
could still see highs temperatures fight to get into the mid 40s
across the south central as cloud cover may be more broken up over
there. Likewise, temperatures over the northwest/the Keweenaw are
expected to be at their zenith during the morning hours as the cold
air advection slowly drops temperatures from the mid 30s to around
30 throughout the day. Blustery northwesterly winds are expected
behind the cold front, with the Keweenaw possibly (65% chance)
gusting up to 40 mph throughout the day. It`s possible, although not
likely (25% chance) that we could see a few gusts up to 45 mph here
and there in the afternoon. Otherwise, expect the winds across the
rest of the U.P. to gust up to 25 to 35 mph.

Snowfall accumulations look to be fairly slushy and limited to the
higher elevations of the western U.P. until the overnight hours. On
Saturday night, a secondary cold front dropping down from northern
Ontario intensifies lake-enhanced snowfall across the northwest to
north snow belts. CAMs show moderate to maybe (50% chance) heavy
snow bands moving across the northern U.P. Saturday night. With the
blustery conditions continuing ahead of and behind the secondary
cold front, thinking it`s very likely (90%+ chance) that we see some
patchy blowing snow along the Lake Superior shoreline. With the SLRs
initially being near 10:1 to the mid teens by around midnight, we
could see a slushy dusting hit the roads before fluffier snowfall
settles over the northern U.P. As the lake-effect snowfall continues
into Sunday, the main impacts look to be slick roads and reduced
visibilities at times. Therefore, be sure to drive with a little
extra caution if you plan on traveling to church/the grocery
store/etc. Sunday. As ridging slowly builds in from the west Sunday
evening through Monday, expect the lake-effect snowfall to decrease.
The ridging looks to take the lake-effect snowfall out of our area
by late Monday afternoon. However, there is a chance (30%) that we
could see light snowfall return again to the area Monday night and
Tuesday due to another shortwave digging through the Upper Midwest.
Ultimately, thinking we could see 2 to 7 inches across the north to
northwest snow belts Saturday night through Sunday night, with minor
accumulations expected Monday into Tuesday.

As we move into the middle to end of next week, expect to see
shortwave activity across the region, causing us to see some light
snowfall chances from time to time. With a rex block setting up over
the Western U.S. and a general troughing pattern remaining over
eastern Canada, normal to below normal temperatures are expected to
continue. While the chance is small (<10%), the deterministic 12z
GFS is hinting at a quick-hitting significant snowfall event across
the U.P. next Thursday night through Friday. On the other end of the
spectrum, the deterministic 00z ECMWF keeps us dry with the
shortwave activity generally missing us to the south from Wednesday
onwards due to localized high pressure ridging over us. Thus,
whether we see snowfall or not for the end of the extended period
will depend on where the localized high pressure ends up; if to our
north, the chances become more likely. But if it moves over us or to
our south, the chances become less likely.

&&

.AVIATION /00Z TAFS THROUGH 00Z SUNDAY/...
Issued at 802 PM EDT Fri Mar 15 2024

VFR is expected at IWD/CMX/SAW tonight despite a cold front sweeping
thru the area in association with low pres tracking across northern
Ontario. Low-level jet just ahead of the front will lead to a 3-4hr
period of LLWS at all terminals tonight. Sfc winds will be gusty at
times, but strongest wind potential will be at CMX where winds may
gust to 35+kt for a short time immediately after fropa overnight. On
Sat, increasingly colder air moving into the area along with daytime
heating will result in gusty wnw winds of 30-35+kt at all terminals,
strongest at CMX. Cyclonic flow and deep moisture will also support
scattered -shsn across the area, including -shrasn in the morning.
Cigs may slip to MVFR for a time during the morning/early aftn at
IWD. Otherwise, VFR should prevail at all terminals on Sat though
MVFR vis will be possible with any passing -shsn.

&&

.MARINE...
Issued at 348 PM EDT Fri Mar 15 2024

Southwest winds of 20 to 25 knots over the western half of Lake
Superior this afternoon increase to gales up to 40 knots late
tonight ahead of a cold front passing through from northwest to
southeast; the greatest winds are expected in the north central lake
around 1-3 AM EDT. Expect the winds to veer to the northwest
Saturday as gales up to 35 knots are expected from time to time
across the lake. Winds could (50% chance) gust up to as high as 40
knots over the eastern half Saturday afternoon through evening ahead
of a secondary cold front moving through the area Saturday night.
Behind the secondary cold front, winds veer to the north, with gales
up to 35 to 40 knots being seen over the central and eastern lake
late Saturday night into Sunday. As the pressure gradient weakens
over the area Sunday afternoon into Sunday night, the winds slowly
decrease with time, becoming northerly winds of 20 to 30 knots
across the central and eastern lake Monday morning. With high
pressure ridging building into Lake Superior Monday, the winds
weaken to 20 to 25 knots over the eastern half as they back to the
northwest. With another shortwave possibly moving through the Upper
Great Lakes Monday night through Tuesday, we could see winds
restrengthen again (40% chance). Additional shortwave activity could
(35% chance) bring higher winds back across Lake Superior into
Wednesday too.

With the higher winds and colder temperatures expected over the next
several days, we could see some moderate freezing spray late
Saturday night through Monday.

&&

.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
  Wind Advisory from 3 AM to 8 AM EDT Saturday for MIZ001-003.

Lake Superior...
  Gale Warning until 8 AM EDT /7 AM CDT/ Sunday for LSZ162-
     240>242-263.

  Gale Warning until 2 AM EDT Monday for LSZ243-244-264.

  Small Craft Advisory from 2 AM to 8 AM EDT Saturday for
     LSZ245>251.

  Gale Warning from 8 AM Saturday to 2 AM EDT Monday for
     LSZ245>251-265>267.

Lake Michigan...
  Small Craft Advisory from 5 AM Saturday to 8 PM EDT Sunday for
     LMZ221-248-250.

&&

$$

UPDATE...Rolfson
SHORT TERM...LC
LONG TERM...TAP
AVIATION...Rolfson
MARINE...TAP


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