Area Forecast Discussion
Issued by NWS Marquette, MI

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FXUS63 KMQT 160705
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
305 AM EDT Sat Mar 16 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.

&&

.SHORT TERM /THROUGH THIS AFTERNOON/...
Issued at 305 AM EDT Sat Mar 16 2024

A rex block has set up on the west coast with a high in the Pacific
NW and a closed low in the desert sw. There is also a strong
shortwave east of Lake Winnipeg this morning which will dive
southeast into the upper Great Lakes and into the lower Great Lakes
by this evening. Deeper moisture and 850-500 mb q-vector convergence
will quickly move through early this morning before the convergence
moves out by afternoon. 850 mb temperatures fall to -6C to -10C by
00z tonight, so lake effect snow showers will be kicked off by this
evening as Lake Superior temperatures are around 2C to 3C and enough
lake-850 mb delta-t is around. This is covered well in the forecast
with a resurgence of pops across the west late this afternoon.
Otherwise, a brief round of pcpn will move through this morning.
Will be quite gusty today especially along the Keweenaw. Winds do
not look as strong though as previously thought, but could still get
up to 40 mph at Houghton. Will be dropping the wind advisory for the
Keweenaw as strongest winds should have occurred by now and a sw
wind direction is not a good wind direction for real gusty winds in
the Keweenaw.

&&

.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 /06Z TAFS THROUGH 06Z SUNDAY/...
Issued at 1250 AM EDT Sat Mar 16 2024

VFR is expected at IWD/CMX/SAW overnight 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 period of LLWS at all terminals until fropa. Sfc winds will also
be gusty at times, but strongest wind potential will be at CMX where
winds may gust to 35-40kt for a short time immediately after fropa
overnight. During today, 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 at times
thru the day at IWD/CMX, but especially during the morning. VFR will
prevail SAW. -SHSN will become more nmrs this evening across western
Upper MI with IFR vis becoming increasingly likely at IWD/CMX.

&&

.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...
None.
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 until 8 AM EDT this morning for
     LSZ245>251.

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

Lake Michigan...
  Small Craft Advisory until 8 PM EDT Sunday for LMZ221-248-250.

&&

$$

SHORT TERM...07
LONG TERM...TAP
AVIATION...Rolfson
MARINE...TAP


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