Area Forecast Discussion
Issued by NWS Marquette, MI

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000
FXUS63 KMQT 280853
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
453 AM EDT Thu Mar 28 2024

.KEY MESSAGES...

- Westerly lake effect snow continues through this afternoon,
  mainly across the Copper Country.
- Next chance of widespread precipitation occurs Friday night
  and Saturday, followed by a system worth monitoring for
  Monday/Tuesday next week.

&&

.SHORT TERM /THROUGH TODAY/...
Issued at 452 AM EDT Thu Mar 28 2024

West-southwesterly surface flow continues early this morning as
Upper Michigan remains under the influence of broad cyclonic flow.
The mid-level low in association with this pattern is currently
situated over the Hudson Bay per latest water vapor imagery/RAP
analysis. Wind gusts have, however, tapered off a bit over the last
few hours with most places only gusting up to 20 mph, highest across
Copper country.  And, as forecast soundings take on more of an
inverted-v signature later this morning, snowfall will taper off
over the Keweenaw.  As a result, the current winter headlines for
that area will be allowed to expire at Thu 12Z.  Nonetheless, HREF
guidance does trend toward an additional 2 to 4 inches along the
spine of the Keweenaw through Thu 18Z.  At that point though,
subsidence will strengthen as high pressure overspreads western
Wisconsin, resulting in a downward trend in lake effect snow showers
over the west wind snow belts through late afternoon.  Meanwhile,
the remainder of the forecast area will generally be dry, and
daytime highs will range from the upper 20s/low 30s across the
west/Keweenaw/north central to mid/upper 30s over south central and
east. Farthest south could top off near 40.

&&

.LONG TERM /FRIDAY THROUGH TUESDAY/...
Issued at 249 PM EDT Wed Mar 27 2024

Medium range guidance continues to handle the overall theme in the
extended forecast period well, presenting a consistent picture of
the main features in play going into the weekend. Starting off on
Thursday, the mid-upper level low that`s been responsible for the
snow and rain these past few days will continue its northeastward
exit toward James Bay while increasing anticyclonic flow and ridging
builds across the Plains. At the surface, high pressure will press
into western Wisconsin through the day, helping to pull in dry air
and subsidence that will result in diminishing lake effect snow
activity for the west wind snow belts. While the trend will be
decreasing activity, another inch or two of snow should be expected
in the Copper County, with the highest amounts being along the Spine
of the Keweenaw. Elsewhere, mostly dry conditions are expected.
Daytime highs should climb into the 30s, maybe near 40F for the
southern portions of Menominee County. The dry conditions will
persist overnight and Friday. Overnight lows should be mostly in the
teens interior west and low to mid 20s elsewhere. Daytime highs
Friday should top out in the 40s except mid to upper 30s near Lake
Superior and in the Keweenaw.

During the day on Friday, the mid-level ridge axis will shift
through the region as a surface low organizes in the Central Plains
and a northern stream shortwave presses through the Northern Tier
along the international border. As these features move into the
Upper Great Lakes, precip will move into the forecast area. Timing
among the various guidance packages suggest increasing precip
chances Friday evening that should persist through Saturday as the
surface low lifts through southern Lake Michigan and southern Lower
Michigan and the attendant inverted trough moves through Upper
Michigan. Precip type appears to be a mix of rain, snow, and maybe,
freezing rain, at least early on. As the event progresses through,
warm nose feature around 2-3k feet should break down as weak cold
air advection sets up. This should help any precip transition over
to rain or snow. Precip should come to an end Saturday evening,
followed by a dry Sunday thanks to another surface high moving
through the region.

Attention then shifts to a the potential interaction of a trough
exiting the Rockies and shortwaves dropping out of Canada. Model
trends with this system appear to be moving south and there is a
general trend toward potential phasing with a shortwave late Monday
and Tuesday. GEFS and EC ensemble systems continue to suggest weak
clustering of their membership and both their ensemble means move
the surface low near southern Lake Michigan and into southern Lower
Michigan. The same ensemble systems suggests the greater probability
of moderate QPF being near the ensemble means. This suggests a
significant precipitation event/snow event is becoming less likely,
but certainly continues to warrant monitoring in the coming days.

&&

.AVIATION /06Z TAFS THROUGH 06Z FRIDAY/...
Issued at 111 AM EDT Thu Mar 28 2024

The lake-effect snowfall will gradually dwindle throughout the TAF
period over the west snow belts as ridging builds in from our west.
While KIWD hangs on to MVFR cigs early this morning, expect it to
improve to VFR before dawn this morning as the cloud cigs lift due
to the departing low. That being said, we could (50% chance) see
MVFR cigs return again for a few hours over KIWD late this morning
before settling into VFR conditions for the rest of the TAF period.
As for KCMX, IFR conditions are expected to continue early this
morning due to the continuing lake-effect snow. With most of the
CAMs showing the snowfall rates lightening up after 8 AM EDT, I`m
thinking we will see an improvement to MVFR conditions by late this
morning over the Keweenaw; we could even see VFR conditions return
this evening as the peak of the incoming ridging moves into the far
western U.P. As for KSAW, expect VFR conditions across the TAF
period. While some blustery westerly winds could be seen early this
morning, winds look to weaken by this evening as the ridging moves
in.

&&

.MARINE...
Issued at 249 PM EDT Wed Mar 27 2024

Strong, mostly westerly and southwesterly winds will persist this
afternoon and evening as a surface low slowly pulls away into Hudson
Bay, leaving behind continued lake-induced instability and modest
pressure gradient forces thanks to high pressure building in across
the Plains. Expecting today`s low end gales to lighten through the
night as these forces begin balancing, but given the persistent
colder airmass aloft, near 30kt gusts should be expected at least
through Thursday. The colder airmass and wind will also make
freezing spray accumulation possible, although the trend to weaker
winds should reduce the risk through late tonight into Thursday. No
changes were made to the current gale warnings. Winds lighten to
around 20kts or less Thursday night, then remain light going into
the weekend.

&&

.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
  Winter Weather Advisory until 8 AM EDT this morning for MIZ001-
     002.

  Winter Storm Warning until 8 AM EDT this morning for MIZ003.

Lake Superior...
  Small Craft Advisory until 8 PM EDT /7 PM CDT/ this evening
     for LSZ240>244.

  Small Craft Advisory until 8 AM EDT this morning for LSZ249.

  Small Craft Advisory until 2 AM EDT Friday for LSZ250-251.

Lake Michigan...
None.

&&

$$

SHORT TERM...TDUD
LONG TERM...JTP
AVIATION...TAP
MARINE...JTP


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