Area Forecast Discussion
Issued by NWS Marquette, MI

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884
FXUS63 KMQT 111129
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
729 AM EDT Sun Aug 11 2024

.KEY MESSAGES...

- Dangerous swimming conditions at the Lake Superior beaches of
  Marquette County and Alger County through this morning.

- Warm and dry weather is expected for the first half of the week.

- Chances for showers and maybe some thunderstorms increase
  late next week, but confidence in timing and track is low.

&&

.SHORT TERM /THROUGH THIS AFTERNOON/...
Issued at 319 AM EDT Sun Aug 11 2024

Water vapor imagery and RAP analysis show an elongating mid-level
low over southern Quebec and the Great Lakes region. Rather vigorous
shortwave wrapping around the circulation crossed Lake
Superior/Upper MI last evening, bringing increased coverage of shra
to the area. That wave is now departing to the se. In its wake,
850mb thermal trof of 3 to 5C across eastern Lake Superior per
latest RAP analysis overtop 14-19C sfc waters is supporting some
lake aided -shra into the eastern fcst area under nw low-level flow.
To the n and ne, a much weaker shortwave is dropping toward eastern
Lake Superior. Current temps are in the upper 40s F over portions of
interior western Upper MI where clouds have thinned out. Otherwise,
mostly low/mid 50s are the rule, though Copper Harbor is 62F.

Aforementioned weak shortwave that will be dropping across eastern
Lake Superior this morning should bring a little uptick in -shra
activity across the eastern fcst area. Expect those -shra to depart
around noon, if not sooner. To the w, most of the CAMS indicate
isold shra developing during the aftn due to sufficient column
moisture and MLCAPE building to 200-400j/kg. With the axis of the
instability running from ne MN se into WI, the CAMS show the shra
developing mostly to the w and s of Upper MI this aftn. For now,
opted to keep western and southern Upper MI dry today. With Lake
Superior waters approaching the annual max temp, some of the shra
developing in ne MN may survive the trip across the lake to produce
some sprinkles toward 00z in Gogebic/Ontonagon counties. Mention was
not included in fcst given low probability. After the fall-like day
yesterday, temps today will rebound to generally the upper 60s to
mid 70s F. Finally, lingering wave action from the stronger winds
across the lake yesterday will result in a high swim risk along the
Lake Superior beaches of Marquette County to the e of Marquette this
morning and at the beaches of Alger County into early aftn.

&&

.LONG TERM /TONIGHT THROUGH SATURDAY/...
Issued at 254 AM EDT Sun Aug 11 2024

Expect dry weather to dominate the first half of this week as a high
pressure block moves over us from the Central U.S. and Canada.
Overall, expect temperatures near to a little above normal for this
week, although a shortwave moving through the Great Lakes for the
latter part of this week could bring ever-so-slightly cooler
temperatures and possibly some rainfall to our area. Additional
details follow below.

As high pressure moves over us for the first half of this week,
expect dry weather tonight through the middle of the week, with
temperatures warming to near to just above normal. With mostly clear
skies remaining over the U.P. tonight, expect lows to get down into
the upper 40s in the interior areas and around 60 by the lakeshores.
As for highs, with lake breeze winds dominating by the afternoon
hours Monday, expect temperatures up to the low to mid 80s in the
interior south central and possibly west of L`Anse in Baraga County;
by the lakeshores, expect cooler high temperatures mainly in the
70s. Expect similar conditions Monday night through Wednesday as the
high pressure continues through the area, with temperatures slightly
increasing each day. While there is a small amount of instability
within the atmosphere early this week, given the lack of forcing, no
precipitation is expected. That being said, expect some diurnal cu
to form by the afternoon hours, particularly over the interior west
Monday as a very weak 1016 mb low moves along the state line into
Lake Michigan.

Uncertainty greatly increases as we move into the latter half of the
week. While there is an agreement that we could see some rainfall
between Wednesday night to the end of the week, timing and track
details are all over the place. That being said, we are still
seeing the trend to push the timing of the rainfall back, and
even the NBM in comparison to yesterday has slowly been catching
on to this. Therefore, due to confidence remaining low on the
rain chances for the latter half of next week, I decided to
leave the NBM precipitation chances in for now. As for
temperatures, they should be around normal for the latter half
of this week as cloud cover looks to move over the area.

&&

.AVIATION /12Z TAFS THROUGH 12Z MONDAY/...
Issued at 728 AM EDT Sun Aug 11 2024

VFR will prevail thru this fcst period at IWD/CMX/SAW. NW winds
(IWD/CMX) and N winds (SAW) at around 10kt will be the rule from
later this morning until near sunset.

&&

.MARINE...
Issued at 254 AM EDT Sun Aug 11 2024

Winds lighten to 20 knots or less this morning and remain that way
through the rest of this week as high pressure moves overhead. While
there is still high uncertainty for the latter half of this week due
to a shortwave low possibly moving through the Great Lakes region,
winds are still generally expected to be 20 knots or less for the
remainder of the week. Otherwise, the only other thing worth noting
is that there could be some occasional thunderstorms around the
time the shortwave approaches the area as troughing fights to get
into the far western lake; this could occur anytime between
Wednesday night and Thursday night/Friday.

&&

.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
  Beach Hazards Statement until noon EDT today for MIZ005.

  Beach Hazards Statement until 2 PM EDT this afternoon for
     MIZ006.

Lake Superior...
None.
Lake Michigan...
None.

&&

$$

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