652
FXUS63 KMQT 301952
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
352 PM EDT Tue Apr 30 2024

.KEY MESSAGES...

- Rain showers and thunderstorms return late tonight.
- Some patchy fog is possible late tonight into Wednesday
  morning.
- Active pattern continues through next week as a series of low
  pressure systems track across the U.S. and affect Upper MI.
  Above precipitation expected, including chance of
  thunderstorms at times.
- Temperatures won`t stray too far from normal, but they will
  probably be above normal more often than below normal.

&&

.SHORT TERM /THROUGH WEDNESDAY/...
Issued at 253 PM EDT Tue Apr 30 2024

As a low pressure center continues lifting into northern Ontario the
rest of this afternoon, expect cloud cover to slowly improve, with
the isolated light rain/drizzle showers ending across the U.P. by
early this evening. However, with cool air aloft still hanging
around, thinking the highs will be limited to the 50s across most of
the area (as some obs are already showing), save for maybe some
spots in the south central getting to 60 and the Lake Superior
shoreline only getting into the upper 40s. As we move into the
overnight hours, expect cloud skies and rain showers to return to
the U.P. late. In addition, there is a small chance (10 to 20%) that
we could hear some rumbles of thunder (particularly in the south
central) as a low pressure lifts from the Upper Mississippi Valley
into Lake Superior. Most of the rainfall is looking to fall in the
western U.P., with up to half an inch possible over the western
counties. Meanwhile over the central and east, up to a quarter and
around a tenth of an inch of liquid is expected, respectively. While
this isn`t looking to be a soaking rainfall, it will help to
alleviate the drought conditions over the western U.P., especially
since they did not get as much precip as the eastern half of the
U.P. over the past few days. In addition, we could see some patchy
fog form ahead of the rainfall and return behind it Wednesday
morning due to the warm air advection moving over the area. Thus,
given the cloud cover and warm air advection, I`m thinking the low
temperatures will only get down into the low to mid 40s tonight. As
we move into Wednesday, the cold front of the low moves through the
U.P. during the morning hours; the patchy fog dissipates behind the
cold front Wednesday morning as some breezy west to northwesterly
winds move across Upper Michigan. However, with the low`s center
still sliding its way from Lake Superior to northern Ontario
throughout the day, expect mostly cloudy skies to hang around, with
some light rain/drizzle showers possibly holding on over the
Keweenaw and east until the late afternoon hours. Expect slightly
warmer temperatures Wednesday, with most of the increase being seen
in the interior eastern half.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/...
Issued at 352 PM EDT Tue Apr 30 2024

Active weather continues for the extended period with on and off
waves of showers and thunderstorms, some showing the potential for
heavier rainfall amounts. Repeated rain chances, with above-normal
precipitation expected for the coming week and beyond, will have the
benefit of easing drought conditions as well as the associated
wildfire concerns. Otherwise, expect temperatures to hover around
normal for the start of the forecast period before climbing above
average for next week.

A brief dry period is expected behind our exiting low pressure
system Wednesday night, with clearing skies and gradually decreasing
winds. Attention then shifts to the next shortwave ejecting out of
the Plains Thursday ahead of a broad parent low centered over the
Canadian Prairies. An associated surface low closes off and heads
into northern MN by the evening. In response, a sfc warm front will
lift northward towards Upper MI with a waa/isentropic ascent regime
advancing across the Upper Mississippi Valley into Upper MI. Expect
shra to spread into west and central Upper MI during the aftn, then
continue Thu night. With precipitable water increasing to 200-250pct
of normal, decent rainfall should occur. Ensemble probability
guidance suggests a 30-60pct chc of rainfall of at least 0.5 inches
and a 10-20pct chc of exceeding 1 inch. Probabilities are highest
over south-central Upper MI. Some thunder is possible with several
models hinting at a few hundred j/kg of elevated CAPE later Thursday
into Thursday night. WPC has us under a Marginal risk for excessive
rainfall during this period, but with flash flood guidance still
running rather high, significant hydro issues are not expected.

With a cold or occluded front passing through sometime early in the
day Friday, with drier air working in behind it, would expect a
trend toward dry weather. Dry weather continues at least through
Saturday morning ahead of another shortwave that will bring our next
chances for showers into the afternoon. Chances for rain showers
continue into the night.

High pres ridge arriving on Sunday will support a dry day.
Uncertainty in timing shortwaves grows significantly early next
week, but that`s not a surprise given the time range. The next wave
should arrive sometime in the Mon/Tues timeframe, as well as our
next round of associated rain showers.

&&

.AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/...
Issued at 152 PM EDT Tue Apr 30 2024

As low pressure continues to move into Ontario the rest of today,
expect the cigs to progressively improve to VFR by this evening
across the TAF sites. However, don`t expect the better conditions to
last all that long as a second low pressure system lifts from the
Upper Mississippi Valley into Lake Superior late tonight. This
brings showers and a low chance (10 to 20%) of thunder across the
area after midnight tonight into Wednesday morning. This will tank
cigs LIFR conditions across the TAF sites late tonight/early
Wednesday morning, although some low-level cloud cover is looking to
set up in the north central U.P. near KSAW before the rainfall
arrives. Thus, there may be some patchy fog or low-level stratus
near KSAW late tonight before the rainfall. As the warm front of the
low moves through late tonight, we could see some marginal LLWS
across the terminals (around 50% chance). While KIWD was the only
one with the LLWS mentioned, each of the TAF sites could see the
marginal LLWS; the LLWS will largely be dependent on how much of the
higher winds aloft mix down to the surface and the direction of the
winds between the sfc and 2 kft aloft. The LLWS threat ends
Wednesday morning as the cold front pushes through the U.P. from
west to east and brings breezy westerly winds (and gusts) to the
sfc. Ahead of the cold front, we could see some patches of
drizzle/light rain and fog; once we get behind the front, expect the
conditions to slowly improve.

&&

.MARINE...
Issued at 352 PM EDT Tue Apr 30 2024

Weakening low pressure centered just east of Lake Superior will
continue to slide eastward this evening, with weak height rises
expected over Superior as ridging briefly builds in from our south.
Winds mainly out of the W/SW will fall below 20 knots heading into
the early evening, but will pick up again out of the E/SE as another
surface low heads towards the area tonight. Expect gusts to increase
to around 20-30 knots across western Lake Superior by midnight, then
to around 20-25 kts over the eastern half of the lake into Wednesday
morning while the surface low begins to move over the lake. The
surface low finally exits eastern Lake Superior near Michipicoten
Island mid to late afternoon on Wed. There is a potential for a
short period of NE gales to 35kt over western Lake Superior late
tonight/early Wed, followed by the westerly winds that strengthen on
the south side of the low as it moves eastward. There is higher
confidence in reaching gales to 35 knots across eastern Lake
Superior during the afternoon/evening (around 50% chance), but there
is still a 3-6hr window during this period of higher gales to 35-
40kts east o the Keweenaw (around 20% chance).

After this period of stronger winds, high pressure arrives Wed
night, resulting in a quick drop of winds to under 20kts across the
lake. These lighter winds will linger across eastern Lake Superior
on Thu. Over western Lake Superior, NE winds will be on the increase
again on Thu as the next low pres moves out over the central Plains.
Expect NE winds to 30kt by late Thu aftn over western Lake Superior.
E to SE winds will increase to 30kt over eastern Lake Superior Thu
night. There is a 25-40pct chc that low end gale gusts could occur.
As low pres lifts into northern Ontario and Fri, winds will shift s
to sw. While gusts up to 30kt will continue over western Lake
Superior, winds will fall off to under 20kt over the eastern lake.
Over the weekend, expect winds mostly under 20kt across the lake.

&&

.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
  Small Craft Advisory from 7 AM EDT /6 AM CDT/ to 3 PM EDT /2
    PM CDT/ Wednesday for LSZ240.

  Small Craft Advisory from 7 AM EDT /6 AM CDT/ to 8 PM EDT /7
    PM CDT/ Wednesday for LSZ241-242.

  Small Craft Advisory from 2 AM to 11 PM EDT Wednesday for
     LSZ243-244.

  Small Craft Advisory from 5 AM to 8 PM EDT Wednesday for
     LSZ245-246.

  Small Craft Advisory from noon to 8 PM EDT Wednesday for
     LSZ247-248.

  Small Craft Advisory from 5 PM to 11 PM EDT Wednesday for
     LSZ249.

  Small Craft Advisory from 3 PM Wednesday to 5 AM EDT Thursday
     for LSZ250-251.

Lake Michigan...
  Small Craft Advisory from 10 AM to 8 PM EDT Wednesday for
     LMZ250.

&&

$$

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