084
FXUS63 KMQT 012032
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
432 PM EDT Sat Jun 1 2024

.KEY MESSAGES...

- Spotty shower activity continues especially across the western
half of the UP through the evening hours, ending late. Some thunder
is possible.
- Patchy fog, possibly dense at times, is expected to develop
tonight across much of the UP.
- Frequent opportunities for showers and thunderstorms over the next
7 days, with a break expected on Sunday and Tuesday.
- Above normal temperatures through the first half of next week,
then turning cooler.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 302 PM EDT Sat Jun 1 2024

A couple features of interest will keep in spotty shower activity
the rest of the afternoon and into the evening. Quite apparent on
water vapor imagery and RAP analysis is a deep midlevel low moving
into northern Ontario. This is currently dragging a weak cold front
through northern MN. To the east, a weak wave rippling from NE WI
into northern lake Michigan has brought in some hit and miss, light
rain showers to the south-central UP. With dry lower levels across
the eastern UP, little by any way of accumulations are expected east
of hwy 41. Dry midlevel air is apparent on water vapor imagery
behind this wave, and more breaks in the clouds are apparent across
the western UP on satellite. However, additional convection is
firing ahead of a weak boundary that has been draped somewhere over
western Lake Superior today. Though some higher cloud tops are
apparent on visible imagery, they still remain fairly warm. Still,
though we haven`t had any thunder just yet, will not totally rule
this out given several hundred j/kg of SBCAPE analyzed over the
western UP.

Heading into the evening hours, as the cold front over MN works
eastward, the spotty convection over the western UP may organize
more into a broken line of showers and storms, reaching the central
UP by 00Z and largely falling apart while continuing its eastward
trek through the first half of the night. With quite a bit of
clearing throughout northern MN behind the front, would expect skies
to likewise quickly clear out from west to east across the UP
tonight. Winds turn calm, and with clearing skies and plenty of
ambient moisture closer to the surface, not to mention a sharp
temperature inversion apparent in model soundings, we could be
looking at a good night for patchy fog across the UP. This would be
most likely in areas where we will have picked up some rain.
Otherwise, expect a quiet night while temperatures fall back into
the lower 50s and perhaps upper 40s in some of the typically cooler
spots.

&&

.LONG TERM /SUNDAY THROUGH SATURDAY/...
Issued at 431 PM EDT Sat Jun 1 2024

Expect dry conditions to return to the U.P. early Sunday morning as
the cold front currently tracking across the western UP exits into
Ontario. Weak sfc ridging returns to the area for Sunday with light
winds and abundant sunshine allowing temps to warm to around 80F
amidst deep mixing to around 6-7 kft across the interior west. Even
though there isn`t an extremely dry layer to mix into, min RH values
dipping below 30% seem likely but light winds and recent rainfall
preclude a greater fire risk. Warm temps and light winds also
instigate lake breezes that should converge across the eastern UP.
Lingering low level moisture may be sufficient for converging lake
breezes to initiate a few showers, with around 30% of HREF
members highlighting a small area around Newberry with lower
chances around 10% across the remainder of the eastern UP. The
NAMnest was one of the models that developed a shower around
Newberry and soundings indicate equilibrium levels around 10 kft
and initially deep inverted-v profiles that may evaporate most
of the precipitation. All that`s to say any rain that occurs
will be tough to measure.

Moving into Sunday night, expect mostly clear skies early before
decaying convection across the Northern Plains sends clouds our way
late. There`s also a chance for a few rain showers or perhaps a
thunderstorm across the far west, but latest model guidance
continues to be trend toward a slower onset of showers. In addition,
the model consensus shows little -if any- CAPE to work with,
probably due to cloud cover and southeast flow off the cold waters
of the lower Great Lakes. The better chance for showers and
thunderstorms is Monday afternoon/evening during peak heating if the
slower cold front is still across our area. Bulk shear values around
20-25 knots could result in a few stronger pulsey storms, but
thunderstorm chances are closely linked with frontal timing.

A drier air mass follows the cool front for Tuesday, but pwat values
stay above normal with due southerly flow extending all the way to
the western Gulf of Mexico. By Tuesday afternoon, a negatively tiled
shortwave or perhaps closed low develops across the Northern Plains
or Canadian Prairies with an associated ~990 mb surface low west of
Lake Winnipeg. As with the previous system, timing the frontal
boundary will be important for any associated thunderstorm chances
and there doesn`t appear to be a model trend at this time. However,
the most likely outcome appears to be strong to severe thunderstorms
develop to our west across the Northern Plains on Tuesday with the
decaying remnants moving into our area Tuesday night. EFI guidance
is hinting at potential for seasonably unusual CAPE and QPF Tuesday
into Wednesday across the west while NAEFS is highlighting pwats
>90th percentile implying heavy rain may be a prescient hazard.

Once the cold front passes through, the vertically-stacked low sits
over northern Ontario and brings cold air advection across our area.
As this occurs, expect additional weak shortwaves rotating around
the parent low to move across the Upper Great Lakes, bringing
additional rain shower chances to finish out the work week. Think
CAA and loss of Gulf of Mexico moisture limit thunder chances, but a
few rumbles can`t be ruled out around peak heating. CAA also results
in temperatures trending below normal late next week with highs in
the 60s and lows in the 40s.

&&

.AVIATION /18Z TAFS THROUGH 18Z SUNDAY/...
Issued at 133 PM EDT Sat Jun 1 2024

Scattered light rain showers continue across the UP this afternoon
and evening with a couple weak disturbances moving through this
afternoon ahead of a weak cold front. VCSH continue at SAW, but a
broken line of showers is beginning to work into the western UP with
impacts most likely at IWD and CMX. This may drop ceilings to MVFR,
and some thunder will not be ruled out at IWD over the next couple
of hours. Rain showers and associated restrictions end this evening
with clearing skies behind the cold front. However, as winds turn
light, patchy fog is expected to develop late. This is most likely
at CMX and SAW, with MVFR to IFR visiblity developing after 06Z.
There is around a 20% chance for patchy fog and associated
restrictions at IWD as well. Fog lifts after 12Z, then expect VFR
the rest of the forecast period with light winds.

&&

.MARINE...
Issued at 431 PM EDT Sat Jun 1 2024

Light winds of 20 knots or less continue across Lake Superior
through the weekend. Winds become southeasterly Sunday night
and increase to 20-25 kts by Monday morning ahead of a cold
front slowly tracking east across the lake on Monday. A
southerly low level jet accompanies this period of stronger
winds and stable conditions across the lake indicate potential
for stronger winds at higher elevation platforms. Behind the
front, expect a return to light winds Tuesday before the next
chance for stronger winds arrives with another cold front
Tuesday night into Wednesday. Southeasterly gusts ahead of the
front and southwesterly behind the front are forecast to gust to
around 20 kts, but cold air advection may reduce stability and
allow for better mixing and stronger winds behind the front.

Thunderstorms are possible across the south central and eastern
portions of Lake Superior this afternoon and evening as a weak cold
front moves through. Thunderstorm chances return from Monday morning
through early Tuesday morning as the second cold front tracks across
the lake. Additional thunder chances return late on Tuesday and
continue through Wednesday as yet another cold front pushes through
from west to east across the lake. No severe weather is expected
from thunderstorms at this time.

&&

.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
  Dense Fog Advisory until 8 AM EDT /7 AM CDT/ Sunday for LSZ162-
     263-264.

Lake Michigan...
None.

&&

$$

SHORT TERM...LC
LONG TERM...EK
AVIATION...LC
MARINE...EK