872
FXUS63 KMQT 011733
AFDMQT

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

.KEY MESSAGES...

- Showers gradually move eastward across western Upper MI this morning
  into central Upper MI late this afternoon and evening.
- 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.

&&

.UPDATE...
Issued at 955 AM EDT Sat Jun 1 2024

Hit and miss showers continue mainly across the western UP so far
this morning, in proximity to a diffuse frontal boundary over
western Lake Superior and the western UP. However, another wave
moving through northern WI into the UP for the late morning and
early afternoon will allow some more shower activity to spread into
the central UP. PoPs have been adjusted to reflect greater extent of
showers through the early afternoon. A few rumbles of thunder are
not out of the question.

Otherwise, the forecast remains on track.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 311 AM EDT Sat Jun 1 2024

Water vapor imagery and RAP analysis show a deep mid-level low w and
sw of Hudson Bay, centered along the northern border of Saskatchewan
and Manitoba. Prominent shortwave associated with this mid-level low
has lifted to Hudson Bay. Its associated cold front has essentially
stalled over western Lake Superior as the shortwave has tracked well
to the n now. A small, but well-defined wave is noted tracking along
the border of ND/Saskatchewan/Manitoba. This wave is also working to
hold up progression of the front. Upper diffluence from the right
entrance of 100kt upper jet extending from far northern MN toward
southern Hudson Bay is aiding a band of shra extending from western
Lake Superior thru southern MN. This band of shra as been lifting
more n than e during the night, and at present, the shra are now
just to the w of Upper MI. Otherwise, it`s a quiet night across the
fcst area with light winds and abundant high cloudiness. Temps range
thru the 50s to lwr 60s F.

With the upper diffluence aiding the band of shra to the w shifting
e this morning, expect the shra to also shift e back into western
Upper MI. To the s, a shortwave is currently over the Mid-
Mississippi Valley. Shra associated with this feature may try to
develop northward into southern Upper MI late morning/early aftn.
Most guidance suggests that won`t happen, and fcst reflects that
idea. This aftn, the shortwave currently tracking e vcnty of far
northern ND will lift into northern Ontario. This wave will give an
eastward kick to what`s left of the cold front currently over
western Lake Superior. Front at the sfc essentially dissipates, but
up at 850mb, a trof and rather sharp theta-e boundary is noted. This
trof/boundary shifts e during the later aftn/evening and should
support invigoration of shra over western Upper MI. With up to a few
hundred j/kg of MLCAPE avbl this aftn, isold tsra will be possible
as well. This band of shra/isold tsra will shift into central Upper
MI late aftn/early evening then continue e thru the evening while
diminishing. Most, if not all, of the shra may dissipate before
reaching Luce/Schoolcraft counties. Clearing skies, little wind, and
the rainfall from today may lead to patchy fog development overnight
tonight. Expect high temps today mostly in the upper 60s to mid 70s
F. Temps tonight will fall back to the upper 40s and lwr 50s F.

&&

.LONG TERM /SUNDAY THROUGH FRIDAY/...
Issued at 259 AM EDT Sat Jun 1 2024

Expect dry conditions to return to the U.P. Sunday as the cold front
leaves the far east during the early morning hours and weak sfc
ridging returns to the area. With sfc ridging and zonal flow in the
mid-levels over the area during the day Sunday, expect a diurnal cu
field to develop over Upper MI by the afternoon hours as troughing
and warm air advection begins to make its way back over the area by
early Sunday evening. With PWATs around 0.75 inches, there is an
outside chance (around 10%) that we could see a stray lake breeze
induced rain shower or two over the central and east late in the
day. However, given the high pressure ridging at the sfc, the dry
air in the PBL should eat away any moisture that falls out of the cu
field. Should anything make it to the sfc, expect short-lived
sprinkles to light rainfall.

Moving into Sunday night, expect the mostly clear skies to
progressively give way to clouds as a cold front bringing showers
and storms approaches from northern MN. The most recent NBM run has
pushed back the timing of the showers and storms arriving over the
western U.P. late Sunday night and Monday morning. In addition, the
model consensus shows little, if any CAPE to work with and 0-6 km
bulk shear values generally less than 30 kts. Therefore, severe
weather is not expected at this time over the western U.P. Monday
and Monday evening. The cold front will slowly crawl from west to
east early this week across our area before weak high pressure
ridging returns to the U.P. Tuesday. As this occurs, expect rain
showers and thunderstorms across our area from Monday into early
Tuesday morning.

The low behind the cold front early this upcoming week will lift
towards Hudson Bay with time before being phased with an amplifying
Clipper low by the middle of next week. Strong warm air advection
from the Gulf is brought over our region ahead of the cold front of
the low`s arrival Tuesday and Tuesday night. Therefore, expect high
temperatures Tuesday to break into the 80s across the interior
areas. I could see dewpoints and RHs being lower than what`s
currently being predicted by the NBM for Tuesday; if there is less
cloud coverage than what`s currently predicted (partly cloudy skies
at the moment), then mixing in the boundary layer will be greater,
and thus dewpoints and RHs will be lower (I would wager their is
around a 50% chance of this occurring at this time). As it stands
now though, RHs are not expected to dip below 50%.

The cold front of this low begins moving into the area late Tuesday
afternoon/early Tuesday evening over the far west, with showers and
thunderstorms moving over the rest of the U.P. Tuesday night through
Wednesday. 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 showers and possibly (15% chance) a
thunderstorm or two back across the area to finish out the work
week. Thus, along with the scattered rain chances, expect to see
below normal high temperatures late next week; this is reflected
well in yesterday`s 12z run of the EFI for the daytime Friday, with
some of the ensemble runs showing highs in the 10th percentile or
cooler of climatology. Therefore, we could see some unseasonably
cool daytime temperatures come late next week.

&&

.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 259 AM EDT Sat Jun 1 2024

Light winds of 20 knots or less continue across Lake Superior until
a cold front crawling eastwards across the lake brings southeasterly
winds of 20 to 25 knots over the higher elevation platforms and the
Lake Superior southerly nearshores Monday. Behind this, expect a
return to light winds Tuesday, before stronger winds could possibly
return with the coming of a second cold front Tuesday night into
Wednesday; expect gusts to around 20 knots from the southwest over
the western half. Moving into the latter half of next week, we could
see higher winds from the northwest as cold air advection from
Canada works in tandem with weak shortwaves dropping down across the
area to mix stronger winds aloft to the lake`s sfc.

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 Sunday night
to early Tuesday morning as a second cold front slowly makes its way
from west to east across the lake. Additional thunder chances return
late 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 these storms.

&&

.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
  Dense Fog Advisory until 11 PM EDT /10 PM CDT/ this evening
     for LSZ162-263-264.

Lake Michigan...
None.

&&

$$

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