280
FXUS63 KMQT 010659
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
259 AM EDT Sat Jun 1 2024

.KEY MESSAGES...

- Scattered showers continue across the west through tonight
  with a few embedded thunderstorms. Locally heavy rainfall >1"
  possible, especially with thunderstorms.
- Frequent opportunities for showers and thunderstorms over the
  next 7 days.
- Above normal temperatures through the first half of next week, then
  turning cooler.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 410 PM EDT Fri May 31 2024

Only minor forecast updates were needed today with sunnier skies
allowing for slightly warmer temperatures approaching 80F. Deeper
mixing also allowed for somewhat stronger winds, but overall the
fire weather forecast was spot on across the east with RH dipping to
around 25% and SSW winds of 10-15 mph with gusts to 20mph. The only
exception was the Newberry RAWS which is reporting a dew point 11-
17F lower than all surrounding observations raising questions about
how representative the observation is. On the other side of the
Peninsula, an area of rain/rain showers lifted northeast across our
western tier of counties for most of the day. While no thunder has
been reported, CMX reported a brief period of heavy rainfall as it
moved overhead. Coverage is currently waning suggesting a general
lull head of the next wave this evening. As of 355 PM our radar
started picking up the frontal boundary extending southeast from Big
Bay.

Looking ahead through tonight, the frontal boundary is expected to
slow and eventually stall tonight. As the boundary stalls, the
nocturnal LLJ ramps up to around 35 kts as it noses into our area
this evening. This disturbance and the associated area of of showers
and embedded thunderstorms is already showing up on regional radar
in the vicinity of Minneapolis. CAPE is insufficient for severe
concerns, but pwat values >1 inch (approaching the 90th percentile)
and potential for multiple rounds of rain suggests a chance for
locally heavy rainfall and perhaps patchy fog too. 12z HREF PMM
guidance paints a stripe of heavier QPF between Watersmeet and
L`Anse, which is primarily instigated by NAMnest and HRW NSSL
guidance. However, it`s worth noting that most other guidance is
further west roughly between Ironwood and Copper Harbor.
Fortunately, river levels remain low and flooding concerns are
limited to ponding in poor drainage areas.

&&

.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 /06Z TAFS THROUGH 06Z SUNDAY/...
Issued at 129 AM EDT Sat Jun 1 2024

Delayed onset of MVFR (possible IFR) conditions at IWD/CMX until the
10-14Z time frame as showers continue to filter into TAF sites in
association with a cold front. Thunder potential for the overnight
has diminished and will not be included in fcst. Until deterioration
later this morning, VFR will be the prevailing flight category at
IWD and CMX. Elsewhere, flight restrictions are not expected at SAW
and VFR will be the predominant flight category for duration of TAF
period. Meanwhile, winds will generally be light and variable with
little to no impact.

&&

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

&&

$$

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