455
FXUS63 KMQT 060726
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
326 AM EDT Sat Jul 6 2024

.KEY MESSAGES...

-Slight chance (~20%) for late afternoon showers and
 thunderstorms across interior western Upper MI today.

-Sunday through Wednesday, daily chances of showers and thunderstorms,
 highest chances in the afternoons. Could see a couple of
 strong storms Sunday and maybe Monday (higher uncertainty).

-Dry period begins Thursday, could be dry into next weekend.

&&

.SHORT TERM /THROUGH THIS AFTERNOON/...
Issued at 321 AM EDT Sat Jul 6 2024

Water vapor imagery and RAP analysis show that the shortwave that
brought shra to the area yesterday is exiting eastern Upper MI. A
few -shra associated with that feature are still lingering over the
eastern fcst area. The rainfall that occurred over Lake Superior has
generated fog/stratus, and the fog/stratus has been moving onshore
across the e half of the fcst area, roughly e of Marquette to
Menominee line. To the w, skies are clear, and with winds light to
calm, patchy fog is developing. Current temps generally range
through the 50s F, but some mid and upper 40s F are noted at
traditional interior cold spots over the w.

Patchy fog over the w will dissipate within an hr or so after
sunrise. To the e, fog/stratus will also dissipate this morning
after sunrise from s to n. However, GOES night fog imagery shows
quite a bit of fog/stratus over eastern Lake Superior. With meso
high developing over eastern Lake Superior today, resulting in
onshore winds, areas very close to the lake may see fog/stratus
linger well into the aftn. Attention then turns to possible aftn
convection over western Upper MI. Models show MLCAPE building to
anywhere from a few hundred j/kg to up to around 1000j/kg this aftn.
Although weak mid-level shortwave ridging moving over the area is a
negative for convection, nearly all of the 00z models show isolated
convection developing this aftn, similar to previous runs. Have thus
opted for slight chc pops (15-24%) over interior w half of Upper MI,
roughly s of a line from around Ironwood to Champion, Gwinn to
Menominee. High temps today will range thru the 70s to around 80,
except 60s F along Lake Superior, especially from around Marquette
eastward. If fog and stratus linger thru the day close to the lake,
lakeside locations in Alger/Luce counties will only top out at about
60F.

&&

.LONG TERM /TONIGHT THROUGH FRIDAY/...
Issued at 325 AM EDT Sat Jul 6 2024

Ridging building over the West Coast of the U.S. early next week
will allow weak shortwaves to cycle over us, bringing daily chances
for rain showers and thunderstorms across our area for the afternoon
to evening hours out to the middle of next week; we could see a
couple strong sub-severe storms Sunday and maybe even Monday.
However, moving into the second half of next week, as the high
pressure ridge over the West Coast moves eastward into the Central
and Eastern U.S., drier weather looks to move over us to end next
week. Additional details follow below.

Some isolated diurnal rain showers and thunderstorms end over the
interior west this evening as the sun sets. While MUCAPEs are
projected to be between 1000 to 1500 J/kg early this evening, with
there being very little shearing in the atmosphere due to the
departing weak sfc ridge overhead, only garden-variety pop-up
showers and storms are expected. Moving into tonight, we could see
some patchy fog develop across the interior areas as we look to be
mostly clear until late tonight; expect the fog to burn away a
couple of hours after dawn. However, as we approach dawn late
tonight, expect clouds to roll in from our west as another shortwave
low moving in from the Northern Plains encroaches our area. While
this 1010mb low is nothing to write home about, it does look to
bring in more showers and thunderstorms across the western half of
the U.P. by late Sunday morning. CAMs show rain shower and
thunderstorm coverage to be fairly scattered throughout the western
half of the CWA Sunday, with convection dying out as it tries to
enter into the eastern half due to subsidence remaining from the
departing weak high pressure ridge. With over 1000 J/kg to work with
in the atmosphere by Sunday afternoon and 0-6 km bulk shear being
around 30 knots, we could see a couple strong thunderstorms bring
sub-severe winds and hail across the western half late in the day.
However, as we move into the evening to overnight hours Sunday
night, expect the convection to weaken after the sunset, with
showers and thunderstorms becoming isolated by the overnight hours.

A second weak sfc shortwave lifting from the Central Plains fires up
more rain showers and thunderstorms over our area Monday. Expect to
see similar conditions to Sunday, with even a couple strong storms
being possible late in the day (although there is greater
uncertainty in the CAPE and bulk shear). However, once we get into
the late night hours Monday night, expect the convection to die-out
as the forcing weakens. More of the same is expected Tuesday and
Wednesday as additional, weaker sfc shortwaves rotate through our
area; expect the convection to be dependent on the diurnal heating
through the daytime hours in order to fire during the afternoon and
early evening hours across the U.P. before the convection dies out
by the late night hours. As this occurs, expect the temperatures to
generally be in the 70s, with a slight increase occurring between
Tuesday and Wednesday. This increasing temperature trend continues
into the last half of next week as the high pressure ridging that
initially was building over the Western U.S. travels over the
Central and Eastern U.S. by the latter half of the extended period.
This high pressure ridging is expected to keep us dry from Thursday
into next weekend.

&&

.AVIATION /06Z TAFS THROUGH 06Z SUNDAY/...
Issued at 137 AM EDT Sat Jul 6 2024

Patch of LIFR/IFR cigs/vsby originating from Lake Superior continues
to blow into SAW. They are near the edge of this cloud patch, so
conditions may fluctuate between VFR/LIFR through around 12Z before
any remaining low cigs/vsby mixes out, with VFR expected for the
remainder of the day. Shallow MVFR/IFR fog patches will probably
plague IWD up until shortly after sunrise. VFR should prevail there
for the upcoming day, but a few showers and perhaps an isolated
thunderstorm will be possible during the 21-03Z timeframe. VFR
expected to continue through the TAF period at CMX, but will be
watching for fog/stratus patches over the lake to upslope to the
terminal under WNW winds. Included SCT clouds at 400ft for now, but
there is potential for a few hrs of LIFR conditions until shortly
after sunrise.

&&

.MARINE...
Issued at 325 AM EDT Sat Jul 6 2024

Light winds of 20 knots or less continue this weekend through next
week as weak shortwaves bring showers and storms along mainly the
Lake Superior nearshores early this week before high pressure
ridging brings dry and calm conditions over the lake late next week;
while we may see a strong storm or two along the southern nearshores
for wind and hail Sunday and maybe Monday (higher uncertainty),
little, if any storms are expected over the open waters due to the
subsidence caused by the Lakes. In addition, we could be seeing some
patchy fog over the lake early this morning through today, mainly
over the north central and eastern portions as weak sfc high
pressure ridging moves through.

&&

.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
None.
Lake Michigan...
None.

&&

$$

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