120
FXUS63 KMQT 050804
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
404 AM EDT Fri Jul 5 2024

.KEY MESSAGES...

-Showers today. A 40-60% chance of some areas across the south
 receiving over an inch of rainfall.

-Mainly dry Saturday, but a rain shower cannot be entirely
 ruled out in the interior west late in the afternoon.

-Sunday through Wednesday, daily chances of showers and
 thunderstorms, highest chances in the afternoons.

-Dry period could begin Thursday and continue into next
 weekend.

&&

.SHORT TERM /THROUGH THIS AFTERNOON/...
Issued at 341 AM EDT Fri Jul 5 2024

Water vapor imagery and RAP analysis show a well-defined
shortwave/mid-level low over eastern MN/western WI. Ahead of the mid-
level dry slot lifting around e side of the circulation, a band of
shra extends from ne WI wnw into MN, aided by isentropic ascent,
especially over ne WI. These shra have spread across the MI/WI
stateline recently with new development also occurring in s central
Upper MI ahead of the main band of shra. Current temps range thru
the 50s with some lwr 60s F s central.

Mid-level low will drift e today with deep layer forcing per q-
vectors strongest during the morning thru early to mid-aftn. With
more persistent isentropic ascent focused into the central and
eastern fcst area, expect the more persistent/heavier pcpn over that
area, but especially s central/se where isentropic ascent is
generally best focused this morning. The nw fcst area, Keweenaw in
particular, may not see any shra today. Beyond mid-aftn, forcing
weakens, and models all show a corresponding decrease in
coverage/intensity of pcpn at that time. Precipitable water is
running about 130-140pct of normal with the pcpn today, so not
unusually high to support excessive rainfall. However, given the
persistence of the shra, local amounts of an inch or two are
possible. 00z HREF has the probability of exceeding 1 inch at 40-
60pct, but exceeding 2 inches at no more than around 20pct. At least
to this point, KMQT radar has only showed some of the shra having
small cores with instantaneous rainfall rate estimates of 1-3
inches/hr. There is some instability noted for non sfc-based
parcels, and with mid-level dry slot advecting toward the area,
can`t rule out some rumbles of thunder today across the southern
fcst area. So far, GOES GLM has only detected a few lightning
flashes either side of the MI/WI stateline. Clouds/shra will hold
temps down today with highs ranging thru the 60s F. Will be coolest
across the central, especially n central, due to ne winds off of the
lake.

&&

.LONG TERM /TONIGHT THROUGH THURSDAY/...
Issued at 403 AM EDT Fri Jul 5 2024

The active weather pattern continues through this weekend and at
least the first half of next week as a building high pressure over
the western U.S. directs multiple shortwaves towards us over the
next several days. The first of these shortwaves looks to be leaving
our neck-of-the-woods come tonight as it lifts from Lower Michigan
into southern Ontario. Given that the comma-head of the low will be
over us tonight, expect mainly light rain showers to dwindle from
the west to east with time tonight as the shortwave low moves
eastward with time. While there`s enough energy to maybe squeak out
a rumble of thunder or two, with the already weak sfc forcing
dwindling throughout the overnight hours, expect the convection to
be rather sporadic and light, especially given the decreasing energy
in the atmosphere once the sun sets. The last of the rainfall
associated with the shortwave looks to end over the far eastern U.P.
late tonight/early Saturday morning. Behind the rain showers, we
could see some fog develop across the area late tonight into early
Saturday morning (as seen on the latest run of the HREF). Therefore,
be on the watch out for rapidly reduced visibilities from time-to-
time if you`re traveling Saturday morning.

Weak high pressure ridging moves over us Saturday as the fog burns-
off during the mid morning hours. With the sfc high being based in
the Ohio River Valley/TN and being fairly weak at around 1014mb, the
subsidence over us may be weak enough to allow for late afternoon
garden-variety showers and thunderstorms to form over the interior
west. In addition, expect the temperatures to be quite a bit warmer
than what they are to be today, returning to generally the 70s
across the area (closer to 70 near Lake Superior and around 80 in
the interior west and south central). The convection dies out by
Saturday evening, but another shortwave low looks to bring
additional rain showers and possibly a few thunderstorms back over
the area by Sunday, mainly during the afternoon when diurnal heating
becomes maximized.

Additional weak shortwave activity looks to continue diurnally-
induced convection over our area Monday, Tuesday, and possibly even
Wednesday. While we have some modest CAPE during the afternoon hours
those days, with the lack of shearing overtop of the region, only
garden-variety showers and thunderstorms are expected. Temperatures
look to be near normal for this time of year this weekend through
next week, and the medium range guidance hints at us possibly drying
out for the latter half of next week as the high pressure over the
western U.S. slowly shifts east into our neck-of-the-woods and sets
up shop over the Upper Midwest by the end of next week.

&&

.AVIATION /06Z TAFS THROUGH 06Z SATURDAY/...
Issued at 112 AM EDT Fri Jul 5 2024

VFR conditions in place to start the 06Z TAF cycle. A surge of
moisture and rain showers should impact at least IWD/SAW
overnight into the morning, with cigs falling to MVFR and IFR.
CMX looks to be on the edge of the rainfall so VFR was
maintained with this cycle, although confidence on placement of
precipitation is fairly low. An embedded TS cannot be ruled out
at IWD roughly 08-14Z and SAW 10-16Z, but coverage too low for
inclusion in the TAFs. Gradual improvement in cigs expected
through the day, but IFR conditions may hang on at SAW until
early afternoon.

&&

.MARINE...
Issued at 403 AM EDT Fri Jul 5 2024

Light winds of 20 knots or less will continue across Lake Superior
this weekend through next week as a cycle of weak shortwave lows
followed by weak ridging continues across the Upper Great Lakes as
high pressure continues to build over the western half of the U.S..
That being said, a few of the disturbances will be strong enough to
produce some thunderstorms across the lake from time-to-time over
the next several days, mainly along the nearshores today into this
evening and again each day during the daylight hours Sunday through
at least next Tuesday.

&&

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

&&

$$

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