325
FXUS63 KMQT 190716
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
316 AM EDT Thu Sep 19 2024

.KEY MESSAGES...

- Extended stretch of well above normal temperatures continues
  through at least Saturday with highs mainly in the upper 70s
  and 80s.

- A cold front brings scattered showers and a few thunderstorms
  late today into Friday. Some stronger storms are possible in
  western Upper Michigan early this evening.

- Temperatures around normal are expected to return for next
  week.

&&

.SHORT TERM /THROUGH TODAY/...
Issued at 122 PM EDT Wed Sep 18 2024

Another warm and dry day over Upper Michigan has developed. This,
after morning temps in the 40s and 50s, and fog, some dense, across
portions of central and eastern Upper Michigan. So far, temps have
warmed into the 70s to low 80s, with the warmest spots being the
southerly wind downsloping locations near Lake Superior. Effective
mixing into a very dry airmass aloft has enabled dewpoints to fall
into the upper 40s to 50s in the driest interior locations, which
with the heat, is supporting RH values in the 30s and 40s in many
locations. Thankfully, winds have been mostly light, which is
limiting fire weather potential.

As we progress through the remainder of the afternoon and tonight,
expecting some additional warming before the heat wanes. Still
expecting widespread low to mid 80s everywhere away from Lake
Michigan`s influence where 70s will dominate. RH will respond as
well and will support continued near and/or isolated elevated fire
weather concerns into the evening. Overnight lows will again dip
into the 40s and 50s. Also expecting another round of
radiational fog to develop in interior locations of Upper
Michigan`s south-central and eastern locations.

Upstream, vertically stacked low spinning over North Dakota
will lift northeast into Canada. An associated cold front will
march east into western Minnesota overnight. Ahead of the front,
theta-e ridge with a plume of robust instability will support
showers and thunderstorms overnight. Its possible that some of
these showers/storms may continue into western Lake Superior by
morning.

&&

.LONG TERM /TONIGHT THROUGH WEDNESDAY/...
Issued at 315 AM EDT Thu Sep 19 2024

Some active weather starts off the extended forecast tonight as a
cool front pushes in from the west, bringing with it showers and
thunderstorms over Upper Michigan. With MUCAPE between 1k to 2k J/kg
and 0-6 km bulk shear being around 25 to 35 knots, we could see a
few strong thunderstorms over the western U.P. this evening a couple
of hours after the sunset, with namely strong winds and large hail
being the main threats. However, as the front and precipitation
travel eastward with time tonight, the convection looks to outrun
the better CAPE and shearing, causing the strong storm threat to end
around midnight over the central U.P.. While rainfall amounts from
the front won`t be all that impressive (mainly between 0.10 and 0.30
inches), we could see a few isolated spots, mainly over the west and
central, that could see some localized soaking rainfalls as the
heaviest downpours move over them (PWATs will be around 1.50
inches). In addition to the rainfall, we could also see some record
warm low temperatures tonight as the antecedent warm air along with
the cloud cover will work to keep lows from reaching the 50s. The
showers and storms continue over the east half Friday as convection
redevelops behind the initial line. While not expected, there is a
small, outside chance (2% or less) that we could see a strong storm
or two over the central and east, even though the conditions are not
as ideal as what they will be over the far west this evening. Expect
slightly cooler temperatures too on Friday, with highs only being in
the 70s. The rainfall associated with the front looks to get out of
here by Saturday morning as weak ridging moves overhead.

More dry weather and well above normal temperatures return Saturday
as weak, localized ridging looks to keep precipitation and cloud
cover away. Expect to see high temperatures return into the upper
70s to low 80s once again Saturday, meaning that some spots in the
U.P. may flirt with tying or breaking their daily max temperature
record. However, as a cold front from our north and west phases with
a shortwave low lifting from the Plains through the U.P. Saturday
night and Sunday, we could see showers return to the area.
Currently, the expectation is that the rainfall from this will be
fairly light.

Temperatures will return to around normal next week behind this cold
front, with highs generally being in the 60s and lows in the 50s to
mid 40s later in the week. We may see additional rainfall over
mainly the central and east around next Tuesday as a low lifts from
the Southern Rockies into the Upper Midwest. However, model
agreement is still shaky at this time, so confidence in this
occurring is still pretty low (30-40% chance). Behind this low,
expect surface ridging to return to the Great Lakes region by the
latter half of next week.

&&

.AVIATION /06Z TAFS THROUGH 06Z FRIDAY/...
Issued at 127 AM EDT Thu Sep 19 2024

VFR conditions will prevail in this TAF period.

&&

.MARINE...
Issued at 315 AM EDT Thu Sep 19 2024

Light winds of 20 knots or less today give way to southeast to
southerly winds of 20 to 25 knots over the central lake this evening
as a cool front slowly trudges from west to east today through
Friday. This front will bring some showers and storms across the
lake, with some storms possibly being strong to severe over the west
(the main threats being strong, erratic winds and large, damaging
hail). As the front moves eastwards with time, expect the severe
threat to diminish, particularly by around midnight tonight EDT.
While winds generally decrease to 20 knots or less across Lake
Superior by Friday morning, the showers and storms continue along
the front through Friday night. Weak ridging over the area keeps
winds light Saturday before a cold front passes through Saturday
night and Sunday from the west. Currently, we could see
northwesterly winds gust to 20 to 25 knots behind the cold front
over the western half of the lake late Saturday night and Sunday. In
addition, expect to see some showers and a few thunderstorms with
the front`s passage Saturday night through Sunday, although the
convection isn`t a guarantee as some models do keep the lake rain-
free (50 to 60% chance of occurrence). Another low lifting from the
Southern Rockies may lift into the Upper Great Lakes around the
Tuesday time period too and bring stronger winds and thunderstorms
back across the lake, but uncertainty on this occurring is higher
(around 30 to 40% chance of occurrence).

&&

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

&&

$$

SHORT TERM...JTP
LONG TERM...TAP
AVIATION...07
MARINE...TAP