192
FXUS63 KMQT 261906
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
306 PM EDT Wed Jun 26 2024

.KEY MESSAGES...

- Cool late June night tonight.

-Pattern remains active, especially from late week into early next
week, with yet more rounds of showers and storms

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 306 PM EDT Wed Jun 26 2024

Water vapor imagery and RAP analysis show mid-level ridging over the
Rockies and troffing over eastern Canada into the adjacent U.S.,
resulting in nw flow into the Great Lakes. Shortwave that was over
southern Saskatchewan 24hrs ago is over northern Lower MI. Shra
associated with this feature spread across Upper MI this morning,
but diminished dramatically while doing so. Heaviest rainfall
occurred over portions of the Keweenaw, CMX received 0.48 inches.
Where sun dominated the morning, shra have developed in ne WI, and
some of these -shra are affecting portions of southern Menominee
County. In the wake of the shortwave, it has been a cool aftn with
considerable low cloudiness across the w and n central. Clouds are
slowly lifting and showing some signs of scattering out, but cloud
cover extends across the lake into ne MN/and northern Ontario where
cloud cover is taking on a decidedly more diurnal cellular look.
Current temps range only from the low/mid 50s w and n to the upper
60s F s central where more sun has occurred today.

Expect some thinning out of clouds for the rest of the aftn. Despite
the more cellular look of the clouds upstream of the lake, the
considerable coverage suggests that these clouds are not likely to
completely dissipate tonight, leading to increased uncertainty in
min temps. With center of high pres shifting se to northern MN/nw WI
by sunrise, winds will become light to calm. Precipitable water also
falls to 50-60pct of normal, aiding radiational cooling potential.
Leaned toward the lower side of avbl guidance, which puts min temps
down into the upper 30s F at traditional cold spots interior w.
Given the cloud cover uncertainty and wet soils that dampen
radiational cooling, seems highly unlikely that it would be even
colder to support patchy frost development. If more cloudiness hangs
on tonight, min temps will easily be at least 5 degrees higher.
Otherwise, expect min temps tonight to range thru the 40s F.

&&

.LONG TERM /THURSDAY THROUGH TUESDAY/...
Issued at 252 AM EDT Wed Jun 26 2024

The pattern will remain fairly active and progressive through the
extended fcst period as a couple of Pacific-based shortwave troughs
traverse the northern tier of the CONUS and bring more rounds of
showers and t-storms to the Upper Great Lakes mainly in the Friday-
Saturday night and Monday night into Wednesday time periods.

Starting Thursday, a weak high pressure ridge persists across the
region into much of Thu night as dry weather prevails. Weak pressure
gradient and light winds will result in lake breezes during the day
on Thursday. Expect highs generally in the lower 70s, except a touch
cooler in the mid to upper 60s near the Great Lakes shores. Look for
lows Thu night in the lower to mid 50s, except for some cooler upper
40s readings over the eastern interior.

Friday and Saturday, a mid-level trough/closed low just off the
Pacific Northwest coast as noted on satellite imagery early this
morning will move onshore later this morning. This trough will
support cyclogenesis in the lee of the Northern Rockies Thursday
night with the sfc low ejecting east into the Dakotas and along the
international border/northern MN Friday and into the Upper Great
Lakes on Saturday. WAA/isentropic ascent and theta-e advection ahead
of the low will support showers and thunderstorms spreading into
Upper Mi on Friday. The initial shortwave embedded within the mid-
level trough will move into the region Saturday while pushing a cold
front through the area Friday night into Saturday. Increased
instability noted ahead and along the cold front should increase
chances for thunder as it passes through the area at this time. A
second shortwave moving through the trough axis will send a
secondary cold front across the area late Sat into early Sun perhaps
triggering some isolated to scattered light showers along with a
burst of gustier nw-n winds and colder temps.

High pressure building in quickly behind the front will result in
drier, albeit cooler conditions Sunday afternoon into Monday. Models
then advertise another mid-level trough moving in off the West Coast
which again will promote lee-side cyclogenesis over the Northern
Rockies early next week. The associated sfc low is fcst to lift
northeast through the Northern Rockies into Manitoba and northern
Ontario Mon night into Tuesday as it propels a cold front across the
Upper Great Lakes on Tuesday. Ahead of and along this front another
round of showers/t-storms is expected next Mon night into Tuesday.
The passage of another shortwave and secondary cold front from this
system could bring more light showers into the area on Wednesday.

&&

.AVIATION /18Z TAFS THROUGH 18Z THURSDAY/...
Issued at 145 PM EDT Wed Jun 26 2024

A stratus deck, IFR cigs, that developed during the morning at
IWD/CMX/SAW has lifted to MVFR recently. Expect MVFR cigs to
gradually lift to VFR BKN clouds at 3500ft over the next 2-4hrs at
all terminals. VFR will then continue for the remainder of the fcst
period.

&&

.MARINE...
Issued at 252 AM EDT Wed Jun 26 2024

Winds have switched northerly early this morning at 15-20 kts behind
a cold front dropping south across the lake but will taper off below
15 kts during the day today. With high pressure over the lake
through Thursday, winds are expected to mainly remain below 20 kts.
A weakening low pressure tracking through the Upper Great Lakes
early this weekend will allow for s-se gusts 20-25 kt Friday over
mainly the east half ahead of the front and then nw gusts 20-25 kt
behind the cold frontal passage on Saturday before building high
pressure returns Sunday and ushers in lighter winds into Monday.

&&

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

&&

$$

SHORT TERM...Rolfson
LONG TERM...Voss
AVIATION...Rolfson
MARINE...Voss