760
FXUS63 KMQT 260655
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
255 AM EDT Wed Jun 26 2024

.KEY MESSAGES...

- Scattered showers arrive over northwest Upper MI around
  sunrise today.

- 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 343 PM EDT Tue Jun 25 2024

Water vapor imagery and RAP analysis show that the convectively
enhanced shortwave that brought shra/tsra to the area last night is
over Georgian Bay. Another shortwave trof extends from James Bay to
nw of Lake Superior and a third shortwave is over southern
Saskatchewan. At the sfc, a trof extends across eastern Lake
Superior and central Upper MI, and a cold front extends from James
Bay to just nw of Lake Superior. Rapidly deepening mixed layer to
the w of the sfc trof is leading to sharp drying this aftn as sfc
dwpts are plummeting into the mid 40s to lwr 50s F across western
Upper MI. To the e, sfc trof and lake breeze development off of Lake
Superior has led to a few shra developing recently.

For the next couple of hrs, expect isold shra over the eastern fcst
area ahead of sfc trof/lake breeze. Otherwise, dwpts will continue
to fall from w to e in the wake of passing sfc trof, leading to more
comfortable conditions under temps in the mid 70s to mid 80s F.
Across the Keweenaw, fcst soundings suggest wind gusts to around 40
mph over the next several hrs. Wouldn`t be surprised to see a few
gusts to around 45 mph for a couple of hrs based on winds at top of
mixed layer. Otherwise, wind gusts of 20-30mph will be fairly common
over roughly the w half of Upper MI.

Cold front approaching Lake Superior will drop s across the area
later this evening/overnight. Other than a wind shift to n to ne, it
should pass uneventfully given the drying that is currently
underway. Expect clear to partly cloudy skies thru the evening. Late
tonight, attention turns to shortwave currently over southern
Saskatchewan. This wave will reach nw WI/western Lake Superior
around 12z Wed. Given the decent, small cluster of shra currently
associated with this feature, models seem on track bringing shra
into nw Upper MI in the 10-12z timeframe. Cold front that drops into
the area tonight will be aligned from northern MN se thru northern
WI early Wed morning, and that should also provide some focusing of
forcing as well due to weak waa over the boundary in response to the
wave. Temps tonight will fall back to the mid 40s to mid 50s 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 /06Z TAFS THROUGH 06Z THURSDAY/...
Issued at 124 AM EDT Wed Jun 26 2024

VFR will prevail at IWD/CMX/SAW through tonight. Winds will diminish
toward sunset and then veer n to ne. A few shra may also occur at
CMX btwn 11-14z. The MVFR cigs at CMX and SAW that form in the
morning will scatter out to VFR at CMX/SAW during the aftn.

&&

.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...07
MARINE...Voss