832 
FXUS63 KMQT 181710
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
110 PM EDT Tue Jun 18 2024

.KEY MESSAGES...

-Hot and humid today with southerly winds of 10-20 mph, gusting
 to 30+ mph. Showers/storms returning this evening from the
 west.

- Multiple rounds of showers and thunderstorms expected this 
week. Strong to severe storms possible tonight into Wednesday.

- Potential heavy rain event this weekend.

&&

.SHORT TERM /TODAY/...
Issued at 500 AM EDT Tue Jun 18 2024

Scattered showers with embedded thunder continue to drift across 
northern and southern portions of Upper Michigan early this morning 
due to frontal boundary. Current water vapor imagery/RAP 
analysis show a surface low situated over the spine of the 
Keweenaw with its occluded frontal boundary extending 
northeastward into Ontario and arcing southwestward into 
Minnesota. As that boundary pushes northward as a warm front 
this morning, any remaining showers and thunderstorms will exit 
Upper Michigan to the north after Tue 12Z. And, this will 
result in a short break from the active weather before another 
round by this evening and a mostly sunny day. The downside, 
though, will be the hot temperatures as the UP resides in the 
warm sector along with strong southerly surface winds under 
ample mixing. Temperatures will soar to near the 90 degree mark,
combined with dew points in the 70s, pushing heat index values 
into the mid 90s. And, southerly winds will be sustained at 10 
to 20 mph, gusting to 30 mph, especially across downslope areas 
near Lake Superior.

&&

.LONG TERM /TONIGHT THROUGH MONDAY/...
Issued at 407 AM EDT Tue Jun 18 2024

The overall consensus of both ensemble and deterministic guidance 
packages suggests the pattern across CONUS will continue to include 
a stout mid-upper level ridge over the eastern third of CONUS while 
deep and broad troughing holds fast over the western third. This 
places Upper Michigan in a predominate south to southwest flow 
regime and open to both Gulf of Mexico moisture and a warm/hot 
airmass, and on the path for any shortwave, impulse, or MCS 
developing across the Plains, at least until the weekend when a more 
zonal pattern begins to emerge. 


The low currently ejecting out of the central Plains early this 
morning will move into Ontario tonight, slowly dragging a cold front 
through Upper Michigan tonight through Wednesday. Showers and 
thunderstorms begin to move into the western UP as early as this 
evening, which will present another opportunity for some strong to 
severe storms given impressive CAPE and sufficient shear over the 
area. However, this risk remains limited and wanes further eastward 
as given an unfavorable timing of the frontal passage. Will note 
that most of the hi-res guidance indicates that convection will be 
able to make it even as far eastward as M-95 overnight. However, 
where storms can develop, heavy rain will yet again be a concern 
with near 2in PWATs. As the front continues to slowly track through 
during the day Wednesday, expect additional convection to develop 
along it with weak daytime instability. Otherwise, expect 
temperatures to come in cooler than Tuesday, with highs ranging in 
the 70s behind the front and the upper 70s to lower 80s ahead of it. 
Dewpoints in the 60s ahead of the front will keep things feeling 
rather muggy. 

The front largely clears the area Wednesday evening, with PoPs 
receding southward as high pressure builds in. Thursday looks to be 
mostly dry as the pattern begins to shift into something more zonal, 
but some showers cannot be totally ruled out with weak impulses 
rippling through. As another shortwave begins to eject out of the 
Rockies, another warm front will lift into the Upper Great Lakes 
Thursday night/Friday, potentially supporting showers/storms 
Thursday night into early Friday. The boundary appears to stall out 
Friday over the Upper Great Lakes as a surface low deepens and lifts 
out of the Central Plains. The low will press through the region 
Saturday night and Sunday while the shortwave aloft takes on a 
negative tilt. For a few days now, guidance has been suggesting this 
setup, which could lead to a potential heavy rain/flooding event in 
some areas in Upper Michigan as PWATs again increase to as high as 
200% of normal. Of course, this will be dependent on preceding rain, 
but this system warrants monitoring.

&&

.AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/...
Issued at 109 PM EDT Tue Jun 18 2024

VFR conditions are expected to continue at the TAF sites this 
afternoon into very early this evening, although with a high-end 
MVFR cu deck having already formed over the western half of the 
U.P., we could see some BKN MVFR cigs from time to time across the 
TAF sites for the afternoon hours. As the showers and storms over 
Minnesota move eastwards across our area tonight, expect the 
conditions at the terminals to likewise worsen from west to east 
tonight to MVFR/IFR. In addition, LLWS is expected across all the 
TAF sites when the gusty winds aloft from a low-level jet overhead 
fail to mix to the surface. However, when those gusty winds reach 
the surface from time-to-time tonight into Wednesday morning, the 
LLWS will not be as much of a problem. Conditions improve Wednesday 
morning behind the cold front, with the terminals eventually 
becoming VFR from west to east near the end of the TAF period (save 
for maybe KSAW, which could hold onto high-end MVFR cigs until after 
18z).  

&&

.MARINE...
Issued at 407 AM EDT Tue Jun 18 2024

A warm front lifting northward early this morning is supporting 
additional showers and some thunder, but showers largely move north 
of the area shortly after sunrise. Meanwhile, light winds to start 
us off will keep in a potential for some patchy dense fog through 
the morning.

South of the warm front, a strong low level jet will move over Lake 
Superior ahead of a cold front moving eastward through Minnesota. 
This low level jet will support southerly winds upwards of 30kts 
across eastern Lake Superior, possibly some low end gales for higher 
reporting platforms or where topography plays a local influence on 
winds near the lakeshores between Marquette and Whitefish Pt. Cold 
front will press through the lake tonight through Wednesday, 
potentially supporting another round of strong to severe storms 
across western Lake Superior and thunderstorms and showers lake-
wide. Winds slowly fall back below 20 knots while turning mainly to 
the west behind the front Wednesday afternoon. High pressure appears 
to try to work in Thursday but will be dependent on upstream 
systems. Another front moves over the lake Friday/Saturday as a low 
pressure approaches from the west, bringing with it another round of 
showers/storms. Current thinking is for light winds in this system 
outside of thunderstorms.

&&

.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
  Beach Hazards Statement until 10 PM EDT this evening for 
     MIZ014.

Lake Superior...
None.
Lake Michigan...
None.

&&

$$

SHORT TERM...TDUD
LONG TERM...LC
AVIATION...TAP
MARINE...LC