211
FXUS63 KMQT 181955
AFDMQT

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

.KEY MESSAGES...

-Showers and thunderstorms possible tonight, particularly over
 the far west. Some severe weather is possible over the far
 west.
-More showers and thunderstorms possible for the latter half of
 this week.
-Potential heavy rain event this weekend.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 242 PM EDT Tue Jun 18 2024

A scattered cu deck has formed over the western half this afternoon
whereas the eastern half is mostly cloud free as strong southerly
winds off of Lake Michigan are helping to stabilize the air a
little. Observations have already shown temperatures reaching the
80s across much of the area, with some spots such as Ontonagon and
L`Anse already getting to 90+F. Meanwhile, a shortwave low moving
through MN is continuing to lift along a cold front boundary over
the area. As the cold front continues to move eastwards into our
area tonight, expect showers and thunderstorms to move into the far
west before midnight local time. We could see some severe hail and
winds come this evening as the convection moves into our western
area, as models show MUCAPEs in the 1k-3kJ/kg range and shearing
very high in the lowest levels of the atmosphere as a low-level jet
screams across our area. In addition, the hodograph and LCL levels
are supportive of a very small chance (<5%) for an isolated tornado
late tonight. However, with CAMs showing a lot more of the
convection dying than previously anticipated, the severe weather
potential looks to be relegated to the far western U.P. as the cells
die and collapse (similar to how we saw the severe winds over the
eastern U.P. yesterday afternoon). Given the sharp drop in precip
chances as the cold front moves eastwards tonight, I`ve reduced the
chances across the central and eastern U.P. to chance wording (30-
40%). However, this may need to be lowered further as the most
recent CAMs seem to amplify the lack of rainfall late tonight.

&&

.LONG TERM /WEDNESDAY THROUGH TUESDAY/...
Issued at 354 PM EDT Tue Jun 18 2024

Light rain showers and maybe a stray thunderstorm or two could pop-
up over the central and east Wednesday as the cold frontal boundary
slowly stalls out. With CAMs showing only scattered light convective
coverage continuing over the central and east on Wednesday, expect
precipitation amounts to be light. By Wednesday evening, expect the
rain showers and thunderstorms to generally be finished over the
area. That being said, as the flow becomes zonal across our area by
Wednesday night and Thursday, we get weak ridging that sets up over
Lake Superior. At the same time, weak troughing looks to set up over
Wisconsin. With the ridging and inverted troughing fighting one
another around our south central, we could see some rain showers
continue across this area, as well as a few thunderstorms. As warm
frontogenesis starts to develop over our area late this week, the
rain chances begin to crawl northwards across the rest of the U.P.
late Thursday into this weekend. We could see some heavy rainfall
come late this week into early this weekend along the strengthening
warm front, as ensembles show PWATs near the max of modeled
climatology (nearly 2")! With training very possible along the front
given it`s slow movement northwards, we may need to keep an eye on
flooding concerns across our area, particularly over the west half
where the higher rainfall amounts are currently predicted. Once the
low creating the warm frontogenesis moves through Lake Superior
Saturday afternoon, expect a break in the rainfall before a
secondary Clipper low moving over our area Saturday night and
Sunday brings rainfall chances back across our area.

Moving into early next week, expect ridging and finally some drier
weather as a high pressure moves from the Plains through the
Midwest. Overall, expect temperatures to be near normal for the
extended period, with some days showing below normal high
temperatures (such as Thursday, Friday, and Sunday). Outside of the
rain and storm chances throughout the next week, the only other
thing worth mentioning is the possibility for localized river
flooding along the Chocolay River near Harvey. With much of the
basin having received between 2 to 3.5 inches of rainfall over the
past 24+ hours, and the Observation Program Leader having gone out
to the Chocolay near Yelden (around Skandia) and seeing the river
already up to the bridge, there may be some isolated spots along the
river near Harvey that could see some river flooding issues that are
more typical to the Spring-time (water in basements, etc.) This
situation will continue to be monitored by the staff here at WFO
MQT, as well as the NCRFC while the water from the recent rainfall
slowly exits the Chocolay River Basin into Lake Superior.

&&

.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...TAP
LONG TERM...TAP
AVIATION...TAP
MARINE...LC