972
FXUS63 KMQT 161738
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
138 PM EDT Wed Apr 16 2025

.KEY MESSAGES...

- Low relative humidities down into the 20 percents are expected
  today. Relative humidities down into the teens are possible in
  the interior west and south central by mid afternoon.

- Strong southerly winds of 20 to 40 mph will be possible
  Thursday afternoon, likely strongest near the Lake Superior
  shorelines near Copper Harbor and of Marquette, Alger, and
  Baraga counties.

- Widespread rainfall is expected late Thursday into Friday
  evening. Rain and snowmelt will lead to rises on area rivers
  and possible minor flooding on typically flood-prone rivers.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 137 PM EDT Wed Apr 16 2025

Upper air pattern consists of a 500 mb closed low off the CA coast,
a trough in the ern U.S. and a trough in the Canadian Prairies.
Troughing moves into the northern Rockies with a shortwave ridge in
the upper Great Lakes 12z Thu. Quiet for this forecast period and
did not make many changes to the going forecast.

&&

.LONG TERM /TONIGHT THROUGH TUESDAY/...
Issued at 259 AM EDT Wed Apr 16 2025

Beginning tonight at 0z, surface high will be exiting the forecast
area, giving way to light southerly flow and a period of warm air
advection into the region. A strengthening 925-850mb LLJ will help
to warm the 850mb airmass to ~4-7C by the end of Thursday ahead of a
surface low and broad and deep troughing inching closer to the
region. The 35-50kt LLJ, in addition to mixing and terrain
influences, will create breezy downslope winds in the lee of the
Gogebic Range/Porkies, tip of the Keweenaw, and n-central near
Marquette. By afternoon Thursday, widespread 20-30 mph wind gusts
can be expected, with potentially upwards of 35-40 mph across and in
the downslope lees of the high terrain near Copper Harbor and of
Marquette/Baraga/Alger counties, including Marquette and Munising.
Winds should begin relaxing in the evening as daytime mixing ends.
Additionally, an initial wave of isentropically forced rain, with
embedded thunderstorms will lift into the region Thursday
afternoon/evening. While widespread rain is possible, there
continues to be a healthy spread of how much between the various
model sets. Some packages seem to be gravitating toward the heavier
rainfall potential focusing across the south-central and east
Thursday night. On Friday, there continues to be somewhat poor
clustering of the surface low, which lends less confidence as to
where the greatest rainfall potential. However, a potential break in
rainfall looks more plausible Friday morning followed by an
afternoon swath of rainfall and thunderstorms. The growing consensus
with this afternoon feature focuses the more steady/higher rainfall
amounts through the south/central and east. Of course, there are
outliers, namely the GFS and its ensemble system, which pings a more
northern option across the west/Keweenaw late Friday. Overall
though, widespread 0.25-0.75 inches of rain Thursday night into
Friday continues to look good, with low potential (<25% chance)
upwards of 1.25 inches in some locations. This rainfall and
continued snowmelt will lead to rises on area rivers, with possible
minor flooding on typical flood-prone rivers, especially if the
higher end solutions verify. High temperatures on Thursday look to
peak in the upper 50s to low 60s west and low 50s east and by Lake
Superior. Mild overnight Thursday night with temperatures in the
upper 30s to low 40s will follow.

High pressure and dry air will build in late Friday, then stick
around for the weekend. Another system could bring another round of
widespread precip early next week, but large spread in the system`s
track continue in the recent model runs.

&&

.AVIATION /18Z TAFS THROUGH 18Z THURSDAY/...
Issued at 1232 PM EDT Wed Apr 16 2025

VFR conditions remain across the area through the forecast period.

&&

.MARINE...
Issued at 259 AM EDT Wed Apr 16 2025

Northwest winds will continue to lighten tonight as high pressure
builds into the Upper Great Lakes. This will help support mostly
light winds below 20kts by this afternoon lakewide and then tonight.
Low pressure lifting through the Plains into the Great Lakes will
enable a low level jet over the area tonight. This does looks to
support stronger downsloping southerly winds where wind vectors are
perpendicular to upwind terrain. Right now, this looks most
plausible in and around the tip of the Keweenaw along the northern
lakeshore, downwind of the Porkies, near Marquette, and from
Munising eastward to Grand Marais. Unclear how strong these winds
could get, but model soundings suggest 20-30kts to be possible. As
Thursday progresses, the LLJ further increases to 35-50kts. Given
the increasing stability over the lake in this period, the strongest
winds will likely be observed at higher reporting platforms,
although downslope prone locations near the Superior lakeshore
should expect upwards of 30kts by afternoon.

The low will track northeast through the region. There`s still some
question as to how far north it will end up. General idea though is
for winds to fall Thursday night to near 20kts and remain there
until the system passes Friday night. If the northern solutions end
up materializing though, near 30kt winds will be possible Friday
evening central and east. Otherwise, this low will support some
thunderstorm activity over the lake beginning Thursday afternoon
into the overnight. Another wave looks possible Friday
afternoon/evening. Light northwesterlies look to follow for the rest
of the weekend.

&&

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

&&

$$

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