305
FXUS63 KMQT 240900
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
500 AM EDT Tue Jun 24 2025

.KEY MESSAGES...

- Isolated light showers this morning in the south and near Lake
  Michigan.

- Widespread rain is anticipated Wednesday night into Thursday
  night.

&&

.SHORT TERM /THROUGH WEDNESDAY/...
Issued at 459 AM EDT Tue Jun 24 2025

Early morning RAP analysis highlights W-SW flow over the Upper Great
Lakes set up by a mid level ridge over the SE CONUS and a trough
over central Canada. As a result of this, a warmer than normal
airmass with plenty of moisture still resides over the region. Temps
currently reside in the upper 50s to upper 60s with a few spots
still holding on to near 70! PWATs range from 0.7 to 1.4" and Tds
are in the 50/60s, highest values of both to the SE. This does yield
MUCAPE up to 250-500j/kg over the S, so a few rumbles of thunder are
possible, but the lack of forcing will keep convective activity
limited in the wake of yesterday`s cold front. Radar shows some
isolated -shra are drifting over the S as of 9Z, and these will
continue to lift NE along the Lake MI area this morning as temps
settle a bit further. As flow becomes more zonal and high pressure
currently over the N Plains builds over the Upper Great Lakes for
the remainder of the day, a drier and cooler airmass returns to the
region behind a second cold front currently over the far W spine of
the UP. No precip is expected with this fropa. 6/24 0Z HREF and the
1Z NBM only have ~15-40% chance for more than 0.1" of QPF, so little
to no impacts are expected with any -shra. Otherwise temps warm into
the upper 60s to upper 70s this afternoon, except where a lake
breeze off Lake Superior moderates temps in the mid 50s to mid 60s
near the shores. Cloud cover gradually shifts SE for tonight, and
with calm winds, brings temps down into the mid 40s to mid 50s.

Dry wx persists most of Wed with high pressure overhead, but cloud
cover increases through the day as a shortwave approaches from the
SW. This setup better supports lake breezes off both Great Lakes, so
high are expected in the mid 60s to upper 70s, highest in the
interior. Although chance for shra increase late in the day, the
primary focus for widespread measurable precip holds off until Wed
night.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
Issued at 459 AM EDT Tue Jun 24 2025

Wednesday into Thursday, a 500mb cutoff low moving into Florida,
helping erode the blocking ridge over the eastern CONUS. With the
split flow over the Rockies also moving east and deamplifying, flow
goes quasi-zonal, allowing for the former Rockies troughing feature
to shift through the Great Lakes, bringing with it disturbed weather
for the latter half of the work week. Deterministic and ensemble
guidance diverge this coming weekend onward, with some showing weak
ridging recovering Saturday and others staying more zonal. However,
there are some early indications of a prominent trough moving into
the region sometime in the late Sunday to early Tuesday timeframe
which could bring yet another round of disturbed weather. In the
wake of today`s cold front, the temperatures for the midweek period
are forecast to be close to normal (perhaps a few degrees cooler)
with a warming trend late in the week into the weekend.

Chances of rain increase into Wednesday night as a subtle impulse
riding the upper ridge forces precipitation over the area. The Gulf
connection persists with flow aloft arcing from the Texas/Louisiana
coastline to the Great Lakes, so moisture will be plentiful, though
somewhat nebulous forcing and cooler surface temperatures limiting
instability will keep most thunderstorm chances at bay. Guidance
continues to favor a widespread one to two tenths of an inch, with a
"worst case scenario" 90th percentile between one half to one inch
of rain. Highest amounts are expected near Wisconsin, particularly
in the south central UP.

Thursday is when the more pronounced troughing that used to be over
the Rockies arrives in the Great Lakes. Instability is still fairly
limited, but with more robust forcing, expect a few thunderstorms
(30 percent chance, highest in the south). Stronger forcing with
PWATs pushing 1.5 inches will result in higher QPF, with the LREF
showing chances of 2 inches of rain at about 10 percent by the end
of the day Thursday. Everyone is likely to get at least a soaking,
as chances of a half inch of rain is 40-60 percent (highest south,
lowest Keweenaw). The WPC is watching the UP for flash flooding
potential, giving a Slight Risk of Excessive Rainfall (category 2 of
4, or around 15 percent).

Heading into the weekend, some slight chance PoPs (15-25%) linger in
the forecast due to the increasing spread in solutions, but
generally drier conditions are expected as ridging in the wake of
the trough moves over the UP. Attention then turns upstream to the
next trough dropping down from Canada sometime in the Sunday-Tuesday
range, which could bring with it showers and thunderstorms. In the
meantime, a warmup is expected for the weekend, with the NBM
deterministic forecasting highs in the 80s Saturday and Sunday.

&&

.AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/...
Issued at 129 AM EDT Tue Jun 24 2025

VFR conditions prevail at all TAF sites following a drier post cold
fropa airmass. Lighter winds <10 knots will remain in place through
the morning before daytime mixing elevates ~15 kt knots from the NW
to N. Expect afternoon lake breeze development and associated N-
NE wind shifts at SAW ~18-21Z.

&&

.MARINE...
Issued at 459 AM EDT Tue Jun 24 2025

In the wake of a second cold front this morning, high pressure
increasing overhead will keep winds mainly below 20 kts through at
least midweek. On Thu, NE winds briefly increase to ~20 kts across
the W arm of the lake. Winds fall back below 20 kts for Fri as they
back W. Another round of showers and storms will also be possible
Thu into Fri.

&&

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

&&

$$

SHORT TERM...Jablonski
LONG TERM...Jablonski/LC
AVIATION...BW
MARINE...Jablonski/LC