837
FXUS63 KMQT 150854
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
454 AM EDT Tue Jul 15 2025

.KEY MESSAGES...

- Periods of rain and thunderstorms, some strong to severe, are
expected today through Wednesday along a slow moving frontal
boundary.

- Seasonably warm today, then sharply cooler Wednesday into Thursday.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 453 AM EDT Tue Jul 15 2025

Early morning RAP analysis shows quasi-zonal flow aloft with some
low-amplitude shortwave impulses initiating storms across the Upper
Midwest including over the western arm of Lake Superior and along
the Montreal River basin near Ironwood. Whatever thunderstorms do
enter into the region will struggle against sharply decreasing
MUCAPE over the western UP as well as minimal effective bulk shear
outside of Gogebic County and the interior central UP.

Today through tonight, attention will be turning to a quasi-
stationary front that will eventually drop south through the UP as a
cold front, bringing showers and thunderstorms first to the Keweenaw
and western UP this morning and then the remainder of the UP through
this afternoon into tonight. Warming low levels this morning to
early afternoon and slight increasing of lapse rates in the mid to
upper levels will allow for significant destabilization ahead of the
front with HREF mean SBCAPE values climbing to 2000-2500 J/kg across
much of the interior UP this afternoon. As low to mid level flow
begins to increase, shear will as well with 0-3km SRH values of 100-
200 and hodographs showing good veering by the afternoon hours.
Moisture will be plentiful with a blend of the CAMs showing Tds in
the low 70s (!) in some interior eastern locations. Given the
abundance of ingredients and presence of forcing, the SPC has issued
a Slight Risk for primarily damaging winds and hail (15%), though
with low level shear increasing and hooked hodographs late, an
isolated tornado cannot be ruled out (2%). Most of the 00Z CAMs do
show just enough cross-boundary flow to keep training from
occurring, though if training does occur, hydro could be a sneaky
hazard to worry about as HREF LPMM QPF charts show that in worst
case scenarios, multiple inches of rain could fall by 12Z Wednesday,
though the probability of even 1 inch of total rainfall by 12Z
Wednesday is around 50 percent over the west with probabilities of
2+ inches only 20 percent (and generally spread out through the day
with multiple rounds of precip). The aforementioned warm southerly
flow will help highs today climb to the 80s for most and the NBM
once again shows good potential for typical warm spots in the UP to
reach into the 90s today.

&&

.LONG TERM /WEDNESDAY THROUGH MONDAY/...
Issued at 313 PM EDT Mon Jul 14 2025

The low-level front continues to linger in the area Wednesday into
Thursday, with consensus supporting the surface portion of it
sagging mainly south of the area. This will result in sharply cooler
temperatures by Wednesday, with highs stuck in the 60s (and maybe
even 50s closer to the still below-normal temperatures of Lake
Superior) over most of the northern half. Additional rounds of
showers and perhaps thunderstorms are expected along the front, with
LREF and NBM guidance suggesting a 50-60% chance for an additional
0.5" of rain Wednesday through Thursday morning across the western
half of the UP. Latest 12z Euro Ensemble suggests a 50-70% chance
for total rainfall amounts >2" between Wednesday and Thursday
morning along the spine of the Keweenaw southwest across the Porkies
into far northern Wisconsin. Showers begin to wrap up Thursday
morning/afternoon, kicking off a gradual drying trend for the end of
the week as high pressure builds in the wake of this front, with
temps likely rebounding closer to normal Friday into Saturday.

&&

.AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/...
Issued at 142 AM EDT Tue Jul 15 2025

VFR conditions are expected to persist through early this afternoon,
however a slow moving frontal boundary will support shra/tsra and
eventually deteriorating conditions into tonight. Confidence in
timing for shra/tsra has improved enough to include some tempo
groups and deterministic shra/tsra, but fcst confidence
progressively gets lower with time as spread in model guidance
increases prior to this evening. Kept plenty of PROB30 groups near
the end of the period to capture the later rounds of tsra and
deteriorating conditions into tonight. Some storms this evening
could be strong to severe. Otherwise some -shra tracking E over Lake
Superior are expected near or at CMX early. S to SW winds increase
today to 8-12 kts with gusts expected ~20 kts.

&&

.MARINE...
Issued at 326 PM EDT Mon Jul 14 2025

Visibility will continue to be reduced in areas of fog and wildfire
smoke into tonight. Winds will remain below 20 kts through
Tuesday. However, they will increase to 20-25 kt from the north
to northeast on Wednesday mainly across the western half of the
lake with the remainder of the lake in the 15 to 20 kt range
into Thursday. After that, light and variable winds will prevail
into the weekend. Rounds of showers and thunderstorms will be
possible, though, on Tuesday and Wednesday with the potential
for damaging winds and large hail in any storms that do form.
Plus, there is potential for fog where rainfall occurs.

&&

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

&&

$$

SHORT TERM...GS
LONG TERM...BW
AVIATION...Jablonski
MARINE...TDUD