045
FXUS63 KAPX 210002
AFDAPX

Area Forecast Discussion
National Weather Service Gaylord MI
802 PM EDT Mon Jul 20 2026

.KEY MESSAGES...

-Showers and thunderstorms expected this evening into tonight.
 Potential for severe storms and heavy rain.

-Seasonably cool temperatures and breezy conditions continue
 though Wednesday. Showers linger Tuesday and into Wednesday.

-Overall quiet weather returns the rest of the week with little to
 no additional precipitation chances.

&&

.DISCUSSION...
Issued at 407 PM EDT Mon Jul 20 2026

Pattern / Forecast Synopsis:

Northwest flow aloft remains in full swing as a robust shortwave
passes through the Great Lakes region, with attendant occluding
surface cyclone over northern Ontario. Associated occluded frontal
boundary currently stretches from roughly the NW Lake Superior
shore, passing NW of the Twin Cities (at the triple point) and a
cold front runs toward Sioux Falls, SD... warm frontal boundary
associated with the system running south from aforementioned triple
point SSE through Saint Louis. Return flow will draw this front
northward, but it is anticipated to stall out over western upper MI,
south through WI and IL. Thus, most vigorous convection this evening
to be suppressed SW of the CWA. That being said, good mid level
support and diffluent 500mb and 300mb flow will still support deep
convection over our neck of the woods, albeit, with a weakening
trend, through later tonight. Following the passage of the occluded
frontal boundary late tonight, lingering low level moisture should
support additional diurnal convection through the day Tuesday and
perhaps into Wednesday. Subtle ridging and subsidence should return
by Thursday, aligned with surface high pressure passage, resulting
in a drier day. Additional embedded 500mb height disturbances pass
through over the weekend, perhaps supporting a returning rain /
storm threat.

Details:

Severe Potential through Tonight: Current 1pm glance at radar and
satellite shows the remains of some robust convection the initiated
over western upper this morning making a run at eastern upper MI and
the NW lower lakeshore. Anticipating this to continue weakening as
it passes through the region, owing to a complete and utter lack of
instability across the region... which may be an issue we fight
through this event until better thermodynamics are forced into the
region with the system`s approach. As such, potential for a
scattered shower or rumble of thunder anticipated to be confined to
the aforementioned regions through the afternoon. Efficient
mixing has led to surface dewpoints across our area to dip into
the upper 50s and lower 60s... with the much more robust
moisture holding over the western Corn Belt. This drier air will
likely make high instability difficult to attain, but won`t
completely zero us out. As such, with the approach of the
frontal boundary later this evening, anticipate upstream
convection, while weakening, to maintain itself into at least
the western half of the CWA, partially aided by a plume of
developing elevated instability courtesy of an accelerating low
level jet upwards of 50kt. Anticipated convective evolution
entails a transition from discrete supercells over western /
central upper MI to a linear mode by the time it reaches our
doorstep this evening.

With the elevated nature of the storms, will see the threat of
tornadoes diminish considerably, though SPC maintains a 2% risk over
the region. The primary hazard will be damaging winds, which,
despite the elevated instability profile, can still mix down with
any gravity wave interactions to force those LLJ winds to the
surface. As such, SPC has maintained the 15% risk for winds across
the region. Severe hail, while possible (5% risk), is not
anticipated to be overly widespread owing to the discrete mode not
being able to be maintained. Current prognosis favors a window of
roughly 7pm to 4am for the highest risk of severe weather across the
region... and the general weakening trend is highlighted well with
the SPC outlook... maintaining an Enhanced Risk (Level 3/5) over WI
and western / central upper MI... a Slight Risk (2/5) eastward
through most of our CWA, and a Marginal Risk (1/5) from the Lake
Huron shores of Saginaw Bay north to the Alpena area.

Hydro Concerns Tonight: Not to be lost in all the noise of the
severe potential, torrential rainfall will be possible with these
storms as they make it through the region. PWATS progged to go north
of 1.25 this evening / tonight. Some CAMs do support localized
training convection, which could easily put some embedded 2.00"+
rainfall amounts down over any area that realizes this. Overall
current SPC HREF guidance shows two concentrated highest probability
areas of convection across the Great Lakes: one just to our SW
across WI and leaking into IL and IA... and another that
originates from western / central upper MI and carrying through
the Straits region and eastern upper (should be noted
probabilities for thunder exist CWA-wide, these are just the
highest probability regions across the Great Lakes / Midwest).
Considering recent rainfall trends (including all the way back
to April), the Tip of the Mitt region southeast to APN, along
with portions of eastern upper, and the Leelanau / Antrim /
Otsego corridor remain highly sensitive to torrential rainfall
rates. Toyed with the idea of a targeted Flood Watch for some of
these areas, but thinking is that convection should remain
transient enough to limit widespread issues. This too will need
to be assessed with time through the evening.

Tuesday - Wednesday: Tight pressure gradient with this system will
keep quite breezy conditions overhead as winds turn more NW
(sustained 10-20mph, gusts 25-35mph) and cooler air begins to spill
into the region. Lingering low level moisture supports additional
diurnal shower and thunder development Tuesday , and with continued
skinny CAPE profiles, may be heavy at times. Greatest instability
favors NE lower, so while severe storms are not anticipated, that
would be the area that serves most likely to see severe convection.
Lesser shower coverage into the day Wednesday, but another trough
passage will permit continued convection through the afternoon amid
continued, but lesser breezy conditions (NW winds 10-15mph, gusts up
to 25-30mph). Bigger story will be the seasonably cool weather...
highs struggle to break 70 north and approach 80 south on Tuesday,
and even cooler Wednesday with highs in the 60s to maybe mid 70s in
the south.

Rest of the Period: High pressure returns drier weather Thursday.
Return flow slowly materializes through the weekend, bringing back
seasonable temperatures in the upper 70s to lower 80s. With subtle
increases in humidity and the potential for additional 500mb height
disturbances, there will be potential for more rain / thunder Friday
through the weekend, but details are a bit murky this far out.

&&

.AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/...
Issued at 801 PM EDT Mon Jul 20 2026

Storms currently across the central U.P. and far northern Lake
Michigan will continue to track southeast this evening and tonight
and are expected to work into most TAF sites at this time --
potentially with the exception of MBL depending on the evolution of
storms over the next hours. Regardless, most likely timing of storms
for most of the area will be between 9PM and 2AM. Recently issued
Severe Thunderstorm Watch is valid until 2AM for most of northern
Michigan away from Saginaw Bay/Thunder Bay. Primary risks will be
damaging winds and large hail. After storms and the front passes,
gusty west-northwest winds will set in for Tuesday. Sustained winds
to 10-15 kts with gusts to 25-35 kts are expected into Tuesday
evening.


&&

.APX WATCHES/WARNINGS/ADVISORIES...
MI...Beach Hazards Statement until 8 AM EDT Tuesday for MIZ016-024-
     025-031-095-096-098.
MARINE...Small Craft Advisory until 11 PM EDT Wednesday for LHZ345>349.
     Small Craft Advisory until 11 PM EDT Wednesday for LMZ323-341-
     342-344>346.
     Small Craft Advisory until 11 PM EDT Wednesday for LSZ321-322.

&&

$$

DISCUSSION...HAD
AVIATION...DJC