Damaging Winds in Michigan, June 11 to 12, 2026

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
708 PM EDT Thu Jun 11 2026

.KEY MESSAGES...

- Severe thunderstorms possible tonight, mainly between 9 PM and 1
  AM; damaging winds, large hail, and/or spin-up tornadoes possible.

- Not as warm and much less humid Friday through the weekend with
  additional showers and some thunderstorms possible Saturday night
  into Sunday morning.

&&

.AVIATION...

The upstream thunderstorm complex is the weather highlight for Lower
Mi tonight. The storms are tied to WI surface low pressure and the
southward trailing cold front that is pulled across Lower Mi as the
low moves toward the Straits this evening. Light southerly wind
ahead of the system maintains warm and humid air across the region
to support thunderstorm coverage along the cold front, however
intensity still carries some uncertainty, especially toward FNT and
MBS. Flight conditions range widely as the line of storms moves
through the SE Mi terminal corridor followed closely by the cold
front, all of which exit eastward during the 06Z to 10Z time window
tonight. Post front westerly wind carries in cooler and less humid
air with intervals of broken MVFR ceiling through about mid Friday
morning. Boundary layer growth then promotes cloud improvement into
scattered/shallow cumulus, and also leads to wind gusts in the 20 kt
range during the afternoon.

D21/DTW Convection... Thunderstorm timing from 04Z to 06Z remains on
track while still evaluating coverage and intensity trends. There is
a chance for the strongest storms to graze southward while a more
general storm pattern moves through the DTW area.

.DTW THRESHOLD PROBABILITIES...

* High for ceiling aob 5000 feet tonight and Friday morning.

* Moderate for thunderstorms from 04Z to 06Z.

&&

.PREV DISCUSSION...
Issued at 323 PM EDT Thu Jun 11 2026

DISCUSSION...

An anomalously muggy airmass persists today with heat indices
attempting to lift back into the 90s for parts of Metro Detroit
south. Expired the heat advisory early as temperatures and dewpoints
have risen slower than forecast. Heat indices are now only expected
to peak in 90s through the rest of today. CAPE values are on the
rise amidst low afternoon cloud fraction. This uptick in instability
prepares the atmosphere for nocturnal convection. An evening squall
line is emerging upstream, attendant to a dynamic cold front, which
tracks eastward into the area after dark. 11.18Z KDTX RAOB shows a
lot of dry air still around with CIN persisting around 580 mb and
825 mb preventing free convection.

CAMs offer slight differences in timing of the main convective line,
once it moves into Southeast Michigan. 9 PM appears to be the
earliest arrival time for western Midland or Lenawee Counties,
before the line continues eastward across the rest of the region.
SPC's SWODY1 continues to advertise Slight to Enhanced Risk for the
forecast area, while model trends indicate increasing potential for
a weaker progression as it moves through. The nocturnal timing
doesn't help with a surface-based CAPE reduction, while the
reservoir of higher instability still lies well-off to the west,
over southwest Lower and northern Indiana. That is where the
greatest instability gradient lies with potential for discrete cells
before they eventually merge with the main line. A bow-echo should
emerge with enhanced RIJ dynamics and very strong shear as the line
reaches the local area presenting highest confidence in a severe
wind threat. The greatest adjustment this forecast cycle is focused
along the northern extent of the anticipated linear convection.
Confidence is falling in sufficient instability for widespread
severe hazards north of I-69, therefore the area of greatest concern
lies between the Ohio border and M-59, especially for areas west of
US-23. 30 knots of EBS and 100 m2/s2 of 0-1 km SRH favors rotating
updrafts, and some hodographs indicate higher potential for QLCS
tornadogenesis. Lower confidence in severe-level winds with
increasing eastward extent across the CWA.

Governing/digging mid-level shortwave clears overhead by 09Z Friday,
ushering the cold front out. Gradient/column flow veers zonally as
500 mb heights rebound with increasing stabilization. Surface high
pressure builds southeastward, out of The Plains, and into the lower
Ohio Valley. Forecast soundings indicate aggressive column drying
during the morning hours with PWATs dropping from 1.75 inches to
0.50 inches between 00Z and 12Z Friday. No precipitation concerns
the rest of the day with limited diurnal cumulus response. Lower
column dynamics still support renewed breeziness with a dry 5 kft
boundary layer, mixing down 20-25 knot flow.

The weekend forecast features a mix of warm and dry weather Saturday
followed by another cold front with precipitation Saturday night
into Sunday morning. 850 mb temperatures climb into the teens
(Celsius) Saturday, with highs in the mid-upper 80s and ample
sunshine. Another wave then moves in late Saturday into Sunday with
potential for some showers and thunderstorms. Much cooler air fills
in behind the front marking a more tranquil period of weather from
Sunday into early next week. Thermal troughing keeps highs below
normal, in the low-mid 70s through at least Wednesday. The next
chance for rainfall comes sometime Tuesday.

MARINE...

The next line of storms is expected to pass through the southern
Great Lakes later this evening into tonight around 11pm to 3am just
ahead of a cold front. The front will be tied to a low pressure
system lifting from southern WI into eastern Ontario. Winds will
increase from the southwest, turning more westerly, behind the front
offering a period of gusts to near 30 knots for Saginaw Bay and the
tip of the Thumb tonight into Friday morning so a Small Craft
Advisory is in effect. In the vicinity of the storms tonight, wind
gusts in excess of 50 kt and large hail would be the main threats
with these storms. This front will pass through early Friday
morning, but a second cold front will set up just west of the Great
Lakes to start the weekend which will keep elevated southwesterly
winds across the lakes through much of Saturday before the front
then sweeps east by Sunday morning. Winds will stay elevated around
20 knots, but out of the northwest Sunday.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...

MI...None.

Lake Huron...Small Craft Advisory until 10 AM EDT Friday for LHZ421-422-441.

Lake St Clair...None.

Michigan waters of Lake Erie...None.

&&

AVIATION.....BT
DISCUSSION...KGK
MARINE.......DRK

You can obtain your latest National Weather Service forecasts online
at www.weather.gov/detroit.

Hazardous Weather Outlook
National Weather Service Detroit/Pontiac MI
319 PM EDT Thu Jun 11 2026

MIZ047>049-053>055-060>063-068>070-075-076-082-083-120830-
Midland-Bay-Huron-Saginaw-Tuscola-Sanilac-Shiawassee-Genesee-Lapeer-
St. Clair-Livingston-Oakland-Macomb-Washtenaw-Wayne-Lenawee-Monroe-
319 PM EDT Thu Jun 11 2026

This hazardous weather outlook is for southeast Michigan.

.DAY ONE...This Afternoon and Tonight

There is potential for an organized line of thunderstorms to track
across SE Michigan between 9 PM and 1 AM tonight. Damaging winds in
excess of 70 mph, spin-up tornadoes, and large hail will all be
possible if the line holds together. Storm motion will be west to
east at 45 mph.

.DAYS TWO THROUGH SEVEN...Friday through Wednesday

A cold front tracks across Lower Michigan Saturday night bringing
potential for thunderstorms, with isolated severe weather possible.

.SPOTTER INFORMATION STATEMENT...

Spotter activation may be needed tonight.

LCZ460-LEZ444-LHZ361>363-421-422-441>443-462>464-120830-
Lake St Clair-
Michigan Waters of Lake Erie from Detroit River to North Cape MI-
Lake Huron from 5NM east of Mackinac Bridge to Presque Isle Lt
beyond 5 NM off shore-
Lake Huron from Presque Isle Light to Sturgeon Point MI beyond 5NM
off shore-
Lake Huron from Sturgeon Point to Alabaster MI beyond 5NM off shore-
Outer Saginaw Bay SW of Alabaster to Port Austin MI to Inner Saginaw
Bay-Inner Saginaw Bay SW of Point Au Gres to Bay Port MI-
Port Austin to Harbor Beach MI-Harbor Beach to Port Sanilac MI-
Port Sanilac to Port Huron MI-
Lake Huron from Port Austin to Harbor Beach beyond 5NM Off Shore-
Lake Huron from Harbor Beach to Port Sanilac beyond 5NM Off Shore-
Lake Huron from Port Sanilac to Port Huron beyond 5NM Off Shore-
319 PM EDT Thu Jun 11 2026

This hazardous weather outlook is for portions of Lake Erie, Lake
Huron and Lake St Clair.

.DAY ONE...This Afternoon and Tonight

There is potential for an organized line of thunderstorms to track
across SE Michigan between 9 PM and 1 AM tonight. Damaging winds in
excess of 70 mph, spin-up tornadoes, and large hail will all be
possible if the line holds together. Storm motion will be west to
east at 45 mph.

.DAYS TWO THROUGH SEVEN...Friday through Wednesday

A cold front tracks across Lower Michigan Saturday night bringing
potential for thunderstorms, with isolated severe weather possible.

.SPOTTER INFORMATION STATEMENT...

Spotter activation may be needed tonight.

You can obtain your latest National Weather Service forecasts online
at www.weather.gov/detroit.

KGK