Hail and Damaging Winds in Michigan, May 4, 2026

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
708 PM EDT Mon May 4 2026

.KEY MESSAGES...

- A chance of thunderstorms this evening into tonight. Much of the
forecast area is in a Marginal or Slight risk designation for Severe
weather with large hail, strong wind gusts, and a brief weak tornado
potential threats.

- Low confidence exists in the timing and duration of rain Tuesday
and Wednesday.

- Much cooler temperatures return Tuesday and last through the end
of the week. A Frost Advisory or Freeze Warning may be needed.

&&

.AVIATION...

Cluster of showers and thunderstorms evident on radar moving east-
northeast will move through the Detroit airspace this evening. To
the north, little evidence to suggest convective development, with
conditions marked by a well mixed environment supporting gusty
southwest wind and a more limited coverage of high based diurnal cu
thru late evening. An inbound cold front then sags southeast across
the region during the early morning hours. This will maintain
potential for shower production, with some embedded thunderstorms
possible. Window for some degree of lower cloud development will
exist along and immediately behind the cold late tonight, affording
brief cigs at low VFR to borderline MVFR. Wind shift to
northwesterly with the frontal passage. Additional pockets of light
showers expected Tuesday along the lingering elevated frontal zone.

D21/DTW Convection...Thunderstorms to lift across DTW through 01-
02z. Upstream radar and observational trends indicate potential for
gusts to push 40 knots with brief heavy rainfall and hail with these
thunderstorms. Some interludes of IFR to LIFR visibility
restrictions possible as heavy activity moves through. Additional
showers are expected overnight into Tuesday morning as a cold front
tracks through, some of which could include embedded thunder. Winds
will shift to the northwest mid-to-late Tuesday morning.

.DTW THRESHOLD PROBABILITIES...

* High for thunderstorms this evening. Low tonight.

* Low for ceiling at or below 5000 feet this evening and tonight;
  medium Tuesday.

&&

.PREV DISCUSSION...
Issued at 328 PM EDT Mon May 4 2026

DISCUSSION...

Well mixed southwesterly flow has developed over all of Southeast
Michigan this afternoon with 2pm wind gusts at a few of the ASOS
sites reaching and exceeding 45 mph. Surface moisture has mixed out
over much of the northern cwa with many observing platforms
reporting relative humidity between 19-25 percent. With dry
southwest flow persisting this afternoon and with collaboration
considerations, decided to go with a Red Flag Warning in effect
until 7pm this evening.

Atypical, in-phase squeezing event of northern stream Canadian
trough and Southwestern United States ridge will result in a
strengthening baroclinic zone over portions of Lower Michigan and
northern Ohio River Valley by Tuesday. Two boundaries reflect this
competing geopotential height pattern: the first is the deep cold
front progressing through the Lake Superior basin, the second is a
thetae/CAPE gradient that will emerge and lift into far southern
portions of Southeast Michigan between 21-03z this evening.

Very subtle forcing mechanism at work across the forecast area this
afternoon with a lack of upper level jet dynamics and synoptic lift
locally. Differential loss of the anticyclonic flow trajectories over
Southeast Michigan is expected to allow for a region of height
falls, inducing northward moisture transport of 900mb thetae
content. Remnant midlevel dry adiabatic lapse rates with help from
the Evening Transition will result in the development of mixed layer
CAPE exceeding 1000 J/kg with the CAPE gradient lifting northward
through Metro Detroit. CAM output is quite bullish on convective
initiation/development along the boundary 22-01z. 0-6mb bulk shear
of 30 to 35 knots will be adequate for storm organization, although
hiresolution data shows little signal for storm right movement. CAPE
gradient boundary does become parallel to the 850-300mb mean flow
suggesting a potential for training of activity. Therefore, large
hail and localized heavy rainfall are the main threats this evening.
Forecast soundings do suggest higher static stability developing
with the loss of daytime heating from the surface to 4.0 kft agl
suggesting strong wind gusts may be more difficult to observe outside
of any organized cold pool or forward propagation. The threat of a
tornado appears to be very low although a boundary is overhead with
0-1km SRH that reaches 150 m2/s2.

The Canadian trough will encroach on the area tonight driving the
deep cold front through the area. Differences exist on how generous
the coverage of showers and embedded thunderstorms will be overnight
highlighted by the latest forecast with PoPs at generally less than
60%. Models show a dead zone of both the 700 and 850mb frontogenesis
over Southeast Michigan but with deep southwest flow the potential
exists for upstream activity to track through the area. MUCAPE of
250-500 J/kg in place ahead of the cold may support some small hail
between 02-05z. The latest SWODY1 has areas south and west of a line
from Chesaning to Grosse Pointe designated as a Marginal Risk for
Severe weather and a Slight risk across southern Lenawee and Monroe
counties.

Uncertainty exists with regards to precipitation timing and coverage
Tuesday midday through late Wednesday morning. Low confidence arises
from stark differences in the occurrence and subsequent timing of a
wave of low pressure set to track northeastward along the baroclinic
zone. Latest data of system relative flow on isentropic surfaces
supports the surface cold front clearing the area 15-18z with
lingering lower column RH overhead. CAM simulated Z supports
decaying nocturnal showers pushing through Metro Detroit southward
between 15-21z Tuesday which is supported by likely PoPs. The
solution space then diverges greatly Wednesday with the NAM the most
bullish on an organized low pressure circulation tracking along the
Ohio River. This would bring a fairly lengthy period of midlevel
isentropic ascent to the southern cwa Wednesday. The current
forecast is very lean on PoPs for the Wednesday period.

Low geopotential heights are forecasted to persist over the central
Great Lakes through the end of the week and upcoming weekend.
Lowered midlevel temperatures will likely support typical afternoon
instability shower chances. The biggest item will likely be the need
for Frost and/or Freeze headlines particularly Thursday morning.
Some moderation in temperatures to near normal is possible by this
weekend but the forecast will likely be determined by the amount of
clouds over the region.

MARINE...

Breezy southwest winds prevail across the area this afternoon,
though the warmer air mass overriding the cooler Great Lakes waters
has allowed for a more stable environment with wind gusts mostly
remaining below 25 knots. Fetch across the Saginaw Bay remains
favorable for locally stronger winds, so have maintained the ongoing
Small Craft Advisory through the evening hours. Isolated to
scattered showers and embedded thunderstorms will be possible later
this afternoon and evening, most favorable across Lake Erie and Lake
St. Clair. Any stronger storm development will be capable of
producing small hail and wind gusts of 34 knots or stronger.

A cold front dropping south across the western half of Lake Superior
this afternoon will gradually work south across the region late
tonight and into Tuesday morning. Winds from the north briefly
dominant behind the cold front, but then lessen in speed and become
more variable during the day Tuesday. Tuesday night through
Thursday, winds will back from the northeast to north and eventually
from the west, as another area of low pressure organizes south of
the region and moves over the Northeast.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...None.
Lake Huron...Small Craft Advisory until 10 PM EDT this evening for LHZ421-422.

Lake St Clair...None.
Michigan waters of Lake Erie...None.
&&

AVIATION.....MR
DISCUSSION...CB
MARINE.......JA

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

Hazardous Weather Outlook
National Weather Service Detroit/Pontiac MI
353 PM EDT Mon May 4 2026

MIZ047>049-053>055-060>062-052000-
Midland-Bay-Huron-Saginaw-Tuscola-Sanilac-Shiawassee-Genesee-Lapeer-
353 PM EDT Mon May 4 2026

This hazardous weather outlook is for southeast Michigan.

.DAY ONE...This Afternoon and Tonight

A Red Flag Warning is in effect until 7pm.

A Marginal and Slight risk of severe thunderstorms exists this
evening south of I 69. Damgaing wind gusts, large hail, and an
isolated weak tornado are possible threats. Thunderstorm motion will
be northeast at 40 MPH. A cold front will result in the chance for
thunderstorms.

.DAYS TWO THROUGH SEVEN...Tuesday through Sunday

A Frost Advisory or Freeze Warning may be needed for portions of
Southeast Michigan Thursday morning.

.SPOTTER INFORMATION STATEMENT...

Spotter activation will not be needed today and tonight.

MIZ063-068>070-075-076-082-083-052000-
St. Clair-Livingston-Oakland-Macomb-Washtenaw-Wayne-Lenawee-Monroe-
353 PM EDT Mon May 4 2026

This hazardous weather outlook is for southeast Michigan.

.DAY ONE...This Afternoon and Tonight

A Marginal and Slight risk of severe thunderstorms exists this
evening south of I 69. Damgaing wind gusts, large hail, and an
isolated weak tornado are possible threats. Thunderstorm motion will
be northeast at 40 MPH. A cold front will result in the chance for
thunderstorms.

.DAYS TWO THROUGH SEVEN...Tuesday through Sunday

A Frost Advisory or Freeze Warning may be needed for portions of
Southeast Michigan Thursday morning.

.SPOTTER INFORMATION STATEMENT...

Spotter activation will not be needed today and tonight.

LCZ460-LEZ444-LHZ361>363-421-422-441>443-462>464-052000-
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-
353 PM EDT Mon May 4 2026

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

.DAY ONE...This Afternoon and Tonight

A Marginal and Slight risk of severe thunderstorms exists this
evening south of I 69. Damgaing wind gusts, large hail, and an
isolated weak tornado are possible threats. Thunderstorm motion will
be northeast at 40 MPH. A cold front will result in the chance for
thunderstorms.

Small craft advisories remain in effect for Saginaw Bay today. Please
refer to the latest nearshore marine forecast for details.

.DAYS TWO THROUGH SEVEN...Tuesday through Sunday

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

Spotter activation will not be needed today and tonight.

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

CB

Special Weather Statement
National Weather Service Detroit/Pontiac MI
646 PM EDT Mon May 4 2026

MIZ083-042315-
Monroe MI-
646 PM EDT Mon May 4 2026

...A STRONG THUNDERSTORM WILL IMPACT NORTHWESTERN MONROE COUNTY
THROUGH 715 PM EDT...

At 646 PM EDT, Doppler radar was tracking a strong thunderstorm over
Britton, or near Tecumseh, moving northeast at 40 mph.

HAZARD...Winds in excess of 40 mph and half inch hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor damage to outdoor objects is
         possible.

Locations impacted include...
Milan, Dundee, Carleton, Maybee, Azalia, Cone, Scofield, and
Oakville.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

&&

LAT...LON 4190 8377 4208 8377 4209 8346 4209 8344
      4204 8336
TIME...MOT...LOC 2246Z 241DEG 34KT 4198 8384

MAX HAIL SIZE...0.50 IN
MAX WIND GUST...40 MPH

SF

Preliminary Local Storm Report
National Weather Service Detroit/Pontiac MI
700 PM EDT Mon May 04 2026

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0650 PM     Hail             2 E Pittsfield Township 42.21N  83.68W
05/04/2026  M0.50 inch       Washtenaw          MI   Emergency Mngr

            Report of half-inch to dime sized hail. Also estimated
            report of gusts to 45 mph.

&&

Event Number DTX2600436

AM

Special Weather Statement
National Weather Service Detroit/Pontiac MI
702 PM EDT Mon May 4 2026

MIZ075-076-083-042345-
Monroe MI-Washtenaw MI-Wayne MI-
702 PM EDT Mon May 4 2026

...A STRONG THUNDERSTORM WILL IMPACT NORTHERN MONROE...SOUTHWESTERN
WAYNE AND SOUTHEASTERN WASHTENAW COUNTIES THROUGH 745 PM EDT...

At 701 PM EDT, Doppler radar was tracking a strong thunderstorm near
Milan, moving east at 45 mph.

HAZARD...Wind gusts up to 50 mph and half inch hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor damage to outdoor objects is
         possible.

Locations impacted include...
Taylor, Romulus, Ypsilanti, Flat Rock, Saline, Milan, Dundee,
Carleton, Canton, Dearborn, Wyandotte, Trenton, Grosse Ile,
Belleville, Maybee, Willis, Westland, Dearborn Heights, Lincoln Park,
and Southgate.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

&&

LAT...LON 4192 8377 4218 8377 4233 8327 4212 8312
      4208 8313
TIME...MOT...LOC 2301Z 252DEG 39KT 4204 8361

MAX HAIL SIZE...0.50 IN
MAX WIND GUST...50 MPH

SF

Preliminary Local Storm Report
National Weather Service Detroit/Pontiac MI
704 PM EDT Mon May 04 2026

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0653 PM     Tstm Wnd Gst     Ann Arbor Municipal Air 42.22N  83.74W
05/04/2026  M48 mph          Washtenaw          MI   ASOS

            Measued at KARB Ann Arbor Municipal Airport.
            Additionally, recevied spotter report in city of Ann
            Arbor of healthy 10 inch tree limb down.

&&

Event Number DTX2600437

AM

Special Weather Statement
National Weather Service Detroit/Pontiac MI
712 PM EDT Mon May 4 2026

MIZ069-075-076-042345-
Oakland MI-Washtenaw MI-Wayne MI-
712 PM EDT Mon May 4 2026

...STRONG THUNDERSTORMS WILL IMPACT NORTHWESTERN WAYNE...SOUTHERN
OAKLAND AND NORTHEASTERN WASHTENAW COUNTIES THROUGH 745 PM EDT...

At 711 PM EDT, Doppler radar was tracking strong thunderstorms along
a line extending from Whitmore Lake to near Salem to near Canton.
Movement was northeast at 40 mph.

HAZARD...Wind gusts up to 50 mph and half inch hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor damage to outdoor objects is
         possible.

Locations impacted include...
Livonia, Troy, Southfield, Pontiac, Novi, Romulus, Canton, Royal Oak,
Birmingham, South Lyon, Northville, Salem, Detroit Zoo, Whitmore
Lake, West Bloomfield, Westland, Farmington Hills, Rochester Hills,
Dearborn Heights, and Madison Heights.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

&&

LAT...LON 4222 8348 4234 8367 4243 8379 4243 8367
      4252 8367 4268 8344 4265 8318 4247 8308
      4246 8308
TIME...MOT...LOC 2311Z 229DEG 33KT 4244 8373 4238 8361 4228 8345

MAX HAIL SIZE...0.50 IN
MAX WIND GUST...50 MPH

SF

Special Weather Statement
National Weather Service Detroit/Pontiac MI
737 PM EDT Mon May 4 2026

MIZ069-070-076-050015-
Macomb MI-Oakland MI-Wayne MI-
737 PM EDT Mon May 4 2026

...A STRONG THUNDERSTORM WILL IMPACT NORTHEASTERN WAYNE...
SOUTHEASTERN OAKLAND AND SOUTHERN MACOMB COUNTIES THROUGH 815 PM
EDT...

At 736 PM EDT, Doppler radar was tracking a strong thunderstorm near
Detroit, or near Southfield, moving east at 45 mph.

HAZARD...Wind gusts up to 50 mph and pea size hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor damage to outdoor objects is
         possible.

Locations impacted include...
Warren, Troy, Southfield, St. Clair Shores, Mount Clemens, Grosse
Pointe, Downtown Detroit, Detroit, Sterling Heights, Dearborn, Royal
Oak, Birmingham, Clinton Township, Detroit Zoo, Belle Isle,
Greenfield Village, Dearborn Heights, Roseville, Eastpointe, and
Madison Heights.

People attending Comerica Park  should seek safe shelter immediately!

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

&&

LAT...LON 4264 8274 4263 8277 4261 8274 4254 8275
      4254 8276 4253 8282 4244 8283 4237 8288
      4234 8297 4232 8306 4228 8310 4229 8328
      4255 8323 4267 8274
TIME...MOT...LOC 2336Z 252DEG 38KT 4242 8316

MAX HAIL SIZE...0.25 IN
MAX WIND GUST...50 MPH

SF