Hail in Michigan, May 9, 2026

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
158 PM EDT Sat May 9 2026

.KEY MESSAGES...

- Warmer today with a Marginal Risk for severe weather this
afternoon, roughly along and south of the I-69 corridor.

- Below normal temperatures return Sunday and likely persist
  through mid-week.

&&

.AVIATION...

Height falls in advance of sharp, digging shortwave maximum is
leading to synoptic scale ascent over Southeast Michigan this
afternoon. Instability is sufficient for scattered to numerous
thunderstorm activity this afternoon between 18-21z. Decided to go
with TEMPO for TSRA at KFNT southward through the Detroit terminals.
A period of midcloud at/around 050-060 is expected in the wake of
the thunderstorm activity this evening with VFR overnight. Strong
midlevel subsidence amidst a cool and dry air mass will support
quiet VFR conditions Sunday.

D21/DTW Convection...Numerous thunderstorm activity is expected in
the airspace between 19-21z. Included a TEMPO at DTW. Low potential
for severe at any one particular location this afternoon.

.DTW THRESHOLD PROBABILITIES...

*  Moderate for ceiling 5000 ft or less this afternoon, and low
   tonight, Sunday.

* Moderate to high for thunderstorms between 19Z and 21Z today.

&&

.PREV DISCUSSION...
Issued at 1144 AM EDT Sat May 9 2026

UPDATE...

Focus for this afternoon and early evening will be thunderstorm
development ahead of a cold front that will bring the potential for
embedded isolated to scattered severe thunderstorm development. Have
trended PoP values higher for this update noting the very well-
defined mid-level wave on water vapor imagery along with the
potential for late afternoon upper-level support within the left exit
region of the approaching jet streak.

Convective mode favors scattered to numerous rain showers with
embedded thunderstorms developing along the boundary with a quick
evolution to a broken line or line segments. While a brief semi-
discrete mode cannot be ruled out initially, the dominate mode will
trend towards this broken line/QLCS setup. Most favorable locations
for thunderstorms and stronger development will be roughly along a
line and south/southeast from Port Sanilac to Hillsdale from
1PM-6PM. Any storm development will move southeast, so locations
downstream have increasing chances for rain showers/thunderstorms
through the afternoon.

Kinematic fields will be supportive of organized convection with 0-6
km bulk shear values around 40-45 knots, noting the slightly curved
and elongated 0-6km segments within the SR-hodographs. Stretched
6-9km segments will bring good storm-top ventilation and will help
support updrafts. Buoyancy remains limited but sufficient with
modeled SBCAPE/MUCAPE values ranging between 500-1000J/kg, but the
stronger low and mid-level lapse rates aid with the buoyancy
equation. The primary hazard with any strong to severe thunderstorm
development will be damaging wind gusts with any organized line
segments/bowing structures. A conditional tornado threat is also
possible given any localized enhanced low-level stretching. Large
hail (1") will be more conditional. Caveats to the above thinking
will be the upstream shower activity across the west half of the
state which will usher in high-based clouds, but this overall setup
warrants attention through the afternoon.

PREV DISCUSSION...
Issued at 245 AM EDT Sat May 9 2026

DISCUSSION...

Strong shortwave/500 MB height fall center to track through the
northern Great Lakes today. Although the height falls struggle to
get much farther south than Saginaw Bay, the optimal timing of the
cold front/low level convergence during the afternoon hours should
be sufficient for numerous showers and scattered thunderstorms.
Surface dew pts aoa 50 degrees already noted along/near the southern
border. With high temperature reaching around 70 degrees, Sbcape
around 1000 J/kg seems likely. With steep mid level lapse rates (700-
500 MB) of 7 C/km and rather strong wind fields (45 knots at 850
MB), isolated severe storms are possible with both wind and hail.
Just enough 0-1 KM helicity/bulk shear to suggest a tornado is not
totally out of the question before unidirectional low level flow
takes over. Far eastern areas, along a Monroe-Detroit-Port Huron
line stand the best chance for severe storms, with actually good
timing agreement amongst hires solutions (RRFS/ARW/NAM/HRRR) mainly
in the 1-5 PM window.

Deep cyclonic flow then develops for the second half of the weekend
into early next week, with 850 mb temps progged to bottom out in the
-2 to -4 C range Monday morning. Min temps drop into the 30s Sunday
night and Monday night; however, there may be just enough wind to
help prevent widespread frost/freeze conditions.

The next strong shortwave and associated low pressure system looks
to be arriving on Tuesday. Warm front should be active, producing
showers as moisture advection is stellar. PW Values start the day on
Tuesday around 0.2 inches and surge to 1 inch by early evening.
Showalter index stays positive through the day on Tuesday, and just
approaches zero Tuesday night, thus not looking for much in the way
of thunderstorm activity.

MARINE...

Southwest winds quickly ramping up this morning as a cold front
tracks into the Central Great Lakes region. Wind gusts at or above
25 knots are expected near the shorelines this afternoon, along with
scattered strong thunderstorms. Thus, small craft advisories have
been issued for most of the nearshore waters. The cold front will
pass through around 21-00Z early this evening, allowing for winds to
shift to the northwest tonight, but under 25 knots over southern
Lake Huron and points south.

Another weaker cold front may clip northern Lake Huron Sunday,
otherwise a bit quieter as high pressure builds back in with
westerly or northwesterly flow persisting into early next week.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...None.
Lake Huron...Small Craft Advisory until 8 PM EDT this evening for LHZ421-422-
     441>443.

Lake St Clair...Small Craft Advisory until 8 PM EDT this evening for LCZ460.

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

AVIATION.....CB
UPDATE.......AM
DISCUSSION...SF
MARINE.......SF

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

Hazardous Weather Outlook
National Weather Service Detroit/Pontiac MI
424 AM EDT Sat May 9 2026

MIZ047>049-053>055-060>063-068>070-075-076-082-083-100930-
Midland-Bay-Huron-Saginaw-Tuscola-Sanilac-Shiawassee-Genesee-Lapeer-
St. Clair-Livingston-Oakland-Macomb-Washtenaw-Wayne-Lenawee-Monroe-
424 AM EDT Sat May 9 2026

This hazardous weather outlook is for southeast Michigan.

.DAY ONE...Today and Tonight

Isolated to scattered thunderstorms are expected to develop this
afternoon. There is a marginal risk of severe weather along and south
of I-69. Hail up to 1 inch in diameter and wind gusts up to 60 mph
are the primary hazards. Storm motion looks to east at 40 mph.
Thunderstorms should end by 6 PM or so.

.DAYS TWO THROUGH SEVEN...Sunday through Friday

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

Spotter activation will not be needed today and tonight.

LCZ460-LEZ444-LHZ361>363-421-422-441>443-462>464-100930-
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-
424 AM EDT Sat May 9 2026

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

.DAY ONE...Today and Tonight

Isolated to scattered thunderstorms are expected to develop this
afternoon. There is a marginal risk of severe weather over far
southern Lake Huron, Lake St. Clair and Lake Erie. Hail up to 1 inch
in diameter and wind gusts up to 50 knots are the primary hazards.
Storm motion looks to east at 35 knots.

.DAYS TWO THROUGH SEVEN...Sunday through Friday

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.

SF

Special Weather Statement
National Weather Service Detroit/Pontiac MI
111 PM EDT Sat May 9 2026

MIZ060-061-069-091815-
Shiawassee MI-Genesee MI-Oakland MI-
111 PM EDT Sat May 9 2026

...STRONG THUNDERSTORMS WILL IMPACT NORTHWESTERN OAKLAND...
SOUTHEASTERN SHIAWASSEE AND GENESEE COUNTIES THROUGH 215 PM EDT...

At 111 PM EDT, Doppler radar was tracking a cluster of strong
thunderstorms over Swartz Creek to Perry, moving east at 35 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...
Flint, Fenton, Flushing, Grand Blanc, Holly, Davison, Durand, Burton,
Swartz Creek, Linden, Goodrich, Morrice, Byron, Bancroft, Lennon,
Gaines, Lake Fenton, Beecher, Atlas, and Argentine.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

&&

LAT...LON 4304 8400 4312 8346 4279 8345 4278 8422
TIME...MOT...LOC 1711Z 259DEG 30KT 4299 8387

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

KDK

Special Weather Statement
National Weather Service Detroit/Pontiac MI
143 PM EDT Sat May 9 2026

MIZ062-091845-
Lapeer MI-
143 PM EDT Sat May 9 2026

...STRONG THUNDERSTORMS WILL IMPACT LAPEER COUNTY THROUGH 245 PM
EDT...

At 143 PM EDT, Doppler radar was tracking a cluster of strong
thunderstorms from Comlumbiaville to over Davison, moving east at 40
mph.

HAZARD...Winds in excess of 40 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...
Lapeer, Imlay City, Almont, Columbiaville, Hadley, Dryden, Metamora,
Lum, Attica, Elba, Goodland Township, Thornville, and Kings Mill.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

&&

LAT...LON 4288 8345 4311 8346 4319 8333 4320 8300
      4289 8299
TIME...MOT...LOC 1743Z 266DEG 36KT 4301 8350

MAX HAIL SIZE...0.25 IN
MAX WIND GUST...40 MPH

KDK