Severe Thunderstorm Warning 9, NWS Detroit, MI

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
756 PM EDT Mon Apr 13 2026

.KEY MESSAGES...

- Stretch of warm conditions throughout the work week with daytime
temperatures in the 70s each day for most locations.

- Scattered to numerous showers and thunderstorms develop tonight.
Potential exists for isolated severe storms capable of producing
wind gusts to 60 mph and large hail. Locally heavy rainfall also
possible.

- An active pattern will maintain periodic chances for showers and
thunderstorms Tuesday through Thursday. Each episode brings the
possibility for locally heavy rainfall.

- There is a Slight Risk for severe thunderstorms Tuesday night,
mainly between 8 pm and 2 am. Storms will be capable of producing
wind gusts to 60 mph, large hail and isolated tornadoes.

&&

.AVIATION...

Low level thetae advection along a diffuse warm front combined with
right entrance region jet dynamics has resulted in lift/thunderstorm
activity across far southern portions of Lower Michigan this
evening. Movement of convective activity with general mean flow
should allow activity to move out by/around 03z. Wind gusts to 35
knots will be possible with convective activity and included in the
TEMPO. Deeper thetae advection associated with shortwave impacting
Wisconsin will expand eastward with time this evening. Latest
thought is that thunderstorm activity will break out/redevelop at
KMBS and KFNT after 05z this evening, then a line of weakening
shower and thunderstorms catching up/pushing across all of Southeast
Michigan including the Detroit sites between 10-14z. Low confidence
exists on exact timing late tonight/Tuesday morning. Much of Tuesday
is quiet with shower/thunderstorm activity likely holding off until
after 03z Wednesday.

DTW/D21 Convection...Showers and thundestorms with wind gusts to 35
knots likely at the start of the period between 00-02z. Thunderstorm
activity will then be possible between 10-14z Tuesday.

.DTW THRESHOLD PROBABILITIES...

*  High for ceilings aob 5000 feet tonight and Tuesday.

*  Moderate for thunderstorms this evening and  early Tuesday
   morning.

&&

.PREV DISCUSSION...
Issued at 252 PM EDT Mon Apr 13 2026

DISCUSSION...

Higher magnitude warmth within breezy southwest wind marking
conditions late afternoon. High temperatures again arriving a solid
15 to 20 degrees above normal - mid to upper 70s most locations.
General mid level stability will hold into the early evening hours
as shortwave upper ridging propagates through, ensuring dry
conditions persist into the early evening hours. Attention then
turns to two seperate areas of focus for convective development and
expansion tonight. Remnant convective cluster evident on water vapor
and radar lifting northeast into northern IL now forecast by an
increasing number of hi res solutions to maintain some degree of
integrity as it ejects across southern lake MI/northern IN. This will
occur with the backdrop of another period of nocturnal warm/moist
air advection as 850 mb flow strengthens within southwest flow across
the warm sector. Forecast now highlights an increasing potential for
convective development/expansion within the 00z-06z window as
associated ascent works through. Any late evening activity likely to
be slightly elevated as nocturnal boundary layer cooling affords a
standard stable near surface layer. With that, isolated deeper
updrafts plausible given the steepness of lapse rates above the
stable layer, with adequate bulk shear for greater organization. This
maintains potential for some instances of larger hail and gusty
winds, in addition to brief heavy rainfall. Additional convective
organization and expansion expected this evening along/north of a
frontal boundary extending across central WI. This activity likely
to consolidate with time as it spills east/southeast into the early
morning hours, but mixed signal yet on both trajectory and scale.
Steep mid level lapse rates will maintain a risk for hail with any
healthier cores. Latest SPC Day 1 outlook continues to highlight all
of Southeast Michigan within a Marginal Risk for severe weather for
tonight.

The resident airmass remains virtually unchanged heading into
Tuesday. Some degree of stability may exist for a portion of the
daylight period, pending the coverage and pace of exit of overnight
activity. Solid diurnal destabilization likely by afternoon, at
least across the south, where MLCAPE pushes 1500+ as temps again
climb well into the 70s and dewpoint hovers in the lower 60s. Some
evidence of a weak frontal zone or differential heating boundary
bisecting the area. This could offer a lower coverage of convection
for peak heating. Otherwise, still no evidence of more meaningful
forced ascent materializing prior to 00z Tuesday evening.

Existing mid level southwest flow ripe with minor perturbations and
bouts of greater moist isentropic ascent continue to present a
favorable, yet challenging background environment to gauge
convective potential locally Tuesday night. There remains strong
model evidence for convective initation and expansion to occur in the
vicinity of the frontal boundary across northern IL/southern WI and
western lower MI Tuesday evening. Very supportive environment will
exist for the maintenance and possible upscale growth of this
activity into portions of southeast Michigan sometime within the 00z
to 04z window. While the nocturnal timing brings lessening
instability with time near the surface, MuCape projected to exceed
2000 j/kg. Frontal zone now draped across the Saginaw valley and
thumb will offer a greater focus across this region. In fact,
noteworthy backed/southeast low level flow at the frontal interface
gives pause to the possibility for organized updrafts to rotate. A
mix of discreet and multicellular clusters will bring the risk of all
hazards - strong winds, large hail and isolated tornadoes. All of
Southeast Michigan remains with a Slight Risk for severe weather
Tuesday night. Some areas of heavy rainfall also a concern given
expectation for efficient rates given high end moisture content /PW
near 1.3"/.

Mild/moist airmass still entrenched Wednesday and Thursday. Outgoing
forecast continues to highlight expectation for a high coverage of
showers and thunderstorms Wednesday, but some downward revision in
precip chances possible as greater focus may again hold to the south
and west during the daylight period. Another nocturnal convective
response likely Wed night as moisture transport increases along the
nose of the low level jet. Periodic chances for additional showers
and thunderstorms lasting into Thursday. Dry and continued mild
Friday, then rain chances increase again early next weekend.

MARINE...

Shortwave ridging this afternoon has led to pleasant marine
conditions under a modest southwest breeze. Pockets of 25 knot gusts
are observed over land, but quickly drop off offshore where profiles
are more stable. Attention turns to an upstream cluster of
thunderstorms over northern Illinois that will track into southeast
Michigan after sunset this evening. These storms will be capable of
large hail to an inch, frequent lightning, and isolated gusty winds
over 35 knots. This will be the first of several rounds of nocturnal
thunderstorms this week as multiple waves of low pressure ripple
along a stalled frontal zone. Each round of storms will bring
potential for strong to severe storms to the southern half of Lake
Huron, Lake St. Clair, and western Lake Erie. The front is forecast
to hover around the Saginaw Bay area, with northerly winds emerging
north of front and southwest winds for points south. Wind and wave
concerns this week will be tied to thunderstorm activity.

HYDROLOGY...

An active pattern will bring periodic chances for showers and
thunderstorms tonight through Thursday. Each episode brings the
possibility for locally heavy rainfall, particularly where focused
areas of thunderstorms develop. Rainfall amounts in excess of half
an inch will be possible for a round of rain tonight. Additional
rainfall between one and two inches currently forecast to fall
between Tuesday and Thursday. While widespread flooding is not
expected, some minor flooding of low lying, poor drainage and urban
areas along with rises on area rivers are possible.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...
MI...None.
Lake Huron...None.
Lake St Clair...None.
Michigan waters of Lake Erie...None.
&&

AVIATION.....CB
DISCUSSION...MR
MARINE.......MV
HYDROLOGY....MR

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 AM EDT Mon Apr 13 2026

MIZ047>049-053>055-060>063-068>070-075-076-082-083-141000-
Midland-Bay-Huron-Saginaw-Tuscola-Sanilac-Shiawassee-Genesee-Lapeer-
St. Clair-Livingston-Oakland-Macomb-Washtenaw-Wayne-Lenawee-Monroe-
353 AM EDT Mon Apr 13 2026

This hazardous weather outlook is for southeast Michigan.

.DAY ONE...Today and Tonight

A marginal risk of severe weather exists tonight, with potential for
large hail. Storm motion will be northeast around 35 mph.

.DAYS TWO THROUGH SEVEN...Tuesday through Sunday

There is a Slight Risk for severe weather Tuesday and Tuesday night
with potential for large hail, damaging wind and isolated tornadoes.
Storm motion will be east around 45 mph.

Periodic chances of thunderstorms continue Wednesday and Thursday.

.SPOTTER INFORMATION STATEMENT...

Spotter activation may be needed tonight.

LCZ460-LEZ444-LHZ361>363-421-422-441>443-462>464-141000-
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 AM EDT Mon Apr 13 2026

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

.DAY ONE...Today and Tonight

A marginal risk of severe weather exists tonight, with potential for
large hail. Storm motion will be northeast around 30 knots.

.DAYS TWO THROUGH SEVEN...Tuesday through Sunday

There is a Slight Risk for severe weather Tuesday and Tuesday night
with potential for large hail, damaging wind and isolated tornadoes.
Storm motion will be east around 40 knots.

Periodic chances of thunderstorms continue Wednesday and Thursday.

.SPOTTER INFORMATION STATEMENT...

Spotter activation may be needed tonight.

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

DRK

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Special Weather Statement
National Weather Service Detroit/Pontiac MI
820 PM EDT Mon Apr 13 2026

MIZ076-140130-
Wayne MI-
820 PM EDT Mon Apr 13 2026

...STRONG THUNDERSTORMS WILL IMPACT WAYNE COUNTY THROUGH 930 PM
EDT...

At 820 PM EDT, Doppler radar was tracking strong thunderstorms along
a line extending from near Ann Arbor to Milan to near Dundee.
Movement was east at 40 mph.

HAZARD...Wind gusts up to 50 mph.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects.

Strong thunderstorms will be near...
  Canton around 825 PM EDT.
  Belleville around 830 PM EDT.
  Romulus around 835 PM EDT.
  Taylor and Flat Rock around 845 PM EDT.
  Dearborn and Trenton around 850 PM EDT.
  Wyandotte and Greenfield Village around 855 PM EDT.
  Grosse Ile around 900 PM EDT.

Other locations impacted by these storms include Inkster, Brownstown
Township, Melvindale, Gibraltar, New Boston, Sumpter Township, Garden
City, Riverview, Wayne, and Westland.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

Torrential rainfall is also occurring with these storms and may lead
to localized flooding. Do not drive your vehicle through flooded
roadways.

&&

LAT...LON 4235 8290 4232 8306 4230 8309 4224 8313
      4217 8313 4212 8312 4209 8315 4209 8354
      4235 8354 4237 8289
TIME...MOT...LOC 0020Z 267DEG 34KT 4225 8371 4210 8370 4201 8373

MAX HAIL SIZE...0.00 IN
MAX WIND GUST...50 MPH

MV

Special Weather Statement
National Weather Service Detroit/Pontiac MI
833 PM EDT Mon Apr 13 2026

MIZ069-075-076-140130-
Oakland MI-Washtenaw MI-Wayne MI-
833 PM EDT Mon Apr 13 2026

...STRONG THUNDERSTORMS WILL IMPACT NORTHWESTERN WAYNE...OAKLAND AND
NORTHEASTERN WASHTENAW COUNTIES THROUGH 930 PM EDT...

At 833 PM EDT, Doppler radar was tracking strong thunderstorms along
a line extending from near Howell to near Novi to Romulus. Movement
was east at 30 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.

Strong thunderstorms will be near...
  Livonia, Novi, Milford, and Northville around 840 PM EDT.
  Southfield around 845 PM EDT.
  West Bloomfield around 850 PM EDT.
  Detroit, Royal Oak, and Birmingham around 900 PM EDT.
  Troy and Detroit Zoo around 905 PM EDT.
  Warren around 910 PM EDT.
  Pontiac and Sterling Heights around 915 PM EDT.

Other locations impacted by these storms include Franklin, Keego
Harbor, Waterford, Orchard Lake, Commerce, Lathrup Village, Auburn
Hills, Bingham Farms, Lake Angelus, and Farmington Hills.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

Torrential rainfall is also occurring with these storms and may lead
to localized flooding. Do not drive your vehicle through flooded
roadways.

&&

LAT...LON 4235 8367 4246 8366 4269 8368 4273 8309
      4237 8308
TIME...MOT...LOC 0033Z 263DEG 25KT 4256 8391 4249 8355 4221 8337

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

MV