Alert archive / Michigan / Mesoscale Discussions in 2021

Mesoscale Discussion 1711

September 7, 20216 counties in Michigan; Lucas County, Ohio

The Storm Prediction Center issued this mesoscale discussion at Sep 7, 2021, 8:16 PM EDT for 6 counties in Michigan; Lucas County, Ohio. It was in force for 89 min.

The area

The outline as issued.

The facts

Issued
Sep 7, 2021, 8:16 PM EDT (00:16 UTC)
Expired
Sep 7, 2021, 9:45 PM EDT
In force
89 min
Issued by
the Storm Prediction Center
Concerning
Severe thunderstorm watch 490

Counties Hillsdale County, MI, Jackson County, MI, Lenawee County, MI, Monroe County, MI, Washtenaw County, MI, Wayne County, MI, Lucas County, OH

The radar

The Detroit radar (KDTX), 93 km from the middle of the area, began a volume at 00:18 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

The nearest sounding before it

Cncnati-Daytn, OH (KILN), launched 00:00Z, 0.3 hours before the alert went out and 279 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-pSkew-T log-p diagram, Cncnati-Daytn, OH at 00:00Z on 2021-09-08Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 6 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Cncnati-Daytn, OH at 00:00Z on 2021-09-08The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 87 square meters per square second.193958Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
6 J/kg
Mixed-layer CIN
-332 J/kg
Mixed-layer LCL
1474 m above ground
0-6 km bulk shear
38 kt
0-1 km storm-relative helicity
87 m²/s²
0-3 km storm-relative helicity
121 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

319 
ACUS11 KWNS 080016
SWOMCD
SPC MCD 080016 
OHZ000-MIZ000-080145-

Mesoscale Discussion 1711
NWS Storm Prediction Center Norman OK
0716 PM CDT Tue Sep 07 2021

Areas affected...portions of southeast Lower Michigan

Concerning...Severe Thunderstorm Watch 490...

Valid 080016Z - 080145Z

The severe weather threat for Severe Thunderstorm Watch 490
continues.

SUMMARY...The severe threat continues across Severe Thunderstorm
Watch 490, mainly in association with a strong storm across
southeast Lower Michigan. Damaging gusts are expected to be the main
threat with this storm.

DISCUSSION...A near-surface based supercell has recently evolved
into a small bowing complex with an MCV while exiting Hillsdale
County/moving into Lenawee County, MI. KIWX and KDTX radar data
suggests that at least mid-level rotation persists with this storm,
where 50+ kts of effective bulk shear (based on 00Z mesoanalysis)
and over 200 m2/s2 effective SRH are present despite meager
buoyancy. As such, a couple damaging gusts cannot be completely
ruled out with this storm before it progresses over Lake Eerie.

..Squitieri/Guyer.. 09/08/2021

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...CLE...DTX...IWX...GRR...

LAT...LON   41618421 41838459 42008471 42228462 42468392 42418332
            42038300 41618313 41608374 41618421

Nearby

Mesoscale Discussions in Michigan, 2021Mesoscale Discussions in Ohio, 2021Every mesoscale discussion in 2021

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.