Alert archive / Michigan / Mesoscale Discussions in 2021

Mesoscale Discussion 1632

August 28, 20219 counties in Michigan

The Storm Prediction Center issued this mesoscale discussion at Aug 28, 2021, 6:42 PM EDT for 9 counties in Michigan. It was in force for 93 min.

The area

The outline as issued.

The facts

Issued
Aug 28, 2021, 6:42 PM EDT (22:42 UTC)
Expired
Aug 28, 2021, 8:15 PM EDT
In force
93 min
Issued by
the Storm Prediction Center
Concerning
Severe potential...watch unlikely
Chance of a watch
20%

Counties Bay County, MI, Genesee County, MI, Huron County, MI, Lapeer County, MI, Saginaw County, MI, Saint Clair County, MI, Sanilac County, MI, Shiawassee County, MI, Tuscola County, MI

The radar

The Detroit radar (KDTX), 68 km from the middle of the area, began a volume at 22:42 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

Detroit, MI (KDTX), launched 12:00Z, 10.7 hours before the alert went out and 65 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, Detroit, MI at 12:00Z on 2021-08-28Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1891 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, Detroit, MI at 12:00Z on 2021-08-28The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 51 square meters per square second.1939Sfc1 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
1891 J/kg
Mixed-layer CIN
-30 J/kg
Mixed-layer LCL
860 m above ground
0-6 km bulk shear
23 kt
0-1 km storm-relative helicity
51 m²/s²
0-3 km storm-relative helicity
65 m²/s²
Significant tornado parameter
0.3
Supercell composite
1.8

Open this sounding in Storm Lab

The text

As transmitted.

734 
ACUS11 KWNS 282242
SWOMCD
SPC MCD 282242 
MIZ000-290015-

Mesoscale Discussion 1632
NWS Storm Prediction Center Norman OK
0542 PM CDT Sat Aug 28 2021

Areas affected...portions of eastern Lower Michigan

Concerning...Severe potential...Watch unlikely 

Valid 282242Z - 290015Z

Probability of Watch Issuance...20 percent

SUMMARY...A couple damaging gusts or instances of large hail may
accompany the stronger storms over the next few hours. A WW issuance
is not expected.

DISCUSSION...Multicellular storm clusters have recently intensified
over the last hour or so while forming into loosely organized linear
segments, with a couple of 50+ kt gust and 1.0 inch hail reports
recently received. While deep-layer shear/ascent is quite modest
over Lower Michigan, ample buoyancy (2000 J/kg MLCAPE driven by 7.5
C/km low-level lapse rates per 22Z mesoanalysis) will continue to
support a couple more strong to potentially severe wind gusts and
perhaps marginally severe hail for a few more hours. Given the
brief, localized extent of the severe threat, a WW issuance is not
anticipated.

..Squitieri/Guyer.. 08/28/2021

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

ATTN...WFO...DTX...APX...GRR...

LAT...LON   43198453 43858383 44148333 44148289 43558234 43128225
            42868240 42728304 42748370 42888447 43198453

Nearby

Mesoscale Discussions in Michigan, 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.