Alert archive / Michigan / Mesoscale Discussions in 2021

Mesoscale Discussion 1951

November 28, 202111 counties in Michigan; 5 counties in Ohio

The Storm Prediction Center issued this mesoscale discussion at Nov 28, 2021, 3:15 PM EST for 11 counties in Michigan; 5 counties in Ohio. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued: Nov 28, 2021, 3:15 PM EST (20:15 UTC)
Expired: Nov 28, 2021, 5:15 PM EST
In force: 2 hr
Issued by: the Storm Prediction Center
Concerning: Snow squall

Counties Clinton County, MI, Hillsdale County, MI, Ingham County, MI, Jackson County, MI, Lenawee County, MI, Livingston County, MI, Monroe County, MI, Oakland County, MI, Shiawassee County, MI, Washtenaw County, MI, Wayne County, MI, Fulton County, OH, Lucas County, OH, Ottawa County, OH, Sandusky County, OH, Wood County, OH

The radar

The Detroit radar (KDTX), 52 km from the middle of the area, began a volume at 20:19 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, 8.3 hours before the alert went out and 55 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 488 m above ground
0-6 km bulk shear: 60 kt
0-1 km storm-relative helicity: -2 m²/s²
0-3 km storm-relative helicity: 73 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

459 
ACUS11 KWNS 282016
SWOMCD
SPC MCD 282015 
OHZ000-MIZ000-282215-

Mesoscale Discussion 1951
NWS Storm Prediction Center Norman OK
0215 PM CST Sun Nov 28 2021

Areas affected...southeast Lower Michigan into portions of northern
Ohio

Concerning...Snow Squall 

Valid 282015Z - 282215Z

SUMMARY...The potential for snow squalls may continue for a few more
hours as transient lake effect bands merge and move southeast with
time.

DISCUSSION...As of 2000 UTC, regional radar and visible imagery
showed several bands of lake-effect snow showers ongoing across
lower Michigan and northern Ohio. Developing in response to the
passage of an upper low across the Great Lakes, the merger of the
several of these bands over the previous hour resulted in the
development of a heavier snow squall in the vicinity of Detroit.
Snow squall conditions will be possible downstream in the vicinity
of the western shores of Lake Erie and across portions of
northern/northwestern Ohio where surface conditions remain moist and
marginally unstable.

Through the afternoon, low-level flow is expected to veer to the
west/northwest as the upper low moves to the south and east. Visible
satellite trends over the last several hours also show a gradual
clearing of convective clouds likely in response to weak subsidence
on the periphery of the ejecting upper low. The decrease in
convective coverage suggests that snow squall maintenance is more
uncertain with southward extent.

..Lyons.. 11/28/2021

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

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

LAT...LON   42628299 42308277 41808271 41418273 41268303 41378383
            41648444 42168482 42668479 42918474 43098460 43128424
            42938367 42628299

Nearby

Mesoscale Discussions in Michigan, 2021 Mesoscale Discussions in Ohio, 2021 Every 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.