Alert archive / Michigan / Mesoscale Discussions in 2022
Mesoscale Discussion 1521
The Storm Prediction Center issued this mesoscale discussion at Jul 20, 2022, 12:29 PM EDT for DeKalb County, Steuben County, Indiana; 25 counties in Michigan; 8 counties in Ohio. It was in force for 61 min.
The area
The outline as issued.
The facts
- Issued
- Jul 20, 2022, 12:29 PM EDT (16:29 UTC)
- Expired
- Jul 20, 2022, 1:30 PM EDT
- In force
- 61 min
- Issued by
- the Storm Prediction Center
- Concerning
- Severe potential...watch likely
- Chance of a watch
- 80%
All 35 counties
DeKalb County, IN, Steuben County, IN, Bay County, MI, Branch County, MI, Calhoun County, MI, Clinton County, MI, Eaton County, MI, Genesee County, MI, Gratiot County, MI, Hillsdale County, MI, Huron County, MI, Ingham County, MI, Jackson County, MI, Lapeer County, MI, Lenawee County, MI, Livingston County, MI, Macomb County, MI, Midland County, MI, Monroe County, MI, Oakland County, MI, Saginaw County, MI, Saint Clair County, MI, Sanilac County, MI, Shiawassee County, MI, Tuscola County, MI, Washtenaw County, MI, Wayne County, MI, Defiance County, OH, Fulton County, OH, Henry County, OH, Lucas County, OH, Ottawa County, OH, Sandusky County, OH, Williams County, OH, Wood County, OH
The radar
The Detroit radar (KDTX), 55 km from the middle of the area, began a volume at 16:29 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 watches that followed
Watches SPC issued over any of the same counties within four hours of this discussion.
The nearest sounding before it
Detroit, MI (KDTX), launched 12:00Z, 4.5 hours before the alert went out and 59 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.
- Mixed-layer CAPE
- 264 J/kg
- Mixed-layer CIN
- -247 J/kg
- Mixed-layer LCL
- 913 m above ground
- 0-6 km bulk shear
- 25 kt
- 0-1 km storm-relative helicity
- 91 m²/s²
- 0-3 km storm-relative helicity
- 78 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.3
The text
As transmitted.
335
ACUS11 KWNS 201630
SWOMCD
SPC MCD 201629
MIZ000-OHZ000-INZ000-201730-
Mesoscale Discussion 1521
NWS Storm Prediction Center Norman OK
1129 AM CDT Wed Jul 20 2022
Areas affected...portions of Lower Michigan into northeastern
Indiana and northwestern Ohio
Concerning...Severe potential...Watch likely
Valid 201629Z - 201730Z
Probability of Watch Issuance...80 percent
SUMMARY...Thunderstorm development is expected to begin over the
next hour, accompanied by an increase in severe risk. WW issuance
may be required.
DISCUSSION...Latest visible satellite and radar loops show
convection developing across parts of central and eastern Lower
Michigan at this time, near and ahead of an advancing surface cold
front. The moist boundary layer ahead of the front -- characterized
by dewpoints around 70 -- has continued to heat through midday,
which has now pushed mixed-layer CAPE values into the 1500 to 2500
J/kg range. Continued/gradual heating will support continued
destabilization, and a corresponding increase in convective
development/eventual storm initiation.
Moderately strong cyclonic/southwesterly flow currently resides
across Lower Michigan, on the southeastern side of the upper low
moving eastward across central portions of the U.P. Resulting shear
-- around 35 kt per a combination of VWP data and RAP soundings --
suggests potential for organized storms, including a couple of
supercells initially, later possibly growing upscale locally into
small-scale bands. While a tornado can't be ruled out, primary
severe risk will likely manifest as locally damaging gusts. Current
indications are that storm coverage -- and thus degree of severe
risk -- will likely increase sufficient to warrant WW consideration
over the next half hour or so.
..Goss/Hart.. 07/20/2022
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...CLE...DTX...APX...IWX...GRR...
LAT...LON 43988453 44068291 43208243 41288300 41048403 41298526
41878543 42628505 43988453SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 20, 6:33 PM EDT | Mesoscale Discussion | SPC | Crawford, Harrison, Perry, Spencer, Vanderburgh, Warrick | 87 min |
| Jul 20, 12:52 PM EDT | Severe Thunderstorm Watch | SPC | Alcona, Alpena, Arenac, Bay, Cheboygan, Crawford and 27 more | 7 hr |
| Jul 20, 2:38 PM EDT | Mesoscale Discussion | SPC | Huron, Lapeer, Macomb, Monroe, Oakland, Saint Clair and 3 more | 97 min |
| Jul 20, 4:30 PM EDT | Mesoscale Discussion | SPC | Allen, Auglaize, Crawford, Delaware, Erie, Hancock and 10 more | 90 min |
| Jul 20, 6:08 PM EDT | Mesoscale Discussion | SPC | Ashland, Ashtabula, Coshocton, Cuyahoga, Delaware, Franklin and 16 more | 67 min |
| Jul 20, 6:18 PM EDT | Severe Thunderstorm Watch | SPC | Ashland, Ashtabula, Cuyahoga, Geauga, Holmes, Knox and 11 more | 4 hr |
| Jul 20, 7:56 PM EDT | Mesoscale Discussion | SPC | Ashland, Ashtabula, Crawford, Cuyahoga, Geauga, Holmes and 12 more | 94 min |
Nearby
Mesoscale Discussions in Michigan, 2022Mesoscale Discussions in Ohio, 2022Mesoscale Discussions in Indiana, 2022Every mesoscale discussion in 2022
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.