Alert archive / Michigan / Mesoscale Discussions in 2021
Mesoscale Discussion 1701
The Storm Prediction Center issued this mesoscale discussion at Sep 7, 2021, 10:15 AM EDT for 16 counties in Michigan; 9 counties in Wisconsin. It was in force for 90 min.
The area
The outline as issued.
The facts
- Issued
- Sep 7, 2021, 10:15 AM EDT (14:15 UTC)
- Expired
- Sep 7, 2021, 11:45 AM EDT
- In force
- 90 min
- Issued by
- the Storm Prediction Center
- Concerning
- Severe potential...watch unlikely
- Chance of a watch
- 20%
All 25 counties
Antrim County, MI, Benzie County, MI, Crawford County, MI, Grand Traverse County, MI, Kalkaska County, MI, Lake County, MI, Manistee County, MI, Mason County, MI, Missaukee County, MI, Montmorency County, MI, Ogemaw County, MI, Osceola County, MI, Oscoda County, MI, Otsego County, MI, Roscommon County, MI, Wexford County, MI, Adams County, WI, Brown County, WI, Calumet County, WI, Kewaunee County, WI, Manitowoc County, WI, Outagamie County, WI, Waupaca County, WI, Waushara County, WI, Winnebago County, WI
The radar
The Green Bay radar (KGRB), 118 km from the middle of the area, began a volume at 14:15 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
Green Bay/Straub, WI (KGRB), launched 12:00Z, 2.3 hours before the alert went out and 117 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
- 14 J/kg
- Mixed-layer CIN
- -216 J/kg
- Mixed-layer LCL
- 1012 m above ground
- 0-6 km bulk shear
- 44 kt
- 0-1 km storm-relative helicity
- -120 m²/s²
- 0-3 km storm-relative helicity
- 35 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 2.1
The text
As transmitted.
906
ACUS11 KWNS 071416
SWOMCD
SPC MCD 071415
MIZ000-WIZ000-071545-
Mesoscale Discussion 1701
NWS Storm Prediction Center Norman OK
0915 AM CDT Tue Sep 07 2021
Areas affected...East central WI into northern Lower MI
Concerning...Severe potential...Watch unlikely
Valid 071415Z - 071545Z
Probability of Watch Issuance...20 percent
SUMMARY...The threat for isolated large hail and strong/damaging
winds will persist through the morning from east central Wisconsin
into northern Lower Michigan, but a watch may not be needed.
DISCUSSION...A band of ascent is spreading eastward over WI, in
advance of a pronounced midlevel trough moving east-southeastward
from MN. The convection this morning has been elevated atop a
shallow cool layer near the ground, immediately north/northeast of a
surface warm front moving northeastward. Per the 12z GRB sounding,
MUCAPE up to 2000 J/kg has supported a few strong updrafts this
morning, and there will be some potential for storms to persist
through the morning with an isolated large hail threat. However, it
will take a few hours for the low levels to destabilize sufficiently
and far enough northeast for surface-based storms with more of a
damaging wind threat. At this time, it appears that a watch is
probably not needed, but the threat for damaging winds will increase
by midday to early afternoon from extreme southeast WI into
northeast IL and Lower MI, when a watch will likely be needed. This
damaging wind threat will be addressed by late morning to midday.
..Thompson/Hart.. 09/07/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...APX...GRR...GRB...MKX...ARX...
LAT...LON 44948361 44248409 43858534 43858649 43938762 43898868
43858961 44059000 44418958 44658771 44988591 45138396
44948361SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Sep 7, 3:40 AM EDT | Mesoscale Discussion | SPC | Baraga, Gogebic, Houghton, Iron, Ontonagon | 3 hr |
| Sep 7, 8:05 AM EDT | Mesoscale Discussion | SPC | Antrim, Benzie, Cheboygan, Emmet, Grand Traverse, Kalkaska and 1 more | 115 min |
| Sep 7, 11:47 AM EDT | Mesoscale Discussion | SPC | Clare, Gladwin, Isabella, Lake, Manistee, Mason and 10 more | 58 min |
| Sep 7, 12:21 PM EDT | Severe Thunderstorm Watch | SPC | Alcona, Arenac, Bay, Clare, Crawford, Gladwin and 20 more | 6 hr |
| Sep 7, 1:49 PM EDT | Mesoscale Discussion | SPC | Gratiot, Isabella, Mecosta, Montcalm, Muskegon, Newaygo and 2 more | 86 min |
| Sep 7, 2:48 PM EDT | Mesoscale Discussion | SPC | Barry, Branch, Calhoun, Cass, Eaton, Genesee and 14 more | 117 min |
| Sep 7, 3:20 PM EDT | Severe Thunderstorm Watch | SPC | Allegan, Barry, Berrien, Branch, Calhoun, Cass and 24 more | 7 hr |
| Sep 7, 5:37 PM EDT | Mesoscale Discussion | SPC | Allegan, Barry, Berrien, Branch, Calhoun, Cass and 23 more | 83 min |
Nearby
Mesoscale Discussions in Michigan, 2021Mesoscale Discussions in Wisconsin, 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.