Alert archive / Michigan / Mesoscale Discussions in 2021
Mesoscale Discussion 1700
The Storm Prediction Center issued this mesoscale discussion at Sep 7, 2021, 8:05 AM EDT for 7 counties in Michigan. It was in force for 115 min.
The area
The outline as issued.
The facts
- Issued
- Sep 7, 2021, 8:05 AM EDT (12:05 UTC)
- Expired
- Sep 7, 2021, 10:00 AM EDT
- In force
- 115 min
- Issued by
- the Storm Prediction Center
- Concerning
- Severe potential...watch unlikely
- Chance of a watch
- 20%
Counties Antrim County, MI, Benzie County, MI, Cheboygan County, MI, Emmet County, MI, Grand Traverse County, MI, Kalkaska County, MI, Leelanau County, MI
The radar
The NCL Michigan radar (KAPX), 59 km from the middle of the area, began a volume at 12:07 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
Green Bay/Straub, WI (KGRB), launched 12:00Z, 0.1 hours before the alert went out and 216 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.
977
ACUS11 KWNS 071206
SWOMCD
SPC MCD 071205
MIZ000-071400-
Mesoscale Discussion 1700
NWS Storm Prediction Center Norman OK
0705 AM CDT Tue Sep 07 2021
Areas affected...Portions of northern Lower MI
Concerning...Severe potential...Watch unlikely
Valid 071205Z - 071400Z
Probability of Watch Issuance...20 percent
SUMMARY...An isolated threat for strong/gusty winds may continue
with a small cluster of storms, but watch issuance is unlikely in
the short term.
DISCUSSION...A cluster of storms presently moving across northern
Lake Michigan has persisted early this morning as continued ascent
associated with a 30-40 kt southwesterly low-level jet shifts
eastward across the Great Lakes. Occasional strong/gusty (but
sub-severe) winds occurred with this convection earlier this morning
across parts of northern WI and the U.P. of MI. These storms are
outpacing the low-level moisture return and related instability that
is gradually advancing northeastward, and they will probably remain
slightly elevated. Still, seasonably warm lake temperatures and
reduced friction over the lake may support isolated strong to
perhaps damaging winds as the cluster crosses over the rest of Lake
Michigan and impacts parts of northern Lower MI over the next couple
of hours. Any isolated wind threat associated with this convection
should remain confined fairly close to the coast, as the
thermodynamic environment across interior portions of northern Lower
MI quickly becomes very unfavorable. Current expectations are for
this cluster to weaken as it moves inland, and watch issuance is
unlikely in the next couple of hours.
..Gleason/Edwards.. 09/07/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...APX...
LAT...LON 44578635 45078615 45498583 45678538 45738483 45638442
45298448 44858472 44538512 44368559 44258630 44578635SPC 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, 10:15 AM EDT | Mesoscale Discussion | SPC | Antrim, Benzie, Crawford, Grand Traverse, Kalkaska, Lake and 10 more | 90 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, 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.