Alert archive / Michigan / Mesoscale Discussions in 2018
Mesoscale Discussion 939
The Storm Prediction Center issued this mesoscale discussion at Jun 29, 2018, 12:22 PM EDT for 13 counties in Michigan. It was in force for 113 min.
The area
The outline as issued.
The facts
- Issued
- Jun 29, 2018, 12:22 PM EDT (16:22 UTC)
- Expired
- Jun 29, 2018, 2:15 PM EDT
- In force
- 113 min
- Issued by
- the Storm Prediction Center
Counties Alger County, MI, Baraga County, MI, Charlevoix County, MI, Delta County, MI, Dickinson County, MI, Emmet County, MI, Houghton County, MI, Iron County, MI, Luce County, MI, Mackinac County, MI, Marquette County, MI, Menominee County, MI, Schoolcraft County, MI
The radar
The Marquette radar (KMQT), 48 km from the middle of the area, began a volume at 16:24 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, 4.4 hours before the alert went out and 229 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
- 620 J/kg
- Mixed-layer CIN
- -374 J/kg
- Mixed-layer LCL
- 1148 m above ground
- 0-6 km bulk shear
- 21 kt
- 0-1 km storm-relative helicity
- 125 m²/s²
- 0-3 km storm-relative helicity
- 116 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
012
ACUS11 KWNS 291622
SWOMCD
SPC MCD 291622
MIZ000-WIZ000-291815-
Mesoscale Discussion 0939
NWS Storm Prediction Center Norman OK
1122 AM CDT Fri Jun 29 2018
Areas affected...Upper Michigan...Lake Superior
Concerning...Severe Thunderstorm Watch 241...
Valid 291622Z - 291815Z
The severe weather threat for Severe Thunderstorm Watch 241
continues.
SUMMARY...A wind damage and hail threat will likely affect Upper
Michigan late this morning into early afternoon. A new weather watch
or a local extension will need to be considered once the line
approaches the eastern edge of WW 241.
DISCUSSION...A well developed short bowing line segment is ongoing
along a gradient of instability in western Upper Michigan. The RAP
is showing MLCAPE in the 1000 to 1500 J/kg range from western Upper
Michigan into far northeast Wisconsin. In addition, the Marquette
WSR-88D VWP has about 50 kt of 0-6 km shear with veering winds with
height in the lowest 2 km AGL. This will continue to be favorable
for bowing line segments with wind damage potential. The bowing line
is forecast to turn more southeast and will probably affect areas
across central Upper Michigan and perhaps northern Lake Michigan
over the next few hours. If the line can hold together as approaches
the eastern edge of WW 241, a new watch and or a local extension
will need to be considered.
..Broyles/Hart.. 06/29/2018
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...APX...MQT...GRB...
LAT...LON 47518803 47048866 46468888 46068875 45628783 45308693
45158573 45448494 45878474 46348507 47128591 47518708
47518803SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jun 29, 5:14 AM EDT | Mesoscale Discussion | SPC | Gogebic, Ontonagon | 2 hr |
| Jun 29, 10:45 AM EDT | Severe Thunderstorm Watch | SPC | Baraga, Houghton, Keweenaw, Marquette, Ontonagon | 3 hr |
Nearby
Mesoscale Discussions in Michigan, 2018Every mesoscale discussion in 2018
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.