Alert archive / Michigan / Mesoscale Discussions in 2017
Mesoscale Discussion 1439
The Storm Prediction Center issued this mesoscale discussion at Aug 3, 2017, 5:45 PM EDT for 15 counties in Michigan. It was in force for 90 min.
The area
The outline as issued.
The facts
- Issued
- Aug 3, 2017, 5:45 PM EDT (21:45 UTC)
- Expired
- Aug 3, 2017, 7:15 PM EDT
- In force
- 90 min
- Issued by
- the Storm Prediction Center
- Chance of a watch
- 5%
Counties Antrim County, MI, Clare 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, Osceola County, MI, Oscoda County, MI, Otsego County, MI, Roscommon County, MI, Wexford County, MI
The radar
The NCL Michigan radar (KAPX), 58 km from the middle of the area, began a volume at 21:46 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
Alpena, MI (KAPX), launched 12:00Z, 9.8 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
- 45 J/kg
- Mixed-layer CIN
- -51 J/kg
- Mixed-layer LCL
- 672 m above ground
- 0-6 km bulk shear
- 26 kt
- 0-1 km storm-relative helicity
- 62 m²/s²
- 0-3 km storm-relative helicity
- 98 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.1
The text
As transmitted.
806
ACUS11 KWNS 032145
SWOMCD
SPC MCD 032145
MIZ000-032315-
Mesoscale Discussion 1439
NWS Storm Prediction Center Norman OK
0445 PM CDT Thu Aug 03 2017
Areas affected...Northern Lower MI
Concerning...Severe potential...Watch unlikely
Valid 032145Z - 032315Z
Probability of Watch Issuance...5 percent
SUMMARY...A risk for isolated damaging winds and a brief tornado may
persist through about 00-01Z across a spatially confined area of
northern Lower MI. WW issuance will not be necessary.
DISCUSSION...A cluster of storms across central Lake MI has spread
into parts of western Lower MI, with the most intense updrafts
(based on reflectivity) currently across Mason and Manistee
counties. Although inflow temperatures are mild around the middle
70s across central MI, presence of a diffuse surface front and
modest low-level warm air advection should support this cluster
persisting east-northeast over the next few hours, a scenario
consistent with the 20Z HRRR. Veering of the wind profile with
height is yielding effective shear of 30-35 kt and 0-1 km shear of
20-25 kt per area VWP and Mesoanalysis data. This should result in
isolated damaging winds as the primary hazard, but a brief tornado
will also be possible.
..Grams.. 08/03/2017
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...APX...GRR...
LAT...LON 44638623 45228524 45368463 45178417 44888400 44328414
43968455 43748517 43578627 44048649 44638623Nearby
Mesoscale Discussions in Michigan, 2017Every mesoscale discussion in 2017
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.