Alert archive / Michigan / Mesoscale Discussions in 2012
Mesoscale Discussion 1389
The Storm Prediction Center issued this mesoscale discussion at Jul 4, 2012, 3:59 PM EDT for 28 counties in Michigan. It was in force for 91 min.
The area
The outline as issued.
The facts
- Issued
- Jul 4, 2012, 3:59 PM EDT (19:59 UTC)
- Expired
- Jul 4, 2012, 5:30 PM EDT
- In force
- 91 min
- Issued by
- the Storm Prediction Center
- Chance of a watch
- 60%
All 28 counties
Arenac County, MI, Bay County, MI, Clare County, MI, Genesee County, MI, Gladwin County, MI, Gratiot County, MI, Huron County, MI, Isabella County, MI, Lake County, MI, Lapeer County, MI, Macomb County, MI, Mason County, MI, Mecosta County, MI, Midland County, MI, Missaukee County, MI, Montcalm County, MI, Newaygo County, MI, Oakland County, MI, Oceana County, MI, Ogemaw County, MI, Osceola County, MI, Roscommon County, MI, Saginaw County, MI, Saint Clair County, MI, Sanilac County, MI, Shiawassee County, MI, Tuscola County, MI, Wexford County, MI
The radar
The Detroit radar (KDTX), 108 km from the middle of the area, began a volume at 20:00 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, 8.0 hours before the alert went out and 108 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
- 2763 J/kg
- Mixed-layer CIN
- -54 J/kg
- Mixed-layer LCL
- 1189 m above ground
- 0-6 km bulk shear
- 26 kt
- 0-1 km storm-relative helicity
- -7 m²/s²
- 0-3 km storm-relative helicity
- -19 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- -0.4
The text
As transmitted, in the capitals the NWS used until 2016.
267
ACUS11 KWNS 041959
SWOMCD
SPC MCD 041959
MIZ000-042130-
MESOSCALE DISCUSSION 1389
NWS STORM PREDICTION CENTER NORMAN OK
0259 PM CDT WED JUL 04 2012
AREAS AFFECTED...LOWER MI
CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE
VALID 041959Z - 042130Z
PROBABILITY OF WATCH ISSUANCE...60 PERCENT
SUMMARY...A SEVERE THREAT MAY DEVELOP AS STORMS INITIATE ACROSS
CNTRL LOWER MI THIS AFTERNOON. WIND DAMAGE AND LARGE HAIL WILL
LIKELY BE THE PRIMARY THREATS. WW ISSUANCE WILL BE POSSIBLE ONCE
CERTAINTY INCREASES CONCERNING THE LOCATION OF THE GREATEST SEVERE
THREAT.
DISCUSSION...THE LATEST SFC ANALYSIS SHOWS A ZONE OF CONFLUENCE
LOCATED ACROSS CNTRL LOWER MI WHERE A VERY MOIST AIRMASS IS IN
PLACE. SFC DEWPOINTS ARE IN THE MID 70S F EXTENDING FROM NORTH OF
MUSKEGON ESEWD TO NEAR FLINT. MESOANALYSIS ALONG THIS CORRIDOR
ESTIMATES MLCAPE VALUES ARE IN THE 3000 TO 4500 J/KG RANGE AND THIS
SHOULD BE THE FAVORED AREA FOR INITIATION THIS AFTERNOON. IN
ADDITION...WATER VAPOR IMAGERY SHOWS A DISTURBANCE MOVING ESEWD INTO
LOWER MI FROM THE NRN PART OF LAKE MICHIGAN WHICH SHOULD HELP TO
INCREASE STORM COVERAGE ONCE STORMS INITIATE. THE LATEST WSR-88D
VWPS ACROSS LOWER MI SHOW UNIDIRECTIONAL WIND PROFILES WITH 30 KT OF
FLOW IN THE MID-LEVELS WHICH SHOULD BE SUFFICIENT FOR A WIND DAMAGE
THREAT ESPECIALLY IF A LINE SEGMENT CAN DEVELOP. ISOLATED LARGE HAIL
WILL ALSO BE POSSIBLE ESPECIALLY IF ANY OF THE STORMS CAN EXHIBIT
ROTATION.
..BROYLES/THOMPSON.. 07/04/2012
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...DTX...APX...GRR...
LAT...LON 43818256 44538389 44538573 44058654 43578647 43218542
42968460 42568363 42538260 43048226 43818256SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 4, 4:42 PM EDT | Severe Thunderstorm Watch | SPC | Bay, Clare, Clinton, Genesee, Gratiot, Ingham and 19 more | 5 hr |
| Jul 4, 4:57 PM EDT | Mesoscale Discussion | SPC | Baraga, Gogebic, Houghton, Iron, Keweenaw, Ontonagon | 93 min |
| Jul 4, 6:36 PM EDT | Mesoscale Discussion | SPC | Alger, Baraga, Delta, Dickinson, Iron, Luce and 4 more | 54 min |
| Jul 4, 7:08 PM EDT | Mesoscale Discussion | SPC | Monroe, Wayne | 2 hr |
Nearby
Mesoscale Discussions in Michigan, 2012Every mesoscale discussion in 2012
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.