Alert archive / Indiana / Mesoscale Discussions in 2012
Mesoscale Discussion 1701
The Storm Prediction Center issued this mesoscale discussion at Aug 4, 2012, 3:57 PM CDT for Cook County, Lake County, Illinois; 25 counties in Indiana; 13 counties in Michigan. It was in force for 63 min.
The area
The outline as issued.
The facts
- Issued
- Aug 4, 2012, 3:57 PM CDT (20:57 UTC)
- Expired
- Aug 4, 2012, 5:00 PM CDT
- In force
- 63 min
- Issued by
- the Storm Prediction Center
- Chance of a watch
- 60%
All 40 counties
Cook County, IL, Lake County, IL, Benton County, IN, Carroll County, IN, Cass County, IN, Elkhart County, IN, Fulton County, IN, Howard County, IN, Huntington County, IN, Jasper County, IN, Kosciusko County, IN, LaGrange County, IN, Lake County, IN, LaPorte County, IN, Marshall County, IN, Miami County, IN, Newton County, IN, Noble County, IN, Porter County, IN, Pulaski County, IN, Saint Joseph County, IN, Starke County, IN, Steuben County, IN, Tippecanoe County, IN, Wabash County, IN, White County, IN, Whitley County, IN, Allegan County, MI, Barry County, MI, Berrien County, MI, Branch County, MI, Calhoun County, MI, Cass County, MI, Eaton County, MI, Ionia County, MI, Kalamazoo County, MI, Kent County, MI, Ottawa County, MI, Saint Joseph County, MI, Van Buren County, MI
The radar
The Northern Indiana radar (KIWX), 90 km from the middle of the area, began a volume at 21:00 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, 9.0 hours before the alert went out and 262 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
- 79 J/kg
- Mixed-layer CIN
- -100 J/kg
- Mixed-layer LCL
- 1364 m above ground
- 0-6 km bulk shear
- 20 kt
- 0-1 km storm-relative helicity
- -15 m²/s²
- 0-3 km storm-relative helicity
- -15 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted, in the capitals the NWS used until 2016.
581
ACUS11 KWNS 042058
SWOMCD
SPC MCD 042057
MIZ000-INZ000-ILZ000-042200-
MESOSCALE DISCUSSION 1701
NWS STORM PREDICTION CENTER NORMAN OK
0357 PM CDT SAT AUG 04 2012
AREAS AFFECTED...NRN IND...SRN LWR MI
CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE
VALID 042057Z - 042200Z
PROBABILITY OF WATCH ISSUANCE...60 PERCENT
SUMMARY...LINE OF TSTMS CURRENTLY MOVING ACROSS NRN IL WILL LIKELY
REMAIN STRONG AS IT MOVES INTO NRN IND AND SRN LWR MI AND A
DOWNSTREAM WW MAY BE NEEDED.
DISCUSSION...LINE OF STG/SVR TSTMS CONTINUES PROGRESSING EWD ACROSS
NRN IL. THIS LINE IS BEGINNING TO MOVE AHEAD OF THE BEST SHEAR BUT
SHOULD REMAIN ORGANIZED ENOUGH FOR AN INCREASED SVR THREAT ACROSS
NRN IND AND SRN LWR MI. DEWPOINT VALUES IN THE MID 70S AND
TEMPERATURES IN THE UPPER 80S/LOW 90S ACROSS NRN IND WILL SUPPORT
MLCAPE AOA 2500 J/KG WHILE SLIGHTLY LOWER DEWPOINT VALUES WILL
SUPPORT MLCAPE NEAR 1500 J/KG FARTHER N. GIVEN THE TIME OF DAY AND
ENVIRONMENT DOWNSTREAM OF THE CURRENT MCS...CONTINUED EWD
PROGRESSION IS EXPECTED AND A DOWNSTREAM WW MAY BE NEEDED.
UNCERTAINTY REGARDING THE PROGRESSION OF THE MCS ACROSS LWR LK MI
PRECLUDES HIGHER WATCH PROBABILITIES.
..MOSIER/THOMPSON.. 08/04/2012
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...IWX...GRR...IND...LOT...
LAT...LON 42418788 42978709 43368618 43268516 42758438 40938522
40458599 40238713 40738753 42418788SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 4, 3:08 AM CDT | Mesoscale Discussion | SPC | Bond, Calhoun, Clinton, Greene, Jersey, Macoupin and 1 more | 2 hr |
| Aug 4, 10:26 AM CDT | Mesoscale Discussion | SPC | Adams, Boone, Brown, Bureau, Carroll, Cass and 46 more | 49 min |
| Aug 4, 10:50 AM CDT | Severe Thunderstorm Watch | SPC | Bureau, Carroll, Fulton, Hancock, Henderson, Henry and 16 more | 5 hr |
| Aug 4, 1:09 PM CDT | Mesoscale Discussion | SPC | Boone, Bureau, Carroll, DeKalb, DuPage, Fulton and 28 more | 66 min |
| Aug 4, 1:46 PM CDT | Severe Thunderstorm Watch | SPC | Boone, Cook, DeKalb, DuPage, Ford, Grundy and 12 more | 4 hr |
| Aug 4, 6:12 PM CDT | Severe Thunderstorm Watch | SPC | Madison, Monroe, Randolph, Saint Clair | 6 hr |
| Aug 4, 1:13 PM CDT | Mesoscale Discussion | SPC | Brown, Crawford, Daviess, Dubois, Floyd, Gibson and 14 more | 92 min |
| Aug 4, 4:35 PM CDT | Severe Thunderstorm Watch | SPC | Adams, Allen, Blackford, Cass, DeKalb, Elkhart and 18 more | 5 hr |
| Aug 4, 6:23 PM CDT | Mesoscale Discussion | SPC | Adams, Allen, Blackford, DeKalb, Delaware, Elkhart and 13 more | 2 hr |
| Aug 4, 6:50 PM CDT | Severe Thunderstorm Watch | SPC | Wayne | 5 hr |
Nearby
Mesoscale Discussions in Indiana, 2012Mesoscale Discussions in Michigan, 2012Mesoscale Discussions in Illinois, 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.