Alert archive / Indiana / Mesoscale Discussions in 2012
Mesoscale Discussion 1772
The Storm Prediction Center issued this mesoscale discussion at Aug 16, 2012, 10:01 AM CDT for 4 states. It was in force for 89 min.
The area
The outline as issued.
The facts
- Issued
- Aug 16, 2012, 10:01 AM CDT (15:01 UTC)
- Expired
- Aug 16, 2012, 11:30 AM CDT
- In force
- 89 min
- Issued by
- the Storm Prediction Center
- Chance of a watch
- 20%
All 86 counties
Clark County, IL, Coles County, IL, Crawford County, IL, Cumberland County, IL, Douglas County, IL, Edgar County, IL, Jasper County, IL, Lawrence County, IL, Moultrie County, IL, Vermilion County, IL, Adams County, IN, Allen County, IN, Bartholomew County, IN, Blackford County, IN, Boone County, IN, Brown County, IN, Carroll County, IN, Cass County, IN, Clay County, IN, Clinton County, IN, Decatur County, IN, DeKalb County, IN, Delaware County, IN, Elkhart County, IN, Fayette County, IN, Fountain County, IN, Fulton County, IN, Grant County, IN, Greene County, IN, Hamilton County, IN, Hancock County, IN, Hendricks County, IN, Henry County, IN, Howard County, IN, Huntington County, IN, Jay County, IN, Johnson County, IN, Kosciusko County, IN, LaGrange County, IN, Madison County, IN, Marion County, IN, Marshall County, IN, Miami County, IN, Monroe County, IN, Montgomery County, IN, Morgan County, IN, Noble County, IN, Owen County, IN, Parke County, IN, Putnam County, IN, Randolph County, IN, Rush County, IN, Shelby County, IN, Steuben County, IN, Sullivan County, IN, Tippecanoe County, IN, Tipton County, IN, Vermillion County, IN, Vigo County, IN, Wabash County, IN, Warren County, IN, Wayne County, IN, Wells County, IN, Whitley County, IN, Branch County, MI, Calhoun County, MI, Eaton County, MI, Hillsdale County, MI, Ingham County, MI, Jackson County, MI, Lenawee County, MI, Livingston County, MI, Saint Joseph County, MI, Washtenaw County, MI, Wayne County, MI, Allen County, OH, Auglaize County, OH, Darke County, OH, Defiance County, OH, Fulton County, OH, Henry County, OH, Mercer County, OH, Paulding County, OH, Putnam County, OH, Van Wert County, OH, Williams County, OH
The radar
The Northern Indiana radar (KIWX), 53 km from the middle of the area, began a volume at 15:03 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
Lincoln, IL (KILX), launched 12:00Z, 3.0 hours before the alert went out and 240 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
- 817 J/kg
- Mixed-layer CIN
- -262 J/kg
- Mixed-layer LCL
- 1559 m above ground
- 0-6 km bulk shear
- 22 kt
- 0-1 km storm-relative helicity
- 36 m²/s²
- 0-3 km storm-relative helicity
- 69 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 1.0
The text
As transmitted, in the capitals the NWS used until 2016.
560
ACUS11 KWNS 161502
SWOMCD
SPC MCD 161501
MIZ000-OHZ000-INZ000-ILZ000-161630-
MESOSCALE DISCUSSION 1772
NWS STORM PREDICTION CENTER NORMAN OK
1001 AM CDT THU AUG 16 2012
AREAS AFFECTED...CNTRL IL INTO SRN MI...NRN AND CNTRL IND...PARTS OF
NW OH AND SRN LWR MI
CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY
VALID 161501Z - 161630Z
PROBABILITY OF WATCH ISSUANCE...20 PERCENT
SUMMARY...STRONGEST CONVECTION APPEARS LIKELY TO SPREAD ACROSS
CENTRAL INDIANA...NEAR/NORTH OF THE INDIANAPOLIS METROPOLITAN
AREA... BETWEEN NOW AND 17-18Z. OCCASIONAL STRONG SURFACE GUSTS ARE
POSSIBLE...BUT THE SEVERE WEATHER POTENTIAL STILL APPEARS RELATIVELY
LOW...AND MAY NOT BE LONG-LIVED. HOWEVER...TRENDS WILL CONTINUE TO
BE MONITORED.
DISCUSSION...A FAIRLY STRONG SURFACE COLD POOL APPEARS TO HAVE
DEVELOPED ON THE SOUTHWESTERN FLANK OF THE ONGOING EAST
SOUTHEASTWARD PROPAGATING CONVECTIVE CLUSTER. FORWARD MOTION HAS
INCREASED TO AROUND 40+ KT ON THIS SEGMENT OF THE LEADING EDGE OF
THE CONVECTIVE OUTFLOW...ACCOMPANIED BY SIMILAR GUSTS IN ASOS
SURFACE OBSERVATIONS ACROSS CENTRAL ILLINOIS.
MODELS APPEAR SUGGESTIVE THAT LARGE-SCALE FORCING FOR UPWARD
VERTICAL MOTION SUPPORTING THIS ACTIVITY IS IN THE PROCESS OF
WEAKENING...AND SOUTHEASTERLY NEAR SURFACE/BOUNDARY LAYER INFLOW
INTO THE CONVECTIVE CLUSTER APPEARS RELATIVELY STABLE ACROSS THE
LOWER OHIO VALLEY. SO...LONGER TERM SUSTENANCE OF ACTIVITY IS
UNCERTAIN. HOWEVER...LOW-LEVEL WARM ADVECTION AND SIZABLE CAPE /FOR
ELEVATED LIFTED PARCELS/ MAY MAINTAIN VIGOROUS CONVECTION ACROSS
CENTRAL INDIANA THROUGH AT LEAST THE 15-17Z TIME FRAME. AND HEAVY
PRECIPITATION LOADING...COUPLED WITH EVAPORATIVE COOLING IN A
SUB-CLOUD LAYER CHARACTERIZED BY SIZABLE TEMPERATURE-DEW POINT
SPREADS...MAY CONTINUE TO CONTRIBUTE TO POTENTIAL FOR STRONG SURFACE
GUSTS
..KERR/CARBIN.. 08/16/2012
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...CLE...ILN...DTX...IWX...GRR...IND...LOT...ILX...
LAT...LON 42368533 42758451 42588303 41948351 40708411 39128533
38668766 39218873 39778889 40218793 40668687 41658606
42368533SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 16, 3:57 AM CDT | Mesoscale Discussion | SPC | Boone, Bureau, Carroll, Cook, DeKalb, DuPage and 19 more | 3 hr |
| Aug 16, 12:47 PM CDT | Mesoscale Discussion | SPC | Bond, Calhoun, Champaign, Christian, Clark, Clay and 40 more | 88 min |
| Aug 16, 1:05 PM CDT | Severe Thunderstorm Watch | SPC | Bond, Brown, Calhoun, Cass, Champaign, Christian and 36 more | 7 hr |
| Aug 16, 3:07 PM CDT | Mesoscale Discussion | SPC | Clark, Clay, Coles, Crawford, Cumberland, Edwards and 8 more | 83 min |
| Aug 16, 3:27 PM CDT | Severe Thunderstorm Watch | SPC | Alexander, Clark, Crawford, Edwards, Franklin, Gallatin and 14 more | 8 hr |
| Aug 16, 5:25 PM CDT | Mesoscale Discussion | SPC | Alexander, Bond, Clark, Clay, Clinton, Crawford and 27 more | 2 hr |
| Aug 15, 8:20 PM CDT | Mesoscale Discussion | SPC | Gogebic | 85 min |
| Aug 16, 5:28 PM CDT | Mesoscale Discussion | SPC | Alcona, Allegan, Alpena, Arenac, Barry, Bay and 33 more | 92 min |
Nearby
Mesoscale Discussions in Indiana, 2012Mesoscale Discussions in Michigan, 2012Mesoscale Discussions in Ohio, 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.