Alert archive / Ohio / Mesoscale Discussions in 2011

Mesoscale Discussion 1920

August 9, 201115 counties in Indiana; 35 counties in Ohio

The Storm Prediction Center issued this mesoscale discussion at Aug 9, 2011, 6:35 PM EDT for 15 counties in Indiana; 35 counties in Ohio. It was in force for 85 min.

The area

The outline as issued.

The facts

Issued
Aug 9, 2011, 6:35 PM EDT (22:35 UTC)
Expired
Aug 9, 2011, 8:00 PM EDT
In force
85 min
Issued by
the Storm Prediction Center
All 50 counties

Adams County, IN, Blackford County, IN, Boone County, IN, Delaware County, IN, Fayette County, IN, Hamilton County, IN, Hancock County, IN, Hendricks County, IN, Henry County, IN, Jay County, IN, Madison County, IN, Marion County, IN, Randolph County, IN, Rush County, IN, Wayne County, IN, Allen County, OH, Ashland County, OH, Auglaize County, OH, Champaign County, OH, Clark County, OH, Crawford County, OH, Cuyahoga County, OH, Darke County, OH, Delaware County, OH, Erie County, OH, Geauga County, OH, Hancock County, OH, Hardin County, OH, Holmes County, OH, Huron County, OH, Knox County, OH, Logan County, OH, Lorain County, OH, Marion County, OH, Medina County, OH, Mercer County, OH, Miami County, OH, Morrow County, OH, Ottawa County, OH, Putnam County, OH, Richland County, OH, Sandusky County, OH, Seneca County, OH, Shelby County, OH, Summit County, OH, Union County, OH, Van Wert County, OH, Wayne County, OH, Wood County, OH, Wyandot County, OH

The radar

The Cincinnati radar (KILN), 128 km from the middle of the area, began a volume at 22:37 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, 10.6 hours before the alert went out and 246 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.

Skew-T log-pSkew-T log-p diagram, Detroit, MI at 12:00Z on 2011-08-09Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 22 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Detroit, MI at 12:00Z on 2011-08-09The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 44 square meters per square second.193958Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
22 J/kg
Mixed-layer CIN
-38 J/kg
Mixed-layer LCL
628 m above ground
0-6 km bulk shear
33 kt
0-1 km storm-relative helicity
44 m²/s²
0-3 km storm-relative helicity
76 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

296 
ACUS11 KWNS 092236
SWOMCD
SPC MCD 092235
OHZ000-INZ000-100000-

MESOSCALE DISCUSSION 1920
NWS STORM PREDICTION CENTER NORMAN OK
0535 PM CDT TUE AUG 09 2011

AREAS AFFECTED...CNTRL IND...NRN/CNTRL OH

CONCERNING...SEVERE THUNDERSTORM WATCH 753...

VALID 092235Z - 100000Z

THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 753
CONTINUES.

DAMAGING WIND AND MARGINAL HAIL THREATS CONTINUE WITH SEMI-DISCRETE
CELLS ALONG AND AHEAD OF A COLD FRONT...WHICH MAY TEND TO GROW
UPSCALE INTO SHORT-LINE SEGMENTS. PORTIONS OF THE WW BEHIND THE
FRONT CAN BE CLEARED...WHILE DOWNSTREAM INTO NRN OH AN EXTENSION IN
AREA MAY BECOME NECESSARY IN THE NEXT HOUR.

22Z SURFACE ANALYSIS PLACED A COLD FRONT FROM SERN LOWER MI SWWD TO
CNTRL IND WITH SCATTERED CELLS ALONG AND AHEAD OF THE FRONT. PRIMARY
THREAT WILL REMAIN STRONG TO SEVERE WIND GUSTS /56 KT MEASURED AT
FWA AT 2207Z/...GIVEN 30-40 W/NWLYS PREVALENT AT 2-4 KM AGL PER AREA
VWP DATA. THESE UNIDIRECTIONAL WIND PROFILES NEARLY PERPENDICULAR TO
THE INITIATING BOUNDARY HAVE FOSTERED MAINLY DISCRETE CELLS SO
FAR...BUT UPSCALE GROWTH INTO SHORT-LINE SEGMENTS APPEARS PLAUSIBLE
PER INDICATIONS BY RECENT HRRR GUIDANCE.

..GRAMS.. 08/09/2011

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...PBZ...CLE...ILN...IWX...IND...

LAT...LON   39968680 40598533 41288417 41578308 41768127 41608105
            40688155 40178233 39848421 39558562 39718665 39968680

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Aug 8, 8:27 PM EDTMesoscale DiscussionSPCBenton, Boone, Carroll, Cass, Clinton, Fountain and 16 more93 min
Aug 9, 1:17 PM EDTMesoscale DiscussionSPCAdams, Benton, Blackford, Boone, Carroll, Cass and 28 more58 min
Aug 9, 3:28 PM EDTSevere Thunderstorm WatchSPCAdams, Allen, Bartholomew, Blackford, Boone, Brown and 54 more7 hr
Aug 9, 6:56 PM EDTSevere Thunderstorm WatchSPCAshland, Ashtabula, Carroll, Columbiana, Coshocton, Cuyahoga and 15 more5 hr

Nearby

Mesoscale Discussions in Ohio, 2011Mesoscale Discussions in Indiana, 2011Every mesoscale discussion in 2011

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.