Alert archive / Ohio / Mesoscale Discussions in 2012

Mesoscale Discussion 408

April 1, 201212 counties in Indiana; Boone County, Campbell County, Kenton County, Kentucky; 17 counties in Ohio

The Storm Prediction Center issued this mesoscale discussion at Apr 1, 2012, 9:23 PM EDT for 12 counties in Indiana; Boone County, Campbell County, Kenton County, Kentucky; 17 counties in Ohio. It was in force for 67 min.

The area

The outline as issued.

The facts

Issued: Apr 1, 2012, 9:23 PM EDT (01:23 UTC)
Expired: Apr 1, 2012, 10:30 PM EDT
In force: 67 min
Issued by: the Storm Prediction Center

All 32 counties

Dearborn County, IN, Decatur County, IN, Fayette County, IN, Franklin County, IN, Hamilton County, IN, Hancock County, IN, Henry County, IN, Madison County, IN, Rush County, IN, Shelby County, IN, Union County, IN, Wayne County, IN, Boone County, KY, Campbell County, KY, Kenton County, KY, Adams County, OH, Brown County, OH, Butler County, OH, Clermont County, OH, Clinton County, OH, Fayette County, OH, Greene County, OH, Hamilton County, OH, Highland County, OH, Jackson County, OH, Montgomery County, OH, Pickaway County, OH, Pike County, OH, Preble County, OH, Ross County, OH, Scioto County, OH, Warren County, OH

The radar

The Cincinnati radar (KILN), 40 km from the middle of the area, began a volume at 01:25 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.

Severe Thunderstorm Watch 125Apr 1, 10:05 PM EDT

The nearest sounding before it

Cncnati-Daytn, OH (KILN), launched 00:00Z, 1.4 hours before the alert went out and 42 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 663 J/kg
Mixed-layer CIN: -41 J/kg
Mixed-layer LCL: 943 m above ground
0-6 km bulk shear: 51 kt
0-1 km storm-relative helicity: 160 m²/s²
0-3 km storm-relative helicity: 267 m²/s²
Significant tornado parameter: 0.8
Supercell composite: 6.4

Open this sounding in Storm Lab

The text

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

351 
ACUS11 KWNS 020124
SWOMCD
SPC MCD 020123
OHZ000-KYZ000-INZ000-020230-

MESOSCALE DISCUSSION 0408
NWS STORM PREDICTION CENTER NORMAN OK
0823 PM CDT SUN APR 01 2012

AREAS AFFECTED...E-CNTRL/SERN IND...SWRN OH

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE

VALID 020123Z - 020230Z

THREAT FOR ISOLATED SEVERE HAIL APPEARS TO HAVE COMMENCED WITH
SCATTERED DISCRETE CELLS FORMING ALONG A SWD-MOVING COLD FRONT. THE
PROBABILITY OF A SEVERE TSTM WATCH ISSUANCE IS 40 PERCENT.

01Z SURFACE ANALYSIS PLACED A COLD FRONT FROM AROUND 30 S CMH TO 35
N IND...WITH SEVERAL CELLS FORMING IN THE PAST 45 MINUTES ALONG THE
BOUNDARY. EVEN THOUGH SURFACE TEMPERATURES HAD FALLEN INTO THE
MIDDLE 60S TO LOWER 70S IN THE WARM SECTOR...CONVECTION MAY REMAIN
NEAR SURFACE-BASED FOR THE NEXT SEVERAL HOURS. 700-500 MB LAPSE
RATES AROUND 7.5 DEG C/KM AS SAMPLED BY THE 00Z ILN RAOB ALONG WITH
EFFECTIVE SHEAR AROUND 40 KT WILL SUPPORT POTENTIAL FOR UPDRAFT
ROTATION. HOWEVER...DUE TO THE UNDERCUTTING NATURE OF THE COLD
FRONT...SUPERCELL STRUCTURES MAY BE DIFFICULT TO SUSTAIN WITH THE
PRIMARY RISK BEING ISOLATED MARGINALLY SEVERE HAIL.

..GRAMS.. 04/02/2012

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

ATTN...WFO...RLX...ILN...IND...

LAT...LON   40128492 39708306 39288252 38908259 38688289 38608319
            38748420 39028502 39508597 40068617 40298599 40128492

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Apr 1, 10:03 PM EDT	Severe Thunderstorm Watch	SPC	Bartholomew, Dearborn, Decatur, Fayette, Franklin, Hamilton and 11 more	4 hr
Apr 1, 11:31 PM EDT	Mesoscale Discussion	SPC	Clark, Dearborn, Decatur, Franklin, Jefferson, Jennings and 4 more	59 min
Apr 2, 12:30 AM EDT	Mesoscale Discussion	SPC	Dearborn, Ohio, Ripley, Switzerland	60 min

Nearby

Mesoscale Discussions in Ohio, 2012 Mesoscale Discussions in Indiana, 2012 Mesoscale Discussions in Kentucky, 2012 Every 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.