Alert archive / Ohio / Severe Thunderstorm Watches in 2012

Severe Thunderstorm Watch 508

July 24, 20126 counties in Indiana; 8 counties in Kentucky; 18 counties in Ohio

The Storm Prediction Center issued this severe thunderstorm watch at Jul 24, 2012, 10:35 AM EDT for 6 counties in Indiana; 8 counties in Kentucky; 18 counties in Ohio. It was in force for 3 hr.

The area

The outline as issued.

The facts

Issued
Jul 24, 2012, 10:35 AM EDT (14:35 UTC)
Expired
Jul 24, 2012, 1:37 PM EDT
In force
3 hr
Issued by
the Storm Prediction Center
Largest hail expected
2 in
Strongest gust expected
60 kt
All 32 counties

Dearborn County, IN, Fayette County, IN, Franklin County, IN, Ripley County, IN, Union County, IN, Wayne County, IN, Boone County, KY, Bracken County, KY, Campbell County, KY, Kenton County, KY, Lewis County, KY, Mason County, KY, Pendleton County, KY, Robertson County, KY, Adams County, OH, Brown County, OH, Butler County, OH, Clark County, OH, Clermont County, OH, Clinton County, OH, Darke County, OH, Fayette County, OH, Greene County, OH, Hamilton County, OH, Highland County, OH, Miami County, OH, Montgomery County, OH, Pike County, OH, Preble County, OH, Ross County, OH, Scioto County, OH, Warren County, OH

The radar

The Cincinnati radar (KILN), 49 km from the middle of the area, began a volume at 14:38 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.

What SPC expected

The probabilities SPC published with the watch, for the watch area over its life.

Two or more tornadoes
20%
One or more EF2 to EF5 tornadoes
5%
Ten or more severe wind reports
80%
One or more gusts of 65 knots or more
50%
Ten or more severe hail reports
30%
One or more hailstones of 2 inches or more
20%
Six or more combined severe hail and wind reports
95%

Warnings issued inside it

9 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.

IssuedProductOfficeCountiesLasted
Jul 24, 10:49 AM EDTSevere Thunderstorm WarningILNUnion, Wayne26 min
Jul 24, 10:56 AM EDTSevere Thunderstorm WarningILNClark, Miami34 min
Jul 24, 11:13 AM EDTSevere Thunderstorm WarningILNUnion, Wayne32 min
Jul 24, 11:22 AM EDTSevere Thunderstorm WarningILNClark, Clinton, Fayette, Greene23 min
Jul 24, 11:34 AM EDTSevere Thunderstorm WarningILNBrown, Clermont, Clinton, Highland, Warren26 min
Jul 24, 11:42 AM EDTSevere Thunderstorm WarningILNCampbell48 min
Jul 24, 12:03 PM EDTSevere Thunderstorm WarningILNAdams, Brown, Clermont, Clinton, Highland, Warren27 min
Jul 24, 12:23 PM EDTSevere Thunderstorm WarningILNLewis37 min
Jul 24, 12:25 PM EDTSevere Thunderstorm WarningILNBracken, Lewis, Mason50 min

Discussions around it

SPC mesoscale discussions over the same counties from four hours before the watch to its end.

The nearest sounding before it

Cncnati-Daytn, OH (KILN), launched 12:00Z, 2.6 hours before the alert went out and 50 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, Cncnati-Daytn, OH at 12:00Z on 2012-07-24Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1858 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, Cncnati-Daytn, OH at 12:00Z on 2012-07-24The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 187 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
1858 J/kg
Mixed-layer CIN
-130 J/kg
Mixed-layer LCL
1124 m above ground
0-6 km bulk shear
30 kt
0-1 km storm-relative helicity
187 m²/s²
0-3 km storm-relative helicity
154 m²/s²
Significant tornado parameter
0.4
Supercell composite
1.7

Open this sounding in Storm Lab

The text

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

543 
WWUS20 KWNS 241437
SEL8
SPC WW 241437
INZ000-KYZ000-OHZ000-241900-

URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 508
NWS STORM PREDICTION CENTER NORMAN OK
1035 AM EDT TUE JUL 24 2012

THE NWS STORM PREDICTION CENTER HAS ISSUED A
SEVERE THUNDERSTORM WATCH FOR PORTIONS OF

       SOUTHEAST INDIANA
       NORTHEAST KENTUCKY
       SOUTHWEST OHIO

EFFECTIVE THIS TUESDAY MORNING AND AFTERNOON FROM 1035 AM UNTIL
300 PM EDT.

HAIL TO 2 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 70
MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.

THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 50
STATUTE MILES EAST AND WEST OF A LINE FROM 40 MILES NORTH
NORTHWEST OF DAYTON OHIO TO 65 MILES SOUTHEAST OF CINCINNATI
OHIO.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED
WATCH OUTLINE UPDATE (WOUS64 KWNS WOU8).

REMEMBER...A SEVERE THUNDERSTORM WATCH MEANS CONDITIONS ARE
FAVORABLE FOR SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH
AREA. PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR
THREATENING WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS
AND POSSIBLE WARNINGS. SEVERE THUNDERSTORMS CAN AND OCCASIONALLY
DO PRODUCE TORNADOES.

OTHER WATCH INFORMATION...CONTINUE...WW 507...

DISCUSSION...A FAST MOVING CLUSTER OF THUNDERSTORMS OVER NORTHERN
IND HAS A HISTORY OF DAMAGING WINDS.  THIS ACTIVITY IS FORECAST TO
TRACK SOUTHEASTWARD ACROSS THE WATCH AREA THROUGH THE LATE MORNING
AND EARLY AFTERNOON HOURS.  WIDESPREAD CLOUDS ARE LIMITING
CONFIDENCE IN THE DEGREE OF DESTABILIZATION...BUT FAST STORM MOTION
AND FAVORABLE MID LEVEL LAPSE RATES WARRANT CONCERN FOR SEVERE WINDS
AT LEAST AS FAR SOUTHEAST AS THE OH RIVER.

AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT
TO 2 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60
KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 500. MEAN STORM
MOTION VECTOR 31045.


...HART

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jul 24, 5:47 AM EDTSevere Thunderstorm WatchSPCJasper, Lake, Newton, Porter4 hr
Jul 24, 7:35 AM EDTMesoscale DiscussionSPCBlackford, Carroll, Cass, Clinton, Delaware, Elkhart and 23 more55 min
Jul 24, 8:00 AM EDTSevere Thunderstorm WatchSPCAdams, Allen, Blackford, Boone, Carroll, Cass and 27 more3 hr
Jul 24, 10:08 AM EDTMesoscale DiscussionSPCAdams, Blackford, Delaware, Fayette, Grant, Hamilton and 11 more97 min
Jul 24, 4:25 PM EDTMesoscale DiscussionSPCCrawford, Daviess, Dubois, Gibson, Knox, Orange and 6 more95 min
Jul 24, 11:43 AM EDTMesoscale DiscussionSPCBath, Bourbon, Boyd, Breathitt, Carter, Clark and 26 more62 min
Jul 24, 11:59 AM EDTMesoscale DiscussionSPCBoone, Bracken, Campbell, Greenup, Kenton, Lewis and 3 more61 min
Jul 24, 12:33 PM EDTSevere Thunderstorm WatchSPCAdair, Anderson, Bath, Bell, Bourbon, Boyd and 61 more6 hr
Jul 24, 1:52 PM EDTMesoscale DiscussionSPCAnderson, Bath, Bourbon, Boyd, Boyle, Breathitt and 47 more53 min
Jul 24, 3:25 PM EDTMesoscale DiscussionSPCAdair, Anderson, Bell, Bourbon, Boyle, Breathitt and 44 more95 min
Jul 24, 6:20 PM EDTSevere Thunderstorm WatchSPCAdair, Allen, Barren, Bell, Breckinridge, Butler and 26 more4 hr
Jul 24, 11:48 AM EDTMesoscale DiscussionSPCBelmont, Carroll, Columbiana, Harrison, Jefferson, Stark87 min

Nearby

Severe Thunderstorm Watches in Ohio, 2012Severe Thunderstorm Watches in Kentucky, 2012Severe Thunderstorm Watches in Indiana, 2012Every severe thunderstorm watch 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.