Alert archive / Ohio / Mesoscale Discussions in 2012
Mesoscale Discussion 1491
The Storm Prediction Center issued this mesoscale discussion at Jul 18, 2012, 12:54 PM EDT for 4 states. It was in force for 2 hr.
The area
The outline as issued.
The facts
- Issued
- Jul 18, 2012, 12:54 PM EDT (16:54 UTC)
- Expired
- Jul 18, 2012, 3:00 PM EDT
- In force
- 2 hr
- Issued by
- the Storm Prediction Center
- Chance of a watch
- 60%
All 103 counties
Adams County, IN, Allen County, IN, Blackford County, IN, Decatur County, IN, Delaware County, IN, Fayette County, IN, Franklin County, IN, Grant County, IN, Hancock County, IN, Henry County, IN, Huntington County, IN, Jay County, IN, Johnson County, IN, Madison County, IN, Randolph County, IN, Rush County, IN, Shelby County, IN, Union County, IN, Wayne County, IN, Wells County, IN, Whitley County, IN, Allen County, OH, Ashland County, OH, Athens County, OH, Auglaize County, OH, Belmont County, OH, Butler County, OH, Carroll County, OH, Champaign County, OH, Clark County, OH, Clinton County, OH, Columbiana County, OH, Coshocton County, OH, Crawford County, OH, Darke County, OH, Delaware County, OH, Fairfield County, OH, Fayette County, OH, Franklin County, OH, Greene County, OH, Guernsey County, OH, Hamilton County, OH, Hancock County, OH, Hardin County, OH, Harrison County, OH, Highland County, OH, Hocking County, OH, Holmes County, OH, Huron County, OH, Jackson County, OH, Jefferson County, OH, Knox County, OH, Licking County, OH, Logan County, OH, Madison County, OH, Mahoning County, OH, Marion County, OH, Medina County, OH, Meigs County, OH, Mercer County, OH, Miami County, OH, Monroe County, OH, Montgomery County, OH, Morgan County, OH, Morrow County, OH, Muskingum County, OH, Noble County, OH, Paulding County, OH, Perry County, OH, Pickaway County, OH, Pike County, OH, Portage County, OH, Preble County, OH, Putnam County, OH, Richland County, OH, Ross County, OH, Seneca County, OH, Shelby County, OH, Stark County, OH, Summit County, OH, Trumbull County, OH, Tuscarawas County, OH, Union County, OH, Van Wert County, OH, Vinton County, OH, Warren County, OH, Washington County, OH, Wayne County, OH, Wyandot County, OH, Allegheny County, PA, Beaver County, PA, Greene County, PA, Lawrence County, PA, Washington County, PA, Brooke County, WV, Hancock County, WV, Marion County, WV, Marshall County, WV, Ohio County, WV, Pleasants County, WV, Tyler County, WV, Wetzel County, WV, Wood County, WV
The radar
The Cleveland radar (KCLE), 116 km from the middle of the area, began a volume at 16:56 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
Cncnati-Daytn, OH (KILN), launched 12:00Z, 4.9 hours before the alert went out and 169 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
- 2497 J/kg
- Mixed-layer CIN
- -63 J/kg
- Mixed-layer LCL
- 1093 m above ground
- 0-6 km bulk shear
- 4 kt
- 0-1 km storm-relative helicity
- -23 m²/s²
- 0-3 km storm-relative helicity
- -5 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted, in the capitals the NWS used until 2016.
212
ACUS11 KWNS 181654
SWOMCD
SPC MCD 181654
PAZ000-WVZ000-OHZ000-INZ000-181900-
MESOSCALE DISCUSSION 1491
NWS STORM PREDICTION CENTER NORMAN OK
1154 AM CDT WED JUL 18 2012
AREAS AFFECTED...PORTIONS OF INDIANA/OH/WV TO WESTERN PA
CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE
VALID 181654Z - 181900Z
PROBABILITY OF WATCH ISSUANCE...60 PERCENT
SUMMARY...POTENTIAL FOR ISOLATED BOUTS OF DAMAGING WINDS/SOME HAIL
WILL INCREASE THIS AFTERNOON ACROSS PORTIONS OF INDIANA/MUCH OF OH
INTO WESTERN PA/NORTHERN WV.
DISCUSSION...THE AIRMASS TO THE SOUTH OF A FRONTAL BOUNDARY...THAT
EXTENDS ROUGHLY WEST-EAST FROM SOUTHERN LAKE MI VICINITY TO NEAR
LAKE ERIE...HAS BECOME MODERATE TO STRONGLY UNSTABLE ACROSS BROAD
PORTIONS OF INDIANA/MUCH OF OH AS WELL AS ADJACENT PARTS OF WESTERN
PA/NORTHERN WV. AS SURFACE TEMPERATURES CONTINUE TO CLIMB
INTO/THROUGH THE 90S F...RELATIVELY STEEP LOW-MID LEVEL LAPSE RATES
AND AMPLE PRECIPITABLE WATER ENVIRONMENT ARE SUPPORTING SBCAPE
VALUES TO AS HIGH AS 2500-3500 J/KG...AS PER MODIFICATIONS TO 12Z
OBSERVED SOUNDINGS FROM LINCOLN IL/WILMINGTON OH/PITTSBURGH PA.
WHILE STRONG UPDRAFTS/DOWNDRAFTS WILL BE POSSIBLE GIVEN THE DEGREE
OF BUOYANCY/LAPSE RATES...WEAK VERTICAL SHEAR /PER WSR-88D VWPS AND
AFOREMENTIONED 12Z SOUNDINGS/ MAY TEND TO LIMIT THE OVERALL
ORGANIZATION. NONETHELESS...MICROBURSTS/DAMAGING WINDS...ALONG WITH
SOME HAIL...WILL BE POSSIBLE WITH PULSE/MULTICELLULAR STORMS THIS
AFTERNOON. A SEVERE TSTM WATCH MAY BE NEEDED THIS AFTERNOON FOR
PORTIONS OF THE REGION...ESPECIALLY IF STORMS BEGIN TO
CONGEAL/ORGANIZE TO A DEGREE.
..GUYER/MEAD.. 07/18/2012
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...PBZ...RLX...CLE...ILN...IWX...IND...
LAT...LON 41368190 41338054 40197964 39508024 38948253 39388617
41308545 41368190SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 18, 1:16 PM EDT | Severe Thunderstorm Watch | SPC | Adams, Allen, Bartholomew, Blackford, Carroll, Cass and 28 more | 8 hr |
| Jul 18, 1:58 PM EDT | Severe Thunderstorm Watch | SPC | Benton, Jasper, Lake, Newton, Porter | 7 hr |
| Jul 18, 4:21 PM EDT | Mesoscale Discussion | SPC | Bartholomew, Blackford, Boone, Brown, Cass, Clinton and 30 more | 84 min |
| Jul 18, 7:56 PM EDT | Mesoscale Discussion | SPC | Lake, LaPorte, Porter, Starke | 94 min |
| Jul 18, 10:25 AM EDT | Mesoscale Discussion | SPC | Berks, Blair, Bradford, Bucks, Cambria, Cameron and 39 more | 2 hr |
| Jul 18, 12:41 PM EDT | Severe Thunderstorm Watch | SPC | Adams, Bedford, Berks, Blair, Bucks, Cambria and 36 more | 8 hr |
| Jul 18, 3:44 PM EDT | Mesoscale Discussion | SPC | Adams, Berks, Bucks, Chester, Delaware, Lancaster and 5 more | 91 min |
Nearby
Mesoscale Discussions in Ohio, 2012Mesoscale Discussions in Indiana, 2012Mesoscale Discussions in West Virginia, 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.