Alert archive / Ohio / Mesoscale Discussions in 2011

Mesoscale Discussion 1821

August 1, 201170 counties in Ohio; Brooke County, Hancock County, Ohio County, West Virginia

The Storm Prediction Center issued this mesoscale discussion at Aug 1, 2011, 3:39 PM EDT for 70 counties in Ohio; Brooke County, Hancock County, Ohio County, West Virginia. It was in force for 66 min.

The area

The outline as issued.

The facts

Issued
Aug 1, 2011, 3:39 PM EDT (19:39 UTC)
Expired
Aug 1, 2011, 4:45 PM EDT
In force
66 min
Issued by
the Storm Prediction Center
All 73 counties

Allen County, OH, Ashland County, OH, Ashtabula County, OH, Auglaize County, OH, Belmont County, OH, Carroll County, OH, Champaign County, OH, Clark County, OH, Columbiana County, OH, Coshocton County, OH, Crawford County, OH, Cuyahoga County, OH, Darke County, OH, Defiance County, OH, Delaware County, OH, Erie County, OH, Fairfield County, OH, Fayette County, OH, Franklin County, OH, Fulton County, OH, Geauga County, OH, Greene County, OH, Guernsey County, OH, Hancock County, OH, Hardin County, OH, Harrison County, OH, Henry County, OH, Hocking County, OH, Holmes County, OH, Huron County, OH, Jefferson County, OH, Knox County, OH, Lake County, OH, Licking County, OH, Logan County, OH, Lorain County, OH, Lucas County, OH, Madison County, OH, Mahoning County, OH, Marion County, OH, Medina 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, Ottawa County, OH, Paulding County, OH, Perry County, OH, Pickaway County, OH, Portage County, OH, Putnam County, OH, Richland County, OH, Sandusky 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, Washington County, OH, Wayne County, OH, Williams County, OH, Wood County, OH, Wyandot County, OH, Brooke County, WV, Hancock County, WV, Ohio County, WV

The radar

The Cleveland radar (KCLE), 89 km from the middle of the area, began a volume at 19:42 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 nearest sounding before it

Detroit, MI (KDTX), launched 12:00Z, 7.7 hours before the alert went out and 185 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 2011-08-01Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2432 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 2011-08-01The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 118 square meters per square second.19395878Sfc1 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
2432 J/kg
Mixed-layer CIN
-38 J/kg
Mixed-layer LCL
864 m above ground
0-6 km bulk shear
38 kt
0-1 km storm-relative helicity
118 m²/s²
0-3 km storm-relative helicity
139 m²/s²
Significant tornado parameter
1.0
Supercell composite
7.2

Open this sounding in Storm Lab

The text

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

794 
ACUS11 KWNS 011939
SWOMCD
SPC MCD 011939 
PAZ000-WVZ000-OHZ000-MIZ000-INZ000-012045-

MESOSCALE DISCUSSION 1821
NWS STORM PREDICTION CENTER NORMAN OK
0239 PM CDT MON AUG 01 2011

AREAS AFFECTED...NRN/CNTRL OH

CONCERNING...SEVERE THUNDERSTORM WATCH 710...

VALID 011939Z - 012045Z

THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 710
CONTINUES.

STORM CLUSTERS...INCLUDING ISOLATED SUPERCELLS...ARE EXPECTED TO
MAINTAIN INTENSITY DURING THE NEXT FEW HRS WITHIN AN ENVIRONMENT
CHARACTERIZED BY MODERATE TO STRONG INSTABILITY AND 30-40 KT DEEP
LAYER NWLY SHEAR. PRIMARY SVR WEATHER THREATS WILL CONTINUE TO BE
LARGE HAIL AND DAMAGING WINDS. HOWEVER...RELATIVELY LONGER-LIVED
SUPERCELL MOVING THROUGH WYANDOT COUNTY AT 1930Z MAY BE CAPABLE OF
PRODUCE A TORNADO DURING THE NEXT HR. AS THUNDERSTORMS MOVE SEWD
ACROSS CNTRL OH AND EXIT INTO SRN OH THEY WILL ENCOUNTER WEAKER
INSTABILITY AND MORE SUBSIDENT LARGE-SCALE REGIME /ADJACENT TO
SURFACE HIGH PRESSURE CENTERED OVER THE LWR-MID OH VALLEY REGION/.
AS THIS TAKES PLACE...STORMS MAY WEAKEN AND REDUCE THE SVR WEATHER
THREAT...WHICH IS SUPPORTED BY LATEST 17Z HRRR.

..GARNER.. 08/01/2011

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

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

LAT...LON   41688480 41728342 41958311 41858308 41708271 41678241
            42208125 42308055 40018049 39458121 39368271 39688450
            40318483 41688480

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Aug 1, 3:47 AM EDTMesoscale DiscussionSPCAshtabula, Lake58 min
Aug 1, 8:01 AM EDTMesoscale DiscussionSPCAshtabula, Cuyahoga, Erie, Fulton, Geauga, Huron and 11 more89 min
Aug 1, 1:06 PM EDTMesoscale DiscussionSPCAllen, Ashland, Auglaize, Belmont, Carroll, Champaign and 48 more24 min
Aug 1, 1:19 PM EDTSevere Thunderstorm WatchSPCAllen, Ashland, Ashtabula, Auglaize, Belmont, Carroll and 49 more6 hr
Aug 1, 3:22 PM EDTMesoscale DiscussionSPCBerkeley, Grant, Hampshire, Hardy, Jefferson, Mineral and 2 more83 min

Nearby

Mesoscale Discussions in Ohio, 2011Mesoscale Discussions in West Virginia, 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.