Alert archive / Ohio / Mesoscale Discussions in 2007

Mesoscale Discussion 1816

August 20, 20075 states

The Storm Prediction Center issued this mesoscale discussion at Aug 20, 2007, 12:18 PM EDT for 5 states. It was in force for 117 min.

The area

The outline as issued.

The facts

Issued
Aug 20, 2007, 12:18 PM EDT (16:18 UTC)
Expired
Aug 20, 2007, 2:15 PM EDT
In force
117 min
Issued by
the Storm Prediction Center
All 83 counties

Adams County, IN, Blackford County, IN, Delaware County, IN, Fayette County, IN, Grant County, IN, Hamilton County, IN, Hancock County, IN, Henry County, IN, Howard County, IN, Jay County, IN, Madison County, IN, Marion County, IN, Randolph County, IN, Rush County, IN, Tipton County, IN, Union County, IN, Wayne County, IN, Wells County, IN, Garrett County, MD, 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, 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, Hardin County, OH, Harrison County, OH, Hocking County, OH, Holmes County, OH, Jefferson County, OH, Knox County, OH, Licking County, OH, Logan County, OH, Madison County, OH, Marion 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, Perry County, OH, Pickaway County, OH, Preble County, OH, Richland County, OH, Ross County, OH, Shelby County, OH, Tuscarawas County, OH, Union County, OH, Vinton County, OH, Warren County, OH, Washington County, OH, Wyandot County, OH, Greene County, PA, Washington County, PA, Brooke County, WV, Doddridge County, WV, Hancock County, WV, Marion County, WV, Marshall County, WV, Monongalia County, WV, Ohio County, WV, Pleasants County, WV, Preston County, WV, Taylor County, WV, Tyler County, WV, Wetzel County, WV, Wood County, WV

The radar

The Cincinnati radar (KILN), 104 km from the middle of the area, began a volume at 16:19 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, 4.3 hours before the alert went out and 102 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 2007-08-20Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 579 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 2007-08-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 131 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
579 J/kg
Mixed-layer CIN
-84 J/kg
Mixed-layer LCL
924 m above ground
0-6 km bulk shear
42 kt
0-1 km storm-relative helicity
131 m²/s²
0-3 km storm-relative helicity
166 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.8

Open this sounding in Storm Lab

The text

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

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SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Aug 20, 1:19 PM EDTSevere Thunderstorm WatchSPCDearborn, Fayette, Franklin, Ohio, Ripley, Switzerland and 2 more7 hr
Aug 20, 4:24 PM EDTMesoscale DiscussionSPCDearborn, Ohio, Switzerland66 min
Aug 19, 8:14 PM EDTMesoscale DiscussionSPCCalvert, Caroline, Charles, Dorchester, Prince George's, Saint Mary's and 4 more91 min
Aug 19, 11:58 PM EDTMesoscale DiscussionSPCDorchester, Saint Mary's, Somerset, Wicomico, Worcester92 min
Aug 20, 7:11 PM EDTMesoscale DiscussionSPCAllegany, Anne Arundel, Baltimore, Calvert, Caroline, Carroll and 17 more94 min

Nearby

Mesoscale Discussions in Ohio, 2007Mesoscale Discussions in Indiana, 2007Mesoscale Discussions in West Virginia, 2007Every mesoscale discussion in 2007

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.