Alert archive / West Virginia / Mesoscale Discussions in 2017

Mesoscale Discussion 526

April 20, 20174 states

The Storm Prediction Center issued this mesoscale discussion at Apr 20, 2017, 2:40 PM EDT for 4 states. It was in force for 65 min.

The area

The outline as issued.

The facts

Issued
Apr 20, 2017, 2:40 PM EDT (18:40 UTC)
Expired
Apr 20, 2017, 3:45 PM EDT
In force
65 min
Issued by
the Storm Prediction Center
Chance of a watch
20%
All 81 counties

Allegany County, MD, Garrett County, MD, Washington County, MD, Ashtabula County, OH, Belmont County, OH, Carroll County, OH, Columbiana County, OH, Coshocton County, OH, Cuyahoga County, OH, Geauga County, OH, Guernsey County, OH, Harrison County, OH, Holmes County, OH, Jefferson County, OH, Lake County, OH, Mahoning County, OH, Medina County, OH, Monroe County, OH, Morgan County, OH, Muskingum County, OH, Noble County, OH, Portage County, OH, Stark County, OH, Summit County, OH, Trumbull County, OH, Tuscarawas County, OH, Washington County, OH, Wayne County, OH, Allegheny County, PA, Armstrong County, PA, Beaver County, PA, Bedford County, PA, Blair County, PA, Butler County, PA, Cambria County, PA, Clarion County, PA, Clearfield County, PA, Crawford County, PA, Elk County, PA, Fayette County, PA, Forest County, PA, Franklin County, PA, Fulton County, PA, Greene County, PA, Huntingdon County, PA, Indiana County, PA, Jefferson County, PA, Lawrence County, PA, Mercer County, PA, Somerset County, PA, Venango County, PA, Warren County, PA, Washington County, PA, Westmoreland County, PA, Barbour County, WV, Berkeley County, WV, Brooke County, WV, Doddridge County, WV, Gilmer County, WV, Grant County, WV, Hampshire County, WV, Hancock County, WV, Harrison County, WV, Jefferson County, WV, Lewis County, WV, Marion County, WV, Marshall County, WV, Mineral County, WV, Monongalia County, WV, Morgan County, WV, Ohio County, WV, Pleasants County, WV, Preston County, WV, Ritchie County, WV, Taylor County, WV, Tucker County, WV, Tyler County, WV, Upshur County, WV, Wetzel County, WV, Wirt County, WV, Wood County, WV

The radar

The Pittsburgh radar (KPBZ), 24 km from the middle of the area, began a volume at 18:43 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

Pittsburgh, PA (KAGC), launched 12:00Z, 6.7 hours before the alert went out and 33 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, Pittsburgh, PA at 12:00Z on 2017-04-20Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 59 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, Pittsburgh, PA at 12:00Z on 2017-04-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 186 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
59 J/kg
Mixed-layer CIN
-86 J/kg
Mixed-layer LCL
791 m above ground
0-6 km bulk shear
38 kt
0-1 km storm-relative helicity
186 m²/s²
0-3 km storm-relative helicity
182 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

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SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 20, 1:36 PM EDTMesoscale DiscussionSPCAllen, Ashland, Auglaize, Champaign, Crawford, Darke and 27 more84 min
Apr 20, 2:08 PM EDTSevere Thunderstorm WatchSPCAllen, Ashland, Auglaize, Crawford, Defiance, Erie and 22 more6 hr
Apr 20, 4:31 PM EDTMesoscale DiscussionSPCAllen, Auglaize, Champaign, Crawford, Darke, Defiance and 28 more119 min
Apr 20, 7:01 PM EDTMesoscale DiscussionSPCAllen, Auglaize, Crawford, Defiance, Erie, Fulton and 19 more59 min

Nearby

Mesoscale Discussions in West Virginia, 2017Mesoscale Discussions in Pennsylvania, 2017Mesoscale Discussions in Ohio, 2017Every mesoscale discussion in 2017

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.