Alert archive / West Virginia / Mesoscale Discussions in 2018

Mesoscale Discussion 391

May 12, 20184 states

The Storm Prediction Center issued this mesoscale discussion at May 12, 2018, 1:51 PM EDT for 4 states. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued
May 12, 2018, 1:51 PM EDT (17:51 UTC)
Expired
May 12, 2018, 4:15 PM EDT
In force
2 hr
Issued by
the Storm Prediction Center
Chance of a watch
95%
All 59 counties

Allegany County, MD, Garrett County, MD, Athens County, OH, Belmont County, OH, Carroll County, OH, Columbiana County, OH, Coshocton County, OH, Guernsey County, OH, Harrison County, OH, Hocking County, OH, Holmes County, OH, Jefferson County, OH, Knox County, OH, Licking County, OH, Meigs County, OH, Monroe County, OH, Morgan County, OH, Muskingum County, OH, Noble County, OH, Perry County, OH, Tuscarawas County, OH, Vinton County, OH, Washington County, OH, Allegheny County, PA, Armstrong County, PA, Beaver County, PA, Bedford County, PA, Cambria County, PA, Fayette County, PA, Greene County, PA, Indiana County, PA, Somerset County, PA, Washington County, PA, Westmoreland County, PA, Barbour County, WV, Brooke County, WV, Doddridge County, WV, Gilmer County, WV, Grant County, WV, Hampshire County, WV, Hancock County, WV, Hardy County, WV, Harrison 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, Wetzel County, WV, Wirt County, WV, Wood County, WV

The radar

The Pittsburgh radar (KPBZ), 64 km from the middle of the area, began a volume at 17:52 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

Pittsburgh, PA (KAGC), launched 12:00Z, 5.9 hours before the alert went out and 51 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 2018-05-12Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1 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 2018-05-12The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 312 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
1 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
1381 m above ground
0-6 km bulk shear
53 kt
0-1 km storm-relative helicity
312 m²/s²
0-3 km storm-relative helicity
354 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
May 12, 2:47 PM EDTSevere Thunderstorm WatchSPCAllegany, Calvert, Charles, Frederick, Garrett, Montgomery and 3 more8 hr
May 12, 3:59 PM EDTMesoscale DiscussionSPCBaltimore, Carroll, Cecil, Harford, Howard, Kent and 3 more3 hr
May 12, 4:58 PM EDTTornado WatchSPCAnne Arundel, Baltimore, Caroline, Carroll, Cecil, Harford and 5 more5 hr
May 12, 5:05 PM EDTMesoscale DiscussionSPCAllegany, Frederick, Garrett, Washington115 min
May 12, 7:16 PM EDTMesoscale DiscussionSPCAnne Arundel, Baltimore, Caroline, Carroll, Cecil, Harford and 5 more59 min
May 12, 4:20 PM EDTMesoscale DiscussionSPCButler, Champaign, Clark, Clinton, Darke, Fairfield and 12 more115 min

Nearby

Mesoscale Discussions in West Virginia, 2018Mesoscale Discussions in Ohio, 2018Mesoscale Discussions in Pennsylvania, 2018Every mesoscale discussion in 2018

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.