Alert archive / West Virginia / Mesoscale Discussions in 2017

Mesoscale Discussion 655

May 5, 20179 counties in Pennsylvania; 11 counties in West Virginia

The Storm Prediction Center issued this mesoscale discussion at May 5, 2017, 4:07 PM EDT for 9 counties in Pennsylvania; 11 counties in West Virginia. It was in force for 113 min.

The area

The outline as issued.

The facts

Issued
May 5, 2017, 4:07 PM EDT (20:07 UTC)
Expired
May 5, 2017, 6:00 PM EDT
In force
113 min
Issued by
the Storm Prediction Center
Chance of a watch
20%

Counties Allegheny County, PA, Armstrong County, PA, Butler County, PA, Clarion County, PA, Fayette County, PA, Greene County, PA, Jefferson County, PA, Washington County, PA, Westmoreland County, PA, Barbour County, WV, Braxton County, WV, Harrison County, WV, Lewis County, WV, Marion County, WV, Monongalia County, WV, Preston County, WV, Randolph County, WV, Taylor County, WV, Upshur County, WV, Webster County, WV

The radar

The Pittsburgh radar (KPBZ), 97 km from the middle of the area, began a volume at 20:09 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, 8.1 hours before the alert went out and 83 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 2017-05-05Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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 2017-05-05The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 454 square meters per square second.1939587897Sfc1 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
532 m above ground
0-6 km bulk shear
55 kt
0-1 km storm-relative helicity
454 m²/s²
0-3 km storm-relative helicity
474 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 5, 6:15 PM EDTMesoscale DiscussionSPCFranklin90 min

Nearby

Mesoscale Discussions in West Virginia, 2017Mesoscale Discussions in Pennsylvania, 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.