Alert archive / West Virginia / Mesoscale Discussions in 2015

Mesoscale Discussion 1337

July 9, 20154 states

The Storm Prediction Center issued this mesoscale discussion at Jul 9, 2015, 11:27 AM EDT for 4 states. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued: Jul 9, 2015, 11:27 AM EDT (15:27 UTC)
Expired: Jul 9, 2015, 1:30 PM EDT
In force: 2 hr
Issued by: the Storm Prediction Center
Chance of a watch: 40%

All 42 counties

Garrett County, MD, Belmont County, OH, Jefferson County, OH, Monroe County, OH, Washington County, OH, Allegheny County, PA, Beaver County, PA, Fayette County, PA, Greene County, PA, Washington County, PA, Westmoreland County, PA, Barbour County, WV, Braxton County, WV, Brooke County, WV, Calhoun County, WV, Clay County, WV, Doddridge County, WV, Fayette County, WV, Gilmer County, WV, Grant County, WV, Hancock County, WV, Harrison County, WV, Lewis County, WV, Marion County, WV, Marshall County, WV, Monongalia County, WV, Nicholas County, WV, Ohio County, WV, Pendleton County, WV, Pleasants County, WV, Preston County, WV, Randolph County, WV, Ritchie County, WV, Roane County, WV, Taylor County, WV, Tucker County, WV, Tyler County, WV, Upshur County, WV, Webster County, WV, Wetzel County, WV, Wirt County, WV, Wood County, WV

The radar

The Pittsburgh radar (KPBZ), 127 km from the middle of the area, began a volume at 15:28 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.

Tornado Watch 397Jul 9, 1:25 PM EDT

The nearest sounding before it

Pittsburgh, PA (KAGC), launched 12:00Z, 3.5 hours before the alert went out and 118 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 104 J/kg
Mixed-layer CIN: -48 J/kg
Mixed-layer LCL: 631 m above ground
0-6 km bulk shear: 37 kt
0-1 km storm-relative helicity: 208 m²/s²
0-3 km storm-relative helicity: 233 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.2

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.

Issued	Product	Office	Counties	Lasted
Jul 9, 12:59 PM EDT	Mesoscale Discussion	SPC	Allegany, Anne Arundel, Baltimore, Carroll, Cecil, Frederick and 7 more	2 hr
Jul 9, 1:27 PM EDT	Tornado Watch	SPC	Allegany, Baltimore, Carroll, Frederick, Garrett, Harford and 2 more	6 hr
Jul 9, 3:09 PM EDT	Mesoscale Discussion	SPC	Allegany, Anne Arundel, Baltimore, Caroline, Carroll, Cecil and 10 more	96 min
Jul 9, 4:55 PM EDT	Mesoscale Discussion	SPC	Allegany, Baltimore, Carroll, Cecil, Frederick, Garrett and 5 more	95 min
Jul 9, 4:57 PM EDT	Severe Thunderstorm Watch	SPC	Caroline, Cecil, Kent, Queen Anne's, Talbot	5 hr
Jul 9, 6:25 PM EDT	Mesoscale Discussion	SPC	Cecil, Harford	95 min
Jul 9, 7:04 PM EDT	Mesoscale Discussion	SPC	Anne Arundel, Calvert, Caroline, Charles, Dorchester, Prince George's and 6 more	86 min
Jul 9, 12:15 PM EDT	Mesoscale Discussion	SPC	Boone, Logan, McDowell, Mingo, Wyoming	3 hr
Jul 9, 5:58 PM EDT	Mesoscale Discussion	SPC	McDowell	2 hr

Nearby

Mesoscale Discussions in West Virginia, 2015 Mesoscale Discussions in Pennsylvania, 2015 Mesoscale Discussions in Ohio, 2015 Every mesoscale discussion in 2015

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.