Alert archive / Pennsylvania / Mesoscale Discussions in 2017

Mesoscale Discussion 626

May 1, 20174 states

The Storm Prediction Center issued this mesoscale discussion at May 1, 2017, 4:36 PM EDT for 4 states. It was in force for 84 min.

The area

The outline as issued.

The facts

Issued: May 1, 2017, 4:36 PM EDT (20:36 UTC)
Expired: May 1, 2017, 6:00 PM EDT
In force: 84 min
Issued by: the Storm Prediction Center

All 41 counties

Allegany County, MD, Broome County, NY, Cayuga County, NY, Chemung County, NY, Chenango County, NY, Cortland County, NY, Madison County, NY, Oneida County, NY, Onondaga County, NY, Ontario County, NY, Oswego County, NY, Schuyler County, NY, Seneca County, NY, Steuben County, NY, Tioga County, NY, Tompkins County, NY, Wayne County, NY, Yates County, NY, Bedford County, PA, Blair County, PA, Bradford County, PA, Centre County, PA, Clinton County, PA, Franklin County, PA, Fulton County, PA, Huntingdon County, PA, Juniata County, PA, Lycoming County, PA, Mifflin County, PA, Montour County, PA, Northumberland County, PA, Perry County, PA, Potter County, PA, Snyder County, PA, Sullivan County, PA, Susquehanna County, PA, Tioga County, PA, Union County, PA, Wyoming County, PA, Grant County, WV, Mineral County, WV

The radar

The State College radar (KCCX), 48 km from the middle of the area, began a volume at 20:38 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.

Severe Thunderstorm Watch 186May 1, 5:55 PM EDT

The nearest sounding before it

Buffalo Intl Airport, NY (KBUF), launched 12:00Z, 8.6 hours before the alert went out and 209 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 1242 m above ground
0-6 km bulk shear: 48 kt
0-1 km storm-relative helicity: 306 m²/s²
0-3 km storm-relative helicity: 318 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.

Issued	Product	Office	Counties	Lasted
May 1, 11:59 AM EDT	Mesoscale Discussion	SPC	Garrett	2 hr
May 1, 12:32 PM EDT	Tornado Watch	SPC	Garrett	4 hr
May 1, 5:54 PM EDT	Severe Thunderstorm Watch	SPC	Allegany, Baltimore, Carroll, Charles, Frederick, Harford and 5 more	5 hr
May 1, 1:41 PM EDT	Mesoscale Discussion	SPC	Allegany, Cattaraugus, Genesee, Livingston, Ontario, Steuben and 2 more	64 min
May 1, 2:12 PM EDT	Tornado Watch	SPC	Allegany, Broome, Cattaraugus, Cayuga, Chautauqua, Chemung and 23 more	8 hr
May 1, 6:29 PM EDT	Mesoscale Discussion	SPC	Albany, Chenango, Clinton, Columbia, Delaware, Dutchess and 20 more	61 min
May 1, 6:52 PM EDT	Severe Thunderstorm Watch	SPC	Albany, Columbia, Delaware, Dutchess, Essex, Franklin and 15 more	4 hr
May 1, 7:16 PM EDT	Mesoscale Discussion	SPC	New York, Richmond, Rockland, Westchester	2 hr
May 1, 2:29 PM EDT	Mesoscale Discussion	SPC	Greenbrier, Mercer, Monroe, Nicholas, Pendleton, Pocahontas and 3 more	2 hr

Nearby

Mesoscale Discussions in Pennsylvania, 2017 Mesoscale Discussions in New York, 2017 Mesoscale Discussions in West Virginia, 2017 Every 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.