Alert archive / Pennsylvania / Mesoscale Discussions in 2011

Mesoscale Discussion 987

May 26, 2011Sullivan County, New York; 47 counties in Pennsylvania

The Storm Prediction Center issued this mesoscale discussion at May 26, 2011, 5:49 PM EDT for Sullivan County, New York; 47 counties in Pennsylvania. It was in force for 56 min.

The area

The outline as issued.

The facts

Issued
May 26, 2011, 5:49 PM EDT (21:49 UTC)
Expired
May 26, 2011, 6:45 PM EDT
In force
56 min
Issued by
the Storm Prediction Center
All 48 counties

Sullivan County, NY, Adams County, PA, Armstrong County, PA, Bedford County, PA, Blair County, PA, Bradford County, PA, Cambria County, PA, Cameron County, PA, Carbon County, PA, Centre County, PA, Clarion County, PA, Clearfield County, PA, Clinton County, PA, Columbia County, PA, Cumberland County, PA, Dauphin County, PA, Elk County, PA, Forest County, PA, Franklin County, PA, Fulton County, PA, Huntingdon County, PA, Indiana County, PA, Jefferson County, PA, Juniata County, PA, Lackawanna County, PA, Lancaster County, PA, Lebanon County, PA, Luzerne County, PA, Lycoming County, PA, McKean County, PA, Mifflin County, PA, Montour County, PA, Northumberland County, PA, Perry County, PA, Pike County, PA, Potter County, PA, Schuylkill County, PA, Snyder County, PA, Somerset County, PA, Sullivan County, PA, Susquehanna County, PA, Tioga County, PA, Union County, PA, Warren County, PA, Wayne County, PA, Westmoreland County, PA, Wyoming County, PA, York County, PA

The radar

The State College radar (KCCX), 66 km from the middle of the area, began a volume at 21:52 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

Phillips Aaf/Abe, MD (KAPG), launched 12:00Z, 9.8 hours before the alert went out and 191 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, Phillips Aaf/Abe, MD at 12:00Z on 2011-05-26Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 970 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, Phillips Aaf/Abe, MD at 12:00Z on 2011-05-26The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 257 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
970 J/kg
Mixed-layer CIN
-145 J/kg
Mixed-layer LCL
989 m above ground
0-6 km bulk shear
37 kt
0-1 km storm-relative helicity
257 m²/s²
0-3 km storm-relative helicity
288 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

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.

IssuedProductOfficeCountiesLasted
May 26, 11:55 AM EDTMesoscale DiscussionSPCBroome, Cayuga, Chemung, Chenango, Cortland, Delaware and 15 more95 min
May 26, 12:29 PM EDTTornado WatchSPCClinton, Essex, Franklin, St. Lawrence8 hr
May 26, 2:16 PM EDTTornado WatchSPCAlbany, Broome, Cayuga, Chemung, Chenango, Cortland and 26 more8 hr
May 26, 2:57 PM EDTMesoscale DiscussionSPCAlbany, Broome, Chemung, Chenango, Clinton, Cortland and 20 more63 min
May 26, 6:06 PM EDTSevere Thunderstorm WatchSPCAllegany, Cattaraugus, Chautauqua, Erie, Livingston, Ontario and 1 more6 hr
May 26, 6:41 PM EDTMesoscale DiscussionSPCAlbany, Broome, Chenango, Cortland, Delaware, Essex and 16 more64 min
May 25, 8:14 PM EDTMesoscale DiscussionSPCCrawford, Lawrence, Mercer2 hr
May 26, 2:37 AM EDTMesoscale DiscussionSPCBeaver, Lawrence83 min
May 26, 2:53 PM EDTTornado WatchSPCAdams, Bedford, Blair, Centre, Clinton, Columbia and 20 more7 hr

Nearby

Mesoscale Discussions in Pennsylvania, 2011Mesoscale Discussions in New York, 2011Every mesoscale discussion in 2011

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.