Alert archive / Pennsylvania / Severe Thunderstorm Watches in 2015

Severe Thunderstorm Watch 296

June 12, 20156 counties in New York; 23 counties in Pennsylvania

The Storm Prediction Center issued this severe thunderstorm watch at Jun 12, 2015, 7:25 PM EDT for 6 counties in New York; 23 counties in Pennsylvania. It was in force for 4 hr.

The area

The outline as issued.

The facts

Issued
Jun 12, 2015, 7:25 PM EDT (23:25 UTC)
Expired
Jun 12, 2015, 11:20 PM EDT
In force
4 hr
Issued by
the Storm Prediction Center
Largest hail expected
1 in
Strongest gust expected
60 kt
All 29 counties

Broome County, NY, Chenango County, NY, Delaware County, NY, Otsego County, NY, Sullivan County, NY, Tioga County, NY, Bedford County, PA, Blair County, PA, Bradford County, PA, Cambria County, PA, Centre County, PA, Columbia County, PA, Fulton County, PA, Huntingdon County, PA, Juniata County, PA, Lackawanna County, PA, Luzerne County, PA, Mifflin County, PA, Montour County, PA, Northumberland County, PA, Perry County, PA, Pike County, PA, Snyder County, PA, Somerset County, PA, Sullivan County, PA, Susquehanna County, PA, Union County, PA, Wayne County, PA, Wyoming County, PA

The radar

The State College radar (KCCX), 68 km from the middle of the area, began a volume at 23:24 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.

What SPC expected

The probabilities SPC published with the watch, for the watch area over its life.

Two or more tornadoes
10%
One or more EF2 to EF5 tornadoes
2%
Ten or more severe wind reports
40%
One or more gusts of 65 knots or more
10%
Ten or more severe hail reports
20%
One or more hailstones of 2 inches or more
10%
Six or more combined severe hail and wind reports
60%

Warnings issued inside it

13 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.

IssuedProductOfficeCountiesLasted
Jun 12, 7:27 PM EDTSevere Thunderstorm WarningBGMChenango, Madison, Otsego48 min
Jun 12, 7:36 PM EDTSevere Thunderstorm WarningBGMBroome, Chenango, Cortland, Tioga39 min
Jun 12, 7:41 PM EDTSevere Thunderstorm WarningBGMTioga64 min
Jun 12, 7:42 PM EDTSevere Thunderstorm WarningCTPBlair, Centre, Clearfield, Clinton, Huntingdon, Juniata and 4 more63 min
Jun 12, 7:52 PM EDTSevere Thunderstorm WarningCTPBedford, Blair, Cambria, Huntingdon, Somerset53 min
Jun 12, 7:57 PM EDTSevere Thunderstorm WarningBGMBroome, Chenango, Delaware, Otsego48 min
Jun 12, 8:01 PM EDTSevere Thunderstorm WarningBGMBradford, Susquehanna59 min
Jun 12, 8:01 PM EDTSevere Thunderstorm WarningCTPColumbia, Lycoming, Sullivan, Tioga59 min
Jun 12, 8:14 PM EDTSevere Thunderstorm WarningCTPCentre, Huntingdon, Juniata, Mifflin, Perry61 min
Jun 12, 8:25 PM EDTSevere Thunderstorm WarningBGMOtsego20 min
Jun 12, 8:41 PM EDTSevere Thunderstorm WarningBGMDelaware34 min
Jun 12, 8:43 PM EDTSevere Thunderstorm WarningCTPCentre, Clinton, Columbia, Juniata, Lycoming, Mifflin and 4 more77 min
Jun 12, 9:18 PM EDTSevere Thunderstorm WarningCTPCumberland, Dauphin, Lancaster, Lebanon, Northumberland, Perry and 2 more57 min

Discussions around it

SPC mesoscale discussions over the same counties from four hours before the watch to its end.

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 12:00Z, 11.4 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-pSkew-T log-p diagram, Washington/Dulle, VA at 12:00Z on 2015-06-12Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 325 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, Washington/Dulle, VA at 12:00Z on 2015-06-12The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 38 square meters per square second.1939Sfc1 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
325 J/kg
Mixed-layer CIN
-121 J/kg
Mixed-layer LCL
1369 m above ground
0-6 km bulk shear
22 kt
0-1 km storm-relative helicity
38 m²/s²
0-3 km storm-relative helicity
67 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.1

Open this sounding in Storm Lab

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jun 12, 1:26 PM EDTMesoscale DiscussionSPCAllegany, Cattaraugus, Cayuga, Chautauqua, Cortland, Erie and 17 more64 min
Jun 12, 2:54 PM EDTSevere Thunderstorm WatchSPCAllegany, Cattaraugus, Chautauqua, Erie, Genesee, Jefferson and 7 more6 hr
Jun 12, 3:07 PM EDTTornado WatchSPCAlbany, Broome, Cayuga, Chemung, Chenango, Columbia and 27 more8 hr
Jun 12, 6:22 PM EDTMesoscale DiscussionSPCAlbany, Broome, Cayuga, Chemung, Chenango, Columbia and 29 more83 min
Jun 12, 12:52 PM EDTMesoscale DiscussionSPCBeaver, Crawford, Lawrence, Mercer113 min
Jun 12, 1:14 PM EDTSevere Thunderstorm WatchSPCAllegheny, Armstrong, Beaver, Butler, Cameron, Clarion and 16 more8 hr
Jun 12, 2:03 PM EDTMesoscale DiscussionSPCAdams, Carbon, Columbia, Cumberland, Dauphin, Franklin and 14 more87 min
Jun 12, 4:21 PM EDTMesoscale DiscussionSPCAllegheny, Armstrong, Beaver, Butler, Clarion, Clearfield and 7 more84 min
Jun 12, 6:53 PM EDTMesoscale DiscussionSPCAllegheny, Armstrong, Cambria, Cameron, Centre, Clarion and 13 more97 min

Nearby

Severe Thunderstorm Watches in Pennsylvania, 2015Severe Thunderstorm Watches in New York, 2015Every severe thunderstorm watch 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.