Alert archive / Pennsylvania / Severe Thunderstorm Watches in 2004

Severe Thunderstorm Watch 766

August 20, 2004Morris County, Sussex County, Warren County, New Jersey; Sullivan County, New York; 33 counties in Pennsylvania

The Storm Prediction Center issued this severe thunderstorm watch at Aug 20, 2004, 2:05 PM EDT for Morris County, Sussex County, Warren County, New Jersey; Sullivan County, New York; 33 counties in Pennsylvania. It was in force for 5 hr.

The area

The outline as issued.

The facts

Issued
Aug 20, 2004, 2:05 PM EDT (18:05 UTC)
Expired
Aug 20, 2004, 7:00 PM EDT
In force
5 hr
Issued by
the Storm Prediction Center
All 37 counties

Morris County, NJ, Sussex County, NJ, Warren County, NJ, Sullivan County, NY, Blair County, PA, Bradford County, PA, Cambria County, PA, Cameron County, PA, Carbon County, PA, Centre County, PA, Clearfield County, PA, Clinton County, PA, Columbia County, PA, Dauphin County, PA, Elk County, PA, Huntingdon County, PA, Juniata County, PA, Lackawanna County, PA, Lehigh County, PA, Luzerne County, PA, Lycoming County, PA, Mifflin County, PA, Monroe County, PA, Montour County, PA, Northampton County, PA, Northumberland County, PA, Perry County, PA, Pike County, PA, Potter County, PA, Schuylkill County, PA, Snyder County, PA, Sullivan County, PA, Susquehanna County, PA, Tioga County, PA, Union County, PA, Wayne County, PA, Wyoming County, PA

The radar

The State College radar (KCCX), 90 km from the middle of the area, began a volume at 18:06 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.

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
Aug 20, 2:29 PM EDTSevere Thunderstorm WarningCTPLycoming61 min
Aug 20, 2:42 PM EDTSevere Thunderstorm WarningCTPCentre48 min
Aug 20, 3:11 PM EDTSevere Thunderstorm WarningCTPUnion64 min
Aug 20, 3:25 PM EDTSevere Thunderstorm WarningCTPLycoming50 min
Aug 20, 3:30 PM EDTSevere Thunderstorm WarningBGMLuzerne60 min
Aug 20, 3:46 PM EDTSevere Thunderstorm WarningCTPColumbia59 min
Aug 20, 3:48 PM EDTSevere Thunderstorm WarningCTPMontour, Northumberland42 min
Aug 20, 3:55 PM EDTSevere Thunderstorm WarningCTPSullivan50 min
Aug 20, 4:01 PM EDTSevere Thunderstorm WarningCTPClearfield89 min
Aug 20, 4:16 PM EDTSevere Thunderstorm WarningBGMLackawanna59 min
Aug 20, 4:27 PM EDTSevere Thunderstorm WarningBGMWyoming63 min
Aug 20, 4:52 PM EDTSevere Thunderstorm WarningPHISussex53 min
Aug 20, 5:04 PM EDTSevere Thunderstorm WarningCTPCentre56 min
Aug 20, 5:19 PM EDTSevere Thunderstorm WarningCTPSchuylkill56 min
Aug 20, 6:02 PM EDTSevere Thunderstorm WarningPHILehigh43 min
Aug 20, 6:25 PM EDTSevere Thunderstorm WarningPHINorthampton50 min
Aug 20, 6:49 PM EDTSevere Thunderstorm WarningCTPClearfield, Elk56 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

Buffalo Intl Airport, NY (KBUF), launched 12:00Z, 6.1 hours before the alert went out and 230 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, Buffalo Intl Airport, NY at 12:00Z on 2004-08-20Temperature 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, Buffalo Intl Airport, NY at 12:00Z on 2004-08-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 100 square meters per square second.19395878Sfc1 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
1107 m above ground
0-6 km bulk shear
53 kt
0-1 km storm-relative helicity
100 m²/s²
0-3 km storm-relative helicity
150 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Aug 20, 3:41 PM EDTMesoscale DiscussionSPCMorris, Sussex, Warren2 hr
Aug 20, 6:10 PM EDTSevere Thunderstorm WatchSPCPassaic, Sussex, Warren5 hr
Aug 20, 11:56 AM EDTMesoscale DiscussionSPCAlbany, Broome, Chemung, Chenango, Columbia, Delaware and 11 more2 hr
Aug 20, 1:05 PM EDTSevere Thunderstorm WatchSPCAlbany, Columbia, Dutchess, Greene, Orange, Putnam and 3 more6 hr
Aug 19, 8:28 PM EDTMesoscale DiscussionSPCAdams92 min
Aug 20, 4:03 PM EDTMesoscale DiscussionSPCAdams, Bedford, Berks, Cumberland, Franklin, Fulton and 4 more2 hr
Aug 20, 4:25 PM EDTSevere Thunderstorm WatchSPCAllegheny, Armstrong, Beaver, Butler, Cambria, Clearfield and 7 more5 hr
Aug 20, 7:15 PM EDTMesoscale DiscussionSPCCambria, Clearfield, Indiana, Somerset, Westmoreland90 min

Nearby

Severe Thunderstorm Watches in Pennsylvania, 2004Severe Thunderstorm Watches in New Jersey, 2004Severe Thunderstorm Watches in New York, 2004Every severe thunderstorm watch in 2004

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.