Alert archive / Pennsylvania / Mesoscale Discussions in 2003

Mesoscale Discussion 1943

July 21, 20038 counties in New York; 31 counties in Pennsylvania

The Storm Prediction Center issued this mesoscale discussion at Jul 21, 2003, 3:51 PM EDT for 8 counties in New York; 31 counties in Pennsylvania. It was in force for 114 min.

The area

The outline as issued.

The facts

Issued: Jul 21, 2003, 3:51 PM EDT (19:51 UTC)
Expired: Jul 21, 2003, 5:45 PM EDT
In force: 114 min
Issued by: the Storm Prediction Center

All 39 counties

Allegany County, NY, Broome County, NY, Chemung County, NY, Cortland County, NY, Schuyler County, NY, Steuben County, NY, Tioga County, NY, Tompkins County, NY, Blair County, PA, Bradford County, PA, Cambria County, PA, Cameron County, PA, Centre County, PA, Clearfield County, PA, Clinton County, PA, Columbia County, PA, Elk County, PA, Fayette County, PA, Forest County, PA, Huntingdon County, PA, Indiana County, PA, Jefferson County, PA, Juniata County, PA, Luzerne County, PA, Lycoming County, PA, McKean County, PA, Mifflin County, PA, Montour County, PA, Northumberland County, PA, Perry County, PA, Potter County, PA, Schuylkill County, PA, Snyder County, PA, Somerset County, PA, Sullivan County, PA, Tioga County, PA, Union County, PA, Warren County, PA, Wyoming County, PA

The radar

The State College radar (KCCX), 57 km from the middle of the area, began a volume at 19:52 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 nearest sounding before it

Pittsburgh, PA (KPIT), launched 12:00Z, 7.9 hours before the alert went out and 133 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: 1009 J/kg
Mixed-layer CIN: -36 J/kg
Mixed-layer LCL: 823 m above ground
0-6 km bulk shear: 27 kt
0-1 km storm-relative helicity: 134 m²/s²
0-3 km storm-relative helicity: 131 m²/s²
Significant tornado parameter: 0.4
Supercell composite: 3.2

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 21, 1:15 PM EDT	Mesoscale Discussion	SPC	Allegany, Broome, Cattaraugus, Chemung, Schuyler, Steuben and 2 more	2 hr
Jul 21, 1:40 PM EDT	Severe Thunderstorm Watch	SPC	Allegany, Broome, Chemung, Cortland, Schuyler, Steuben and 2 more	6 hr
Jul 21, 2:46 PM EDT	Mesoscale Discussion	SPC	Albany, Columbia, Delaware, Greene, Montgomery, Otsego and 5 more	119 min
Jul 21, 3:35 PM EDT	Severe Thunderstorm Watch	SPC	Albany, Chenango, Columbia, Delaware, Dutchess, Greene and 9 more	6 hr
Jul 21, 6:30 PM EDT	Severe Thunderstorm Watch	SPC	Bronx, Kings, Nassau, New York, Orange, Putnam and 4 more	5 hr
Jul 21, 7:51 PM EDT	Mesoscale Discussion	SPC	Albany, Bronx, Columbia, Dutchess, Fulton, Greene and 17 more	84 min
Jul 21, 8:40 AM EDT	Severe Thunderstorm Watch	SPC	Allegheny, Armstrong, Beaver, Butler, Clarion, Greene and 4 more	5 hr

Nearby

Mesoscale Discussions in Pennsylvania, 2003 Mesoscale Discussions in New York, 2003 Every mesoscale discussion in 2003

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.