Alert archive / New York / Mesoscale Discussions in 2004

Mesoscale Discussion 2056

August 20, 20045 states

The Storm Prediction Center issued this mesoscale discussion at Aug 20, 2004, 11:56 AM EDT for 5 states. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued: Aug 20, 2004, 11:56 AM EDT (15:56 UTC)
Expired: Aug 20, 2004, 2:00 PM EDT
In force: 2 hr
Issued by: the Storm Prediction Center

All 44 counties

Berkshire County, MA, Franklin County, MA, Hampden County, MA, Hampshire County, MA, Worcester County, MA, Cheshire County, NH, Hillsborough County, NH, Merrimack County, NH, Sullivan County, NH, Albany County, NY, Broome County, NY, Chemung County, NY, Chenango County, NY, Columbia County, NY, Delaware County, NY, Dutchess County, NY, Greene County, NY, Montgomery County, NY, Otsego County, NY, Rensselaer County, NY, Saratoga County, NY, Schenectady County, NY, Schoharie County, NY, Sullivan County, NY, Tioga County, NY, Ulster County, NY, Bradford County, PA, Centre County, PA, Clinton County, PA, Columbia County, PA, Lackawanna County, PA, Luzerne County, PA, Lycoming County, PA, Montour County, PA, Pike County, PA, Potter County, PA, Sullivan County, PA, Susquehanna County, PA, Tioga County, PA, Union County, PA, Wayne County, PA, Wyoming County, PA, Bennington County, VT, Windham County, VT

The radar

The Albany radar (KENX), 49 km from the middle of the area, began a volume at 15:55 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

Albany, NY (KALY), launched 12:00Z, 3.9 hours before the alert went out and 70 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: 244 J/kg
Mixed-layer CIN: -24 J/kg
Mixed-layer LCL: 569 m above ground
0-6 km bulk shear: 51 kt
0-1 km storm-relative helicity: 77 m²/s²
0-3 km storm-relative helicity: 142 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.2

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
Aug 20, 1:05 PM EDT	Severe Thunderstorm Watch	SPC		6 hr
Aug 20, 3:41 PM EDT	Mesoscale Discussion	SPC		2 hr
Aug 20, 6:10 PM EDT	Severe Thunderstorm Watch	SPC		5 hr
Aug 20, 2:05 PM EDT	Severe Thunderstorm Watch	SPC	Sullivan	5 hr
Aug 19, 8:28 PM EDT	Mesoscale Discussion	SPC	Adams	92 min
Aug 20, 4:03 PM EDT	Mesoscale Discussion	SPC	Adams, Bedford, Berks, Cumberland, Franklin, Fulton and 4 more	2 hr
Aug 20, 4:25 PM EDT	Severe Thunderstorm Watch	SPC	Allegheny, Armstrong, Beaver, Butler, Cambria, Clearfield and 7 more	5 hr
Aug 20, 7:15 PM EDT	Mesoscale Discussion	SPC	Cambria, Clearfield, Indiana, Somerset, Westmoreland	90 min

Nearby

Mesoscale Discussions in New York, 2004 Mesoscale Discussions in Pennsylvania, 2004 Mesoscale Discussions in Massachusetts, 2004 Every mesoscale discussion 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.