Alert archive / Pennsylvania / Mesoscale Discussions in 2009
Mesoscale Discussion 845
The Storm Prediction Center issued this mesoscale discussion at May 16, 2009, 12:05 PM EDT for 5 states. It was in force for 55 min.
The area
The outline as issued.
The facts
- Issued
- May 16, 2009, 12:05 PM EDT (16:05 UTC)
- Expired
- May 16, 2009, 1:00 PM EDT
- In force
- 55 min
- Issued by
- the Storm Prediction Center
All 118 counties
Allegany County, MD, Garrett County, MD, Allegany County, NY, Broome County, NY, Cattaraugus County, NY, Cayuga County, NY, Chautauqua County, NY, Chemung County, NY, Chenango County, NY, Cortland County, NY, Erie County, NY, Genesee County, NY, Lewis County, NY, Livingston County, NY, Madison County, NY, Monroe County, NY, Niagara County, NY, Oneida County, NY, Onondaga County, NY, Ontario County, NY, Orleans County, NY, Oswego County, NY, Schuyler County, NY, Seneca County, NY, Steuben County, NY, Tioga County, NY, Tompkins County, NY, Wayne County, NY, Wyoming County, NY, Yates County, NY, Belmont County, OH, Jefferson County, OH, Monroe County, OH, Washington County, OH, Allegheny County, PA, Armstrong County, PA, Beaver County, PA, Bedford County, PA, Blair County, PA, Bradford County, PA, Butler County, PA, Cambria County, PA, Cameron County, PA, Centre County, PA, Clarion County, PA, Clearfield County, PA, Clinton County, PA, Columbia County, PA, Crawford County, PA, Cumberland County, PA, Dauphin County, PA, Elk County, PA, Fayette County, PA, Forest County, PA, Franklin County, PA, Fulton County, PA, Greene County, PA, Huntingdon County, PA, Indiana County, PA, Jefferson County, PA, Juniata County, PA, Lackawanna County, PA, Lawrence County, PA, Luzerne County, PA, Lycoming County, PA, McKean County, PA, Mercer County, PA, Mifflin County, PA, Montour County, PA, Northumberland County, PA, Perry County, PA, Potter County, PA, Snyder County, PA, Somerset County, PA, Sullivan County, PA, Susquehanna County, PA, Tioga County, PA, Union County, PA, Venango County, PA, Warren County, PA, Washington County, PA, Westmoreland County, PA, Wyoming County, PA, Barbour County, WV, Braxton County, WV, Brooke County, WV, Calhoun County, WV, Clay County, WV, Doddridge County, WV, Gilmer County, WV, Grant County, WV, Hancock County, WV, Harrison County, WV, Jackson County, WV, Kanawha County, WV, Lewis County, WV, Marion County, WV, Marshall County, WV, Mason County, WV, Mineral County, WV, Monongalia County, WV, Morgan County, WV, Nicholas County, WV, Ohio County, WV, Pleasants County, WV, Preston County, WV, Putnam County, WV, Randolph County, WV, Ritchie County, WV, Roane County, WV, Taylor County, WV, Tucker County, WV, Tyler County, WV, Upshur County, WV, Webster County, WV, Wetzel County, WV, Wirt County, WV, Wood County, WV
The radar
The State College radar (KCCX), 69 km from the middle of the area, began a volume at 16:08 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
Pittsburgh, PA (KPIT), launched 12:00Z, 4.1 hours before the alert went out and 138 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.
- Mixed-layer CAPE
- 88 J/kg
- Mixed-layer CIN
- -90 J/kg
- Mixed-layer LCL
- 1095 m above ground
- 0-6 km bulk shear
- 38 kt
- 0-1 km storm-relative helicity
- 190 m²/s²
- 0-3 km storm-relative helicity
- 190 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted, in the capitals the NWS used until 2016.
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</html>SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 16, 2:36 PM EDT | Mesoscale Discussion | SPC | Baltimore, Carroll, Frederick, Howard, Montgomery, Prince George's and 1 more | 24 min |
| May 16, 1:00 PM EDT | Severe Thunderstorm Watch | SPC | Allegany, Broome, Cattaraugus, Cayuga, Chemung, Chenango and 16 more | 7 hr |
| May 16, 3:55 PM EDT | Mesoscale Discussion | SPC | Allegany, Broome, Cattaraugus, Cayuga, Chemung, Chenango and 17 more | 65 min |
| May 16, 6:29 PM EDT | Mesoscale Discussion | SPC | Albany, Broome, Chemung, Chenango, Cortland, Delaware and 12 more | 2 hr |
| May 15, 9:14 PM EDT | Mesoscale Discussion | SPC | Allen, Auglaize, Butler, Champaign, Clark, Darke and 11 more | 2 hr |
| May 15, 11:28 PM EDT | Mesoscale Discussion | SPC | Adams, Auglaize, Brown, Butler, Champaign, Clark and 13 more | 2 hr |
| May 16, 2:46 PM EDT | Mesoscale Discussion | SPC | Gallia, Lawrence | 59 min |
Nearby
Mesoscale Discussions in Pennsylvania, 2009Mesoscale Discussions in West Virginia, 2009Mesoscale Discussions in New York, 2009Every mesoscale discussion in 2009
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.