Alert archive / Pennsylvania / Mesoscale Discussions in 2009

Mesoscale Discussion 849

May 16, 200923 counties in New York; 49 counties in Pennsylvania; Monongalia County, West Virginia

The Storm Prediction Center issued this mesoscale discussion at May 16, 2009, 3:55 PM EDT for 23 counties in New York; 49 counties in Pennsylvania; Monongalia County, West Virginia. It was in force for 65 min.

The area

The outline as issued.

The facts

Issued
May 16, 2009, 3:55 PM EDT (19:55 UTC)
Expired
May 16, 2009, 5:00 PM EDT
In force
65 min
Issued by
the Storm Prediction Center
All 73 counties

Allegany County, NY, Broome County, NY, Cattaraugus County, NY, Cayuga County, NY, Chemung County, NY, Chenango County, NY, Cortland County, NY, Delaware County, NY, Herkimer County, NY, Livingston County, NY, Madison County, NY, Oneida County, NY, Onondaga County, NY, Ontario County, NY, Oswego County, NY, Otsego County, NY, Schuyler County, NY, Seneca County, NY, Steuben County, NY, Tioga County, NY, Tompkins County, NY, Wayne County, NY, Yates County, NY, Adams County, PA, Allegheny County, PA, Armstrong County, PA, Bedford County, PA, Berks County, PA, Blair County, PA, Bradford County, PA, Cambria County, PA, Cameron County, PA, Carbon County, PA, Centre County, PA, Clarion County, PA, Clearfield County, PA, Clinton County, PA, Columbia 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, Lancaster County, PA, Lebanon 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, Susquehanna County, PA, Tioga County, PA, Union County, PA, Wayne County, PA, Westmoreland County, PA, Wyoming County, PA, York County, PA, Monongalia County, WV

The radar

The Binghamton radar (KBGM), 106 km from the middle of the area, began a volume at 19:55 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 nearest sounding before it

Buffalo Intl Airport, NY (KBUF), launched 12:00Z, 7.9 hours before the alert went out and 157 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 2009-05-16Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 434 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, Buffalo Intl Airport, NY at 12:00Z on 2009-05-16The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 303 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
434 J/kg
Mixed-layer CIN
-63 J/kg
Mixed-layer LCL
1076 m above ground
0-6 km bulk shear
45 kt
0-1 km storm-relative helicity
303 m²/s²
0-3 km storm-relative helicity
301 m²/s²
Significant tornado parameter
0.6
Supercell composite
5.8

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.

IssuedProductOfficeCountiesLasted
May 16, 12:05 PM EDTMesoscale DiscussionSPCAllegany, Broome, Cattaraugus, Cayuga, Chautauqua, Chemung and 22 more55 min
May 16, 1:00 PM EDTSevere Thunderstorm WatchSPCAllegany, Broome, Cattaraugus, Cayuga, Chemung, Chenango and 16 more7 hr
May 16, 6:29 PM EDTMesoscale DiscussionSPCAlbany, Broome, Chemung, Chenango, Cortland, Delaware and 12 more2 hr
May 16, 2:36 PM EDTMesoscale DiscussionSPCJefferson24 min
May 16, 2:46 PM EDTMesoscale DiscussionSPCBarbour, Boone, Braxton, Cabell, Calhoun, Clay and 20 more59 min

Nearby

Mesoscale Discussions in Pennsylvania, 2009Mesoscale Discussions in New York, 2009Mesoscale Discussions in West Virginia, 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.