Alert archive / Pennsylvania / Mesoscale Discussions in 2011

Mesoscale Discussion 2212

September 28, 2011New Castle County, Delaware; 5 counties in Maryland; 19 counties in Pennsylvania

The Storm Prediction Center issued this mesoscale discussion at Sep 28, 2011, 4:45 PM EDT for New Castle County, Delaware; 5 counties in Maryland; 19 counties in Pennsylvania. It was in force for 60 min.

The area

The outline as issued.

The facts

Issued
Sep 28, 2011, 4:45 PM EDT (20:45 UTC)
Expired
Sep 28, 2011, 5:45 PM EDT
In force
60 min
Issued by
the Storm Prediction Center
All 25 counties

New Castle County, DE, Baltimore County, MD, Cecil County, MD, City of Baltimore, MD, Harford County, MD, Kent County, MD, Berks County, PA, Bucks County, PA, Carbon County, PA, Chester County, PA, Columbia County, PA, Dauphin County, PA, Delaware County, PA, Lancaster County, PA, Lebanon County, PA, Lehigh County, PA, Luzerne County, PA, Monroe County, PA, Montgomery County, PA, Montour County, PA, Northampton County, PA, Northumberland County, PA, Philadelphia County, PA, Schuylkill County, PA, York County, PA

The radar

The Philadelphia radar (KDIX), 143 km from the middle of the area, began a volume at 20:49 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

Phillips Aaf/Abe, MD (KAPG), launched 12:00Z, 8.8 hours before the alert went out and 93 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, Phillips Aaf/Abe, MD at 12:00Z on 2011-09-28Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 822 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, Phillips Aaf/Abe, MD at 12:00Z on 2011-09-28The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 34 square meters per square second.193958Sfc1 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
822 J/kg
Mixed-layer CIN
-16 J/kg
Mixed-layer LCL
526 m above ground
0-6 km bulk shear
22 kt
0-1 km storm-relative helicity
34 m²/s²
0-3 km storm-relative helicity
65 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.5

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

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Nearby

Mesoscale Discussions in Pennsylvania, 2011Mesoscale Discussions in Maryland, 2011Mesoscale Discussions in Delaware, 2011Every mesoscale discussion in 2011

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.