Alert archive / Pennsylvania / Mesoscale Discussions in 2019

Mesoscale Discussion 452

April 26, 20194 states

The Storm Prediction Center issued this mesoscale discussion at Apr 26, 2019, 2:09 PM EDT for 4 states. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued: Apr 26, 2019, 2:09 PM EDT (18:09 UTC)
Expired: Apr 26, 2019, 4:15 PM EDT
In force: 2 hr
Issued by: the Storm Prediction Center

All 35 counties

Kent County, DE, New Castle County, DE, Baltimore County, MD, Carroll County, MD, Cecil County, MD, City of Baltimore, MD, Frederick County, MD, Harford County, MD, Howard County, MD, Kent County, MD, Atlantic County, NJ, Burlington County, NJ, Camden County, NJ, Cape May County, NJ, Cumberland County, NJ, Gloucester County, NJ, Salem County, NJ, Adams County, PA, Berks County, PA, Bucks County, PA, Chester County, PA, Cumberland County, PA, Dauphin County, PA, Delaware County, PA, Juniata County, PA, Lancaster County, PA, Lebanon County, PA, Lehigh County, PA, Montgomery County, PA, Northumberland County, PA, Perry County, PA, Philadelphia County, PA, Schuylkill County, PA, Snyder County, PA, York County, PA

The radar

The Dover AFB radar (KDOX), 126 km from the middle of the area, began a volume at 18:10 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

Washington/Dulle, VA (KIAD), launched 12:00Z, 6.2 hours before the alert went out and 151 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: 49 J/kg
Mixed-layer CIN: -221 J/kg
Mixed-layer LCL: 715 m above ground
0-6 km bulk shear: 43 kt
0-1 km storm-relative helicity: 293 m²/s²
0-3 km storm-relative helicity: 355 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.8

Open this sounding in Storm Lab

The text

As transmitted.

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SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Apr 26, 11:37 AM EDT	Mesoscale Discussion	SPC	Kent, New Castle, Sussex	113 min
Apr 26, 1:33 PM EDT	Tornado Watch	SPC	Kent, New Castle, Sussex	6 hr
Apr 26, 4:26 PM EDT	Mesoscale Discussion	SPC	Kent, New Castle, Sussex	94 min

Nearby

Mesoscale Discussions in Pennsylvania, 2019 Mesoscale Discussions in Maryland, 2019 Mesoscale Discussions in New Jersey, 2019 Every mesoscale discussion in 2019

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.