Alert archive / Pennsylvania / Mesoscale Discussions in 2016

Mesoscale Discussion 1808

October 30, 20165 counties in Maryland; 10 counties in Pennsylvania

The Storm Prediction Center issued this mesoscale discussion at Oct 30, 2016, 3:55 PM EDT for 5 counties in Maryland; 10 counties in Pennsylvania. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued
Oct 30, 2016, 3:55 PM EDT (19:55 UTC)
Expired
Oct 30, 2016, 6:00 PM EDT
In force
2 hr
Issued by
the Storm Prediction Center
Chance of a watch
20%

Counties Baltimore County, MD, Carroll County, MD, Frederick County, MD, Harford County, MD, Washington County, MD, Adams County, PA, Berks County, PA, Chester County, PA, Cumberland County, PA, Dauphin County, PA, Delaware County, PA, Lancaster County, PA, Lebanon County, PA, Montgomery County, PA, York County, PA

The radar

The Sterling radar (KLWX), 121 km from the middle of the area, began a volume at 19:54 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, 7.9 hours before the alert went out and 120 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, Washington/Dulle, VA at 12:00Z on 2016-10-30Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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, Washington/Dulle, VA at 12:00Z on 2016-10-30The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 72 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
1691 m above ground
0-6 km bulk shear
35 kt
0-1 km storm-relative helicity
72 m²/s²
0-3 km storm-relative helicity
142 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

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Nearby

Mesoscale Discussions in Pennsylvania, 2016Mesoscale Discussions in Maryland, 2016Every mesoscale discussion in 2016

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.