Alert archive / Pennsylvania / Mesoscale Discussions in 2015

Mesoscale Discussion 1344

July 9, 20154 states

The Storm Prediction Center issued this mesoscale discussion at Jul 9, 2015, 4:55 PM EDT for 4 states. It was in force for 95 min.

The area

The outline as issued.

The facts

Issued
Jul 9, 2015, 4:55 PM EDT (20:55 UTC)
Expired
Jul 9, 2015, 6:30 PM EDT
In force
95 min
Issued by
the Storm Prediction Center
All 48 counties

Allegany County, MD, Baltimore County, MD, Carroll County, MD, Cecil County, MD, City of Baltimore, MD, Frederick County, MD, Garrett County, MD, Harford County, MD, Howard County, MD, Kent County, MD, Washington County, MD, Adams County, PA, Bedford County, PA, Berks County, PA, Blair County, PA, Cambria County, PA, Carbon County, PA, Centre County, PA, Chester County, PA, Clearfield County, PA, Clinton County, PA, Columbia County, PA, Cumberland County, PA, Dauphin County, PA, Franklin County, PA, Fulton County, PA, Huntingdon County, PA, Juniata County, PA, Lancaster County, PA, Lebanon County, PA, Lehigh County, PA, Lycoming County, PA, Mifflin County, PA, Montour County, PA, Northumberland County, PA, Perry County, PA, Schuylkill County, PA, Snyder County, PA, Somerset County, PA, Union County, PA, York County, PA, City of Winchester, VA, Frederick County, VA, Berkeley County, WV, Hampshire County, WV, Jefferson County, WV, Mineral County, WV, Morgan County, WV

The radar

The State College radar (KCCX), 100 km from the middle of the area, began a volume at 20:55 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 watches that followed

Watches SPC issued over any of the same counties within four hours of this discussion.

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 12:00Z, 8.9 hours before the alert went out and 128 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 2015-07-09Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1 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, Washington/Dulle, VA at 12:00Z on 2015-07-09The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -19 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
1 J/kg
Mixed-layer CIN
-194 J/kg
Mixed-layer LCL
1091 m above ground
0-6 km bulk shear
21 kt
0-1 km storm-relative helicity
-19 m²/s²
0-3 km storm-relative helicity
-2 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

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
Jul 9, 11:27 AM EDTMesoscale DiscussionSPCGarrett2 hr
Jul 9, 12:59 PM EDTMesoscale DiscussionSPCAllegany, Anne Arundel, Baltimore, Carroll, Cecil, Frederick and 7 more2 hr
Jul 9, 1:27 PM EDTTornado WatchSPCAllegany, Baltimore, Carroll, Frederick, Garrett, Harford and 2 more6 hr
Jul 9, 3:09 PM EDTMesoscale DiscussionSPCAllegany, Anne Arundel, Baltimore, Caroline, Carroll, Cecil and 10 more96 min
Jul 9, 4:57 PM EDTSevere Thunderstorm WatchSPCCaroline, Cecil, Kent, Queen Anne's, Talbot5 hr
Jul 9, 6:25 PM EDTMesoscale DiscussionSPCCecil, Harford95 min
Jul 9, 7:04 PM EDTMesoscale DiscussionSPCAnne Arundel, Calvert, Caroline, Charles, Dorchester, Prince George's and 6 more86 min
Jul 9, 12:15 PM EDTMesoscale DiscussionSPCBuchanan, Dickenson, Lee, Wise, City of Norton3 hr
Jul 9, 5:58 PM EDTMesoscale DiscussionSPCBland, Buchanan, Dickenson, Russell, Smyth, Tazewell and 2 more2 hr

Nearby

Mesoscale Discussions in Pennsylvania, 2015Mesoscale Discussions in Maryland, 2015Mesoscale Discussions in West Virginia, 2015Every mesoscale discussion in 2015

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.