Alert archive / Virginia / Mesoscale Discussions in 2015

Mesoscale Discussion 1017

June 14, 20154 states

The Storm Prediction Center issued this mesoscale discussion at Jun 14, 2015, 2:06 PM EDT for 4 states. It was in force for 84 min.

The area

The outline as issued.

The facts

Issued: Jun 14, 2015, 2:06 PM EDT (18:06 UTC)
Expired: Jun 14, 2015, 3:30 PM EDT
In force: 84 min
Issued by: the Storm Prediction Center
Chance of a watch: 60%

All 103 counties

Allegany County, MD, Anne Arundel County, MD, Baltimore County, MD, Calvert County, MD, Carroll County, MD, Charles County, MD, City of Baltimore, MD, Frederick County, MD, Garrett County, MD, Howard County, MD, Montgomery County, MD, Prince George's County, MD, Saint Mary's County, MD, Washington County, MD, Adams County, PA, Allegheny County, PA, Armstrong County, PA, Beaver County, PA, Bedford County, PA, Blair County, PA, Butler County, PA, Cambria County, PA, Clarion County, PA, Clearfield County, PA, Cumberland 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, Lawrence County, PA, Mercer County, PA, Somerset County, PA, Venango County, PA, Washington County, PA, Westmoreland County, PA, Albemarle County, VA, Amelia County, VA, Arlington County, VA, Augusta County, VA, Buckingham County, VA, Caroline County, VA, City of Alexandria, VA, City of Charlottesville, VA, City of Fairfax, VA, City of Falls Church, VA, City of Fredericksburg, VA, City of Harrisonburg, VA, City of Manassas, VA, City of Manassas Park, VA, City of Richmond, VA, City of Staunton, VA, City of Waynesboro, VA, City of Winchester, VA, Clarke County, VA, Culpeper County, VA, Cumberland County, VA, Essex County, VA, Fairfax County, VA, Fauquier County, VA, Fluvanna County, VA, Frederick County, VA, Goochland County, VA, Greene County, VA, Hanover County, VA, Highland County, VA, King and Queen County, VA, King George County, VA, King William County, VA, Loudoun County, VA, Louisa County, VA, Madison County, VA, Nelson County, VA, Orange County, VA, Page County, VA, Powhatan County, VA, Prince William County, VA, Rappahannock County, VA, Richmond County, VA, Rockingham County, VA, Shenandoah County, VA, Spotsylvania County, VA, Stafford County, VA, Warren County, VA, Westmoreland County, VA, Barbour County, WV, Berkeley County, WV, Grant County, WV, Hampshire County, WV, Hardy County, WV, Jefferson County, WV, Marion County, WV, Mineral County, WV, Monongalia County, WV, Morgan County, WV, Pendleton County, WV, Preston County, WV, Randolph County, WV, Taylor County, WV, Tucker County, WV

The radar

The Sterling radar (KLWX), 140 km from the middle of the area, began a volume at 18:06 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

Pittsburgh, PA (KAGC), launched 12:00Z, 6.1 hours before the alert went out and 135 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: 131 J/kg
Mixed-layer CIN: -69 J/kg
Mixed-layer LCL: 689 m above ground
0-6 km bulk shear: 25 kt
0-1 km storm-relative helicity: 54 m²/s²
0-3 km storm-relative helicity: 74 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.

754 
ACUS11 KWNS 141806
SWOMCD
SPC MCD 141806 
MDZ000-VAZ000-PAZ000-DCZ000-WVZ000-141930-

MESOSCALE DISCUSSION 1017
NWS STORM PREDICTION CENTER NORMAN OK
0106 PM CDT SUN JUN 14 2015

AREAS AFFECTED...MUCH OF WRN/SRN PA...CENTRAL/WRN MD...CENTRAL/NRN
VA...DC...NRN WV/PANHANDLE

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE 

VALID 141806Z - 141930Z

PROBABILITY OF WATCH ISSUANCE...60 PERCENT

SUMMARY...INCREASING THUNDERSTORM COVERAGE/INTENSITY IS EXPECTED
THROUGH THE REMAINDER OF THIS AFTERNOON WITH A THREAT FOR DAMAGING
WINDS WITH THE STRONGEST STORMS/CLUSTERS. A WATCH IS POSSIBLE FOR
PORTIONS OF THE AREA PRIOR TO 1930Z.

DISCUSSION...A VERY MOIST AIR MASS WAS IN PLACE ACROSS THE
DISCUSSION AREA AT 17Z WITH UPPER 60S/LOWER 70S SURFACE DEW POINTS
AND PW VALUES OF 1.6 OR GREATER.  DESPITE WEAK MID-LEVEL LAPSE
RATES...STRONG DAYTIME HEATING OF THE VERY MOIST AIR MASS HAS
RESULTED IN MLCAPE AVERAGING 1000 TO 1500 J/KG. SCATTERED
THUNDERSTORMS HAVE DEVELOPED WITHIN THE UNCAPPED ENVIRONMENT...AND
COVERAGE IS EXPECTED TO INCREASE THROUGH THE REMAINDER OF THIS
AFTERNOON.

LARGELY UNIDIRECTIONAL FLOW IN THE 2-6 KM LAYER IS AVERAGING 20-30
KTS...STRONGER ACROSS NORTHERN PORTIONS OF THE DISCUSSION AREA...AND
COMBINED WITH THE VERY MOIST AIR MASS WILL RESULT IN A RISK FOR
DAMAGING WINDS WITH SOUTHEAST-MOVING CLUSTERS/SHORT LINE SEGMENTS
THROUGH THIS AFTERNOON. ALTHOUGH LOW-MID LEVEL FLOW IS WEAKER
FARTHER SOUTH ACROSS CENTRAL/NORTHERN VIRGINIA...STEEP LOW-LEVEL
LAPSE RATES IN COMBINATION WITH THE HIGH PW ENVIRONMENT WILL ALSO
PROMOTE A RISK OF DAMAGING DOWNBURST WINDS WITH THE STRONGEST
STORMS. 

TRENDS IN THUNDERSTORM COVERAGE/INTENSITY WILL BE MONITORED FOR THE
POSSIBILITY OF A SEVERE THUNDERSTORM WATCH FOR PORTIONS OF THE AREA
PRIOR TO 1930Z.

..BUNTING/CORFIDI.. 06/14/2015

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...PHI...AKQ...CTP...LWX...RNK...PBZ...RLX...CLE...

LAT...LON   40528043 41278047 41628040 41648006 41607938 41107837
            39637658 38967622 37977643 37517712 37307797 37587894
            38297977 39358036 40528043

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jun 14, 7:08 PM EDT	Mesoscale Discussion	SPC	Cecil, Kent, Queen Anne's	52 min
Jun 14, 1:46 PM EDT	Severe Thunderstorm Watch	SPC	Crawford, Erie	7 hr
Jun 14, 4:14 PM EDT	Mesoscale Discussion	SPC	Crawford, Erie	2 hr
Jun 14, 7:59 PM EDT	Mesoscale Discussion	SPC	Crawford, Erie, Lawrence, Mercer, Venango	61 min

Nearby

Mesoscale Discussions in Virginia, 2015 Mesoscale Discussions in Pennsylvania, 2015 Mesoscale Discussions in West Virginia, 2015 Every 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.