Alert archive / Virginia / Mesoscale Discussions in 2011

Mesoscale Discussion 1049

June 1, 20114 states

The Storm Prediction Center issued this mesoscale discussion at Jun 1, 2011, 1:37 PM EDT for 4 states. It was in force for 83 min.

The area

The outline as issued.

The facts

Issued: Jun 1, 2011, 1:37 PM EDT (17:37 UTC)
Expired: Jun 1, 2011, 3:00 PM EDT
In force: 83 min
Issued by: the Storm Prediction Center

All 65 counties

Kent County, DE, New Castle County, DE, Anne Arundel County, MD, Baltimore County, MD, Calvert County, MD, Caroline County, MD, Carroll County, MD, Cecil County, MD, Charles County, MD, City of Baltimore, MD, Dorchester County, MD, Frederick County, MD, Harford County, MD, Howard County, MD, Kent County, MD, Montgomery County, MD, Prince George's County, MD, Queen Anne's County, MD, Saint Mary's County, MD, Talbot County, MD, Albemarle County, VA, Amelia County, VA, Arlington County, VA, Caroline County, VA, Charles City County, VA, Chesterfield County, VA, City of Alexandria, VA, City of Charlottesville, VA, City of Colonial Heights, VA, City of Fairfax, VA, City of Falls Church, VA, City of Fredericksburg, VA, City of Hopewell, VA, City of Manassas, VA, City of Manassas Park, VA, City of Petersburg, VA, City of Richmond, VA, Clarke County, VA, Culpeper County, VA, Cumberland County, VA, Essex County, VA, Fairfax County, VA, Fauquier County, VA, Fluvanna County, VA, Goochland County, VA, Greene County, VA, Hanover County, VA, Henrico County, VA, King and Queen County, VA, King George County, VA, King William County, VA, Loudoun County, VA, Louisa County, VA, Madison County, VA, New Kent County, VA, Orange County, VA, Powhatan County, VA, Prince William County, VA, Rappahannock County, VA, Richmond County, VA, Spotsylvania County, VA, Stafford County, VA, Warren County, VA, Westmoreland County, VA, Jefferson County, WV

The radar

The Sterling radar (KLWX), 65 km from the middle of the area, began a volume at 17:39 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.

Severe Thunderstorm Watch 412Jun 1, 2:25 PM EDT

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 12:00Z, 5.6 hours before the alert went out and 61 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: 3637 J/kg
Mixed-layer CIN: -50 J/kg
Mixed-layer LCL: 975 m above ground
0-6 km bulk shear: 20 kt
0-1 km storm-relative helicity: 54 m²/s²
0-3 km storm-relative helicity: 67 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 2.1

Open this sounding in Storm Lab

The text

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

134 
ACUS11 KWNS 011737
SWOMCD
SPC MCD 011737 
NJZ000-DEZ000-PAZ000-MDZ000-VAZ000-DCZ000-WVZ000-011900-

MESOSCALE DISCUSSION 1049
NWS STORM PREDICTION CENTER NORMAN OK
1237 PM CDT WED JUN 01 2011

AREAS AFFECTED...VA...MD...DE...NJ...SE PA

CONCERNING...SEVERE POTENTIAL...WATCH LIKELY 

VALID 011737Z - 011900Z

A SEVERE THREAT IS EXPECTED TO DEVELOP ACROSS THE MID-ATLANTIC
REGION THIS AFTERNOON. WIND DAMAGE AND ISOLATED LARGE HAIL WILL BE
POSSIBLE WITH THE STRONGER CELLS. WW ISSUANCE WILL LIKELY BE NEEDED
OVER THE NEXT 1 TO 2 HOURS.

MESOANALYSIS CURRENTLY SHOWS AN AXIS OF STRONG INSTABILITY FROM SRN
VA NNEWD INTO SE PA WHERE MLCAPE VALUES ARE ESTIMATED IN THE 3500 TO
4500 J/KG RANGE. THUNDERSTORMS ARE BEGINNING TO INITIATE ON THE WRN
EDGE OF THE INSTABILITY AXIS ACROSS SRN PA...WRN MD AND ERN WV. THIS
ACTIVITY WILL EXPAND IN COVERAGE MOVING EWD INTO THE MCD AREA WHERE
STRONG INSTABILITY AND STEEP LOW-LEVEL LAPSE ARE ALREADY IN PLACE.
0-3 KM LAPSE RATES OF 7.5 TO 8.0 C/KM LIKELY ALREADY EXIST WHICH
ALONG WITH VEERED LOW-LEVEL FLOW SHOULD BE FAVORABLE FOR DAMAGING
WIND GUSTS ESPECIALLY WITH LINE-SEGMENTS THAT ORGANIZE. THE STRONG
INSTABILITY AND VERY STEEP MID-LEVEL LAPSE RATES OF 8.0 TO 8.5 C/KM
WILL ALSO BE FAVORABLE FOR ISOLATED LARGE HAIL.

..BROYLES.. 06/01/2011

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

ATTN...WFO...PHI...AKQ...CTP...LWX...RNK...

LAT...LON   37167738 37167788 37327837 37647856 37867862 38297859
            38757843 39297797 39697745 39897665 39807570 39557537
            39017551 38617591 37407682 37167738

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jun 1, 2:24 PM EDT	Severe Thunderstorm Watch	SPC	Kent, New Castle, Sussex	7 hr
Jun 1, 6:27 PM EDT	Mesoscale Discussion	SPC	Kent, New Castle, Sussex	93 min
Jun 1, 4:35 PM EDT	Mesoscale Discussion	SPC	Alleghany, Bland, Botetourt, Buchanan, Carroll, Craig and 26 more	85 min

Nearby

Mesoscale Discussions in Virginia, 2011 Mesoscale Discussions in Maryland, 2011 Mesoscale Discussions in Delaware, 2011 Every 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.