Alert archive / Virginia / Mesoscale Discussions in 2012

Mesoscale Discussion 1008

June 1, 20126 states

The Storm Prediction Center issued this mesoscale discussion at Jun 1, 2012, 3:49 PM EDT for 6 states. It was in force for 56 min.

The area

The outline as issued.

The facts

Issued
Jun 1, 2012, 3:49 PM EDT (19:49 UTC)
Expired
Jun 1, 2012, 4:45 PM EDT
In force
56 min
Issued by
the Storm Prediction Center
All 88 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, 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, Granville County, NC, Halifax County, NC, Northampton County, NC, Person County, NC, Vance County, NC, Warren County, NC, Camden County, NJ, Gloucester County, NJ, Salem County, NJ, Chester County, PA, Delaware County, PA, Lancaster County, PA, Philadelphia County, PA, York County, PA, Amelia County, VA, Arlington County, VA, Brunswick County, VA, Caroline County, VA, Charles City County, VA, Charlotte County, VA, Chesterfield County, VA, City of Alexandria, VA, City of Colonial Heights, VA, City of Emporia, VA, City of Fairfax, VA, City of Falls Church, VA, City of Franklin, 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, City of Williamsburg, VA, Cumberland County, VA, Dinwiddie County, VA, Essex County, VA, Fairfax County, VA, Fluvanna County, VA, Gloucester County, VA, Goochland County, VA, Greensville County, VA, Halifax County, VA, Hanover County, VA, Henrico County, VA, James City County, VA, King and Queen County, VA, King George County, VA, King William County, VA, Lancaster County, VA, Louisa County, VA, Lunenburg County, VA, Mecklenburg County, VA, Middlesex County, VA, New Kent County, VA, Northumberland County, VA, Nottoway County, VA, Orange County, VA, Powhatan County, VA, Prince Edward County, VA, Prince George County, VA, Prince William County, VA, Richmond County, VA, Southampton County, VA, Spotsylvania County, VA, Stafford County, VA, Surry County, VA, Sussex County, VA, Westmoreland County, VA

The radar

The Norfolk radar (KAKQ), 97 km from the middle of the area, began a volume at 19:51 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, 7.8 hours before the alert went out and 133 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 2012-06-01Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 26 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 2012-06-01The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 148 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
26 J/kg
Mixed-layer CIN
-174 J/kg
Mixed-layer LCL
1061 m above ground
0-6 km bulk shear
32 kt
0-1 km storm-relative helicity
148 m²/s²
0-3 km storm-relative helicity
174 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.

508 
ACUS11 KWNS 011949
SWOMCD
SPC MCD 011949 
NJZ000-PAZ000-DEZ000-MDZ000-VAZ000-NCZ000-DCZ000-012045-

MESOSCALE DISCUSSION 1008
NWS STORM PREDICTION CENTER NORMAN OK
0249 PM CDT FRI JUN 01 2012

AREAS AFFECTED...SERN PA...ERN MD...ERN VA...D.C...NRN NC

CONCERNING...TORNADO WATCH 333...

VALID 011949Z - 012045Z

THE SEVERE WEATHER THREAT FOR TORNADO WATCH 333 CONTINUES.

SUMMARY...TORNADO THREAT CONTINUES IN ASSOCIATION WITH ONGOING
SUPERCELL ACTIVITY.

DISCUSSION...NUMEROUS DISCRETE SUPERCELLS HAVE EVOLVED ACROSS THE
WARM SECTOR FROM PORTIONS OF NC...NWD INTO MD.  THIS NRN ACTIVITY IS
COINCIDENT WITH ADVANCING WARM FRONT THAT NOW STRETCHES FROM BEDFORD
COUNTY PA...SEWD INTO CNTRL DE NEAR DOV.  SEVERAL OF THE DISCRETE
SUPERCELLS HAVE EXHIBITED TORNADIC CHARACTERISTICS AS THEY LIFT NEWD
WITH ONE LONGER-LIVED UPDRAFT IN PARTICULAR NOW CROSSING THE WARM
FRONT OVER BALTIMORE COUNTY IN MD.  NRN SUPERCELLS SHOULD ENCOUNTER
SOMEWHAT HIGHER LOW LEVEL HELICITY ALONG THE WARM FRONT WHICH MAY
ENHANCE THE TORNADIC POTENTIAL WHILE WITHIN THIS ZONE.

HIGHER THETA-E AIR MASS SHOULD GRADUALLY RETURN INTO SERN PA/DE AND
SWRN NJ OVER THE NEXT FEW HOURS.  SUPERCELL ACTIVITY WILL INCREASE
AS THIS BOUNDARY ADVANCES NWD.

FRONTAL SQUALL LINE SHOULD APPROACH THE WRN-MOST PART OF WW 333 BY
00Z AND AN ENHANCED DAMAGING WIND THREAT MAY ENSUE WITH ASSOCIATED
CONVECTION.

..DARROW.. 06/01/2012

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

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

LAT...LON   36217937 40087694 40087467 36217721 36217937

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jun 1, 4:25 PM EDTMesoscale DiscussionSPCKent, New Castle, Sussex65 min
Jun 1, 12:29 PM EDTMesoscale DiscussionSPCAnne Arundel, Calvert, Carroll, Charles, Frederick, Howard and 5 more61 min
Jun 1, 1:03 PM EDTMesoscale DiscussionSPCAllegany, Anne Arundel, Baltimore, Calvert, Carroll, Charles and 11 more87 min
Jun 1, 1:28 PM EDTTornado WatchSPCAllegany, Frederick, Garrett, Washington8 hr
Jun 1, 1:50 PM EDTTornado WatchSPCAnne Arundel, Baltimore, Calvert, Caroline, Carroll, Cecil and 13 more7 hr
Jun 1, 3:35 PM EDTMesoscale DiscussionSPCAllegany, Frederick, Garrett, Washington55 min
Jun 1, 6:54 PM EDTMesoscale DiscussionSPCAnne Arundel, Baltimore, Calvert, Caroline, Carroll, Cecil and 14 more2 hr
Jun 1, 1:54 PM EDTMesoscale DiscussionSPCAnson, Bladen, Brunswick, Chatham, Columbus, Craven and 23 more66 min
Jun 1, 2:13 PM EDTSevere Thunderstorm WatchSPCAlamance, Anson, Beaufort, Bladen, Brunswick, Carteret and 41 more8 hr
Jun 1, 4:31 PM EDTMesoscale DiscussionSPCAlamance, Anson, Beaufort, Bertie, Bladen, Brunswick and 44 more59 min
Jun 1, 7:42 PM EDTMesoscale DiscussionSPCAlamance, Anson, Beaufort, Bertie, Bladen, Brunswick and 40 more2 hr
Jun 1, 5:46 PM EDTMesoscale DiscussionSPCCameron, Centre, Clearfield, Clinton, Elk, Forest and 10 more89 min
Jun 1, 6:04 PM EDTTornado WatchSPCCameron, Centre, Clearfield, Clinton, Columbia, Elk and 10 more5 hr

Nearby

Mesoscale Discussions in Virginia, 2012Mesoscale Discussions in Maryland, 2012Mesoscale Discussions in North Carolina, 2012Every mesoscale discussion in 2012

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.