Alert archive / Virginia / Mesoscale Discussions in 2012

Mesoscale Discussion 346

March 24, 201210 counties in North Carolina; 14 counties in Virginia; 9 counties in West Virginia

The Storm Prediction Center issued this mesoscale discussion at Mar 24, 2012, 2:31 PM EDT for 10 counties in North Carolina; 14 counties in Virginia; 9 counties in West Virginia. It was in force for 59 min.

The area

The outline as issued.

The facts

Issued
Mar 24, 2012, 2:31 PM EDT (18:31 UTC)
Expired
Mar 24, 2012, 3:30 PM EDT
In force
59 min
Issued by
the Storm Prediction Center
All 33 counties

Alexander County, NC, Alleghany County, NC, Ashe County, NC, Avery County, NC, Burke County, NC, Caldwell County, NC, Catawba County, NC, Surry County, NC, Watauga County, NC, Wilkes County, NC, Alleghany County, VA, Bland County, VA, Carroll County, VA, City of Covington, VA, City of Galax, VA, City of Radford, VA, Craig County, VA, Floyd County, VA, Giles County, VA, Grayson County, VA, Montgomery County, VA, Pulaski County, VA, Roanoke County, VA, Wythe County, VA, Fayette County, WV, Greenbrier County, WV, Mercer County, WV, Monroe County, WV, Nicholas County, WV, Pocahontas County, WV, Raleigh County, WV, Summers County, WV, Webster County, WV

The radar

The Roanoke radar (KFCX), 67 km from the middle of the area, began a volume at 18:34 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

Roanoke, VA (KRNK), launched 12:00Z, 6.5 hours before the alert went out and 131 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, Roanoke, VA at 12:00Z on 2012-03-24Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 250 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, Roanoke, VA at 12:00Z on 2012-03-24The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 45 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
250 J/kg
Mixed-layer CIN
-9 J/kg
Mixed-layer LCL
519 m above ground
0-6 km bulk shear
45 kt
0-1 km storm-relative helicity
45 m²/s²
0-3 km storm-relative helicity
-13 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.

718 
ACUS11 KWNS 241831
SWOMCD
SPC MCD 241831 
WVZ000-VAZ000-NCZ000-TNZ000-241930-

MESOSCALE DISCUSSION 0346
NWS STORM PREDICTION CENTER NORMAN OK
0131 PM CDT SAT MAR 24 2012

AREAS AFFECTED...SWRN VA...SRN WV...WRN NC

CONCERNING...SEVERE THUNDERSTORM WATCH 105...

VALID 241831Z - 241930Z

THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 105
CONTINUES.

SEVERE HAIL/WIND THREAT HAS PRIMARILY BEEN CONFINED TO THE NWRN
QUADRANT OF WW 105. PROPAGATION AND DEVELOPMENT N/NEWD IS OCCURRING
WHICH MAY RESULT IN AN ISOLATED SEVERE THREAT DEVELOPING NWD INTO
SRN WV. SOME UNCERTAINTY EXISTS OVER THE AMPLITUDE OF THE SEVERE
RISK HERE...OWING TO AN APPARENT STABLE BOUNDARY LAYER ON VIS
IMAGERY IN THE WAKE OF CONVECTION DURING THE MORNING AND REMNANT
OUTFLOW BOUNDARY DRAPED FROM AROUND 30 S PSK TO LYH.
STILL...SUBSTANTIAL INSOLATION OCCURRING N OF THE BOUNDARY MAY PROVE
SUFFICIENT FOR DESTABILIZATION AND A MAINTENANCE OF SEVERE POTENTIAL
NWD. MODEL FORECAST SOUNDINGS SUGGEST MEAGER LOW-LEVEL FLOW ALONG
WITH BACKING WINDS IN THE MID-LEVELS SHOULD MITIGATE MORE ROBUST
UPDRAFT ROTATION WITH MIXED CONVECTIVE MODES.

..GRAMS.. 03/24/2012

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

ATTN...WFO...RNK...RLX...GSP...MRX...

LAT...LON   36928135 37558131 38068128 38428101 38598068 38628019
            38337989 37947982 36908022 35518106 35588151 35788202
            36048205 36928135

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Mar 24, 12:03 PM EDTMesoscale DiscussionSPCAlamance, Alexander, Alleghany, Anson, Cabarrus, Caswell and 20 more117 min
Mar 24, 12:46 PM EDTSevere Thunderstorm WatchSPCAlamance, Alexander, Alleghany, Anson, Ashe, Avery and 33 more7 hr
Mar 24, 2:54 PM EDTMesoscale DiscussionSPCCaswell, Forsyth, Guilford, Rockingham, Stokes, Surry and 1 more66 min
Mar 24, 3:38 PM EDTTornado WatchSPCAlamance, Anson, Caswell, Chatham, Cumberland, Davidson and 30 more7 hr
Mar 24, 4:16 PM EDTMesoscale DiscussionSPCCabarrus, Davidson, Davie, Forsyth, Iredell, Mecklenburg and 6 more59 min
Mar 24, 6:03 PM EDTMesoscale DiscussionSPCBeaufort, Bertie, Bladen, Brunswick, Camden, Carteret and 24 more2 hr
Mar 24, 6:43 PM EDTTornado WatchSPCCaswell, Rockingham4 hr
Mar 24, 6:58 PM EDTMesoscale DiscussionSPCAlexander, Alleghany, Burke, Cabarrus, Caldwell, Catawba and 9 more92 min
Mar 24, 7:34 PM EDTMesoscale DiscussionSPCAlamance, Anson, Caswell, Chatham, Cumberland, Durham and 23 more116 min
Mar 24, 3:02 PM EDTSevere Thunderstorm WatchSPCAlbemarle, Alleghany, Amherst, Appomattox, Augusta, Bath and 13 more5 hr

Nearby

Mesoscale Discussions in Virginia, 2012Mesoscale Discussions in North Carolina, 2012Mesoscale Discussions in West Virginia, 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.