Alert archive / Virginia / Mesoscale Discussions in 2011

Mesoscale Discussion 992

May 26, 20115 counties in North Carolina; 24 counties in Virginia

The Storm Prediction Center issued this mesoscale discussion at May 26, 2011, 11:22 PM EDT for 5 counties in North Carolina; 24 counties in Virginia. It was in force for 113 min.

The area

The outline as issued.

The facts

Issued: May 26, 2011, 11:22 PM EDT (03:22 UTC)
Expired: May 27, 2011, 1:15 AM EDT
In force: 113 min
Issued by: the Storm Prediction Center

All 29 counties

Caswell County, NC, Forsyth County, NC, Rockingham County, NC, Stokes County, NC, Yadkin County, NC, Albemarle County, VA, Amherst County, VA, Appomattox County, VA, Augusta County, VA, Bedford County, VA, Buckingham County, VA, Campbell County, VA, City of Buena Vista, VA, City of Charlottesville, VA, City of Danville, VA, City of Lexington, VA, City of Lynchburg, VA, City of Martinsville, VA, City of Staunton, VA, City of Waynesboro, VA, Fluvanna County, VA, Franklin County, VA, Greene County, VA, Halifax County, VA, Henry County, VA, Nelson County, VA, Patrick County, VA, Pittsylvania County, VA, Rockbridge County, VA

The radar

The Roanoke radar (KFCX), 80 km from the middle of the area, began a volume at 03:24 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

Roanoke, VA (KRNK), launched 00:00Z, 3.4 hours before the alert went out and 18 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: 278 J/kg
Mixed-layer CIN: -21 J/kg
Mixed-layer LCL: 1807 m above ground
0-6 km bulk shear: 33 kt
0-1 km storm-relative helicity: 176 m²/s²
0-3 km storm-relative helicity: 254 m²/s²
Significant tornado parameter: 0.1
Supercell composite: 4.8

Open this sounding in Storm Lab

The text

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

422 
ACUS11 KWNS 270322
SWOMCD
SPC MCD 270322 
VAZ000-NCZ000-270515-

MESOSCALE DISCUSSION 0992
NWS STORM PREDICTION CENTER NORMAN OK
1022 PM CDT THU MAY 26 2011

AREAS AFFECTED...NWRN NC...CNTRL VA

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE 

VALID 270322Z - 270515Z

AN ORGANIZED BUT SMALL SCALE AREA OF STORMS CONTINUES TO MOVE NEWD
ACROSS NC AND WILL ENTER SWRN VA SOON. THIS STORM SYSTEM CONTINUES
TO PRODUCE SEVERE WIND GUSTS...AND IS BEING PROPELLED NNEWD BY SLY
FLOW ALOFT. AT THE SURFACE...OBSERVED SOUNDINGS AND OBJECTIVE
ANALYSIS SHOWS INSTABILITY POOL AHEAD OF THIS STORM...BUT BOUNDARY
LAYER TEMPERATURES WILL CONTINUE TO COOL AND MAY ALLOW FOR AN
EVENTUAL WEAKENING TREND. ALSO...OUTFLOW FROM ACTIVITY TO THE N MAY
LIMIT THE NWD EXTENT OF THIS SYSTEM.  AS SUCH...AN ADDITIONAL WATCH
IS NOT EXPECTED AND THE THREAT SHOULD REMAIN ISOLATED.

..JEWELL.. 05/27/2011

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

ATTN...WFO...AKQ...LWX...RAH...RNK...GSP...

LAT...LON   35968059 36328073 37098000 38067930 38347897 38347834
            38007818 37657827 37287840 36677900 36337941 35998007
            35968059

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
May 27, 11:26 AM EDT	Mesoscale Discussion	SPC	Alamance, Anson, Caswell, Chatham, Cumberland, Durham and 27 more	94 min
May 27, 12:06 PM EDT	Severe Thunderstorm Watch	SPC	Alamance, Anson, Cabarrus, Caswell, Chatham, Cumberland and 34 more	7 hr
May 27, 3:29 PM EDT	Mesoscale Discussion	SPC	Alamance, Anson, Bertie, Bladen, Caswell, Chatham and 37 more	91 min
May 27, 6:24 PM EDT	Mesoscale Discussion	SPC	Alamance, Anson, Bladen, Caswell, Chatham, Columbus and 29 more	66 min
May 27, 12:24 PM EDT	Mesoscale Discussion	SPC	Arlington, Caroline, Clarke, Culpeper, Fairfax, Fauquier and 24 more	96 min
May 27, 12:57 PM EDT	Severe Thunderstorm Watch	SPC	Albemarle, Arlington, Augusta, Clarke, Culpeper, Fairfax and 28 more	9 hr
May 27, 6:14 PM EDT	Mesoscale Discussion	SPC	Arlington, Clarke, Culpeper, Fairfax, Fauquier, Frederick and 12 more	2 hr

Nearby

Mesoscale Discussions in Virginia, 2011 Mesoscale Discussions in North Carolina, 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.