Alert archive / Virginia / Mesoscale Discussions in 2012
Mesoscale Discussion 2003
The Storm Prediction Center issued this mesoscale discussion at Sep 28, 2012, 2:36 PM EDT for 42 counties in North Carolina; 5 counties in Tennessee; 47 counties in Virginia. It was in force for 114 min.
The area
The outline as issued.
The facts
- Issued
- Sep 28, 2012, 2:36 PM EDT (18:36 UTC)
- Expired
- Sep 28, 2012, 4:30 PM EDT
- In force
- 114 min
- Issued by
- the Storm Prediction Center
- Chance of a watch
- 20%
All 94 counties
Alamance County, NC, Alexander County, NC, Avery County, NC, Buncombe County, NC, Burke County, NC, Cabarrus County, NC, Caldwell County, NC, Caswell County, NC, Catawba County, NC, Chatham County, NC, Cleveland County, NC, Davidson County, NC, Davie County, NC, Durham County, NC, Forsyth County, NC, Gaston County, NC, Granville County, NC, Guilford County, NC, Haywood County, NC, Henderson County, NC, Iredell County, NC, Jackson County, NC, Lincoln County, NC, Macon County, NC, Madison County, NC, McDowell County, NC, Mitchell County, NC, Orange County, NC, Person County, NC, Polk County, NC, Randolph County, NC, Rockingham County, NC, Rowan County, NC, Rutherford County, NC, Stokes County, NC, Transylvania County, NC, Vance County, NC, Warren County, NC, Watauga County, NC, Wilkes County, NC, Yadkin County, NC, Yancey County, NC, Carter County, TN, Cocke County, TN, Greene County, TN, Unicoi County, TN, Washington County, TN, Amelia County, VA, Appomattox County, VA, Brunswick County, VA, Buckingham County, VA, Campbell County, VA, Caroline County, VA, Charles City County, VA, Charlotte County, VA, Chesterfield County, VA, City of Colonial Heights, VA, City of Danville, VA, City of Emporia, VA, City of Fredericksburg, VA, City of Hopewell, VA, City of Martinsville, VA, City of Petersburg, VA, City of Richmond, VA, City of Williamsburg, VA, Cumberland County, VA, Dinwiddie County, VA, Essex County, VA, Fluvanna County, VA, Goochland County, VA, Greensville County, VA, Halifax County, VA, Hanover County, VA, Henrico County, VA, Henry County, VA, James City County, VA, King and Queen County, VA, King George County, VA, King William County, VA, Louisa County, VA, Lunenburg County, VA, Mecklenburg County, VA, New Kent County, VA, Nottoway County, VA, Orange County, VA, Pittsylvania County, VA, Powhatan County, VA, Prince Edward County, VA, Prince George County, VA, Richmond County, VA, Spotsylvania County, VA, Surry County, VA, Sussex County, VA, Westmoreland County, VA
The radar
The Roanoke radar (KFCX), 37 km from the middle of the area, began a volume at 18:39 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 nearest sounding before it
Greensboro/Hi Pt, NC (KGSO), launched 12:00Z, 6.6 hours before the alert went out and 74 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.
- Mixed-layer CAPE
- 51 J/kg
- Mixed-layer CIN
- -94 J/kg
- Mixed-layer LCL
- 1361 m above ground
- 0-6 km bulk shear
- 24 kt
- 0-1 km storm-relative helicity
- 26 m²/s²
- 0-3 km storm-relative helicity
- 50 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted, in the capitals the NWS used until 2016.
762
ACUS11 KWNS 281836
SWOMCD
SPC MCD 281836
VAZ000-MDZ000-NCZ000-TNZ000-SCZ000-282030-
MESOSCALE DISCUSSION 2003
NWS STORM PREDICTION CENTER NORMAN OK
0136 PM CDT FRI SEP 28 2012
AREAS AFFECTED...ERN TN...WRN THROUGH CNTRL NC AND CNTRL THROUGH ERN
VA
CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY
VALID 281836Z - 282030Z
PROBABILITY OF WATCH ISSUANCE...20 PERCENT
SUMMARY...WIDELY SCATTERED THUNDERSTORMS DEVELOPING FROM THE TN
VALLEY THROUGH WRN AND CNTRL NC AND CNTRL/ERN VA MAY POSE A THREAT
FOR ISOLATED STRONG WIND GUSTS THIS AFTERNOON. OVERALL THREAT DOES
NOT APPEAR SUFFICIENT FOR A WW ISSUANCE.
DISCUSSION...THE WARM SECTOR IS DESTABILIZING FROM PORTIONS OF THE
TN VALLEY THROUGH NC AND SRN/ERN VA...BUT WEAK MID LEVEL LAPSE RATES
AND ONLY LOW 60S BOUNDARY LAYER DEWPOINTS SHOULD LIMIT MLCAPE TO AOB
1000 J/KG. STORMS WILL LIKELY CONTINUE DEVELOPING OVER THE HIGHER
TERRAIN AND IN ASSOCIATION WITH WEAK LOW LEVEL CONVERGENCE ZONES
WITHIN THE WEAKLY CAPPED ENVIRONMENT THIS AFTERNOON. WEAK VERTICAL
SHEAR /AOB 30 KT/ AND MODEST WLY FLOW THROUGH 6 KM WILL SUPPORT
MULTICELL STORMS. A FEW STORMS MAY BECOME CAPABLE OF PRODUCING
ISOLATED STRONG WIND GUSTS AS LOW LEVEL LAPSE RATES STEEPEN.
..DIAL/HART.. 09/28/2012
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...AKQ...LWX...RAH...RNK...GSP...MRX...
LAT...LON 36378311 36228102 37177934 38317801 38337659 37267659
35417936 35078367 36378311SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Sep 27, 8:57 PM EDT | Mesoscale Discussion | SPC | Arlington, Culpeper, Fairfax, Fauquier, King George, Loudoun and 11 more | 63 min |
Nearby
Mesoscale Discussions in Virginia, 2012Mesoscale Discussions in North Carolina, 2012Mesoscale Discussions in Tennessee, 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.