Alert archive / North Carolina / Mesoscale Discussions in 2011
Mesoscale Discussion 421
The Storm Prediction Center issued this mesoscale discussion at Apr 12, 2011, 2:39 AM EDT for 27 counties in North Carolina; 9 counties in South Carolina; Carter County, Unicoi County, Tennessee. It was in force for 36 min.
The area
The outline as issued.
The facts
- Issued
- Apr 12, 2011, 2:39 AM EDT (06:39 UTC)
- Expired
- Apr 12, 2011, 3:15 AM EDT
- In force
- 36 min
- Issued by
- the Storm Prediction Center
All 38 counties
Alexander County, NC, Alleghany County, NC, Ashe County, NC, Avery County, NC, Buncombe County, NC, Burke County, NC, Caldwell County, NC, Catawba County, NC, Cleveland County, NC, Davie County, NC, Gaston County, NC, Haywood County, NC, Henderson County, NC, Iredell County, NC, Jackson County, NC, Lincoln County, NC, Madison County, NC, McDowell County, NC, Mitchell County, NC, Polk County, NC, Rutherford County, NC, Swain County, NC, Transylvania County, NC, Watauga County, NC, Wilkes County, NC, Yadkin County, NC, Yancey County, NC, Anderson County, SC, Cherokee County, SC, Greenville County, SC, Laurens County, SC, Oconee County, SC, Pickens County, SC, Spartanburg County, SC, Union County, SC, York County, SC, Carter County, TN, Unicoi County, TN
The radar
The Greer radar (KGSP), 41 km from the middle of the area, began a volume at 06:43 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 00:00Z, 6.7 hours before the alert went out and 220 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
- 682 J/kg
- Mixed-layer CIN
- -106 J/kg
- Mixed-layer LCL
- 1647 m above ground
- 0-6 km bulk shear
- 53 kt
- 0-1 km storm-relative helicity
- 113 m²/s²
- 0-3 km storm-relative helicity
- 94 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 1.9
The text
As transmitted, in the capitals the NWS used until 2016.
359
ACUS11 KWNS 120639
SWOMCD
SPC MCD 120639
NCZ000-SCZ000-TNZ000-GAZ000-120715-
MESOSCALE DISCUSSION 0421
NWS STORM PREDICTION CENTER NORMAN OK
0139 AM CDT TUE APR 12 2011
AREAS AFFECTED...FAR ERN TN...WRN NC...UPSTATE SC...EXTREME NERN GA
CONCERNING...TORNADO WATCH 132...
VALID 120639Z - 120715Z
THE SEVERE WEATHER THREAT FOR TORNADO WATCH 132 CONTINUES.
...SEVERE THREATS HAVE DIMINISHED...
TORNADO WATCH 132 EXPIRES AT 07Z AND THERE ARE NO PLANS TO ISSUE A
NEW WATCH.
BAND OF TSTMS DIMINISHED AS IT CROSSED THE APPALACHIAN CREST AND
INSPECTION OF DOWNSTREAM RUC SOUNDINGS IN THE FOOTHILLS OF NC/SC
EXHIBIT A WARM LAYER ALOFT AND LITTLE BUOYANCY. AS A RESULT...THERE
IS NO REASON TO BELIEVE THAT STORMS WILL INCREASE IN INTENSITY FOR
THE REMAINDER OF THE NIGHT.
..RACY.. 04/12/2011
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...RAH...RNK...GSP...MRX...
LAT...LON 34578316 35498355 36178284 36568123 36238034 35438066
34858123 34248223 34278269 34578316SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Apr 11, 8:08 PM EDT | Tornado Watch | SPC | Avery, Buncombe, Cherokee, Clay, Graham, Haywood and 8 more | 7 hr |
| Apr 11, 9:23 PM EDT | Mesoscale Discussion | SPC | Buncombe, Cherokee, Clay, Graham, Haywood, Henderson and 7 more | 97 min |
| Apr 12, 1:56 PM EDT | Mesoscale Discussion | SPC | Camden, Chowan, Currituck, Gates, Pasquotank, Perquimans | 64 min |
Nearby
Mesoscale Discussions in North Carolina, 2011Mesoscale Discussions in South Carolina, 2011Mesoscale Discussions in Tennessee, 2011Every 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.