Alert archive / North Carolina / Mesoscale Discussions in 2012

Mesoscale Discussion 189

February 29, 20124 states

The Storm Prediction Center issued this mesoscale discussion at Feb 29, 2012, 5:36 PM EST for 4 states. It was in force for 54 min.

The area

The outline as issued.

The facts

Issued
Feb 29, 2012, 5:36 PM EST (22:36 UTC)
Expired
Feb 29, 2012, 6:30 PM EST
In force
54 min
Issued by
the Storm Prediction Center
All 36 counties

Catoosa County, GA, Fannin County, GA, Murray County, GA, Rabun County, GA, Towns County, GA, Union County, GA, Whitfield County, GA, Avery County, NC, Buncombe County, NC, Cherokee County, NC, Clay County, NC, Graham County, NC, Haywood County, NC, Henderson County, NC, Jackson County, NC, Macon County, NC, Madison County, NC, McDowell County, NC, Mitchell County, NC, Swain County, NC, Transylvania County, NC, Watauga County, NC, Yancey County, NC, Oconee County, SC, Blount County, TN, Bradley County, TN, Carter County, TN, Cocke County, TN, Greene County, TN, Hamilton County, TN, Johnson County, TN, McMinn County, TN, Monroe County, TN, Polk County, TN, Sevier County, TN, Unicoi County, TN

The radar

The Knoxville radar (KMRX), 84 km from the middle of the area, began a volume at 22:38 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

Peachtre/Fal Fld, GA (KFFC), launched 12:00Z, 10.6 hours before the alert went out and 243 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, Peachtre/Fal Fld, GA at 12:00Z on 2012-02-29Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 5 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, Peachtre/Fal Fld, GA at 12:00Z on 2012-02-29The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 177 square meters per square second.1939587897Sfc1 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
5 J/kg
Mixed-layer CIN
-277 J/kg
Mixed-layer LCL
451 m above ground
0-6 km bulk shear
48 kt
0-1 km storm-relative helicity
177 m²/s²
0-3 km storm-relative helicity
184 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.

055 
ACUS11 KWNS 292236
SWOMCD
SPC MCD 292236 
NCZ000-TNZ000-SCZ000-GAZ000-292330-

MESOSCALE DISCUSSION 0189
NWS STORM PREDICTION CENTER NORMAN OK
0436 PM CST WED FEB 29 2012

AREAS AFFECTED...FAR EASTERN TN/NORTH GA/WESTERN NC/WESTERN SC

CONCERNING...TORNADO WATCH 48...

VALID 292236Z - 292330Z

THE SEVERE WEATHER THREAT FOR TORNADO WATCH 48 CONTINUES.

A NEW TORNADO WATCH IS BEING CONSIDERED SHORTLY FOR REMAINING
PORTIONS OF EASTERN TN AS WELL AS FAR NORTH GA INTO WESTERN
NC/PERHAPS SC. AT THE VERY LEAST...A SPATIAL EXTENSION OF TORNADO
WATCH 48 WILL LIKELY BE NEEDED ACROSS EASTERN TN.

A MODESTLY BROKEN LINE OF SEVERE STORMS WITH EMBEDDED SUPERCELLS
WILL CONTINUE TO STEADILY PROGRESS EAST-NORTHEASTWARD ACROSS THE
EASTERN THIRD OF TN OVER THE NEXT FEW HOURS. WHILE UPDRAFT
INTENSITIES HAVE TRENDED A BIT DOWNWARD IN THE SHORT TERM AND
DOWNSTREAM BUOYANCY IN VICINITY OF THE APPALACHIANS IS WEAKER /ONLY
SEVERAL HUNDRED J PER KG SBCAPE/...A CONTINUED WEST-SOUTHWESTERLY
MOISTURE INFLUX AND PROBABLE DOWNSTREAM/PRE-LINE
DESTABILIZATION...ALONG WITH A HIGHLY SHEARED ENVIRONMENT...WILL
CONTINUE TO FAVOR A HIGHLY-ORGANIZED STORM MODE INCLUDING EMBEDDED
SUPERCELLS/BOWS CAPABLE OF A FEW TORNADOES AND WIND DAMAGE.
SHORT-TERM TRENDS ARE BEING MONITORED FOR A NEW TORNADO WATCH.

..GUYER.. 02/29/2012

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

ATTN...WFO...RNK...GSP...MRX...FFC...

LAT...LON   35128550 35818406 36528176 36268117 34728302 34708518
            35128550

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Feb 29, 6:37 PM ESTTornado WatchSPCBanks, Bartow, Catoosa, Chattooga, Cherokee, Dade and 21 more3 hr
Feb 29, 3:23 PM ESTMesoscale DiscussionSPCAlleghany, Ashe67 min
Feb 29, 1:49 AM ESTMesoscale DiscussionSPCBenton, Carroll, Chester, Crockett, Decatur, Dickson and 24 more56 min
Feb 29, 3:40 AM ESTMesoscale DiscussionSPCCheatham, Clay, Davidson, Dickson, Hickman, Houston and 11 more65 min
Feb 29, 4:20 AM ESTTornado WatchSPCCarroll, Crockett, Dyer, Gibson, Haywood, Henry and 6 more9 hr
Feb 29, 4:53 AM ESTMesoscale DiscussionSPCCarroll, Crockett, Dyer, Gibson, Haywood, Henry and 6 more97 min
Feb 29, 5:39 AM ESTTornado WatchSPCBenton, Cheatham, Clay, Davidson, Dickson, Fentress and 14 more7 hr
Feb 29, 8:38 AM ESTMesoscale DiscussionSPCBenton, Cheatham, Clay, Davidson, DeKalb, Dickson and 15 more67 min
Feb 29, 9:07 AM ESTMesoscale DiscussionSPCCarroll, Crockett, Dyer, Gibson, Haywood, Henry and 6 more53 min
Feb 29, 12:11 PM ESTMesoscale DiscussionSPCAnderson, Benton, Campbell, Cannon, Carroll, Cheatham and 49 more2 hr
Feb 29, 12:31 PM ESTTornado WatchSPCAnderson, Bedford, Benton, Bledsoe, Campbell, Cannon and 68 more8 hr
Feb 29, 12:46 PM ESTMesoscale DiscussionSPCFayette, Hardeman, Hardin, McNairy89 min
Feb 29, 2:48 PM ESTTornado WatchSPCFranklin, Lincoln, Moore7 hr
Feb 29, 4:34 PM ESTMesoscale DiscussionSPCAnderson, Bedford, Benton, Campbell, Cannon, Carroll and 52 more116 min

Nearby

Mesoscale Discussions in North Carolina, 2012Mesoscale Discussions in Tennessee, 2012Mesoscale Discussions in Georgia, 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.