Alert archive / North Carolina / Mesoscale Discussions in 2012

Mesoscale Discussion 811

May 14, 201219 counties in North Carolina; 10 counties in South Carolina

The Storm Prediction Center issued this mesoscale discussion at May 14, 2012, 6:14 PM EDT for 19 counties in North Carolina; 10 counties in South Carolina. It was in force for 61 min.

The area

The outline as issued.

The facts

Issued
May 14, 2012, 6:14 PM EDT (22:14 UTC)
Expired
May 14, 2012, 7:15 PM EDT
In force
61 min
Issued by
the Storm Prediction Center
Chance of a watch
5%
All 29 counties

Alexander County, NC, Burke County, NC, Cabarrus County, NC, Caldwell County, NC, Catawba County, NC, Cleveland County, NC, Davie County, NC, Gaston County, NC, Henderson County, NC, Iredell County, NC, Lincoln County, NC, McDowell County, NC, Mecklenburg County, NC, Polk County, NC, Rowan County, NC, Rutherford County, NC, Transylvania County, NC, Wilkes County, NC, Yadkin County, NC, Anderson County, SC, Cherokee County, SC, Chester County, SC, Greenville County, SC, Laurens County, SC, Oconee County, SC, Pickens County, SC, Spartanburg County, SC, Union County, SC, York County, SC

The radar

The Greer radar (KGSP), 96 km from the middle of the area, began a volume at 22:17 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, 10.2 hours before the alert went out and 158 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, Greensboro/Hi Pt, NC at 12:00Z on 2012-05-14Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 26 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, Greensboro/Hi Pt, NC at 12:00Z on 2012-05-14The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 100 square meters per square second.193958Sfc1 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
26 J/kg
Mixed-layer CIN
-122 J/kg
Mixed-layer LCL
713 m above ground
0-6 km bulk shear
25 kt
0-1 km storm-relative helicity
100 m²/s²
0-3 km storm-relative helicity
160 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.

551 
ACUS11 KWNS 142215
SWOMCD
SPC MCD 142214
NCZ000-SCZ000-GAZ000-142315-

MESOSCALE DISCUSSION 0811
NWS STORM PREDICTION CENTER NORMAN OK
0514 PM CDT MON MAY 14 2012

AREAS AFFECTED...PIEDMONT REGION OF NC...SC...AND FAR NERN GA

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY

VALID 142214Z - 142315Z

PROBABILITY OF WATCH ISSUANCE...5 PERCENT

SUMMARY...A FEW STRONG STORMS CAPABLE OF PRODUCING GUSTY WINDS AND
SMALL HAIL WILL BE POSSIBLE INTO EARLY EVENING. THE ISSUANCE OF A WW
IS NOT NEEDED.

DISCUSSION...OROGRAPHICALLY INDUCED ASCENT HAS SUPPORTED THE
DEVELOPMENT OF ISOLATED TO SCATTERED THUNDERSTORMS INVOF THE SRN
APPALACHIANS. THESE STORMS WILL LIKELY DEVELOP EWD INTO A ZONE OF
MLCAPE VALUES OF 750-1500 J/KG ACROSS THE PIEDMONT REGION...WHERE A
BROAD AREA OF INSOLATION/DIABATIC HEATING HAS STEEPENED LOW-LEVEL
LAPSE RATES AMIDST SFC DEWPOINTS IN THE MIDDLE 60S. MODESTLY
ENHANCED MID-LEVEL SWLY FLOW IN ASSOCIATION WITH A MINOR IMPULSE
CROSSING THE APPALACHIANS IS SUPPORTING EFFECTIVE BULK SHEAR
MAGNITUDES OF 25 TO AROUND 30 KT...WHICH WILL PROVIDE SOME WEAK
CONVECTIVE ORGANIZATION THROUGH THE LATE AFTERNOON AND EARLY
EVENING. STRONG WIND GUSTS WITH THE MOST INTENSE MULTICELL CLUSTERS
AND SMALL HAIL WILL BE THE PRIMARY CONCERNS WITH THIS ACTIVITY...AND
AN ISOLATED/MARGINAL SVR STORM CANNOT BE RULED OUT. STORMS WILL
LIKELY DIMINISH IN COVERAGE/INTENSITY AFTER 00Z AS INCREASING CINH
IS DRIVEN BY THE DEVELOPMENT OF THE NOCTURNAL BOUNDARY LAYER.

..COHEN/WEISS.. 05/14/2012

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

ATTN...WFO...RAH...RNK...CAE...GSP...

LAT...LON   36388028 35708028 34618114 34288251 34688343 35288287
            35978174 36408101 36388028

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
May 14, 2:30 PM EDTMesoscale DiscussionSPCBladen, Brunswick, Columbus, Cumberland, Duplin, Jones and 7 more60 min

Nearby

Mesoscale Discussions in North Carolina, 2012Mesoscale Discussions in South Carolina, 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.