Alert archive / North Carolina / Mesoscale Discussions in 2012

Mesoscale Discussion 1767

August 15, 201221 counties in North Carolina

The Storm Prediction Center issued this mesoscale discussion at Aug 15, 2012, 4:34 PM EDT for 21 counties in North Carolina. It was in force for 86 min.

The area

The outline as issued.

The facts

Issued
Aug 15, 2012, 4:34 PM EDT (20:34 UTC)
Expired
Aug 15, 2012, 6:00 PM EDT
In force
86 min
Issued by
the Storm Prediction Center
All 21 counties

Beaufort County, NC, Bladen County, NC, Camden County, NC, Carteret County, NC, Chowan County, NC, Columbus County, NC, Craven County, NC, Currituck County, NC, Dare County, NC, Duplin County, NC, Hyde County, NC, Jones County, NC, Lenoir County, NC, New Hanover County, NC, Onslow County, NC, Pamlico County, NC, Pasquotank County, NC, Pender County, NC, Perquimans County, NC, Tyrrell County, NC, Washington County, NC

The nearest sounding before it

Newport, NC (KMHX), launched 12:00Z, 8.6 hours before the alert went out and 61 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, Newport, NC at 12:00Z on 2012-08-15Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2363 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, Newport, NC at 12:00Z on 2012-08-15The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 80 square meters per square second.1939Sfc1 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
2363 J/kg
Mixed-layer CIN
-22 J/kg
Mixed-layer LCL
852 m above ground
0-6 km bulk shear
26 kt
0-1 km storm-relative helicity
80 m²/s²
0-3 km storm-relative helicity
103 m²/s²
Significant tornado parameter
0.0
Supercell composite
3.7

Open this sounding in Storm Lab

The text

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

569 
ACUS11 KWNS 152035
SWOMCD
SPC MCD 152034
NCZ000-VAZ000-152200-

MESOSCALE DISCUSSION 1767
NWS STORM PREDICTION CENTER NORMAN OK
0334 PM CDT WED AUG 15 2012

AREAS AFFECTED...ERN NC

CONCERNING...SEVERE THUNDERSTORM WATCH 580...

VALID 152034Z - 152200Z

THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 580
CONTINUES.

SUMMARY...A CONSOLIDATING CLUSTER OR LINE OF STORMS IS EXPECTED TO
SPREAD ACROSS NORTH CAROLINA COASTAL AREAS...INCLUDING THE OUTER
BANKS... DURING THE NEXT COUPLE OF HOURS.

DISCUSSION...INCREASING BOUNDARY LAYER CONVERGENCE ALONG THE AXIS OF
STRONGEST PRE-FRONTAL HEATING ACROSS THE NORTH CAROLINA COASTAL
PLAIN NOW APPEARS TO BE CONTRIBUTING TO AN EVOLVING LINE OF STORMS.
IN THE PRESENCE OF HIGH MOISTURE CONTENT AND STRONG DEEP LAYER SHEAR
ASSOCIATED WITH AN EASTWARD ADVANCING BELT OF 30-40 KT WEST
SOUTHWESTERLY 500 MB FLOW...FURTHER CONVECTIVE GROWTH/EXPANSION AND
ORGANIZATION APPEARS POSSIBLE ACROSS COASTAL AREAS AND THE OUTER
BANKS THROUGH 22-23Z.  THIS LIKELY WILL BE ACCOMPANIED BY FREQUENT
CLOUD TO GROUND LIGHTNING...HEAVY RAINFALL AND THE POTENTIAL FOR ONE
OR TWO DOWNBURSTS WITH POTENTIALLY DAMAGING SURFACE GUSTS.

..KERR.. 08/15/2012

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

ATTN...WFO...AKQ...MHX...RAH...ILM...

LAT...LON   34677868 34897825 35797701 36357653 36897570 36127513
            34987559 34057788 34197865 34677868

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Aug 15, 2:01 PM EDTMesoscale DiscussionSPCAlamance, Anson, Beaufort, Bertie, Cabarrus, Camden and 38 more89 min
Aug 15, 2:34 PM EDTSevere Thunderstorm WatchSPCBeaufort, Bertie, Bladen, Brunswick, Camden, Carteret and 46 more6 hr

Nearby

Mesoscale Discussions in North 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.