Alert archive / North Carolina / Mesoscale Discussions in 2004

Mesoscale Discussion 2147

August 29, 200424 counties in North Carolina; 5 counties in South Carolina

The Storm Prediction Center issued this mesoscale discussion at Aug 29, 2004, 6:33 PM EDT for 24 counties in North Carolina; 5 counties in South Carolina. It was in force for 117 min.

The area

The outline as issued.

The facts

Issued
Aug 29, 2004, 6:33 PM EDT (22:33 UTC)
Expired
Aug 29, 2004, 8:30 PM EDT
In force
117 min
Issued by
the Storm Prediction Center
All 29 counties

Bladen County, NC, Brunswick County, NC, Columbus County, NC, Craven County, NC, Cumberland County, NC, Duplin County, NC, Franklin County, NC, Greene County, NC, Harnett County, NC, Hoke County, NC, Johnston County, NC, Jones County, NC, Lee County, NC, Lenoir County, NC, Nash County, NC, New Hanover County, NC, Onslow County, NC, Pender County, NC, Robeson County, NC, Sampson County, NC, Scotland County, NC, Wake County, NC, Wayne County, NC, Wilson County, NC, Chesterfield County, SC, Dillon County, SC, Horry County, SC, Marion County, SC, Marlboro County, SC

The radar

The Wilmington radar (KLTX), 55 km from the middle of the area, began a volume at 22:36 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

Newport, NC (KMHX), launched 12:00Z, 10.6 hours before the alert went out and 152 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 2004-08-29Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1320 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 2004-08-29The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 67 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
1320 J/kg
Mixed-layer CIN
-17 J/kg
Mixed-layer LCL
704 m above ground
0-6 km bulk shear
25 kt
0-1 km storm-relative helicity
67 m²/s²
0-3 km storm-relative helicity
83 m²/s²
Significant tornado parameter
0.3
Supercell composite
1.9

Open this sounding in Storm Lab

The text

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

033 
ACUS11 KWNS 292235
SWOMCD
SPC MCD 292233 
NCZ000-SCZ000-300030-

MESOSCALE DISCUSSION 2147
NWS STORM PREDICTION CENTER NORMAN OK
0533 PM CDT SUN AUG 29 2004

AREAS AFFECTED...PORTIONS ERN NC

CONCERNING...SEVERE THUNDERSTORM WATCH 796...

VALID 292233Z - 300030Z

POTENTIAL FOR SUPERCELLS AND BRIEF/SMALL TORNADOES CONTINUES NE OF
CENTER OF GASTON AND SHOULD GRADUALLY SPREAD NEWD ACROSS NERN NC
THROUGH THIS EVENING.  POTENTIAL WILL END FROM SW-NE ACROSS REGION
AS CENTER OF SYSTEM MOVES NEWD OVER ERN NC.  AREAS NE OF WW 796 WILL
BE MONITORED FOR POSSIBLE ADDITIONAL/REPLACEMENT WW.  MEANWHILE WW
796 SHOULD BE CLEARED FROM SW-NE WITH PASSAGE OF CYCLONE CORE.

AVAILABLE VWP AND MODIFIED FCST SOUNDINGS SUGGEST FAVORABLE VERTICAL
SHEAR PROFILE WILL CONTINUE ACROSS NERN QUADRANT OF GASTON.  MOST
FAVORED AREA BASED ON SFC MESOANALYSIS WILL BE INVOF AXIS OF
STRONGEST PRESSURE FALLS THAT EXTENDS FROM TC CENTER NNEWD NEAR THE
LINE LBT...POB...LHZ.  ISALLOBARIC AXIS CORRESPONDS WELL TO
PRONOUNCED/QUASISTATIONARY SFC TROUGH/WIND SHIFT LINE...WHERE MAXIMA
OF 0-1 KM SHEAR...0-1 KM SRH AND BOUNDARY LAYER CONVERGENCE EACH ARE
INDICATED.  ANY DISCRETE STORM INTERACTING WITH THIS BOUNDARY MAY
DEVELOP/STRENGTHEN THEIR MESOCYCLONES AND ENHANCED TORNADO POTENTIAL
FOR AN HOUR OR TWO BEFORE MOVING INTO MORE WEAKLY SHEARED
ENVIRONMENT FARTHER W. MLCAPE VARIES FROM ABOUT 400-1000 J/KG
ACROSS MOST OF ERN NC NE OF CENTER...WITH AXIS ALSO LOCATED VERY
CLOSE TO PRESSURE FALL/TROUGH LINE.

BUOYANCY SHOULD GRADUALLY DIMINISH THROUGH REMAINDER EVENING BECAUSE
OF WEAK DIABATIC COOLING...HOWEVER SFC BASED PARCELS WILL REMAIN AT
LEAST MARGINALLY UNSTABLE FOR A FEW MORE HOURS IN ENVIRONMENT WITH
VERY LOW LCL.  MEANWHILE...AS CYCLONE CENTER APCHS...VERTICAL SHEAR
WILL INCREASE OVER AREA NE OF WW.  THESE OFFSETTING FACTORS SHOULD
YIELD TORNADO THREAT THERE SIMILAR TO OR SLIGHTLY BELOW PRESENT
PROBABILITY WITHIN WW.

..EDWARDS.. 08/29/2004

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

ATTN...WFO...MHX...RAH...ILM...CAE...

33237865 34638017 36337828 34967676

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Aug 29, 1:30 PM EDTMesoscale DiscussionSPCBladen, Brunswick, Columbus, Craven, Cumberland, Duplin and 15 more2 hr
Aug 29, 2:30 PM EDTTornado WatchSPCBladen, Brunswick, Columbus, Craven, Cumberland, Duplin and 20 more8 hr
Aug 28, 8:57 PM EDTMesoscale DiscussionSPCBerkeley, Georgetown2 hr

Nearby

Mesoscale Discussions in North Carolina, 2004Mesoscale Discussions in South Carolina, 2004Every mesoscale discussion in 2004

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.