Alert archive / North Carolina / Mesoscale Discussions in 2004

Mesoscale Discussion 331

April 11, 200432 counties in North Carolina; 4 counties in South Carolina

The Storm Prediction Center issued this mesoscale discussion at Apr 11, 2004, 12:05 PM EDT for 32 counties in North Carolina; 4 counties in South Carolina. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued: Apr 11, 2004, 12:05 PM EDT (16:05 UTC)
Expired: Apr 11, 2004, 2:30 PM EDT
In force: 2 hr
Issued by: the Storm Prediction Center

All 36 counties

Beaufort County, NC, Bertie County, NC, Bladen County, NC, Chowan County, NC, Columbus County, NC, Craven County, NC, Cumberland County, NC, Duplin County, NC, Edgecombe County, NC, Greene County, NC, Harnett County, NC, Hoke County, NC, Johnston County, NC, Jones County, NC, Lee County, NC, Lenoir County, NC, Martin County, NC, Moore County, NC, Onslow County, NC, Pamlico County, NC, Pasquotank County, NC, Pender County, NC, Perquimans County, NC, Pitt County, NC, Robeson County, NC, Sampson County, NC, Scotland County, NC, Tyrrell County, NC, Wake County, NC, Washington County, NC, Wayne County, NC, Wilson County, NC, Dillon County, SC, Horry County, SC, Marion County, SC, Marlboro County, SC

The radar

The Wilmington radar (KLTX), 85 km from the middle of the area, began a volume at 16:07 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.

Severe Thunderstorm Watch 68Apr 11, 2:15 PM EDT

The nearest sounding before it

Newport, NC (KMHX), launched 12:00Z, 4.1 hours before the alert went out and 129 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 122 J/kg
Mixed-layer CIN: -27 J/kg
Mixed-layer LCL: 837 m above ground
0-6 km bulk shear: 44 kt
0-1 km storm-relative helicity: 165 m²/s²
0-3 km storm-relative helicity: 234 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.4

Open this sounding in Storm Lab

The text

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

062 
ACUS11 KWNS 111605
SWOMCD
SPC MCD 111605 
NCZ000-SCZ000-111830-

MESOSCALE DISCUSSION 0331
NWS STORM PREDICTION CENTER NORMAN OK
1105 AM CDT SUN APR 11 2004

AREAS AFFECTED...PORTIONS ERN NC...EXTREME SRN SC

CONCERNING...SEVERE THUNDERSTORM POTENTIAL 

VALID 111605Z - 111830Z

TSTMS ARE FCST TO DEVELOP OVER PORTIONS ERN NC COASTAL PLAIN AND
INLAND SOUND AREAS...IN RAPIDLY DESTABILIZING AIR MASS.  DAMAGING
GUSTS AND LARGE HAIL ARE POSSIBLE.  THREAT MAY EXTEND AS FAR S AS
VICINITY MYR.  AREA IS BEING MONITORED FOR POSSIBLE WW.  

15Z SFC MESOANALYSIS SHOWED FRONTAL-WAVE LOW OFFSHORE VA
BEACH...EXTENDING SWWD THROUGH ECG REGION TO JUST E CLT.  AIR MASS E
OF THIS BOUNDARY WILL CONTINUE TO WARM INTO UPPER 70S/LOW 80S F
THROUGH MID AFTERNOON...WEAKENING THE MODEST CAP EVIDENT IN 12Z CHS
RAOB.  PER COORD W/CHS...18Z RAOB WILL BE LAUNCHED THERE AS WELL TO
FURTHER ASSESS CHARACTER OF AIR MASS AND WIND FIELDS. 
MEANWHILE...SFC DEW POINTS SHOULD REMAIN GENERALLY MID 60S F AS
SSWLY MOIST ADVECTION OFFSETS VERTICAL MIXING. MAIN LOW LEVEL FOCI
FOR CONVECTION SHOULD BE SEA BREEZE BOUNDARIES AND WEAK CONVERGENCE
LINES WWD TOWARD MAIN BAROCLINIC ZONE. WEAK LOW LEVEL SHEAR
PROFILES BENEATH ROUGHLY 100 KT UPPER JET LEVEL WINDS SUGGEST
ORGANIZED MULTICELLS WILL BE DOMINANT CONVECTIVE MODE. MARGINAL
SUPERCELLS ARE POSSIBLE...HOWEVER...WITH BOUNDARY INTERACTIONS. 
ADDITIONAL DESTABILIZATION AND LOCALIZED SHEAR ENHANCEMENT POSSIBLE
OVER WRN PART OF DISCUSSION AREA FROM CONVECTIVELY INDUCED VORTICITY
MAX -- EVIDENT ATTM ON VIS IMAGERY BETWEEN CLT-AVL -- AND MOVING
ENEWD 30-35 KT TOWARD NERN NC.

..EDWARDS.. 04/11/2004

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

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

33627917 33707933 34147967 34897973 35347966 35627943
36257661 36387581 35777573 34897682 34497767 34037830
33687899

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Apr 11, 2:15 PM EDT	Severe Thunderstorm Watch	SPC	Beaufort, Bladen, Columbus, Craven, Cumberland, Duplin and 14 more	6 hr
Apr 11, 4:35 PM EDT	Mesoscale Discussion	SPC	Beaufort, Bladen, Columbus, Craven, Cumberland, Duplin and 14 more	115 min

Nearby

Mesoscale Discussions in North Carolina, 2004 Mesoscale Discussions in South Carolina, 2004 Every 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.