Alert archive / North Carolina / Mesoscale Discussions in 2003

Mesoscale Discussion 686

May 2, 200329 counties in North Carolina; 17 counties in South Carolina

The Storm Prediction Center issued this mesoscale discussion at May 2, 2003, 4:22 PM EDT for 29 counties in North Carolina; 17 counties in South Carolina. It was in force for 113 min.

The area

The outline as issued.

The facts

Issued
May 2, 2003, 4:22 PM EDT (20:22 UTC)
Expired
May 2, 2003, 6:15 PM EDT
In force
113 min
Issued by
the Storm Prediction Center
All 46 counties

Alamance County, NC, Anson County, NC, Bladen County, NC, Cabarrus County, NC, Chatham County, NC, Cumberland County, NC, Davidson County, NC, Davie County, NC, Durham County, NC, Forsyth County, NC, Guilford County, NC, Harnett County, NC, Hoke County, NC, Johnston County, NC, Lee County, NC, Montgomery County, NC, Moore County, NC, Orange County, NC, Randolph County, NC, Richmond County, NC, Robeson County, NC, Rockingham County, NC, Rowan County, NC, Sampson County, NC, Scotland County, NC, Stanly County, NC, Stokes County, NC, Union County, NC, Wake County, NC, Berkeley County, SC, Calhoun County, SC, Chesterfield County, SC, Clarendon County, SC, Darlington County, SC, Dillon County, SC, Florence County, SC, Horry County, SC, Kershaw County, SC, Lancaster County, SC, Lee County, SC, Lexington County, SC, Marion County, SC, Marlboro County, SC, Richland County, SC, Sumter County, SC, Williamsburg County, SC

The radar

The Raleigh/Durham radar (KRAX), 146 km from the middle of the area, began a volume at 20:21 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

Greensboro/Hi Pt, NC (KGSO), launched 12:00Z, 8.4 hours before the alert went out and 135 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 2003-05-02Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 66 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 2003-05-02The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -28 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
66 J/kg
Mixed-layer CIN
-126 J/kg
Mixed-layer LCL
1115 m above ground
0-6 km bulk shear
12 kt
0-1 km storm-relative helicity
-28 m²/s²
0-3 km storm-relative helicity
49 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.

263 
ACUS11 KWNS 022023
SWOMCD
SPC MCD 022022 
NCZ000-SCZ000-022215-

MESOSCALE DISCUSSION 0686
NWS STORM PREDICTION CENTER NORMAN OK
0322 PM CDT FRI MAY 02 2003

AREAS AFFECTED...CNTRL NC/CNTRL-NERN SC

CONCERNING...SEVERE THUNDERSTORM POTENTIAL 

VALID 022022Z - 022215Z

SEVERE CONVECTIVE LINE ACROSS WRN SC/WRN NC WILL CONTINUE TO MOVE
EWD OVER THE NEXT FEW HOURS. WIND DAMAGE AND ISOLATED HAIL WILL BE
PROBABLE AS THE STORMS MOVE INTO THE LOWER TERRAIN EARLY THIS
EVENING. A NEW WW WILL LIKELY BE ISSUED WITHIN THE NEXT HOUR.

LARGE-SCALE FORCING WITH VORT MAX EVIDENT ON WV ACROSS THE
APPALACHIANS WILL CONTINUE TO SUSTAIN A SEVERE CONVECTIVE LINE AS IT
MOVES EWD. THE LINE WILL MOVE INTO THE LOWER ELEVATIONS WHERE MLCAPE
VALUES WERE 1500-2000 J/KG. LOW-LEVEL JET OVER WRN SC AND MID-LEVEL
JET OVER SRN TN HAD INCREASED DEEP LAYER SHEAR BEHIND THE LINE OVER
THE LAST SEVERAL HOURS. AS A RESULT...THE LINE SHOULD CONTINUE TO
REMAIN ORGANIZED AS IT MOVES EWD INTO THE LOWER ELEVATIONS. DAMAGING
WIND GUSTS AND ISOLATED HAIL WILL BE POSSIBLE WITH THE LINE. WW WILL
LIKELY BE ISSUED WITHIN THE NEXT HOUR.

..BROYLES.. 05/02/2003

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

ATTN...WFO...RAH...ILM...RNK...CHS...CAE...GSP...

33788131 34628104 36008054 36498031 36327900 35977814
35467810 34487855 33627912 33078001

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
May 2, 2:23 PM EDTMesoscale DiscussionSPCAlexander, Avery, Buncombe, Burke, Caldwell, Catawba and 17 more2 hr
May 2, 2:35 PM EDTSevere Thunderstorm WatchSPCAlexander, Alleghany, Ashe, Avery, Buncombe, Burke and 21 more5 hr
May 2, 2:55 PM EDTSevere Thunderstorm WatchSPCCherokee, Clay, Graham, Swain5 hr
May 2, 4:40 PM EDTSevere Thunderstorm WatchSPCAlamance, Anson, Cabarrus, Chatham, Cumberland, Davidson and 22 more5 hr
May 2, 6:36 PM EDTMesoscale DiscussionSPCCherokee, Clay, Graham84 min
May 2, 7:17 PM EDTMesoscale DiscussionSPCAlamance, Anson, Cabarrus, Chatham, Cumberland, Davidson and 21 more88 min
May 2, 7:45 PM EDTSevere Thunderstorm WatchSPCBeaufort, Bladen, Brunswick, Columbus, Craven, Duplin and 11 more3 hr
May 2, 5:43 PM EDTMesoscale DiscussionSPCMcCormick92 min

Nearby

Mesoscale Discussions in North Carolina, 2003Mesoscale Discussions in South Carolina, 2003Every mesoscale discussion in 2003

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.