Alert archive / North Carolina / Mesoscale Discussions in 2005

Mesoscale Discussion 2221

September 18, 200516 counties in North Carolina; Georgetown County, Horry County, Marion County, South Carolina

The Storm Prediction Center issued this mesoscale discussion at Sep 18, 2005, 1:42 PM EDT for 16 counties in North Carolina; Georgetown County, Horry County, Marion County, South Carolina. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued
Sep 18, 2005, 1:42 PM EDT (17:42 UTC)
Expired
Sep 18, 2005, 3:45 PM EDT
In force
2 hr
Issued by
the Storm Prediction Center

Counties Beaufort County, NC, Bladen County, NC, Columbus County, NC, Craven County, NC, Duplin County, NC, Greene County, NC, Hyde County, NC, Jones County, NC, Lenoir County, NC, Martin County, NC, Onslow County, NC, Pamlico County, NC, Pender County, NC, Pitt County, NC, Tyrrell County, NC, Washington County, NC, Georgetown County, SC, Horry County, SC, Marion County, SC

The radar

The Morehead City radar (KMHX), 67 km from the middle of the area, began a volume at 17:43 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, 5.7 hours before the alert went out and 67 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 2005-09-18Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1228 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Newport, NC at 12:00Z on 2005-09-18The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 37 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
1228 J/kg
Mixed-layer CIN
-68 J/kg
Mixed-layer LCL
1012 m above ground
0-6 km bulk shear
19 kt
0-1 km storm-relative helicity
37 m²/s²
0-3 km storm-relative helicity
23 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.

000 
ACUS11 KWNS 181743
SWOMCD
SPC MCD 181742 
NCZ000-SCZ000-181945-

MESOSCALE DISCUSSION 2221
NWS STORM PREDICTION CENTER NORMAN OK
1242 PM CDT SUN SEP 18 2005

AREAS AFFECTED...NERN SC THROUGH ERN NC

CONCERNING...SEVERE THUNDERSTORM POTENTIAL 

VALID 181742Z - 181945Z

THUNDERSTORMS ARE EXPECTED TO DEVELOP FROM PARTS OF ERN SC THROUGH
ERN NC THIS AFTERNOON. THE POTENTIAL WILL EXIST FOR MAINLY ISOLATED
STRONG WIND GUSTS AND MARGINALLY SEVERE HAIL. AREA WILL CONTINUE TO
BE MONITORED.

THIS AFTERNOON A COLD FRONT EXTENDS FROM E CNTRL NC SWWD THROUGH
CNTRL SC. LOW LEVEL DEWPOINTS IN THE UPPER 60S TO LOWER 70S AND
STRONG SURFACE HEATING ARE CONTRIBUTING TO MODERATE INSTABILITY
ACROSS THE ERN CAROLINAS. HOWEVER...RELATIVELY WARM MID LEVEL
TEMPERATURES OF -5C TO -7C AROUND 6 KM WILL TEND TO LIMIT MID LEVEL
LAPSE RATES AND OVERALL DEGREE OF INSTABILITY WITH MLCAPES ON THE
ORDER OF 1500 TO 2000 J/KG EXPECTED. A FEW STORMS ARE ALREADY
DEVELOPING WITHIN THE AXIS OF ENHANCED CUMULUS OVER ERN SC...AND
STORMS SHOULD CONTINUE DEVELOPING ALONG AND AHEAD OF THE FRONT THIS
AFTERNOON...POSSIBLY ENHANCED BY THE SEABREEZE. WV IMAGERY SHOWS THE
MID LEVELS TO BE FAIRLY DRY OVER ERN NC...AND THIS COULD SERVE TO
LIMIT THUNDERSTORM COVERAGE DUE TO THE EFFECTS OF ENTRAINMENT.
HOWEVER...MODELS INITIALIZE A SUBTLE SHORTWAVE TROUGH FROM VA SWD
INTO NC...AND WEAK ASCENT ASSOCIATED WITH THIS FEATURE MIGHT ENHANCE
CONVECTIVE DEVELOPMENT. FLOW IS RATHER WEAK WITHIN THE LOWEST 3
KM...BUT VERTICAL SHEAR THROUGH A DEEPER LAYER IS AT LEAST
MARGINALLY SUFFICIENT FOR SOME ORGANIZED STORMS. THE PRESENCE OF MID
LEVEL DRY AIR WILL SUPPORT POTENTIAL FOR WET MICROBURSTS THROUGH
EARLY EVENING.

..DIAL.. 09/18/2005

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

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

34747711 33377933 33807994 34817856 35757736 36077676
36057594 35397607

Nearby

Mesoscale Discussions in North Carolina, 2005Mesoscale Discussions in South Carolina, 2005Every mesoscale discussion in 2005

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.