Alert archive / North Carolina / Mesoscale Discussions in 2007

Mesoscale Discussion 2136

October 24, 200729 counties in North Carolina; 27 counties in Virginia

The Storm Prediction Center issued this mesoscale discussion at Oct 24, 2007, 4:50 PM EDT for 29 counties in North Carolina; 27 counties in Virginia. It was in force for 115 min.

The area

The outline as issued.

The facts

Issued: Oct 24, 2007, 4:50 PM EDT (20:50 UTC)
Expired: Oct 24, 2007, 6:45 PM EDT
In force: 115 min
Issued by: the Storm Prediction Center

All 56 counties

Alamance County, NC, Bertie County, NC, Camden County, NC, Caswell County, NC, Chatham County, NC, Chowan County, NC, Currituck County, NC, Durham County, NC, Edgecombe County, NC, Franklin County, NC, Gates County, NC, Granville County, NC, Halifax County, NC, Hertford County, NC, Johnston County, NC, Lee County, NC, Martin County, NC, Nash County, NC, Northampton County, NC, Orange County, NC, Pasquotank County, NC, Perquimans County, NC, Person County, NC, Rockingham County, NC, Vance County, NC, Wake County, NC, Warren County, NC, Washington County, NC, Wilson County, NC, Brunswick County, VA, Charlotte County, VA, City of Chesapeake, VA, City of Danville, VA, City of Emporia, VA, City of Franklin, VA, City of Hampton, VA, City of Martinsville, VA, City of Newport News, VA, City of Norfolk, VA, City of Poquoson, VA, City of Portsmouth, VA, City of Suffolk, VA, City of Virginia Beach, VA, Dinwiddie County, VA, Franklin County, VA, Greensville County, VA, Halifax County, VA, Henry County, VA, Isle of Wight County, VA, Lunenburg County, VA, Mecklenburg County, VA, Pittsylvania County, VA, Prince George County, VA, Southampton County, VA, Surry County, VA, Sussex County, VA

The radar

The Norfolk radar (KAKQ), 71 km from the middle of the area, began a volume at 20:50 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

Roanoke, VA (KRNK), launched 12:00Z, 8.8 hours before the alert went out and 187 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: 5 J/kg
Mixed-layer CIN: -102 J/kg
Mixed-layer LCL: 598 m above ground
0-6 km bulk shear: 51 kt
0-1 km storm-relative helicity: 57 m²/s²
0-3 km storm-relative helicity: 95 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 242050
SWOMCD
SPC MCD 242050 
NCZ000-VAZ000-242245-

MESOSCALE DISCUSSION 2136
NWS STORM PREDICTION CENTER NORMAN OK
0350 PM CDT WED OCT 24 2007

AREAS AFFECTED...SRN VA AND NRN NC

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY 

VALID 242050Z - 242245Z

ISOLATED STRONG WIND GUSTS AND PERHAPS A TORNADO WILL REMAIN
POSSIBLE OVER THE NEXT FEW HOURS...BUT A WW IS UNLIKELY.

SURFACE ANALYSIS SHOWS WEAK FRONTAL BOUNDARY ACROSS SRN VA/NRN NC.
MDT INSTABILITY HAS DEVELOPED DUE TO POCKETS OF HEATING AND LOW
LEVEL DEWPOINTS INTO THE LOWER 70S. A GENERALLY CONVERGENT BOUNDARY
LAYER ALONG WITH ENHANCED LIFT ALONG THE FRONT WILL MAINTAIN THE
THREAT OF STORMS THROUGH EARLY EVENING.

ALTHOUGH DEEP LAYER SHEAR IS MARGINAL FOR SUSTAINED SEVERE
CONVECTION...ENHANCED LOW LEVEL SHEAR DOES EXIST ALONG THE FRONT
WITH 100-150 M2/S2 0-3KM SRH NOTED ON AREA VAD WIND PROFILES. IN
ADDITION...RADAR TRENDS HAVE SHOWN AN INCREASE IN ROTATION WITHIN
STORMS. THE AIR MASS COOLS INTO THE 60S N OF THE FRONT...AND THUS
ANY TORNADO/DAMAGING WIND THREAT SHOULD REMAIN NEAR AND JUST S OF
THE FRONT WHERE EFFECTIVE INFLOW PARCELS EXTEND TO THE SURFACE.

..JEWELL.. 10/24/2007

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

ATTN...WFO...AKQ...MHX...RAH...RNK...

36517573 35957619 35457798 35447920 36688028 37227966
37117808 37237677 37207612

Nearby

Mesoscale Discussions in North Carolina, 2007 Mesoscale Discussions in Virginia, 2007 Every mesoscale discussion in 2007

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.