Alert archive / North Carolina / Mesoscale Discussions in 2012

Mesoscale Discussion 82

January 27, 201224 counties in North Carolina; 19 counties in Virginia

The Storm Prediction Center issued this mesoscale discussion at Jan 27, 2012, 8:17 AM EST for 24 counties in North Carolina; 19 counties in Virginia. It was in force for 88 min.

The area

The outline as issued.

The facts

Issued: Jan 27, 2012, 8:17 AM EST (13:17 UTC)
Expired: Jan 27, 2012, 9:45 AM EST
In force: 88 min
Issued by: the Storm Prediction Center

All 43 counties

Beaufort County, NC, Bertie County, NC, Camden County, NC, Chowan County, NC, Craven County, NC, Currituck County, NC, Duplin County, NC, Edgecombe County, NC, Gates County, NC, Greene County, NC, Hertford County, NC, Jones County, NC, Lenoir County, NC, Martin County, NC, Northampton County, NC, Onslow County, NC, Pamlico County, NC, Pasquotank County, NC, Pender County, NC, Perquimans County, NC, Pitt County, NC, Tyrrell County, NC, Washington County, NC, Wayne County, NC, City of Chesapeake, VA, City of Franklin, VA, City of Hampton, 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, City of Williamsburg, VA, Gloucester County, VA, Isle of Wight County, VA, James City County, VA, Mathews County, VA, Middlesex County, VA, Northampton County, VA, Southampton County, VA, Surry County, VA, York County, VA

The radar

The Norfolk radar (KAKQ), 89 km from the middle of the area, began a volume at 13:17 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, 1.3 hours before the alert went out and 157 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: 766 J/kg
Mixed-layer CIN: -2 J/kg
Mixed-layer LCL: 454 m above ground
0-6 km bulk shear: 64 kt
0-1 km storm-relative helicity: 325 m²/s²
0-3 km storm-relative helicity: 317 m²/s²
Significant tornado parameter: 1.7
Supercell composite: 8.2

Open this sounding in Storm Lab

The text

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

891 
ACUS11 KWNS 271317
SWOMCD
SPC MCD 271317 
VAZ000-NCZ000-271445-

MESOSCALE DISCUSSION 0082
NWS STORM PREDICTION CENTER NORMAN OK
0717 AM CST FRI JAN 27 2012

AREAS AFFECTED...SERN VA...ERN NC

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY 

VALID 271317Z - 271445Z

DESPITE THE LACK OF ANY RECENT DETECTED LIGHTNING STRIKES...ISOLATED
DAMAGING WINDS AND PERHAPS A BRIEF TORNADO WILL BE POSSIBLE WITH A
PRE-FRONTAL CONVECTIVE BAND PROGRESSING EWD ACROSS SERN VA/ERN NC.
THE PROBABILITY OF A WW ISSUANCE BY 15Z IS 20 PERCENT.

LOW-TOPPED CONVECTIVE BAND WITH EMBEDDED HIGH REFLECTIVITY ELEMENTS
EXISTED FROM JUST SERN OF RIC S/SWWD INTO BLADEN COUNTY NC AS OF
1310Z. THE MOST ORGANIZED PORTION OF THIS BAND APPEARED TO BE
CONFINED ACROSS SERN VA. MODIFIED 12Z GSO/CHS RAOBS SUGGEST THE
THERMODYNAMIC ENVIRONMENT SHOULD REMAIN MARGINAL FOR CHARGE
SEPARATION. BUT WITH SCANT SHALLOW BUOYANCY CONSISTING OF MLCAPE
FROM 100-200 J/KG...THE PRESENCE OF 50-60 KT SWLYS SUPPORT MODEST
POTENTIAL FOR A FEW DAMAGING WIND GUSTS.

WITH RELATIVELY GREATER BUOYANCY SAMPLED IN THE 12Z MHX RAOB...IT IS
POSSIBLE THAT THIS BAND COULD STRENGTHEN AS IT APPROACHES THE COAST.
STILL...WITH A CORRIDOR OF STRATIFORM RAIN AHEAD OF IT AND
WIDESPREAD OVERCAST...PROSPECTS FOR SUBSTANTIAL DESTABILIZATION SEEM
UNLIKELY AND SEVERE POTENTIAL SHOULD REMAIN MARGINAL.

..GRAMS.. 01/27/2012

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

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

LAT...LON   37197700 37647663 37697577 37377575 35927583 34747666
            34407777 34447847 34797842 36687730 37197700

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jan 27, 2:34 AM EST	Mesoscale Discussion	SPC	Alleghany, Bath, Botetourt, Craig, Giles, Highland and 9 more	86 min

Nearby

Mesoscale Discussions in North Carolina, 2012 Mesoscale Discussions in Virginia, 2012 Every mesoscale discussion in 2012

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.