Alert archive / North Carolina / Mesoscale Discussions in 2012

Mesoscale Discussion 1806

August 24, 2012Carteret County, Pamlico County, North Carolina

The Storm Prediction Center issued this mesoscale discussion at Aug 24, 2012, 8:46 PM EDT for Carteret County, Pamlico County, North Carolina. It was in force for 59 min.

The area

The outline as issued.

The facts

Issued: Aug 24, 2012, 8:46 PM EDT (00:46 UTC)
Expired: Aug 24, 2012, 9:45 PM EDT
In force: 59 min
Issued by: the Storm Prediction Center
Chance of a watch: 5%

Counties Carteret County, NC, Pamlico County, NC

The radar

The Morehead City radar (KMHX), 57 km from the middle of the area, began a volume at 00:50 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

Newport, NC (KMHX), launched 00:00Z, 0.8 hours before the alert went out and 57 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: 952 J/kg
Mixed-layer CIN: -3 J/kg
Mixed-layer LCL: 483 m above ground
0-6 km bulk shear: 41 kt
0-1 km storm-relative helicity: 70 m²/s²
0-3 km storm-relative helicity: 191 m²/s²
Significant tornado parameter: 0.6
Supercell composite: 4.0

Open this sounding in Storm Lab

The text

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

632 
ACUS11 KWNS 250046
SWOMCD
SPC MCD 250046 
NCZ000-250145-

MESOSCALE DISCUSSION 1806
NWS STORM PREDICTION CENTER NORMAN OK
0746 PM CDT FRI AUG 24 2012

AREAS AFFECTED...COASTAL AREAS OF E-CNTRL NC

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY 

VALID 250046Z - 250145Z

PROBABILITY OF WATCH ISSUANCE...5 PERCENT

SUMMARY...A BRIEF WATERSPOUT/WEAK TORNADO MAY BE POSSIBLE OVER THE
NEXT COUPLE HRS ALONG COASTAL AREAS OF E-CNTRL NC AND AREAS
IMMEDIATELY INLAND. DUE TO THE LOCALIZED/MARGINAL NATURE OF THE
THREAT...A WW WILL NOT BE NEEDED.

DISCUSSION...LOOSELY ORGANIZED CONVECTION ASSOCIATED WITH A WEAK
MIDLEVEL OFFSHORE IMPULSE HAS SLOWLY SPREAD NWD TOWARDS COASTAL
PORTIONS OF SRN/CNTRL NC. THESE STORMS HAVE EXHIBITED BRIEF PERIODS
OF ROTATION AT TIMES. ALTHOUGH AMBIENT FLOW IN THE LOWER HALF OF THE
TROPOSPHERE IS NOT PARTICULARLY STRONG...LOW-LEVEL N-NELY WINDS
BENEATH MID/UPPER LEVEL S-SWLY WINDS IS YIELDING 0-6 KM SHEAR
MAGNITUDES OF 30-40 KTS /PER MHX 00Z SOUNDING AND VWP DATA/.
THUS...A BRIEF/LOCALIZED THREAT FOR WATERSPOUTS AND PERHAPS A
TORNADO MAY EXIST...PARTICULARLY ALONG/NEAR THE COAST WHERE
LOW-LEVEL CONVERGENCE AND VORTICITY IS MAXIMIZED.

..ROGERS/MEAD.. 08/25/2012

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

ATTN...WFO...MHX...

LAT...LON   35157579 35047601 34817615 34607644 34587664 34667688
            34747708 34957694 35187665 35257638 35397615 35407594
            35347579 35157579

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Aug 25, 6:12 AM EDT	Mesoscale Discussion	SPC	Camden, Chowan, Currituck, Dare, Gates, Hertford and 5 more	3 hr

Nearby

Mesoscale Discussions in North Carolina, 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.