Alert archive / North Carolina / Mesoscale Discussions in 2014

Mesoscale Discussion 404

April 25, 201452 counties in North Carolina; 27 counties in Virginia

The Storm Prediction Center issued this mesoscale discussion at Apr 25, 2014, 3:22 PM EDT for 52 counties in North Carolina; 27 counties in Virginia. It was in force for 83 min.

The area

The outline as issued.

The facts

Issued
Apr 25, 2014, 3:22 PM EDT (19:22 UTC)
Expired
Apr 25, 2014, 4:45 PM EDT
In force
83 min
Issued by
the Storm Prediction Center
All 79 counties

Alamance County, NC, Anson County, NC, Beaufort County, NC, Bertie County, NC, Camden County, NC, Caswell County, NC, Chatham County, NC, Chowan County, NC, Craven County, NC, Cumberland County, NC, Currituck County, NC, Davidson County, NC, Duplin County, NC, Durham County, NC, Edgecombe County, NC, Franklin County, NC, Gates County, NC, Granville County, NC, Greene County, NC, Guilford County, NC, Halifax County, NC, Harnett County, NC, Hertford County, NC, Hoke County, NC, Johnston County, NC, Jones County, NC, Lee County, NC, Lenoir County, NC, Martin County, NC, Montgomery County, NC, Moore County, NC, Nash County, NC, Northampton County, NC, Orange County, NC, Pamlico County, NC, Pasquotank County, NC, Perquimans County, NC, Person County, NC, Pitt County, NC, Randolph County, NC, Richmond County, NC, Rockingham County, NC, Sampson County, NC, Stanly County, NC, Tyrrell County, NC, Union County, NC, Vance County, NC, Wake County, NC, Warren County, NC, Washington County, NC, Wayne County, NC, Wilson County, NC, Brunswick County, VA, Campbell 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 Newport News, VA, City of Norfolk, VA, City of Petersburg, VA, City of Poquoson, VA, City of Portsmouth, VA, City of Suffolk, VA, City of Virginia Beach, VA, Dinwiddie County, VA, Greensville County, VA, Halifax County, VA, Isle of Wight County, VA, Lunenburg County, VA, Mecklenburg County, VA, Nottoway County, VA, Pittsylvania County, VA, Prince George County, VA, Southampton County, VA, Surry County, VA, Sussex County, VA

The radar

The Raleigh/Durham radar (KRAX), 20 km from the middle of the area, began a volume at 19:24 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

Greensboro/Hi Pt, NC (KGSO), launched 12:00Z, 7.4 hours before the alert went out and 121 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 2014-04-25Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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 2014-04-25The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 141 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
664 m above ground
0-6 km bulk shear
44 kt
0-1 km storm-relative helicity
141 m²/s²
0-3 km storm-relative helicity
164 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.

616 
ACUS11 KWNS 251923
SWOMCD
SPC MCD 251922 
VAZ000-NCZ000-SCZ000-252045-

MESOSCALE DISCUSSION 0404
NWS STORM PREDICTION CENTER NORMAN OK
0222 PM CDT FRI APR 25 2014

AREAS AFFECTED...PORTIONS OF CNTRL/ERN NC AND SRN VA

CONCERNING...TORNADO WATCH 91...

VALID 251922Z - 252045Z

THE SEVERE WEATHER THREAT FOR TORNADO WATCH 91 CONTINUES.

SUMMARY...THE TORNADO POTENTIAL IS INCREASING ACROSS PARTS OF THE
PIEDMONT AND COASTAL PLAIN OF NORTH CAROLINA AND SRN VIRGINIA.

DISCUSSION...SFC MESOANALYSIS REVELS A WWD-ADVANCING AGGREGATE
OUTFLOW/SEA BREEZE BOUNDARY RUNNING ROUGHLY FROM HALIFAX TO
CUMBERLAND COUNTY. AS ONGOING DISCRETE/SEMI-DISCRETE SUPERCELLS
EVOLVING OVER THE PIEDMONT SPREAD E INTO THE MOISTER/MODERATELY
UNSTABLE ENVIRONMENT EAST OF THIS BOUNDARY...THEY WILL ENCOUNTER
RELATIVELY BACKED SFC WINDS TO BOOST EFFECTIVE SRH TO AROUND 200
M2/S2. LOW-LEVEL HELICITY WILL FURTHER INCREASE AS STRONGER DEEP
FLOW ARRIVES IN ASSOCIATION WITH AN ACCOMPANYING PV MAX AND
LOW-LEVEL FLOW RESPONDS. TRENDS IN RAX VWP DATA ALREADY REFLECT THIS
RESPONSE. AS SUCH...THE RISK FOR TORNADOES WILL INCREASE IN THE
NEAR-TERM...PARTICULARLY IN ERN NC AND SERN VA. A STRONG TORNADO
RISK WILL EXIST.

..COHEN.. 04/25/2014

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

ATTN...WFO...AKQ...MHX...RAH...ILM...RNK...CAE...GSP...

LAT...LON   34898083 37217952 37227518 34897662 34898083

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 25, 12:46 PM EDTMesoscale DiscussionSPCAlamance, Beaufort, Bertie, Bladen, Camden, Carteret and 48 more2 hr
Apr 25, 1:19 PM EDTTornado WatchSPCAlamance, Anson, Beaufort, Bertie, Camden, Carteret and 51 more10 hr
Apr 25, 4:45 PM EDTMesoscale DiscussionSPCAlamance, Beaufort, Bertie, Camden, Carteret, Caswell and 47 more90 min
Apr 25, 7:29 PM EDTMesoscale DiscussionSPCBeaufort, Bertie, Camden, Carteret, Chowan, Craven and 24 more61 min
Apr 25, 2:50 PM EDTMesoscale DiscussionSPCAccomack, Albemarle, Buckingham, Caroline, Culpeper, Cumberland and 25 more2 hr

Nearby

Mesoscale Discussions in North Carolina, 2014Mesoscale Discussions in Virginia, 2014Every mesoscale discussion in 2014

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.