Alert archive / Virginia / Mesoscale Discussions in 2004

Mesoscale Discussion 68

February 2, 20045 states

The Storm Prediction Center issued this mesoscale discussion at Feb 2, 2004, 8:58 PM EST for 5 states. It was in force for 5 hr.

The area

The outline as issued.

The facts

Issued: Feb 2, 2004, 8:58 PM EST (01:58 UTC)
Expired: Feb 3, 2004, 2:00 AM EST
In force: 5 hr
Issued by: the Storm Prediction Center

All 66 counties

Allegany County, MD, Garrett County, MD, Alexander County, NC, Alleghany County, NC, Ashe County, NC, Avery County, NC, Caldwell County, NC, Mitchell County, NC, Stokes County, NC, Surry County, NC, Watauga County, NC, Wilkes County, NC, Yadkin County, NC, Bedford County, PA, Somerset County, PA, Westmoreland County, PA, Alleghany County, VA, Amherst County, VA, Augusta County, VA, Bath County, VA, Bedford County, VA, Botetourt County, VA, Carroll County, VA, City of Buena Vista, VA, City of Covington, VA, City of Galax, VA, City of Harrisonburg, VA, City of Lexington, VA, City of Lynchburg, VA, City of Martinsville, VA, City of Radford, VA, City of Roanoke, VA, City of Salem, VA, City of Staunton, VA, City of Waynesboro, VA, City of Winchester, VA, Clarke County, VA, Craig County, VA, Floyd County, VA, Franklin County, VA, Frederick County, VA, Giles County, VA, Grayson County, VA, Henry County, VA, Highland County, VA, Montgomery County, VA, Nelson County, VA, Page County, VA, Patrick County, VA, Pulaski County, VA, Roanoke County, VA, Rockbridge County, VA, Rockingham County, VA, Shenandoah County, VA, Warren County, VA, Wythe County, VA, Berkeley County, WV, Grant County, WV, Hampshire County, WV, Hardy County, WV, Mineral County, WV, Monroe County, WV, Morgan County, WV, Pendleton County, WV, Pocahontas County, WV, Tucker County, WV

The radar

The Roanoke radar (KFCX), 81 km from the middle of the area, began a volume at 02:01 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 00:00Z, 2.0 hours before the alert went out and 79 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 1534 m above ground
0-6 km bulk shear: 37 kt
0-1 km storm-relative helicity: 224 m²/s²
0-3 km storm-relative helicity: 296 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.

851 
ACUS11 KWNS 030159
SWOMCD
SPC MCD 030158 
MDZ000-VAZ000-WVZ000-PAZ000-NCZ000-TNZ000-030700-

MESOSCALE DISCUSSION 0068
NWS STORM PREDICTION CENTER NORMAN OK
0758 PM CST MON FEB 02 2004

AREAS AFFECTED...WRN NC/WRN VA/ERN WV INTO WRN MD/SW PA

CONCERNING...WINTER MIXED PRECIPITATION 

VALID 030158Z - 030700Z

MIXED PRECIPITATION...PRIMARILY IN THE FORM OF FREEZING RAIN...WILL
DEVELOP/SPREAD NEWD ACROSS THE ERN APPALACHIANS THROUGH 09Z.
PRECIPITATION RATES MAY BE ON THE ORDER OF 0.10 IN/HR OR
GREATER...WITH CONSIDERABLE ICE ACCUMULATION POSSIBLE.

COLD AIR DAMMING SCENARIO EXISTS ACROSS THE ERN APPALACHIANS OWING
TO SFC HIGH PRESSURE OVER THE NEW ENGLAND STATES. LOW LEVEL DRY AIR
REMAINS IN PLACE PER LATEST SUBJECTIVE SURFACE ANALYSIS /10F-15F
TEMPERATURE-DEWPOINT SPREADS/ AND 00Z OBSERVED GSO/RNK RAOBS
PORTRAYAL OF DRY AIR BELOW 750 MB. HOWEVER EFFECTIVE SATURATION WILL
OCCUR QUICKLY THIS EVENING AS STRONG FORCING FOR UPWARD VERTICAL
MOTION OVERSPREADS. ALTHOUGH SFC TEMPERATURES AT 01Z GENERALLY
REMAIN ABOVE FREEZING...WITH SFC WET BULB TEMPERATURES BELOW
ZERO...PRECIPITATION UPON EFFECTIVE SATURATION WILL LIKELY
MATERIALIZE IN THE FORM OF FREEZING RAIN OVER THE NEXT SEVERAL
HOURS. WHILE LOW LEVELS SATURATE/COOL...PERSISTENT WARM AIR
ADVECTION IN/ABOVE 850 MB LAYER WILL ESTABLISH/REINFORCE NOSE OF MID
LEVEL WARM AIR ACROSS THE REGION. ACROSS WRN MD AND SW
PA...PRECIPITATION MAY BE MORE OF A FREEZING RAIN/SNOW/SLEET MIX
VERSUS PREDOMINANTLY FREEZING RAIN.

..GUYER.. 02/03/2004

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

ATTN...WFO...CTP...LWX...RAH...RNK...PBZ...RLX...GSP...MRX...

35828122 36028226 37398083 39047961 40367960 40497847
39187786 37217929 36088051

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Feb 3, 4:28 AM EST	Mesoscale Discussion	SPC	Allegany, Frederick, Garrett, Washington	3 hr
Feb 3, 11:45 AM EST	Mesoscale Discussion	SPC	Bradford, Carbon, Lackawanna, Luzerne, Monroe, Northampton and 5 more	6 hr

Nearby

Mesoscale Discussions in Virginia, 2004 Mesoscale Discussions in North Carolina, 2004 Mesoscale Discussions in West Virginia, 2004 Every mesoscale discussion in 2004

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.