Alert archive / West Virginia / Mesoscale Discussions in 2011

Mesoscale Discussion 49

January 26, 2011Garrett County, Maryland; 28 counties in Virginia; 30 counties in West Virginia

The Storm Prediction Center issued this mesoscale discussion at Jan 26, 2011, 11:19 AM EST for Garrett County, Maryland; 28 counties in Virginia; 30 counties in West Virginia. It was in force for 4 hr.

The area

The outline as issued.

The facts

Issued: Jan 26, 2011, 11:19 AM EST (16:19 UTC)
Expired: Jan 26, 2011, 3:15 PM EST
In force: 4 hr
Issued by: the Storm Prediction Center

All 59 counties

Garrett County, MD, Albemarle County, VA, Alleghany County, VA, Amherst County, VA, Augusta County, VA, Bath County, VA, Botetourt County, VA, City of Buena Vista, VA, City of Charlottesville, VA, City of Covington, VA, City of Harrisonburg, VA, City of Lexington, VA, City of Staunton, VA, City of Waynesboro, VA, City of Winchester, VA, Craig County, VA, Culpeper County, VA, Frederick County, VA, Giles County, VA, Greene County, VA, Highland County, VA, Madison County, VA, Nelson County, VA, Page County, VA, Rappahannock County, VA, Rockbridge County, VA, Rockingham County, VA, Shenandoah County, VA, Warren County, VA, Barbour County, WV, Boone County, WV, Braxton County, WV, Calhoun County, WV, Clay County, WV, Fayette County, WV, Gilmer County, WV, Grant County, WV, Greenbrier County, WV, Hampshire County, WV, Hardy County, WV, Harrison County, WV, Kanawha County, WV, Lewis County, WV, Mercer County, WV, Mineral County, WV, Monroe County, WV, Nicholas County, WV, Pendleton County, WV, Pocahontas County, WV, Preston County, WV, Raleigh County, WV, Randolph County, WV, Roane County, WV, Summers County, WV, Taylor County, WV, Tucker County, WV, Upshur County, WV, Webster County, WV, Wyoming County, WV

The radar

The Roanoke radar (KFCX), 170 km from the middle of the area, began a volume at 16:19 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, 4.3 hours before the alert went out and 138 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: 520 m above ground
0-6 km bulk shear: 62 kt
0-1 km storm-relative helicity: 405 m²/s²
0-3 km storm-relative helicity: 426 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.

685 
ACUS11 KWNS 261619
SWOMCD
SPC MCD 261619 
VAZ000-WVZ000-MDZ000-262015-

MESOSCALE DISCUSSION 0049
NWS STORM PREDICTION CENTER NORMAN OK
1019 AM CST WED JAN 26 2011

AREAS AFFECTED...CNTRL/ERN WV...WRN MD...NWRN VA

CONCERNING...HEAVY SNOW 

VALID 261619Z - 262015Z

SNOWFALL WITH RATES OF 1-2 IN/HR IS EXPECTED TO DEVELOP ACROSS
CNTRL/ERN WV...AND PERHAPS WRN MD...DURING THE NEXT FEW HRS...AND
THEN SPREAD EWD ACROSS NWRN VA BY EARLY TO MID AFTERNOON.

LATE MORNING WV IMAGERY SHOWS AN UPPER TROUGH BECOMING INCREASINGLY
NEGATIVELY TILTED AS IT PROGRESSES NEWD TOWARD THE MID ATLANTIC
REGION. INTENSE DEEP LAYER ASCENT ACCOMPANYING THE UPPER DISTURBANCE
IS CURRENTLY SPREADING INTO WV...AIDING IN DYNAMIC COOLING OF THE
ATMOSPHERIC COLUMN AND REMOVAL OF A WARM LAYER OF AIR OBSERVED BELOW
800 MB PER 12Z OBSERVED RNK RAOB. AS THIS OCCURS...PRECIPITATION IS
EXPECTED TO QUICKLY TRANSITION TO SNOW OVER CNTRL/ERN WV. GIVEN THE
VERY STRONG DEEP LAYER ASCENT OCCURRING THROUGH THE DENDRITIC GROWTH
ZONE...SNOWFALL RATES OF 1-2 IN/HR APPEAR PROBABLE.

BY EARLY TO MID AFTERNOON...STRONG ASCENT ACCOMPANYING THE UPPER
TROUGH IS FORECAST TO EXIT WV AND MOVE ACROSS NWRN VA. PRECIPITATION
OVER THIS AREA MAY BRIEFLY TRANSITION TO FREEZING RAIN OR
SLEET...BEFORE PREDOMINANT PRECIPITATION TYPE BECOMES SNOW BY 20Z.
STRONG ASCENT COUPLED WITH MUCAPE VALUES OF 50-150 J/KG ROOTED IN
THE 700-600 MB LAYER SUGGEST THAT SNOWFALL RATES OF 1-2 IN/HR WILL
BE POSSIBLE ACROSS NWRN VA AS WELL.

..GARNER.. 01/26/2011

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

ATTN...WFO...AKQ...LWX...RNK...PBZ...RLX...

LAT...LON   38597785 37767842 37278091 37608173 38608172 39597988
            39557820 38597785

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jan 26, 7:30 AM EST	Mesoscale Discussion	SPC	Allegany, Garrett, Washington	5 hr
Jan 26, 2:19 PM EST	Mesoscale Discussion	SPC	Anne Arundel, Baltimore, Calvert, Caroline, Carroll, Cecil and 13 more	6 hr

Nearby

Mesoscale Discussions in West Virginia, 2011 Mesoscale Discussions in Virginia, 2011 Mesoscale Discussions in Maryland, 2011 Every mesoscale discussion in 2011

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.