Alert archive / Virginia / Mesoscale Discussions in 2016

Mesoscale Discussion 55

January 22, 2016Garrett County, Maryland; 29 counties in Virginia; 17 counties in West Virginia

The Storm Prediction Center issued this mesoscale discussion at Jan 22, 2016, 6:47 PM EST for Garrett County, Maryland; 29 counties in Virginia; 17 counties in West Virginia. It was in force for 5 hr.

The area

The outline as issued.

The facts

Issued: Jan 22, 2016, 6:47 PM EST (23:47 UTC)
Expired: Jan 22, 2016, 11:45 PM EST
In force: 5 hr
Issued by: the Storm Prediction Center

All 47 counties

Garrett County, MD, Alleghany County, VA, Amherst County, VA, Augusta County, VA, Bath County, VA, Bedford County, VA, Botetourt County, VA, City of Buena Vista, VA, City of Covington, VA, City of Harrisonburg, VA, City of Lexington, VA, City of Lynchburg, 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, Craig County, VA, Floyd County, VA, Franklin County, VA, Frederick County, VA, Giles County, VA, Highland County, VA, Montgomery County, VA, Pulaski County, VA, Roanoke County, VA, Rockbridge County, VA, Rockingham County, VA, Shenandoah County, VA, Barbour County, WV, Berkeley County, WV, Grant County, WV, Greenbrier County, WV, Hampshire County, WV, Hardy County, WV, Mineral County, WV, Monroe County, WV, Morgan County, WV, Pendleton County, WV, Pocahontas County, WV, Preston County, WV, Randolph County, WV, Taylor County, WV, Tucker County, WV, Upshur County, WV, Webster County, WV

The radar

The Roanoke radar (KFCX), 121 km from the middle of the area, began a volume at 23:50 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

Roanoke, VA (KRNK), launched 12:00Z, 11.8 hours before the alert went out and 95 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: 595 m above ground
0-6 km bulk shear: 64 kt
0-1 km storm-relative helicity: 116 m²/s²
0-3 km storm-relative helicity: 203 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

986 
ACUS11 KWNS 222348
SWOMCD
SPC MCD 222347 
WVZ000-VAZ000-MDZ000-230445-

MESOSCALE DISCUSSION 0055
NWS STORM PREDICTION CENTER NORMAN OK
0547 PM CST FRI JAN 22 2016

AREAS AFFECTED...PORTIONS OF WV...WRN VA...WRN MD

CONCERNING...HEAVY SNOW 

VALID 222347Z - 230445Z

SUMMARY...A BAND OF HEAVY SNOW WILL DEVELOP NORTHWARD ACROSS WESTERN
VA INTO EASTERN WV AND WESTERN MD OVER THE NEXT FEW HOURS. SNOWFALL
RATES OF 1-2 INCHES PER HR /WITH LOCALIZED RATES UPWARDS OF 2-3
INCHES PER HR/ WILL BE POSSIBLE.

DISCUSSION...WATER-VAPOR IMAGERY AND THE REGIONAL RADAR MOSAIC
SUGGEST A BAND OF HEAVY SNOW IS BLOSSOMING ACROSS THE MCD AREA IN
RESPONSE TO INCREASING LARGE-SCALE ASCENT...AS AN IMPULSE OVER THE
SRN APPALACHIANS CONTINUES TO ROTATE AROUND THE PERIPHERY OF THE
MATURING UPPER TROUGH. STRENGTHENING WAA AT LOW/MID LEVELS...IN
COMBINATION WITH ENHANCED FRONTOGENETIC CIRCULATIONS...WILL FAVOR A
BAND OF HEAVY SNOWFALL RATES THIS EVENING. ADDITIONALLY...LAST
VISIBLE IMAGES PRIOR TO NIGHTFALL INDICATED SMALL CONVECTIVE
ELEMENTS WITHIN THIS GROWING SNOW BAND...FAVORING ENHANCED RATES.
DUAL-POL ZDR AND KDP DATA FROM KFCX CONFIRM THAT DEEPER/STRONGER
CRYSTAL GENERATION ALOFT IS OVERSPREADING THE REGION...IN RESPONSE
TO INCREASING ASCENT WITHIN THE -10 TO -20 C LAYER. KRLX ALSO
DEPICTS SUCH SIGNATURES TO ITS EAST AND NORTHEAST. EFFICIENT CRYSTAL
GENERATION AND THEN AGGREGATION BENEATH THAT LAYER WILL FAVOR VERY
HEAVY SNOW AT TIMES...WITH LOCALIZED RATES UPWARDS OF 3 INCHES PER
HOUR AND LOW VISIBILITIES THIS EVENING.

..PICCA.. 01/22/2016

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

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

LAT...LON   37258092 38508060 39248030 39587965 39587806 39197796
            38407873 37147914 36707970 36728037 36828073 37258092

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jan 22, 12:34 PM EST	Mesoscale Discussion	SPC	Allegany, Anne Arundel, Calvert, Charles, Dorchester, Frederick and 8 more	5 hr
Jan 22, 4:42 PM EST	Mesoscale Discussion	SPC	Calvert, Charles, Prince George's, Saint Mary's	6 hr
Jan 22, 4:47 AM EST	Mesoscale Discussion	SPC	Alleghany, Bath, Bedford, Bland, Botetourt, Buchanan and 26 more	5 hr
Jan 22, 8:56 AM EST	Mesoscale Discussion	SPC	Albemarle, Alleghany, Amherst, Appomattox, Augusta, Bath and 44 more	4 hr
Jan 22, 11:47 AM EST	Mesoscale Discussion	SPC	Henry, Mecklenburg, City of Danville	6 hr
Jan 22, 1:56 PM EST	Mesoscale Discussion	SPC	Boone, Cabell, Kanawha, Lincoln, Logan, Mingo and 2 more	4 hr

Nearby

Mesoscale Discussions in Virginia, 2016 Mesoscale Discussions in West Virginia, 2016 Mesoscale Discussions in Maryland, 2016 Every mesoscale discussion in 2016

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.