Alert archive / Virginia / Mesoscale Discussions in 2016

Mesoscale Discussion 49

January 22, 201650 counties in Virginia; 28 counties in West Virginia

The Storm Prediction Center issued this mesoscale discussion at Jan 22, 2016, 8:56 AM EST for 50 counties in Virginia; 28 counties in West Virginia. It was in force for 4 hr.

The area

The outline as issued.

The facts

Issued
Jan 22, 2016, 8:56 AM EST (13:56 UTC)
Expired
Jan 22, 2016, 1:00 PM EST
In force
4 hr
Issued by
the Storm Prediction Center
All 78 counties

Albemarle County, VA, Alleghany County, VA, Amherst County, VA, Appomattox County, VA, Augusta County, VA, Bath County, VA, Bedford County, VA, Botetourt County, VA, Buckingham County, VA, Campbell 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 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, Craig County, VA, Culpeper County, VA, Cumberland County, VA, Fauquier County, VA, Floyd County, VA, Fluvanna County, VA, Franklin County, VA, Giles County, VA, Goochland County, VA, Greene County, VA, Highland County, VA, Louisa County, VA, Madison County, VA, Montgomery County, VA, Nelson County, VA, Orange County, VA, Page County, VA, Patrick County, VA, Pittsylvania County, VA, Powhatan County, VA, Prince Edward County, VA, Pulaski County, VA, Rappahannock County, VA, Roanoke County, VA, Rockbridge County, VA, Rockingham County, VA, Shenandoah County, VA, Warren County, VA, 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, Kanawha County, WV, Lewis County, WV, Lincoln County, WV, Logan County, WV, Mercer County, WV, Monroe County, WV, Nicholas County, WV, Pendleton County, WV, Pocahontas County, WV, Putnam County, WV, Raleigh County, WV, Randolph County, WV, Roane County, WV, Summers County, WV, Tucker County, WV, Upshur County, WV, Webster County, WV, Wyoming County, WV

The radar

The Roanoke radar (KFCX), 96 km from the middle of the area, began a volume at 14:00 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, 1.9 hours before the alert went out and 100 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, Roanoke, VA at 12:00Z on 2016-01-22Temperature 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°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Roanoke, VA at 12:00Z on 2016-01-22The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 116 square meters per square second.1939587897117Sfc1 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
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.

436 
ACUS11 KWNS 221357
SWOMCD
SPC MCD 221356 
VAZ000-WVZ000-MDZ000-221800-

MESOSCALE DISCUSSION 0049
NWS STORM PREDICTION CENTER NORMAN OK
0756 AM CST FRI JAN 22 2016

AREAS AFFECTED...PORTIONS OF WV/VA

CONCERNING...HEAVY SNOW 

VALID 221356Z - 221800Z

SUMMARY...MODERATE TO HEAVY SNOW IS EXPECTED TO DEVELOP AND
GRADUALLY EXPAND NORTH-NORTHEASTWARD ACROSS SOUTHERN/CENTRAL WV AND
WESTERN/CENTRAL VA THROUGH THE LATE MORNING/EARLY AFTERNOON HOURS.
SNOW RATES WILL LIKELY REACH 1-2 IN/HR IN THE HEAVIER BANDS.

DISCUSSION...STRONGER FORCING FOR ASCENT/WARM ADVECTION WILL SPREAD
INTO/ACROSS THE REGION THROUGH THE AFTERNOON AHEAD OF THE
UPPER-LEVEL TROUGH/JET STREAK CURRENTLY CROSSING THE TN
VALLEY/SOUTHEAST STATES. WITH A SATURATED DENDRITIC LAYER BETWEEN
500-600 MB...THE 12Z OBSERVED SOUNDING FROM ROANOKE VA SAMPLED A
THERMODYNAMIC PROFILE CONDUCIVE FOR DENDRITIC/AGGREGATE SNOW GROWTH.
AS INCREASING UVV/S COINCIDE WITH A FAVORABLE DENDRITIC LAYER AND
SATURATING LOW-LEVEL PROFILES...09Z SREF GUIDANCE SUPPORTED BY
RAP/HRRR FORECAST SOUNDINGS SUGGEST THAT MODERATE TO HEAVY SNOW WILL
EXPAND NORTH-NORTHEASTWARD ACROSS SOUTHERN/CENTRAL WV AND
WESTERN/CENTRAL VA THROUGH LATE MORNING/EARLY AFTERNOON. SNOW RATES
WILL LIKELY REACH 1-2 IN/HR IN THE HEAVIER BANDS THROUGH THE 18Z-21Z
TIME FRAME.

..GUYER.. 01/22/2016

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

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

LAT...LON   37628209 38568224 38998066 39367867 38627753 37517790
            36657924 36648054 37328129 37628209

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jan 22, 4:47 AM ESTMesoscale DiscussionSPCAlleghany, Bath, Bedford, Bland, Botetourt, Buchanan and 26 more5 hr
Jan 22, 11:47 AM ESTMesoscale DiscussionSPCHenry, Mecklenburg, City of Danville6 hr
Jan 22, 12:34 PM ESTMesoscale DiscussionSPCAccomack, Arlington, Caroline, Clarke, Culpeper, Essex and 28 more5 hr
Jan 22, 4:42 PM ESTMesoscale DiscussionSPCAlbemarle, Alleghany, Amelia, Amherst, Appomattox, Arlington and 82 more6 hr
Jan 22, 6:47 PM ESTMesoscale DiscussionSPCAlleghany, Amherst, Augusta, Bath, Bedford, Botetourt and 23 more5 hr
Jan 22, 1:56 PM ESTMesoscale DiscussionSPCBoone, Cabell, Kanawha, Lincoln, Logan, Mingo and 2 more4 hr

Nearby

Mesoscale Discussions in Virginia, 2016Mesoscale Discussions in West Virginia, 2016Every 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.