Alert archive / West Virginia / Mesoscale Discussions in 2012

Mesoscale Discussion 80

January 27, 201215 counties in Virginia; 16 counties in West Virginia

The Storm Prediction Center issued this mesoscale discussion at Jan 27, 2012, 2:34 AM EST for 15 counties in Virginia; 16 counties in West Virginia. It was in force for 86 min.

The area

The outline as issued.

The facts

Issued: Jan 27, 2012, 2:34 AM EST (07:34 UTC)
Expired: Jan 27, 2012, 4:00 AM EST
In force: 86 min
Issued by: the Storm Prediction Center

All 31 counties

Alleghany County, VA, Bath County, VA, Botetourt County, VA, City of Buena Vista, VA, City of Covington, VA, City of Lexington, VA, City of Radford, VA, City of Roanoke, VA, City of Salem, VA, Craig County, VA, Giles County, VA, Highland County, VA, Montgomery County, VA, Roanoke County, VA, Rockbridge County, VA, Barbour County, WV, Greenbrier County, WV, Harrison County, WV, Marion County, WV, Mercer County, WV, Monongalia County, WV, Monroe County, WV, Pendleton County, WV, Pocahontas County, WV, Preston County, WV, Randolph County, WV, Summers County, WV, Taylor County, WV, Tucker County, WV, Upshur County, WV, Webster County, WV

The radar

The Charleston,WV radar (KRLX), 141 km from the middle of the area, began a volume at 07:34 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, 7.6 hours before the alert went out and 159 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: 3 J/kg
Mixed-layer CIN: -85 J/kg
Mixed-layer LCL: 562 m above ground
0-6 km bulk shear: 61 kt
0-1 km storm-relative helicity: 188 m²/s²
0-3 km storm-relative helicity: 167 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.

935 
ACUS11 KWNS 270735
SWOMCD
SPC MCD 270734
VAZ000-WVZ000-MDZ000-PAZ000-270900-

MESOSCALE DISCUSSION 0080
NWS STORM PREDICTION CENTER NORMAN OK
0134 AM CST FRI JAN 27 2012

AREAS AFFECTED...CNTRL/ERN WV...FAR WRN VA

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY

VALID 270734Z - 270900Z

A MARGINAL THREAT FOR ISOLATED DAMAGING WINDS EXISTS WITH
EWD-PROPAGATING LOW-TOPPED CONVECTIVE LINE CROSSING CNTRL WV/FAR
SWRN VA. THIS POTENTIAL SHOULD BE LIMITED IN NEWD EXTENT GIVEN
PERSISTENT COLD DOME ACROSS THE ERN WV/MD PANHANDLES. THE
PROBABILITY OF A WW ISSUANCE BY 09Z IS 20 PERCENT.

AS OF 0725Z...HIGH-REFLECTIVITY CONVECTIVE LINE EXTENDED FROM
HARRISON COUNTY WV INTO SMYTH COUNTY VA...SHALLOW IN VERTICAL EXTENT
WITH MINIMAL LIGHTNING PRODUCTION PER NLDN. SURFACE TEMPERATURES
IMMEDIATELY AHEAD OF THE LINE WERE IN THE UPPER 50S TO LOWER
60S...5-10 DEGREES WARMER COMPARED TO EVENING MODEL GUIDANCE.
MODIFIED RUC/ARW-KF FORECAST SOUNDINGS SUGGEST 100-200 J/KG SBCAPE
MAY BE PRESENT WITH A LACK OF A SURFACE-BASED STABLE LAYER. GIVEN
THIS ALONG WITH 1 KM AGL SWLYS AROUND 60 KT AS THE LINE PASSED THE
RX VWP...POTENTIAL EXISTS FOR ISOLATED SEVERE GUSTS /REF 55 KT AT
KBKW AT 0719Z/ ACROSS PARTS OF ERN WV INTO FAR WRN VA.
HOWEVER...THIS THREAT SHOULD BE SHORT-LIVED WITH NERN EXTENT AS THE
LINE ENCOUNTERS A STRONG SURFACE-BASED COLD DOME /TEMPERATURES IN
THE UPPER 30S TO MIDDLE 40S/ THAT HAS PERSISTED ACROSS THE ERN WV/MD
PANHANDLES.

..GRAMS.. 01/27/2012

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

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

LAT...LON   37788096 38618056 39318038 39578036 39778014 39797974
            39597956 39287951 39007927 38657900 37627939 36998001
            37098087 37338119 37788096

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jan 27, 8:17 AM EST	Mesoscale Discussion	SPC	Gloucester, Isle of Wight, James City, Mathews, Middlesex, Northampton and 13 more	88 min

Nearby

Mesoscale Discussions in West Virginia, 2012 Mesoscale Discussions in Virginia, 2012 Every mesoscale discussion in 2012

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.