Alert archive / West Virginia / Mesoscale Discussions in 2012
Mesoscale Discussion 2201
The Storm Prediction Center issued this mesoscale discussion at Dec 24, 2012, 10:34 AM EST for 5 states. It was in force for 2 hr.
The area
The outline as issued.
The facts
- Issued
- Dec 24, 2012, 10:34 AM EST (15:34 UTC)
- Expired
- Dec 24, 2012, 1:00 PM EST
- In force
- 2 hr
- Issued by
- the Storm Prediction Center
All 37 counties
Garrett County, MD, Belmont County, OH, Guernsey County, OH, Monroe County, OH, Noble County, OH, Washington County, OH, Fayette County, PA, Greene County, PA, Alleghany County, VA, Bath County, VA, City of Covington, VA, Highland County, VA, Barbour County, WV, Doddridge County, WV, Gilmer County, WV, Grant County, WV, Hardy County, WV, Harrison County, WV, Lewis County, WV, Marion County, WV, Marshall County, WV, Mineral County, WV, Monongalia County, WV, Ohio County, WV, Pendleton County, WV, Pleasants County, WV, Pocahontas County, WV, Preston County, WV, Randolph County, WV, Ritchie County, WV, Taylor County, WV, Tucker County, WV, Tyler County, WV, Upshur County, WV, Wetzel County, WV, Wirt County, WV, Wood County, WV
The radar
The Pittsburgh radar (KPBZ), 156 km from the middle of the area, began a volume at 15:36 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
Pittsburgh, PA (KPIT), launched 12:00Z, 3.6 hours before the alert went out and 143 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.
- Mixed-layer CAPE
- 0 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 1057 m above ground
- 0-6 km bulk shear
- 54 kt
- 0-1 km storm-relative helicity
- 119 m²/s²
- 0-3 km storm-relative helicity
- 145 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted, in the capitals the NWS used until 2016.
591
ACUS11 KWNS 241534
SWOMCD
SPC MCD 241534
MDZ000-WVZ000-VAZ000-PAZ000-OHZ000-241800-
MESOSCALE DISCUSSION 2201
NWS STORM PREDICTION CENTER NORMAN OK
0934 AM CST MON DEC 24 2012
AREAS AFFECTED...E-CNTRL/SERN OH...NRN WV...WRN PART OF THE MD
PANHANDLE...SWRN PA...FAR WRN VA
CONCERNING...WINTER MIXED PRECIPITATION
VALID 241534Z - 241800Z
SUMMARY...AREAS OF FREEZING RAIN WITH RATES APPROACHING 0.05 INCH
PER 3 HOURS...AS WELL AS SLEET AND POSSIBLY LIGHT SNOW...WILL SHIFT
NEWD THROUGH 17Z-18Z.
DISCUSSION...UPPER AIR ANALYSIS SUGGESTS AN ONGOING WARM ADVECTION
REGIME FROM THE UPPER OH VALLEY EWD ACROSS THE CNTRL APPALACHIANS IN
ASSOCIATION WITH A LOWER TROPOSPHERIC WAVE PROGRESSING ENEWD/NEWD
ACROSS THE AREA. WHILE RADAR DATA DEPICT LIGHT PRECIPITATION ECHOES
ALOFT...SFC TEMPERATURE-DEWPOINT SPREADS OF 3-5F SUGGEST THAT
SUB-CLOUD EVAPORATION/SUBLIMATION PROCESSES ARE PREVENTING THIS
PRECIPITATION FROM REACHING THE GROUND IN MANY LOCATIONS.
HOWEVER...DOWNWARD COLUMNAR MOISTENING WILL CONTINUE THROUGH LATE
MORNING IN ASSOCIATION WITH CONTINUED PRECIPITATION ALOFT AS WARM
ADVECTION PERSISTS. THIS WILL INCREASE THE POTENTIAL FOR
PRECIPITATION TO REACH THE SFC THROUGH LATE MORNING.
PARTIAL/COMPLETE MELTING WILL OCCUR AS HYDROMETEORS FALL THROUGH AN
ELEVATED WARM LAYER FEATURING TEMPERATURES OF AROUND 1-4C -- NOTED
BETWEEN 920 MB AND 850 MB PER PITTSBURGH PA/WILMINGTON OH 12Z RAOBS.
FOR AREAS WHERE SFC TEMPERATURES REMAIN BELOW FREEZING...ESPECIALLY
OVER SHELTERED VALLEYS...FREEZING RAIN AND SLEET...AND PERHAPS LIGHT
SNOW...WILL BE POSSIBLE. FREEZING RAIN RATES APPROACHING 0.05 INCH
PER 3 HOURS MAY ENSUE THROUGH 17Z-18Z. THEREAFTER...SFC-LAYER WARM
ADVECTION COMBINED WITH DIURNAL HEATING SHOULD SUPPORT PREDOMINANTLY
RAIN.
..COHEN.. 12/24/2012
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...CTP...LWX...RNK...PBZ...RLX...
LAT...LON 40057969 39707877 39237866 38727903 37777989 37758042
38448016 38728040 38908139 39148198 40018173 40198085
40057969Nearby
Mesoscale Discussions in West Virginia, 2012Mesoscale Discussions in Ohio, 2012Mesoscale Discussions in Virginia, 2012Every 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.