Alert archive / West Virginia / Mesoscale Discussions in 2012

Mesoscale Discussion 371

March 28, 20125 states

The Storm Prediction Center issued this mesoscale discussion at Mar 28, 2012, 10:23 AM EDT for 5 states. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued: Mar 28, 2012, 10:23 AM EDT (14:23 UTC)
Expired: Mar 28, 2012, 12:30 PM EDT
In force: 2 hr
Issued by: the Storm Prediction Center

All 55 counties

Allegany County, MD, Frederick County, MD, Garrett County, MD, Montgomery County, MD, Washington County, MD, Belmont County, OH, Allegheny County, PA, Armstrong County, PA, Bedford County, PA, Blair County, PA, Cambria County, PA, Fayette County, PA, Franklin County, PA, Fulton County, PA, Greene County, PA, Huntingdon County, PA, Indiana County, PA, Somerset County, PA, Washington County, PA, Westmoreland County, PA, City of Harrisonburg, VA, City of Winchester, VA, Clarke County, VA, Culpeper County, VA, Fauquier County, VA, Frederick County, VA, Loudoun County, VA, Madison County, VA, Page County, VA, Rappahannock County, VA, Rockingham County, VA, Shenandoah County, VA, Warren County, VA, Barbour County, WV, Berkeley County, WV, Brooke County, WV, Grant County, WV, Hampshire County, WV, Hardy County, WV, Harrison County, WV, Jefferson County, WV, Lewis County, WV, Marion County, WV, Marshall County, WV, Mineral County, WV, Monongalia County, WV, Morgan County, WV, Ohio County, WV, Pendleton County, WV, Preston County, WV, Randolph County, WV, Taylor County, WV, Tucker County, WV, Upshur County, WV, Wetzel County, WV

The radar

The Pittsburgh radar (KPBZ), 122 km from the middle of the area, began a volume at 14:23 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 watches that followed

Watches SPC issued over any of the same counties within four hours of this discussion.

Severe Thunderstorm Watch 112Mar 28, 2:10 PM EDT

The nearest sounding before it

Pittsburgh, PA (KPIT), launched 12:00Z, 2.4 hours before the alert went out and 106 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: 1751 m above ground
0-6 km bulk shear: 55 kt
0-1 km storm-relative helicity: 461 m²/s²
0-3 km storm-relative helicity: 470 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.

759 
ACUS11 KWNS 281424
SWOMCD
SPC MCD 281423
MDZ000-PAZ000-VAZ000-WVZ000-OHZ000-281630-

MESOSCALE DISCUSSION 0371
NWS STORM PREDICTION CENTER NORMAN OK
0923 AM CDT WED MAR 28 2012

AREAS AFFECTED...SOUTHEAST OH AND PA/MD TO ADJACENT PORTIONS OF
NORTHERN WV/VA

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE

VALID 281423Z - 281630Z

MARGINALLY SEVERE HAIL WILL REMAIN POSSIBLE ON AN ISOLATED BASIS
THIS MORNING ACROSS WESTERN PA TO ADJACENT PORTIONS OF NORTHERN
WV/MD/VA. WITH TIME...A DAMAGING WIND THREAT SHOULD BECOME MORE OF A
CONCERN INTO THE AFTERNOON. A WATCH COULD BECOME NECESSARY BY LATE
MORNING/EARLY AFTERNOON.

BANDS OF ELEVATED STORMS...A FEW STRONG/MARGINALLY SEVERE...ARE
ONGOING FROM FAR EASTERN OH INTO THE WESTERN HALF OF PA AT
MID-MORNING. THIS ACTIVITY IS OCCURRING AHEAD OF A COLD FRONT...AND
ON THE NORTHEASTERN EDGE OF A STRONG ELEVATED MIXED LAYER ALOFT.
WHILE THE BOUNDARY LAYER IS RELATIVELY DRY...12Z OBSERVED SOUNDINGS
FROM PITTSBURGH/WILMINGTON OH REFLECT STEEP MID LEVEL LAPSE RATES IN
EXCESS OF 7.0 C/KM BETWEEN 700-500 MB ALONG WITH ELEVATED MOST
UNSTABLE CAPES IN EXCESS OF 1000 J/KG. WITH AMPLE VERTICAL
SHEAR...THIS SCENARIO WILL SUPPORT SOME STRONGER/POTENTIALLY SEVERE
STORMS CAPABLE OF SEVERE HAIL OVER THE NEXT SEVERAL HOURS.

DAMAGING WINDS MAY BECOME MORE OF A CONCERN WITH TIME. VERY STRONG
WESTERLY FLOW IS NOTED IN THE AFOREMENTIONED 12Z OBSERVED RAOBS AND
MORE CONTEMPORARY WSR-88D VWP DATA...WITH 50+ KT WINDS SAMPLED AS
LOW AS 2-4 KM AGL. AND THUS...AS THE PRE-COLD FRONTAL BOUNDARY LAYER
QUICKLY WARMS AMID RELATIVELY CLOUD-FREE SKIES ON THE
SOUTH/SOUTHEASTERN EDGE OF ONGOING ACTIVITY...STORMS WILL LIKELY
FURTHER INCREASE WITH DOWNDRAFTS MORE LIKELY TO COME INTO CONTACT
WITH THE BOUNDARY LAYER. AS SUCH...AT LEAST ISOLATED DAMAGING WIND
GUSTS WILL BECOME MORE OF A CONCERN INTO THE AFTERNOON...SUCH THAT A
WATCH MAY BE NEEDED.

..GUYER.. 03/28/2012

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

ATTN...WFO...CTP...LWX...PBZ...RLX...

LAT...LON   40168119 40887959 40507753 39077709 38267822 38728035
            40168119

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Mar 28, 12:43 PM EDT	Mesoscale Discussion	SPC	Allegany, Garrett	2 hr
Mar 28, 2:06 PM EDT	Severe Thunderstorm Watch	SPC	Gallia, Lawrence	7 hr
Mar 28, 4:37 PM EDT	Mesoscale Discussion	SPC	Alleghany, Augusta, Bath, Bland, Botetourt, Buchanan and 15 more	113 min

Nearby

Mesoscale Discussions in West Virginia, 2012 Mesoscale Discussions in Pennsylvania, 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.