Alert archive / Ohio / Mesoscale Discussions in 2012

Mesoscale Discussion 1386

July 4, 2012Chautauqua County, New York; 9 counties in Ohio; 6 counties in Pennsylvania

The Storm Prediction Center issued this mesoscale discussion at Jul 4, 2012, 8:38 AM EDT for Chautauqua County, New York; 9 counties in Ohio; 6 counties in Pennsylvania. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued: Jul 4, 2012, 8:38 AM EDT (12:38 UTC)
Expired: Jul 4, 2012, 10:45 AM EDT
In force: 2 hr
Issued by: the Storm Prediction Center
Chance of a watch: 40%

Counties Chautauqua County, NY, Ashtabula County, OH, Columbiana County, OH, Cuyahoga County, OH, Geauga County, OH, Lake County, OH, Mahoning County, OH, Portage County, OH, Summit County, OH, Trumbull County, OH, Crawford County, PA, Erie County, PA, Lawrence County, PA, Mercer County, PA, Venango County, PA, Warren County, PA

The radar

The Cleveland radar (KCLE), 105 km from the middle of the area, began a volume at 12:37 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, 0.6 hours before the alert went out and 146 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: 1056 J/kg
Mixed-layer CIN: -119 J/kg
Mixed-layer LCL: 1050 m above ground
0-6 km bulk shear: 29 kt
0-1 km storm-relative helicity: 197 m²/s²
0-3 km storm-relative helicity: 237 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 2.3

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

118 
ACUS11 KWNS 041239
SWOMCD
SPC MCD 041238
PAZ000-NYZ000-OHZ000-041445-

MESOSCALE DISCUSSION 1386
NWS STORM PREDICTION CENTER NORMAN OK
0738 AM CDT WED JUL 04 2012

AREAS AFFECTED...NORTHERN OH/NORTHWEST PA/FAR WESTERN NY

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE

VALID 041238Z - 041445Z

PROBABILITY OF WATCH ISSUANCE...40 PERCENT

SUMMARY...A SEVERE THREAT MAY DEVELOP INTO AREAS SUCH AS NORTHEAST
OH/NORTHWEST PA/FAR WESTERN NY BY MID/LATE MORNING...INCLUDING THE
POTENTIAL FOR SEVERE HAIL/WIND.

DISCUSSION...AN ONGOING STRONG TSTM CLUSTER NEAR THE LONDON ONTARIO
VICINITY /AS OF 1230Z/ WILL LIKELY CONTINUE TO MOVE SOUTHEASTWARD
TOWARD/ACROSS LAKE ERIE THIS MORNING AND EVENTUALLY NORTHEAST
OH/NORTHWEST PA/WESTERN NY. THIS CLUSTER SHOULD CONTINUE TO CROSS AN
INSTABILITY AXIS THAT EXTENDS EASTWARD INTO THE REGION...AND IS
LIKELY BEING FED BY A MODERATELY UNSTABLE ELEVATED AIRMASS FROM THE
WEST WITH A 6.7 C/KM MID-LEVEL LAPSE RATE AND 4000+ J/KG MUCAPE
SAMPLED BY THE 12Z DETROIT OBSERVED SOUNDING. AMID MODERATELY STRONG
NORTHWESTERLY FLOW ALOFT...IT IS POSSIBLE THAT THIS CLUSTER
/ESPECIALLY ITS WESTERN FLANK/...AND/OR NEW PERIPHERAL
DEVELOPMENT...COULD POSE A SEVERE THREAT LATER THIS MORNING INTO
PORTIONS OF NORTHEAST OH/NORTHWEST PA/FAR WESTERN NY AS THE BOUNDARY
LAYER QUICKLY WARMS AMID RELATIVELY CLOUD-FREE SKIES.

..GUYER/MEAD.. 07/04/2012

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

ATTN...WFO...BUF...CTP...PBZ...CLE...

LAT...LON   41848230 42707926 41977887 40977994 40628114 41848230

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jul 4, 4:48 PM EDT	Mesoscale Discussion	SPC	Clinton, Essex, Franklin, Hamilton, Herkimer, St. Lawrence and 3 more	57 min
Jul 4, 6:10 PM EDT	Severe Thunderstorm Watch	SPC	Clinton, Essex	4 hr
Jul 4, 6:46 PM EDT	Mesoscale Discussion	SPC	Bronx, Broome, Delaware, Kings, New York, Orange and 4 more	59 min
Jul 4, 4:04 PM EDT	Mesoscale Discussion	SPC	Belmont, Carroll, Columbiana, Guernsey, Harrison, Jefferson and 2 more	56 min
Jul 4, 4:26 PM EDT	Severe Thunderstorm Watch	SPC	Belmont, Guernsey, Monroe, Noble, Washington	6 hr
Jul 4, 7:08 PM EDT	Mesoscale Discussion	SPC	Erie, Lucas, Ottawa, Sandusky, Seneca, Wood	2 hr

Nearby

Mesoscale Discussions in Ohio, 2012 Mesoscale Discussions in Pennsylvania, 2012 Mesoscale Discussions in New York, 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.