Alert archive / Ohio / Mesoscale Discussions in 2011

Mesoscale Discussion 1021

May 29, 201111 counties in Ohio; 9 counties in Pennsylvania

The Storm Prediction Center issued this mesoscale discussion at May 29, 2011, 7:28 PM EDT for 11 counties in Ohio; 9 counties in Pennsylvania. It was in force for 62 min.

The area

The outline as issued.

The facts

Issued: May 29, 2011, 7:28 PM EDT (23:28 UTC)
Expired: May 29, 2011, 8:30 PM EDT
In force: 62 min
Issued by: the Storm Prediction Center

Counties Ashtabula County, OH, Cuyahoga County, OH, Erie County, OH, Geauga County, OH, Huron County, OH, Lake County, OH, Lorain County, OH, Medina County, OH, Portage County, OH, Summit County, OH, Trumbull County, OH, Clarion County, PA, Crawford County, PA, Elk County, PA, Erie County, PA, Forest County, PA, McKean County, PA, Mercer County, PA, Venango County, PA, Warren County, PA

The radar

The Cleveland radar (KCLE), 106 km from the middle of the area, began a volume at 23:29 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, 11.5 hours before the alert went out and 148 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: 1688 m above ground
0-6 km bulk shear: 31 kt
0-1 km storm-relative helicity: 68 m²/s²
0-3 km storm-relative helicity: 94 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.

925 
ACUS11 KWNS 292328
SWOMCD
SPC MCD 292328 
NYZ000-PAZ000-OHZ000-300030-

MESOSCALE DISCUSSION 1021
NWS STORM PREDICTION CENTER NORMAN OK
0628 PM CDT SUN MAY 29 2011

AREAS AFFECTED...NERN OH/NWRN PA

CONCERNING...SEVERE THUNDERSTORM WATCH 397...

VALID 292328Z - 300030Z

THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 397
CONTINUES.

MCS IS BECOMING BETTER ORGANIZED ACROSS NERN OH AND WRN LAKE ERIE
AND WILL CONTINUE TO PRODUCE A SWATH OF STRONG TO SEVERE WINDS AS IT
QUICKLY PROGRESSES EWD. CURRENT EXTRAPOLATION INDICATES THE APEX OF
THE BOW MAY REACH WRN PA BY 00-01Z. 

AN MCS THAT AFFECTED MUCH OF MI...NERN IND...AND NWRN OH REMAINS
SEMI-ORGANIZED...WITH ONE MCV NOW EXITING MI INTO SRN ONTARIO...AND
A SRN PORTION OF THE COMPLEX BECOMING REINVIGORATED ACROSS WRN LAKE
ERIE AND NERN OH ALONG THE PERIPHERY OF GREATER INSTABILITY. RECENT
RADAR IMAGERY SHOWS THIS PORTION EVOLVING INTO A BOWING SEGMENT THAT
SHOULD REACH THE PA/OH BORDER WITHIN THE NEXT TWO HOURS. SURFACE DEW
POINTS HAVE RISEN A FEW DEGREES OVER THE LAST TWO HOURS IN ADVANCE
OF THE MCS...LIKELY IN RESPONSE TO A LOW LEVEL WARM ADVECTION REGIME
THAT SHOULD MAINTAIN MODERATE INSTABILITY THAT WILL BE CONDUCIVE TO
THE CONTINUANCE OF CONVECTION EWD...DESPITE ONSET OF DIURNAL
COOLING.

..HURLBUT.. 05/29/2011

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

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

LAT...LON   40998285 41568269 42318073 42437980 41987965 42007828
            41197822 40998285

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
May 29, 12:59 PM EDT	Mesoscale Discussion	SPC	Defiance, Fulton, Henry, Lucas, Ottawa, Paulding and 4 more	61 min
May 29, 1:29 PM EDT	Tornado Watch	SPC	Allen, Defiance, Fulton, Hancock, Henry, Lucas and 8 more	7 hr
May 29, 4:17 PM EDT	Mesoscale Discussion	SPC	Defiance, Fulton, Henry, Lucas, Ottawa, Paulding and 3 more	88 min
May 29, 6:05 PM EDT	Mesoscale Discussion	SPC	Ashland, Ashtabula, Cuyahoga, Geauga, Lake, Lorain and 5 more	25 min
May 29, 6:17 PM EDT	Severe Thunderstorm Watch	SPC	Ashtabula, Cuyahoga, Erie, Geauga, Huron, Lake and 5 more	5 hr
May 29, 6:51 PM EDT	Mesoscale Discussion	SPC	Allen, Fulton, Hancock, Henry, Lucas, Ottawa and 4 more	54 min

Nearby

Mesoscale Discussions in Ohio, 2011 Mesoscale Discussions in Pennsylvania, 2011 Every mesoscale discussion in 2011

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.