Alert archive / Ohio / Severe Thunderstorm Watches in 2011

Severe Thunderstorm Watch 698

July 29, 20117 counties in New York; 10 counties in Ohio; Crawford County, Erie County, Pennsylvania

The Storm Prediction Center issued this severe thunderstorm watch at Jul 29, 2011, 3:56 AM EDT for 7 counties in New York; 10 counties in Ohio; Crawford County, Erie County, Pennsylvania. It was in force for 5 hr.

The area

The outline as issued.

The facts

Issued
Jul 29, 2011, 3:56 AM EDT (07:56 UTC)
Expired
Jul 29, 2011, 8:48 AM EDT
In force
5 hr
Issued by
the Storm Prediction Center
Largest hail expected
0.5 in
Strongest gust expected
60 kt

Counties Allegany County, NY, Cattaraugus County, NY, Chautauqua County, NY, Erie County, NY, Genesee County, NY, Livingston County, NY, Wyoming County, NY, Ashtabula County, OH, Cuyahoga County, OH, Erie County, OH, Geauga County, OH, Lake County, OH, Lorain County, OH, Lucas County, OH, Ottawa County, OH, Sandusky County, OH, Wood County, OH, Crawford County, PA, Erie County, PA

The radar

The Buffalo radar (KBUF), 148 km from the middle of the area, began a volume at 07:58 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.

What SPC expected

The probabilities SPC published with the watch, for the watch area over its life.

Two or more tornadoes
20%
One or more EF2 to EF5 tornadoes
5%
Ten or more severe wind reports
30%
One or more gusts of 65 knots or more
5%
Ten or more severe hail reports
10%
One or more hailstones of 2 inches or more
5%
Six or more combined severe hail and wind reports
70%

Warnings issued inside it

1 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.

IssuedProductOfficeCountiesLasted
Jul 29, 4:16 AM EDTSevere Thunderstorm WarningBUFCattaraugus, Chautauqua24 min

Discussions around it

SPC mesoscale discussions over the same counties from four hours before the watch to its end.

The nearest sounding before it

Buffalo Intl Airport, NY (KBUF), launched 00:00Z, 7.9 hours before the alert went out and 150 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-pSkew-T log-p diagram, Buffalo Intl Airport, NY at 00:00Z on 2011-07-29Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 333 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Buffalo Intl Airport, NY at 00:00Z on 2011-07-29The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -6 square meters per square second.19395878Sfc1 km3 km6 km9 kmRMLM
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
333 J/kg
Mixed-layer CIN
-16 J/kg
Mixed-layer LCL
649 m above ground
0-6 km bulk shear
22 kt
0-1 km storm-relative helicity
-6 m²/s²
0-3 km storm-relative helicity
41 m²/s²
Significant tornado parameter
0.0
Supercell composite
-0.1

Open this sounding in Storm Lab

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jul 29, 3:31 AM EDTMesoscale DiscussionSPCAllegany, Cattaraugus, Chautauqua, Erie, Wyoming89 min
Jul 29, 12:57 PM EDTMesoscale DiscussionSPCAlbany, Broome, Chemung, Chenango, Cortland, Delaware and 15 more2 hr
Jul 29, 2:40 PM EDTSevere Thunderstorm WatchSPCBronx, Broome, Chemung, Chenango, Columbia, Cortland and 16 more8 hr
Jul 29, 4:40 PM EDTMesoscale DiscussionSPCBronx, Broome, Chemung, Chenango, Columbia, Delaware and 16 more95 min
Jul 29, 5:03 PM EDTTornado WatchSPCOrange, Putnam, Rockland, Westchester3 hr
Jul 29, 2:15 AM EDTSevere Thunderstorm WatchSPCFulton, Williams6 hr
Jul 29, 2:06 PM EDTMesoscale DiscussionSPCAshland, Belmont, Carroll, Champaign, Clark, Columbiana and 35 more84 min
Jul 29, 4:51 PM EDTMesoscale DiscussionSPCButler, Darke, Miami, Montgomery, Preble84 min

Nearby

Severe Thunderstorm Watches in Ohio, 2011Severe Thunderstorm Watches in New York, 2011Severe Thunderstorm Watches in Pennsylvania, 2011Every severe thunderstorm watch 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.