Alert archive / New York / Severe Thunderstorm Watches in 2020

Severe Thunderstorm Watch 280

June 10, 20206 counties in New York; 6 counties in Pennsylvania

The Storm Prediction Center issued this severe thunderstorm watch at Jun 10, 2020, 10:20 PM EDT for 6 counties in New York; 6 counties in Pennsylvania. It was in force for 3 hr.

The area

The outline as issued.

The facts

Issued
Jun 10, 2020, 10:20 PM EDT (02:20 UTC)
Expired
Jun 11, 2020, 12:56 AM EDT
In force
3 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, Livingston County, NY, Wyoming County, NY, Cameron County, PA, Clearfield County, PA, Elk County, PA, McKean County, PA, Potter County, PA, Warren County, PA

The radar

The Buffalo radar (KBUF), 99 km from the middle of the area, began a volume at 02:22 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
2%
Ten or more severe wind reports
40%
One or more gusts of 65 knots or more
5%
Ten or more severe hail reports
5%
One or more hailstones of 2 inches or more
5%
Six or more combined severe hail and wind reports
50%

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
Jun 10, 10:35 PM EDTSevere Thunderstorm WarningBUFChautauqua55 min
Jun 10, 10:49 PM EDTSevere Thunderstorm WarningBUFErie, Genesee, Niagara, Orleans, Wyoming56 min
Jun 10, 11:26 PM EDTSevere Thunderstorm WarningBUFGenesee, Livingston, Monroe, Ontario, Orleans, Wyoming64 min
Jun 10, 11:44 PM EDTSevere Thunderstorm WarningBUFAllegany, Cattaraugus, Chautauqua47 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, 2.3 hours before the alert went out and 96 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 2020-06-11Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 633 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 2020-06-11The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 69 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
633 J/kg
Mixed-layer CIN
-10 J/kg
Mixed-layer LCL
1918 m above ground
0-6 km bulk shear
27 kt
0-1 km storm-relative helicity
69 m²/s²
0-3 km storm-relative helicity
87 m²/s²
Significant tornado parameter
0.0
Supercell composite
1.9

Open this sounding in Storm Lab

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jun 10, 9:03 PM EDTMesoscale DiscussionSPCAllegheny, Armstrong, Beaver, Butler, Clarion, Crawford and 8 more57 min

Nearby

Severe Thunderstorm Watches in New York, 2020Severe Thunderstorm Watches in Pennsylvania, 2020Every severe thunderstorm watch in 2020

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.