Alert archive / New York / Severe Thunderstorm Watches in 2018

Severe Thunderstorm Watch 75

May 4, 20184 states

The Storm Prediction Center issued this severe thunderstorm watch at May 4, 2018, 2:44 PM EDT for 4 states. It was in force for 6 hr.

The area

The outline as issued.

The facts

Issued: May 4, 2018, 2:44 PM EDT (18:44 UTC)
Expired: May 4, 2018, 8:50 PM EDT
In force: 6 hr
Issued by: the Storm Prediction Center
Largest hail expected: 1 in
Strongest gust expected: 70 kt

All 73 counties

Allegany County, NY, Broome County, NY, Cattaraugus County, NY, Cayuga County, NY, Chautauqua County, NY, Chemung County, NY, Chenango County, NY, Cortland County, NY, Erie County, NY, Genesee County, NY, Jefferson County, NY, Lewis County, NY, Livingston County, NY, Madison County, NY, Monroe County, NY, Niagara County, NY, Oneida County, NY, Onondaga County, NY, Ontario County, NY, Orleans County, NY, Oswego County, NY, Schuyler County, NY, Seneca County, NY, Steuben County, NY, Tioga County, NY, Tompkins County, NY, Wayne County, NY, Wyoming County, NY, Yates County, NY, Belmont County, OH, Carroll County, OH, Columbiana County, OH, Coshocton County, OH, Guernsey County, OH, Harrison County, OH, Jefferson County, OH, Monroe County, OH, Muskingum County, OH, Noble County, OH, Tuscarawas County, OH, Allegheny County, PA, Armstrong County, PA, Beaver County, PA, Bradford County, PA, Butler County, PA, Cambria County, PA, Cameron County, PA, Centre County, PA, Clarion County, PA, Clearfield County, PA, Clinton County, PA, Elk County, PA, Fayette County, PA, Forest County, PA, Greene County, PA, Indiana County, PA, Jefferson County, PA, Lawrence County, PA, Lycoming County, PA, McKean County, PA, Mercer County, PA, Potter County, PA, Somerset County, PA, Sullivan County, PA, Tioga County, PA, Venango County, PA, Warren County, PA, Washington County, PA, Westmoreland County, PA, Brooke County, WV, Hancock County, WV, Marshall County, WV, Ohio County, WV

The radar

The State College radar (KCCX), 122 km from the middle of the area, began a volume at 18:44 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: 90%
One or more gusts of 65 knots or more: 70%
Ten or more severe hail reports: 20%
One or more hailstones of 2 inches or more: 5%
Six or more combined severe hail and wind reports: 95%

Warnings issued inside it

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

Issued	Product	Office	Counties	Lasted
May 4, 3:34 PM EDT	Severe Thunderstorm Warning	PBZ	Mercer	41 min
May 4, 3:35 PM EDT	Severe Thunderstorm Warning	BUF	Cattaraugus, Chautauqua, Erie	55 min
May 4, 3:45 PM EDT	Severe Thunderstorm Warning	PBZ	Butler, Lawrence, Mercer	45 min
May 4, 3:50 PM EDT	Severe Thunderstorm Warning	CTP	Warren	55 min
May 4, 4:05 PM EDT	Severe Thunderstorm Warning	BUF	Jefferson	40 min
May 4, 4:10 PM EDT	Severe Thunderstorm Warning	BUF	Genesee, Monroe, Orleans, Wayne	35 min
May 4, 4:10 PM EDT	Severe Thunderstorm Warning	PBZ	Clarion, Forest, Mercer, Venango	50 min
May 4, 4:26 PM EDT	Severe Thunderstorm Warning	PBZ	Armstrong, Butler, Clarion, Lawrence, Mercer, Venango	34 min
May 4, 4:27 PM EDT	Severe Thunderstorm Warning	BUF	Lewis	33 min
May 4, 4:31 PM EDT	Severe Thunderstorm Warning	CTP	Elk, McKean	89 min
May 4, 4:43 PM EDT	Severe Thunderstorm Warning	PBZ	Carroll, Columbiana	32 min
May 4, 4:50 PM EDT	Severe Thunderstorm Warning	BUF	Lewis	22 min
May 4, 4:59 PM EDT	Severe Thunderstorm Warning	BUF	Cayuga, Jefferson, Lewis, Oswego	61 min
May 4, 5:04 PM EDT	Severe Thunderstorm Warning	PBZ	Carroll, Harrison, Tuscarawas	26 min
May 4, 5:09 PM EDT	Severe Thunderstorm Warning	CTP	Potter	96 min
May 4, 5:21 PM EDT	Severe Thunderstorm Warning	PBZ	Columbiana	24 min
May 4, 5:22 PM EDT	Severe Thunderstorm Warning	CTP	Cameron, Clearfield, Elk	83 min
May 4, 5:32 PM EDT	Severe Thunderstorm Warning	BUF	Jefferson, Lewis	58 min
May 4, 5:44 PM EDT	Severe Thunderstorm Warning	BUF	Lewis, Oswego	61 min
May 4, 5:45 PM EDT	Severe Thunderstorm Warning	BGM	Chemung, Schuyler, Steuben, Tioga, Tompkins	45 min
May 4, 5:49 PM EDT	Severe Thunderstorm Warning	BGM	Broome, Cayuga, Chenango, Cortland, Madison, Oneida and 5 more	41 min
May 4, 5:51 PM EDT	Severe Thunderstorm Warning	PBZ	Allegheny, Armstrong, Butler, Indiana, Westmoreland	54 min
May 4, 5:54 PM EDT	Severe Thunderstorm Warning	CTP	Tioga	81 min
May 4, 5:57 PM EDT	Severe Thunderstorm Warning	BGM	Madison, Oneida, Onondaga	48 min
May 4, 6:00 PM EDT	Severe Thunderstorm Warning	CTP	Centre, Clinton, Lycoming	90 min
May 4, 6:27 PM EDT	Severe Thunderstorm Warning	BGM	Broome, Chenango, Cortland, Madison, Oneida, Otsego and 2 more	63 min
May 4, 6:33 PM EDT	Severe Thunderstorm Warning	CTP	Cambria	72 min
May 4, 6:34 PM EDT	Severe Thunderstorm Warning	BGM	Chemung, Tioga	56 min
May 4, 6:37 PM EDT	Severe Thunderstorm Warning	BGM	Oneida	23 min
May 4, 7:06 PM EDT	Severe Thunderstorm Warning	BGM	Broome, Chenango, Delaware, Otsego	54 min
May 4, 7:13 PM EDT	Severe Thunderstorm Warning	BGM	Bradford, Lackawanna, Luzerne, Susquehanna, Wyoming	62 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 12:00Z, 6.7 hours before the alert went out and 139 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: 4 J/kg
Mixed-layer CIN: -62 J/kg
Mixed-layer LCL: 682 m above ground
0-6 km bulk shear: 58 kt
0-1 km storm-relative helicity: 234 m²/s²
0-3 km storm-relative helicity: 271 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
May 4, 1:04 PM EDT	Mesoscale Discussion	SPC	Cattaraugus, Chautauqua, Erie, Genesee, Livingston, Monroe and 1 more	86 min
May 4, 2:18 PM EDT	Mesoscale Discussion	SPC	Clinton, Essex, Franklin, Fulton, Hamilton, Herkimer and 5 more	87 min
May 4, 2:23 PM EDT	Mesoscale Discussion	SPC	Allegany, Cattaraugus, Cayuga, Chemung, Cortland, Erie and 17 more	97 min
May 4, 3:16 PM EDT	Tornado Watch	SPC	Clinton, Essex, Franklin, Fulton, Hamilton, Herkimer and 5 more	6 hr
May 4, 4:20 PM EDT	Mesoscale Discussion	SPC	Allegany, Broome, Cattaraugus, Cayuga, Chautauqua, Chemung and 21 more	55 min
May 4, 5:52 PM EDT	Mesoscale Discussion	SPC	Albany, Columbia, Delaware, Dutchess, Greene, Montgomery and 11 more	83 min
May 4, 6:20 PM EDT	Severe Thunderstorm Watch	SPC	Albany, Columbia, Delaware, Dutchess, Greene, Montgomery and 6 more	4 hr
May 4, 6:48 PM EDT	Mesoscale Discussion	SPC	Clinton, Essex, Franklin, Fulton, Hamilton, Herkimer and 5 more	117 min
May 4, 1:22 PM EDT	Severe Thunderstorm Watch	SPC	Ashland, Ashtabula, Crawford, Cuyahoga, Erie, Geauga and 22 more	5 hr
May 4, 4:30 PM EDT	Mesoscale Discussion	SPC	Adams, Athens, Brown, Butler, Clark, Clermont and 21 more	2 hr

Nearby

Severe Thunderstorm Watches in New York, 2018 Severe Thunderstorm Watches in Pennsylvania, 2018 Severe Thunderstorm Watches in Ohio, 2018 Every severe thunderstorm watch in 2018

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.