Alert archive / New York / Severe Thunderstorm Watches in 2017

Severe Thunderstorm Watch 237

May 18, 201742 counties in New York; 8 counties in Pennsylvania; 14 counties in Vermont

The Storm Prediction Center issued this severe thunderstorm watch at May 18, 2017, 3:36 PM EDT for 42 counties in New York; 8 counties in Pennsylvania; 14 counties in Vermont. It was in force for 6 hr.

The area

The outline as issued.

The facts

Issued
May 18, 2017, 3:36 PM EDT (19:36 UTC)
Expired
May 18, 2017, 10:04 PM EDT
In force
6 hr
Issued by
the Storm Prediction Center
Largest hail expected
1 in
Strongest gust expected
55 kt
All 64 counties

Albany County, NY, Allegany County, NY, Broome County, NY, Cattaraugus County, NY, Cayuga County, NY, Chautauqua County, NY, Chemung County, NY, Chenango County, NY, Clinton County, NY, Cortland County, NY, Delaware County, NY, Essex County, NY, Franklin County, NY, Fulton County, NY, Hamilton County, NY, Herkimer County, NY, Jefferson County, NY, Lewis County, NY, Livingston County, NY, Madison County, NY, Monroe County, NY, Montgomery County, NY, Oneida County, NY, Onondaga County, NY, Ontario County, NY, Oswego County, NY, Otsego County, NY, Rensselaer County, NY, Saratoga County, NY, Schenectady County, NY, Schoharie County, NY, Schuyler County, NY, Seneca County, NY, St. Lawrence County, NY, Steuben County, NY, Tioga County, NY, Tompkins County, NY, Warren County, NY, Washington County, NY, Wayne County, NY, Wyoming County, NY, Yates County, NY, Bradford County, PA, Cameron County, PA, Elk County, PA, McKean County, PA, Potter County, PA, Susquehanna County, PA, Tioga County, PA, Warren County, PA, Addison County, VT, Bennington County, VT, Caledonia County, VT, Chittenden County, VT, Essex County, VT, Franklin County, VT, Grand Isle County, VT, Lamoille County, VT, Orange County, VT, Orleans County, VT, Rutland County, VT, Washington County, VT, Windham County, VT, Windsor County, VT

The radar

The Ft Drum radar (KTYX), 80 km from the middle of the area, began a volume at 19:35 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
5%
One or more EF2 to EF5 tornadoes
2%
Ten or more severe wind reports
50%
One or more gusts of 65 knots or more
10%
Ten or more severe hail reports
30%
One or more hailstones of 2 inches or more
10%
Six or more combined severe hail and wind reports
80%

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
May 18, 3:57 PM EDTSevere Thunderstorm WarningBUFLivingston, Ontario, Wyoming48 min
May 18, 4:05 PM EDTSevere Thunderstorm WarningBUFOntario40 min
May 18, 4:09 PM EDTSevere Thunderstorm WarningBGMCayuga, Seneca51 min
May 18, 4:33 PM EDTSevere Thunderstorm WarningALYFulton, Herkimer, Montgomery38 min
May 18, 4:39 PM EDTSevere Thunderstorm WarningBGMCayuga, Seneca, Yates51 min
May 18, 4:39 PM EDTSevere Thunderstorm WarningBUFLivingston, Ontario51 min
May 18, 4:49 PM EDTSevere Thunderstorm WarningBGMCayuga, Onondaga41 min
May 18, 5:13 PM EDTSevere Thunderstorm WarningBGMCayuga, Cortland, Onondaga47 min
May 18, 5:28 PM EDTSevere Thunderstorm WarningBUFJefferson, Lewis47 min
May 18, 5:29 PM EDTSevere Thunderstorm WarningBTVCaledonia, Chittenden, Lamoille, Orleans, Washington41 min
May 18, 5:37 PM EDTSevere Thunderstorm WarningALYFulton, Montgomery38 min
May 18, 5:39 PM EDTSevere Thunderstorm WarningBGMChenango, Cortland, Madison, Onondaga51 min
May 18, 5:41 PM EDTSevere Thunderstorm WarningBUFJefferson, Lewis, Oswego64 min
May 18, 5:41 PM EDTSevere Thunderstorm WarningBTVCaledonia, Essex, Orleans64 min
May 18, 5:51 PM EDTSevere Thunderstorm WarningBUFOswego39 min
May 18, 5:52 PM EDTSevere Thunderstorm WarningBGMOnondaga38 min
May 18, 5:53 PM EDTSevere Thunderstorm WarningBGMCayuga, Cortland, Onondaga, Tompkins52 min
May 18, 6:07 PM EDTSevere Thunderstorm WarningBTVEssex53 min
May 18, 6:09 PM EDTSevere Thunderstorm WarningBGMSchuyler, Steuben, Yates36 min
May 18, 6:11 PM EDTSevere Thunderstorm WarningALYFulton, Saratoga, Warren34 min
May 18, 6:12 PM EDTSevere Thunderstorm WarningBGMChenango, Madison, Oneida, Otsego48 min
May 18, 6:17 PM EDTSevere Thunderstorm WarningALYHamilton, Herkimer58 min
May 18, 6:17 PM EDTSevere Thunderstorm WarningALYHerkimer, Montgomery, Schoharie43 min
May 18, 6:17 PM EDTSevere Thunderstorm WarningBUFLewis, Oswego28 min
May 18, 6:19 PM EDTSevere Thunderstorm WarningCTPElk41 min
May 18, 6:29 PM EDTSevere Thunderstorm WarningBTVClinton, Essex, Franklin61 min
May 18, 6:43 PM EDTSevere Thunderstorm WarningALYHamilton, Herkimer, Warren47 min
May 18, 6:55 PM EDTSevere Thunderstorm WarningBTVAddison, Caledonia, Orange, Washington65 min
May 18, 6:58 PM EDTSevere Thunderstorm WarningALYAlbany, Fulton, Montgomery, Saratoga, Schenectady, Schoharie47 min
May 18, 7:10 PM EDTSevere Thunderstorm WarningALYFulton, Saratoga, Warren, Washington65 min
May 18, 7:45 PM EDTSevere Thunderstorm WarningALYAlbany, Rensselaer, Saratoga, Schenectady, Schoharie, Washington45 min
May 18, 7:45 PM EDTSevere Thunderstorm WarningBTVRutland60 min
May 18, 8:10 PM EDTSevere Thunderstorm WarningALYRensselaer, Washington65 min
May 18, 8:33 PM EDTSevere Thunderstorm WarningALYAlbany, Columbia, Greene, Rensselaer42 min
May 18, 9:01 PM EDTSevere Thunderstorm WarningBUFCattaraugus, Chautauqua15 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, 7.6 hours before the alert went out and 191 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 12:00Z on 2017-05-18Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 37 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 12:00Z on 2017-05-18The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 193 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
37 J/kg
Mixed-layer CIN
-209 J/kg
Mixed-layer LCL
1826 m above ground
0-6 km bulk shear
38 kt
0-1 km storm-relative helicity
193 m²/s²
0-3 km storm-relative helicity
165 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.

IssuedProductOfficeCountiesLasted
May 18, 2:04 PM EDTMesoscale DiscussionSPCAlbany, Allegany, Broome, Cattaraugus, Cayuga, Chautauqua and 35 more116 min
May 18, 5:36 PM EDTMesoscale DiscussionSPCAlbany, Allegany, Broome, Cattaraugus, Cayuga, Chemung and 32 more84 min
May 18, 7:33 PM EDTMesoscale DiscussionSPCAlbany, Broome, Chemung, Chenango, Columbia, Cortland and 14 more87 min
May 18, 4:35 PM EDTMesoscale DiscussionSPCAllegheny, Armstrong, Beaver, Butler, Clarion, Fayette and 5 more85 min

Nearby

Severe Thunderstorm Watches in New York, 2017Severe Thunderstorm Watches in Vermont, 2017Severe Thunderstorm Watches in Pennsylvania, 2017Every severe thunderstorm watch in 2017

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.