Alert archive / Vermont / Tornado Watches in 2018

Tornado Watch 76

May 4, 201811 counties in New York; 12 counties in Vermont

The Storm Prediction Center issued this tornado watch at May 4, 2018, 3:16 PM EDT for 11 counties in New York; 12 counties in Vermont. It was in force for 6 hr.

The area

The outline as issued.

The facts

Issued
May 4, 2018, 3:16 PM EDT (19:16 UTC)
Expired
May 4, 2018, 9:28 PM EDT
In force
6 hr
Issued by
the Storm Prediction Center
Largest hail expected
1 in
Strongest gust expected
70 kt
All 23 counties

Clinton County, NY, Essex County, NY, Franklin County, NY, Fulton County, NY, Hamilton County, NY, Herkimer County, NY, Oneida County, NY, Saratoga County, NY, St. Lawrence County, NY, Warren County, NY, Washington County, NY, Addison 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, Windsor County, VT

The radar

The Burlington radar (KCXX), 70 km from the middle of the area, began a volume at 19:16 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
40%
One or more EF2 to EF5 tornadoes
20%
Ten or more severe wind reports
90%
One or more gusts of 65 knots or more
70%
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
95%

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
May 4, 4:08 PM EDTSevere Thunderstorm WarningBTVSt. Lawrence67 min
May 4, 4:28 PM EDTSevere Thunderstorm WarningBTVSt. Lawrence62 min
May 4, 4:49 PM EDTSevere Thunderstorm WarningBTVClinton, Franklin, St. Lawrence56 min
May 4, 5:07 PM EDTSevere Thunderstorm WarningALYHamilton, Herkimer23 min
May 4, 5:26 PM EDTSevere Thunderstorm WarningBTVClinton, Essex, Franklin, St. Lawrence64 min
May 4, 5:31 PM EDTSevere Thunderstorm WarningALYHamilton29 min
May 4, 5:41 PM EDTSevere Thunderstorm WarningBTVClinton, Franklin64 min
May 4, 5:49 PM EDTSevere Thunderstorm WarningBGMBroome, Cayuga, Chenango, Cortland, Madison, Oneida and 5 more41 min
May 4, 5:57 PM EDTSevere Thunderstorm WarningBGMMadison, Oneida, Onondaga48 min
May 4, 6:17 PM EDTSevere Thunderstorm WarningBTVFranklin, St. Lawrence42 min
May 4, 6:22 PM EDTSevere Thunderstorm WarningALYFulton, Hamilton, Herkimer53 min
May 4, 6:24 PM EDTSevere Thunderstorm WarningBTVClinton, Essex66 min
May 4, 6:27 PM EDTSevere Thunderstorm WarningBGMBroome, Chenango, Cortland, Madison, Oneida, Otsego and 2 more63 min
May 4, 6:37 PM EDTSevere Thunderstorm WarningBGMOneida23 min
May 4, 6:51 PM EDTSevere Thunderstorm WarningBTVClinton, Essex, Franklin, St. Lawrence44 min
May 4, 6:54 PM EDTSevere Thunderstorm WarningBTVEssex, Franklin, Orleans45 min
May 4, 7:12 PM EDTSevere Thunderstorm WarningALYFulton, Hamilton, Herkimer, Montgomery, Saratoga, Warren48 min
May 4, 7:12 PM EDTSevere Thunderstorm WarningBTVCaledonia, Chittenden, Franklin, Lamoille, Orleans, Washington63 min
May 4, 7:29 PM EDTSevere Thunderstorm WarningBTVEssex61 min
May 4, 7:41 PM EDTSevere Thunderstorm WarningBTVEssex51 min
May 4, 7:42 PM EDTFlash Flood WarningBTVChittenden, Lamoille, Washington3 hr
May 4, 7:50 PM EDTSevere Thunderstorm WarningALYFulton, Montgomery, Saratoga, Schenectady, Warren, Washington40 min
May 4, 8:00 PM EDTSevere Thunderstorm WarningALYAlbany, Montgomery, Rensselaer, Saratoga, Schenectady, Schoharie and 1 more60 min
May 4, 8:05 PM EDTSevere Thunderstorm WarningBTVCaledonia, Essex, Orleans, Washington55 min
May 4, 8:25 PM EDTSevere Thunderstorm WarningBTVAddison, Caledonia, Chittenden, Orange, Rutland, Washington and 1 more65 min
May 4, 8:28 PM EDTSevere Thunderstorm WarningALYRensselaer, Washington62 min
May 4, 8:29 PM EDTFlash Flood WarningBTVCaledonia, Lamoille, Orleans, Washington3 hr
May 4, 8:36 PM EDTSevere Thunderstorm WarningBTVRutland, Windsor54 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

Albany, NY (KALY), launched 12:00Z, 7.3 hours before the alert went out and 171 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, Albany, NY at 12:00Z on 2018-05-04Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 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, Albany, NY at 12:00Z on 2018-05-04The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 48 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
812 m above ground
0-6 km bulk shear
53 kt
0-1 km storm-relative helicity
48 m²/s²
0-3 km storm-relative helicity
147 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

548 
WWUS20 KWNS 041913
SEL6  
SPC WW 041913
NYZ000-VTZ000-050200-

URGENT - IMMEDIATE BROADCAST REQUESTED
Tornado Watch Number 76
NWS Storm Prediction Center Norman OK
315 PM EDT Fri May 4 2018

The NWS Storm Prediction Center has issued a

* Tornado Watch for portions of 
  Northeast New York
  Much of Vermont

* Effective this Friday afternoon and evening from 315 PM until
  1000 PM EDT.

* Primary threats include...
  A couple tornadoes possible
  Widespread damaging winds and isolated significant gusts to 80
    mph likely
  Isolated large hail events to 1 inch in diameter possible

SUMMARY...Isolated afternoon thunderstorms may pose a risk of
isolated tornadoes and a damaging wind gusts.  Later this afternoon
and evening, the potential for widespread damaging winds will also
increase as storms approach from the west.

The tornado watch area is approximately along and 65 statute miles
north and south of a line from 55 miles north of Utica NY to 35
miles east of Montpelier VT. For a complete depiction of the watch
see the associated watch outline update (WOUS64 KWNS WOU6).

PRECAUTIONARY/PREPAREDNESS ACTIONS...

REMEMBER...A Tornado Watch means conditions are favorable for
tornadoes and severe thunderstorms in and close to the watch
area. Persons in these areas should be on the lookout for
threatening weather conditions and listen for later statements
and possible warnings.

&&

OTHER WATCH INFORMATION...CONTINUE...WW 74...WW 75...

AVIATION...Tornadoes and a few severe thunderstorms with hail
surface and aloft to 1 inch. Extreme turbulence and surface wind
gusts to 70 knots. A few cumulonimbi with maximum tops to 400. Mean
storm motion vector 24040.

...Hart

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
May 4, 2:18 PM EDTMesoscale DiscussionSPCBelknap, Carroll, Cheshire, Coos, Grafton, Merrimack and 1 more87 min
May 4, 5:52 PM EDTMesoscale DiscussionSPCCheshire, Hillsborough83 min
May 4, 6:20 PM EDTSevere Thunderstorm WatchSPCBelknap, Cheshire, Coos, Grafton, Hillsborough, Merrimack and 1 more4 hr
May 4, 6:48 PM EDTMesoscale DiscussionSPCCoos, Grafton117 min
May 4, 7:54 PM EDTMesoscale DiscussionSPCBelknap, Carroll, Coos, Grafton, Strafford3 hr
May 4, 1:04 PM EDTMesoscale DiscussionSPCCattaraugus, Chautauqua, Erie, Genesee, Livingston, Monroe and 1 more86 min
May 4, 2:23 PM EDTMesoscale DiscussionSPCAllegany, Cattaraugus, Cayuga, Chemung, Cortland, Erie and 17 more97 min
May 4, 2:44 PM EDTSevere Thunderstorm WatchSPCAllegany, Broome, Cattaraugus, Cayuga, Chautauqua, Chemung and 23 more6 hr
May 4, 4:20 PM EDTMesoscale DiscussionSPCAllegany, Broome, Cattaraugus, Cayuga, Chautauqua, Chemung and 21 more55 min

Nearby

Tornado Watches in Vermont, 2018Tornado Watches in New York, 2018Every tornado 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.