Alert archive / Vermont / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 37, NWS Burlington, VT

August 11, 20215 counties in Vermont

NWS Burlington, VT issued this severe thunderstorm warning at Aug 11, 2021, 4:47 PM EDT for 5 counties in Vermont. It was in force for 43 min. 2 reports came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued
Aug 11, 2021, 4:47 PM EDT (20:47 UTC)
Expired
Aug 11, 2021, 5:30 PM EDT
In force
43 min
Issued by
NWS Burlington, VT
Area
Storm-based polygon
Hail
0.75 in
Wind
60.0 mph

Counties Addison County, VT, Orange County, VT, Rutland County, VT, Washington County, VT, Windsor County, VT

The radar

The Burlington radar (KCXX), 61 km from the middle of the area, began a volume at 20:47 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 was reported inside it

TimeReportWhereRemark
Aug 11, 4:47 PM EDTTSTM WND DMG2 S Cornwall, VTTREE DOWN ON POWERLINE.
Aug 11, 5:00 PM EDTTSTM WND GST 511 W Middlebury, VT

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Albany, NY (KALY), launched 12:00Z, 8.8 hours before the alert went out and 154 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 2021-08-11Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 112 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Albany, NY at 12:00Z on 2021-08-11The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 230 square meters per square second.1939Sfc1 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
112 J/kg
Mixed-layer CIN
-115 J/kg
Mixed-layer LCL
839 m above ground
0-6 km bulk shear
25 kt
0-1 km storm-relative helicity
230 m²/s²
0-3 km storm-relative helicity
261 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.7

Open this sounding in Storm Lab

The text

As transmitted.

192 
WUUS51 KBTV 112047
SVRBTV
VTC001-017-021-023-027-112130-
/O.NEW.KBTV.SV.W.0037.210811T2047Z-210811T2130Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Burlington VT
447 PM EDT Wed Aug 11 2021

The National Weather Service in Burlington has issued a

* Severe Thunderstorm Warning for...
  West central Orange County in central Vermont...
  Central Addison County in central Vermont...
  Northeastern Rutland County in southern Vermont...
  Northwestern Windsor County in southern Vermont...
  Southwestern Washington County in central Vermont...

* Until 530 PM EDT.

* At 446 PM EDT, a severe thunderstorm was located over Cornwall,
  moving east at 30 mph.

  HAZARD...60 mph wind gusts.

  SOURCE...Radar indicated.

  IMPACT...Expect damage to trees and powerlines.

* Locations impacted include...
  Middlebury, Cornwall, Weybridge, Hancock, Shoreham, Salisbury,
  Warren, Ripton, Lincoln, Rochester, Leicester, Braintree, Whiting,
  Granville, Bridport, Goshen, Roxbury, New Haven, Addison and
  Bristol.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

Torrential rainfall is occurring with this storm, and may lead to 
flash flooding. Do not drive your vehicle through flooded roadways.

&&

LAT...LON 4388 7334 4406 7335 4417 7274 4384 7270
TIME...MOT...LOC 2046Z 266DEG 25KT 4398 7324 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...<.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

Lahiff
2 follow-up statements
168 
WWUS51 KBTV 112111
SVSBTV

Severe Weather Statement
National Weather Service Burlington VT
511 PM EDT Wed Aug 11 2021

VTC001-017-021-023-027-112130-
/O.CON.KBTV.SV.W.0037.000000T0000Z-210811T2130Z/
Orange VT-Addison VT-Rutland VT-Windsor VT-Washington VT-
511 PM EDT Wed Aug 11 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 530 PM EDT
FOR WEST CENTRAL ORANGE...CENTRAL ADDISON...NORTHEASTERN RUTLAND...
NORTHWESTERN WINDSOR AND SOUTHWESTERN WASHINGTON COUNTIES...

At 511 PM EDT, a severe thunderstorm was located over Ripton, moving
east at 30 mph.

HAZARD...60 mph wind gusts.

SOURCE...Radar indicated.

IMPACT...Expect damage to trees and powerlines.

Locations impacted include...
Middlebury, Hancock, Salisbury, Warren, Ripton, Lincoln, Rochester,
Leicester, Braintree, Granville, Goshen, Roxbury, New Haven, Bristol,
Bethel, Waitsfield, Cornwall, Northfield, East Middlebury and
Branbury State Park.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

Torrential rainfall is occurring with this storm, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.

&&

LAT...LON 4387 7317 4409 7318 4417 7274 4384 7270
TIME...MOT...LOC 2111Z 266DEG 25KT 4399 7300 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...<.75 IN
WIND THREAT...OBSERVED
MAX WIND GUST...60 MPH

$$

Lahiff
381 
WWUS51 KBTV 112128
SVSBTV

Severe Weather Statement
National Weather Service Burlington VT
528 PM EDT Wed Aug 11 2021

VTC001-017-021-023-027-112137-
/O.EXP.KBTV.SV.W.0037.000000T0000Z-210811T2130Z/
Orange VT-Addison VT-Rutland VT-Windsor VT-Washington VT-
528 PM EDT Wed Aug 11 2021

...THE SEVERE THUNDERSTORM WARNING FOR WEST CENTRAL ORANGE...CENTRAL
ADDISON...NORTHEASTERN RUTLAND...NORTHWESTERN WINDSOR AND
SOUTHWESTERN WASHINGTON COUNTIES WILL EXPIRE AT 530 PM EDT...
                
The storm which prompted the warning has weakened below severe
limits, and no longer poses an immediate threat to life or property.
Therefore, the warning will be allowed to expire.  However heavy rain
is still possible with this thunderstorm.

LAT...LON 4387 7317 4409 7318 4417 7274 4384 7270
TIME...MOT...LOC 2127Z 266DEG 25KT 4400 7285 

$$

Lahiff

The office that day

Everything else NWS Burlington, VT issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Aug 11, 4:30 PM EDTSpecial Weather StatementBTVAddison30 min
Aug 11, 5:03 PM EDTSpecial Weather StatementBTVChittenden27 min
Aug 11, 5:35 PM EDTSpecial Weather StatementBTVChittenden40 min
Aug 11, 6:11 PM EDTSpecial Weather StatementBTVLamoille34 min

Nearby

Severe Thunderstorm Warnings in Vermont, 2021Every severe thunderstorm warning in 2021

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.