Alert archive / New York / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 28, NWS Burlington, VT

July 20, 2021Franklin County, St. Lawrence County, New York

NWS Burlington, VT issued this severe thunderstorm warning at Jul 20, 2021, 3:53 PM EDT for Franklin County, St. Lawrence County, New York. It was in force for 52 min. 6 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: Jul 20, 2021, 3:53 PM EDT (19:53 UTC)
Expired: Jul 20, 2021, 4:45 PM EDT
In force: 52 min
Issued by: NWS Burlington, VT
Area: Storm-based polygon
Hail: 1.0 in
Wind: 60.0 mph

Counties Franklin County, NY, St. Lawrence County, NY

The radar

The Ft Drum radar (KTYX), 121 km from the middle of the area, began a volume at 19:53 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

Time	Report	Where	Remark
Jul 20, 4:23 PM EDT	TSTM WND GST 63	Ogdensburg Airport, NY
Jul 20, 4:30 PM EDT	TSTM WND DMG	6 N Chipman, NY	BOAT FLIPPED AND TREE DOWN IN WADDINGTON.
Jul 20, 4:31 PM EDT	TSTM WND GST 63	Ogdensburg Airport, NY	AWOS TIME ESTIMATED.
Jul 20, 4:32 PM EDT	TSTM WND DMG	Lisbon, NY	NUMEROUS TREES DOWN.
Jul 20, 4:35 PM EDT	TSTM WND DMG	Heuvelton, NY	TREES DOWN.
Jul 20, 4:48 PM EDT	TSTM WND DMG	Canton, NY	LARGE TREE DOWN.

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

The watch it was issued in

The SPC watch in force over the same counties when this warning went out.

Issued	Product	Office	Lasted
Jul 20, 3:05 PM EDT	Severe Thunderstorm Watch	SPC	8 hr

The nearest sounding before it

Albany, NY (KALY), launched 12:00Z, 7.9 hours before the alert went out and 257 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: 85 J/kg
Mixed-layer CIN: -145 J/kg
Mixed-layer LCL: 793 m above ground
0-6 km bulk shear: 19 kt
0-1 km storm-relative helicity: 45 m²/s²
0-3 km storm-relative helicity: 95 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.3

Open this sounding in Storm Lab

The text

As transmitted.

040 
WUUS51 KBTV 201953
SVRBTV
NYC033-089-202045-
/O.NEW.KBTV.SV.W.0028.210720T1953Z-210720T2045Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Burlington VT
353 PM EDT Tue Jul 20 2021

The National Weather Service in Burlington has issued a

* Severe Thunderstorm Warning for...
  Northwestern Franklin County in northern New York...
  Central St. Lawrence County in northern New York...

* Until 445 PM EDT.

* At 351 PM EDT, severe thunderstorms were located west of the Saint 
  Lawrence River along a line extending from 23 miles northwest of 
  St. Lawrence State Park to 47 miles west of Cedar Island State 
  Park, moving east at 45 mph.

  HAZARD...60 mph wind gusts and quarter size hail.

  SOURCE...Radar indicated.

  IMPACT...Expect wind damage to trees and powerlines. Minor hail 
           damage to vehicles is possible. 

* Locations impacted include...
  Massena, Canton, Potsdam, Ogdensburg, Norfolk, Lisbon, Louisville,
  De Kalb, Fort Covington, Bombay, Rensselaer Falls, Morley, Norwood,
  Edwardsville, Massena International Airport - Richards Field,
  Helena, Chipman, Brasher Falls, Heuvelton and Waddington.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4445 7576 4445 7578 4451 7575 4488 7522
      4487 7516 4497 7497 4496 7492 4498 7494
      4499 7489 4498 7492 4497 7488 4500 7489
      4501 7483 4499 7474 4500 7447 4428 7559
      4439 7584
TIME...MOT...LOC 1951Z 265DEG 42KT 4526 7514 4426 7671 

HAIL...1.00IN
WIND...60MPH
 
$$

Evenson/LaRocca

1 follow-up statement

032 
WWUS51 KBTV 202025
SVSBTV

Severe Weather Statement
National Weather Service Burlington VT
425 PM EDT Tue Jul 20 2021

NYC033-089-202045-
/O.CON.KBTV.SV.W.0028.000000T0000Z-210720T2045Z/
Franklin NY-St. Lawrence NY-
425 PM EDT Tue Jul 20 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 445 PM EDT
FOR NORTHWESTERN FRANKLIN AND CENTRAL ST. LAWRENCE COUNTIES...

At 422 PM EDT, a line of severe thunderstorms were located along the 
Saint Lawrence River in New York extending from 17 miles north of 
St. Regis to 22 miles southwest of Cedar Island State Park, moving 
east at 45 mph.

HAZARD...60 mph wind gusts and quarter size hail.

SOURCE...Radar indicated.

IMPACT...Minor hail damage to vehicles is possible. Expect wind 
         damage to trees and powerlines.

Locations impacted include...
Massena, Canton, Potsdam, Ogdensburg, Norfolk, Lisbon, Louisville, De
Kalb, Fort Covington, Bombay, Rensselaer Falls, Morley, Norwood,
Edwardsville, Massena International Airport - Richards Field, Helena,
Chipman, Brasher Falls, Heuvelton and Waddington.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4445 7576 4445 7578 4451 7575 4488 7522
      4487 7516 4497 7497 4496 7492 4498 7494
      4499 7489 4498 7492 4497 7488 4500 7489
      4501 7483 4499 7474 4500 7447 4428 7559
      4439 7584
TIME...MOT...LOC 2022Z 280DEG 39KT 4524 7456 4424 7613 

HAIL...1.00IN
WIND...60MPH
 
$$

Evenson/LaRocca

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 20, 4:44 PM EDT	Severe Thunderstorm Warning	BTV	Franklin, St. Lawrence	61 min
Jul 20, 5:35 PM EDT	Severe Thunderstorm Warning	BTV	Essex	55 min
Jul 20, 5:50 PM EDT	Severe Thunderstorm Warning	BTV	Clinton, Essex, Franklin	40 min
Jul 20, 6:31 PM EDT	Severe Thunderstorm Warning	BTV	Clinton, Essex	59 min
Jul 20, 7:32 PM EDT	Severe Thunderstorm Warning	BTV	Essex	58 min

Nearby

Severe Thunderstorm Warnings in New York, 2021 Every 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.