Alert archive / New York / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 82, NWS Buffalo, NY

July 20, 2021Jefferson County, Lewis County, Oswego County, New York

NWS Buffalo, NY issued this severe thunderstorm warning at Jul 20, 2021, 5:13 PM EDT for Jefferson County, Lewis County, Oswego County, New York. It was in force for 62 min. 3 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, 5:13 PM EDT (21:13 UTC)
Expired: Jul 20, 2021, 6:15 PM EDT
In force: 62 min
Issued by: NWS Buffalo, NY
Area: Storm-based polygon
Hail: 0.75 in
Wind: 60.0 mph

Counties Jefferson County, NY, Lewis County, NY, Oswego County, NY

The radar

The Ft Drum radar (KTYX), 29 km from the middle of the area, began a volume at 21:16 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 was reported inside it

Time	Report	Where	Remark
Jul 20, 5:55 PM EDT	TSTM WND DMG	Orwell, NY	WIDESPREAD DAMAGE REPORTED IN THE TOWNSHIP OF ORWELL, INCLUDING NUMEROUS TREES AND WIRES DOWN.
Jul 20, 6:08 PM EDT	TSTM WND DMG	New Bremen, NY	TREES AND WIRES DOWN IN NEW BREMEN.
Jul 20, 6:10 PM EDT	TSTM WND DMG	4 Sw Williamstown, NY	REPORTS OF WIDESPREAD DAMAGE INCLUDING DOWNED TREES AND POWERLINES IN THE TOWN OF AMBOY.

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, 9.2 hours before the alert went out and 211 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.

218 
WUUS51 KBUF 202113
SVRBUF
NYC045-049-075-202215-
/O.NEW.KBUF.SV.W.0082.210720T2113Z-210720T2215Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Buffalo NY
513 PM EDT Tue Jul 20 2021

The National Weather Service in Buffalo has issued a

* Severe Thunderstorm Warning for...
  Jefferson County in central New York...
  Lewis County in central New York...
  Northeastern Oswego County in central New York...

* Until 615 PM EDT..

* At 512 PM EDT, severe thunderstorms were located along a line
  extending from 6 miles southwest of Fowler to 13 miles west of
  Stony Point, moving east at 35 mph.

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

  SOURCE...Radar indicated.

  IMPACT...Expect damage to roofs, siding, and trees.

* Locations impacted include...
  Watertown, Sandy Island Beach State Park, Fort Drum, Stony Point,
  Carthage, Lowville, Pulaski, West Carthage, Adams and Dexter.

 This includes Interstate 81 between exits 34 and 48.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Damaging winds and cloud to ground lightning is occurring with these 
storms. Move indoors immediately.
Lightning is one of nature's leading killers. Remember, if you can
hear thunder, you are close enough to be struck by lightning.

Heavy rainfall is occurring with these storms, and may lead to 
localized flooding. Do not drive your vehicle through flooded 
roadways.

&&

LAT...LON 4342 7553 4348 7581 4334 7588 4355 7646
      4357 7636 4356 7631 4356 7628 4369 7626
      4378 7629 4383 7636 4387 7635 4384 7645
      4385 7649 4390 7650 4427 7556 4410 7517
      4361 7511
TIME...MOT...LOC 2112Z 272DEG 30KT 4424 7550 4377 7655 

HAIL...0.75IN
WIND...60MPH
 
$$

Welch

1 follow-up statement

106 
WWUS51 KBUF 202150
SVSBUF

Severe Weather Statement
National Weather Service Buffalo NY
550 PM EDT Tue Jul 20 2021

NYC045-049-075-202215-
/O.CON.KBUF.SV.W.0082.000000T0000Z-210720T2215Z/
Jefferson NY-Lewis NY-Oswego NY-
550 PM EDT Tue Jul 20 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 615 PM EDT
FOR SOUTHERN JEFFERSON...LEWIS AND NORTHEASTERN OSWEGO COUNTIES...

At 550 PM EDT, severe thunderstorms were located along a line
extending from 7 miles southwest of Oswegatchie to near Sandy Island
Beach State Park, moving east at 35 mph.

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

SOURCE...Radar indicated.

IMPACT...Expect damage to roofs, siding, and trees.

Locations impacted include...
Watertown, Sandy Island Beach State Park, Carthage, Lowville,
Pulaski, West Carthage, Adams, Redfield, Herrings and Selkirk Shores
State Park.

 This includes Interstate 81 between exits 34 and 44.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4342 7553 4348 7581 4334 7588 4355 7646
      4356 7628 4358 7626 4378 7629 4382 7634
      4416 7530 4410 7517 4361 7511
TIME...MOT...LOC 2150Z 284DEG 29KT 4411 7518 4360 7616 

HAIL...0.75IN
WIND...60MPH
 
$$

Welch

The office that day

Everything else NWS Buffalo, NY issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jul 20, 2:13 PM EDT	Special Marine Warning	BUF		62 min
Jul 20, 2:57 PM EDT	Special Weather Statement	BUF	Niagara	48 min
Jul 20, 3:14 PM EDT	Special Marine Warning	BUF		61 min
Jul 20, 3:23 PM EDT	Severe Thunderstorm Warning	BUF	Niagara	67 min
Jul 20, 3:39 PM EDT	Special Marine Warning	BUF		81 min
Jul 20, 3:48 PM EDT	Special Marine Warning	BUF		87 min
Jul 20, 4:08 PM EDT	Severe Thunderstorm Warning	BUF	Jefferson, Lewis	67 min
Jul 20, 4:23 PM EDT	Severe Thunderstorm Warning	BUF	Erie, Genesee, Niagara, Orleans	67 min
Jul 20, 4:42 PM EDT	Severe Thunderstorm Warning	BUF	Niagara	48 min
Jul 20, 4:46 PM EDT	Special Marine Warning	BUF		59 min
Jul 20, 4:49 PM EDT	Flash Flood Warning	BUF	Niagara	6 hr
Jul 20, 4:55 PM EDT	Special Marine Warning	BUF		48 min
Jul 20, 4:58 PM EDT	Special Marine Warning	BUF		92 min
Jul 20, 5:00 PM EDT	Special Weather Statement	BUF	Genesee	30 min
Jul 20, 5:10 PM EDT	Special Marine Warning	BUF		2 hr
Jul 20, 5:28 PM EDT	Special Weather Statement	BUF	Oswego	47 min
Jul 20, 5:30 PM EDT	Severe Thunderstorm Warning	BUF	Erie, Genesee, Niagara, Orleans	60 min
Jul 20, 5:43 PM EDT	Special Marine Warning	BUF		92 min
Jul 20, 5:43 PM EDT	Severe Thunderstorm Warning	BUF	Oswego	62 min
Jul 20, 5:56 PM EDT	Special Weather Statement	BUF	Genesee, Monroe, Ontario, Orleans	34 min
Jul 20, 6:07 PM EDT	Severe Thunderstorm Warning	BUF	Cayuga, Jefferson, Lewis, Oswego, Wayne	38 min
Jul 20, 6:21 PM EDT	Flash Flood Warning	BUF	Erie, Niagara	4 hr
Jul 20, 6:26 PM EDT	Special Marine Warning	BUF		34 min
Jul 20, 6:30 PM EDT	Special Weather Statement	BUF	Erie, Genesee	30 min
Jul 20, 6:37 PM EDT	Severe Thunderstorm Warning	BUF	Erie, Genesee, Niagara	46 min
Jul 20, 6:46 PM EDT	Special Weather Statement	BUF	Lewis	29 min
Jul 20, 6:52 PM EDT	Special Marine Warning	BUF		67 min
Jul 20, 7:24 PM EDT	Special Weather Statement	BUF	Erie, Genesee, Livingston, Ontario, Wyoming	36 min
Jul 20, 7:38 PM EDT	Severe Thunderstorm Warning	BUF	Livingston, Monroe, Ontario, Wayne	31 min
Jul 20, 7:58 PM EDT	Special Weather Statement	BUF	Livingston, Wyoming	92 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.