Alert archive / New York / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 89, NWS Buffalo, NY

July 20, 20215 counties in New York

NWS Buffalo, NY issued this severe thunderstorm warning at Jul 20, 2021, 8:39 PM EDT for 5 counties in New York. It was in force for 53 min. 1 report 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, 8:39 PM EDT (00:39 UTC)
Expired: Jul 20, 2021, 9:32 PM EDT
In force: 53 min
Issued by: NWS Buffalo, NY
Area: Storm-based polygon
Hail: 1.0 in
Wind: 60.0 mph

Counties Allegany County, NY, Cattaraugus County, NY, Erie County, NY, Livingston County, NY, Wyoming County, NY

The radar

The Buffalo radar (KBUF), 65 km from the middle of the area, began a volume at 00:37 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, 8:53 PM EDT	TSTM WND DMG	Freedom, NY	TREES REPORTED DOWN IN FREEDOM.

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

Buffalo Intl Airport, NY (KBUF), launched 00:00Z, 0.7 hours before the alert went out and 62 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 1459 m above ground
0-6 km bulk shear: 38 kt
0-1 km storm-relative helicity: -176 m²/s²
0-3 km storm-relative helicity: 87 m²/s²
Significant tornado parameter: 0.0
Supercell composite: -0.2

Open this sounding in Storm Lab

The text

As transmitted.

158 
WUUS51 KBUF 210039
SVRBUF
NYC003-009-029-051-121-210145-
/O.NEW.KBUF.SV.W.0089.210721T0039Z-210721T0145Z/

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

The National Weather Service in Buffalo has issued a

* Severe Thunderstorm Warning for...
  Southern Wyoming County in western New York...
  Northeastern Cattaraugus County in western New York...
  Southeastern Erie County in western New York...
  Southwestern Livingston County in western New York...
  Northwestern Allegany County in western New York...

* Until 945 PM EDT..

* At 839 PM EDT, a severe thunderstorm was located near Arcade, or 19
  miles south of East Aurora, moving east at 25 mph.

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

  SOURCE...Radar indicated.

  IMPACT...Minor damage to vehicles is possible. Expect wind damage 
           to roofs, siding, and trees.

* Locations impacted include...
  Letchworth State Park, Arcade, Franklinville, Belfast, Rushford,
  Houghton, Chaffee, Portageville, Yorkshire and Sardinia.

 This includes Interstate 86 near exit 30.
 
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 4238 7862 4259 7853 4257 7793 4225 7804
TIME...MOT...LOC 0039Z 280DEG 22KT 4249 7854 

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

Reynolds

2 follow-up statements

978 
WWUS51 KBUF 210109
SVSBUF

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

NYC029-210118-
/O.CAN.KBUF.SV.W.0089.000000T0000Z-210721T0145Z/
Erie NY-
909 PM EDT Tue Jul 20 2021

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHEASTERN ERIE COUNTY IS
CANCELLED...
    
The severe thunderstorm which prompted the warning has moved out of 
the warned area. Therefore, the warning has been cancelled.

LAT...LON 4237 7845 4257 7819 4257 7793 4225 7804
TIME...MOT...LOC 0108Z 280DEG 22KT 4246 7830 

$$

NYC003-009-051-121-210145-
/O.CON.KBUF.SV.W.0089.000000T0000Z-210721T0145Z/
Wyoming NY-Cattaraugus NY-Livingston NY-Allegany NY-
909 PM EDT Tue Jul 20 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 945 PM EDT
FOR SOUTH CENTRAL WYOMING...EAST CENTRAL CATTARAUGUS...SOUTHWESTERN
LIVINGSTON AND NORTHWESTERN ALLEGANY COUNTIES...

At 908 PM EDT, a severe thunderstorm was located near Rushford, or 20
miles southwest of Letchworth State Park, moving east at 25 mph.

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

SOURCE...Radar indicated.

IMPACT...Minor damage to vehicles is possible. Expect wind damage to 
         roofs, siding, and trees.

Locations impacted include...
Belfast, Rushford, Houghton, Portageville, Caneadea, Pike, Angelica,
Short Tract, Fillmore and Hunt.

 This includes Interstate 86 near exit 30.
 
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 4237 7845 4257 7819 4257 7793 4225 7804
TIME...MOT...LOC 0108Z 280DEG 22KT 4246 7830 

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

Reynolds

905 
WWUS51 KBUF 210132
SVSBUF

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

NYC003-009-051-121-210142-
/O.CAN.KBUF.SV.W.0089.000000T0000Z-210721T0145Z/
Wyoming NY-Cattaraugus NY-Livingston NY-Allegany NY-
932 PM EDT Tue Jul 20 2021

...THE SEVERE THUNDERSTORM WARNING FOR SOUTH CENTRAL WYOMING...EAST
CENTRAL CATTARAUGUS...SOUTHWESTERN LIVINGSTON AND NORTHWESTERN
ALLEGANY COUNTIES IS CANCELLED...
        
The storm which prompted the warning has weakened below severe
limits, and has exited the warned area. Therefore, the warning has
been cancelled.

LAT...LON 4237 7845 4257 7819 4257 7793 4225 7804
TIME...MOT...LOC 0130Z 280DEG 22KT 4243 7810 

$$

Reynolds

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 20, 8:07 PM EDT	Areal Flood Warning	BUF	Livingston, Monroe, Ontario, Wayne	81 min
Jul 20, 8:28 PM EDT	Severe Thunderstorm Warning	BUF	Allegany, Cattaraugus	62 min
Jul 20, 9:16 PM EDT	Severe Thunderstorm Warning	BUF	Allegany	36 min
Jul 20, 9:45 PM EDT	Special Marine Warning	BUF		60 min
Jul 20, 10:14 PM EDT	Areal Flood Warning	BUF	Niagara	9 hr
Jul 20, 10:19 PM EDT	Severe Thunderstorm Warning	BUF	Chautauqua	56 min
Jul 20, 11:10 PM EDT	Special Weather Statement	BUF	Cattaraugus	35 min
Jul 20, 11:29 PM EDT	Severe Thunderstorm Warning	BUF	Allegany, Cattaraugus, Chautauqua	61 min
Jul 21, 12:31 AM EDT	Special Weather Statement	BUF	Allegany	44 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.