Alert archive / New York / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 90, NWS Buffalo, NY

July 20, 2021Allegany County, New York

NWS Buffalo, NY issued this severe thunderstorm warning at Jul 20, 2021, 9:16 PM EDT for Allegany County, New York. It was in force for 36 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, 9:16 PM EDT (01:16 UTC)
Expired: Jul 20, 2021, 9:52 PM EDT
In force: 36 min
Issued by: NWS Buffalo, NY
Area: Storm-based polygon
Hail: 1.0 in
Wind: 60.0 mph

County Allegany County, NY

The radar

The Buffalo radar (KBUF), 113 km from the middle of the area, began a volume at 01:16 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, 9:16 PM EDT	TSTM WND DMG	Wellsville, NY	TREES DOWN IN WELLSVILLE.

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

The nearest sounding before it

Buffalo Intl Airport, NY (KBUF), launched 00:00Z, 1.3 hours before the alert went out and 110 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.

054 
WUUS51 KBUF 210116
SVRBUF
NYC003-210215-
/O.NEW.KBUF.SV.W.0090.210721T0116Z-210721T0215Z/

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

The National Weather Service in Buffalo has issued a

* Severe Thunderstorm Warning for...
  Southeastern Allegany County in western New York...

* Until 1015 PM EDT..

* At 915 PM EDT, a severe thunderstorm was located near Wellsville,
  moving east at 40 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...
  Wellsville, Alfred, Whitesville, Friendship, Scio, Andover,
  Belmont, Alma, Stannards and Paynesville.

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 4200 7811 4222 7813 4231 7774 4200 7775
TIME...MOT...LOC 0115Z 268DEG 37KT 4210 7804 

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

Reynolds

2 follow-up statements

206 
WWUS51 KBUF 210142
SVSBUF

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

NYC003-210215-
/O.CON.KBUF.SV.W.0090.000000T0000Z-210721T0215Z/
Allegany NY-
942 PM EDT Tue Jul 20 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 1015 PM EDT
FOR SOUTHEASTERN ALLEGANY COUNTY...

At 942 PM EDT, a severe thunderstorm was located over Greenwood, or
14 miles east of Wellsville, moving east at 45 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...
Alfred, Whitesville, Andover and Paynesville. 

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 4200 7787 4225 7794 4231 7774 4200 7775
TIME...MOT...LOC 0142Z 268DEG 37KT 4211 7767 

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

Reynolds

817 
WWUS51 KBUF 210152
SVSBUF

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

NYC003-210201-
/O.CAN.KBUF.SV.W.0090.000000T0000Z-210721T0215Z/
Allegany NY-
952 PM EDT Tue Jul 20 2021

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

LAT...LON 4200 7787 4225 7794 4231 7774 4200 7775
TIME...MOT...LOC 0150Z 268DEG 37KT 4211 7759 

$$

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, 8:39 PM EDT	Severe Thunderstorm Warning	BUF	Allegany, Cattaraugus, Erie, Livingston, Wyoming	53 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.