Alert archive / New York / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 98, NWS Buffalo, NY

August 11, 20216 counties in New York

NWS Buffalo, NY issued this severe thunderstorm warning at Aug 11, 2021, 7:16 AM EDT for 6 counties in New York. It was in force for 59 min. 7 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, 7:16 AM EDT (11:16 UTC)
Expired: Aug 11, 2021, 8:15 AM EDT
In force: 59 min
Issued by: NWS Buffalo, NY
Area: Storm-based polygon
Hail: 0.75 in
Wind: 60.0 mph

Counties Allegany County, NY, Cattaraugus County, NY, Genesee County, NY, Livingston County, NY, Monroe County, NY, Wyoming County, NY

The radar

The Buffalo radar (KBUF), 83 km from the middle of the area, began a volume at 11:15 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
Aug 11, 7:20 AM EDT	TSTM WND DMG	2 S Java Center, NY	MULTIPLE TREES AND POWERLINES DOWN IN THE JAVA AND ARCADE AREA.
Aug 11, 7:20 AM EDT	TSTM WND DMG	5 Nw Gainesville, NY	MULTIPLE TREES DOWN IN THE WETHERSFIELD AREA.
Aug 11, 7:22 AM EDT	TSTM WND DMG	Attica, NY	MULTIPLE TREES AND POWERLINES DOWN IN ATTICA.
Aug 11, 7:22 AM EDT	TSTM WND DMG	Warsaw, NY	MULTIPLE TREES DOWN IN WARSAW.
Aug 11, 7:52 AM EDT	TSTM WND DMG	Livonia, NY	TREE DOWN ON MAIN STREET.
Aug 11, 7:56 AM EDT	TSTM WND DMG	Geneseo, NY	CORRECTS PREVIOUS TSTM WND DMG REPORT FROM GENESEO. TREE DOWN ON 39 COUNTRY CLUB RD.
Aug 11, 7:56 AM EDT	TSTM WND DMG	Geneseo, NY	TREE DOWN ON MAIN STREET.

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, 11.3 hours before the alert went out and 79 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: 1071 J/kg
Mixed-layer CIN: -1 J/kg
Mixed-layer LCL: 910 m above ground
0-6 km bulk shear: 20 kt
0-1 km storm-relative helicity: 97 m²/s²
0-3 km storm-relative helicity: 170 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 2.0

Open this sounding in Storm Lab

The text

As transmitted.

464 
WUUS51 KBUF 111116
SVRBUF
NYC003-009-037-051-055-121-111215-
/O.NEW.KBUF.SV.W.0098.210811T1116Z-210811T1215Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Buffalo NY
716 AM EDT Wed Aug 11 2021

The National Weather Service in Buffalo has issued a

* Severe Thunderstorm Warning for...
  Wyoming County in western New York...
  Northeastern Cattaraugus County in western New York...
  Livingston County in western New York...
  Northwestern Allegany County in western New York...
  Southeastern Genesee County in western New York...
  South central Monroe County in western New York...

* Until 815 AM EDT.

* At 715 AM EDT, a severe thunderstorm was located near Warsaw, or 12
  miles west of Letchworth State Park, moving east at 35 mph.

  HAZARD...60 mph wind gusts.

  SOURCE...Radar indicated.

  IMPACT...Expect damage to trees and power lines.

* Locations impacted include...
  Geneseo, Dansville, Letchworth State Park, Perry, Warsaw, Avon,
  Bennington, Mount Morris, Honeoye Falls and Attica.

This includes Interstate 390 between exits 4 and 10.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4250 7841 4288 7841 4296 7760 4276 7759
      4276 7761 4268 7760 4267 7759 4258 7758
      4258 7766 4253 7766 4253 7772 4247 7772
TIME...MOT...LOC 1115Z 267DEG 32KT 4269 7822 

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

$$

Reynolds

2 follow-up statements

118 
WWUS51 KBUF 111147
SVSBUF

Severe Weather Statement
National Weather Service Buffalo NY
747 AM EDT Wed Aug 11 2021

NYC009-111157-
/O.CAN.KBUF.SV.W.0098.000000T0000Z-210811T1215Z/
Cattaraugus NY-
747 AM EDT Wed Aug 11 2021

...THE SEVERE THUNDERSTORM WARNING FOR NORTHEASTERN CATTARAUGUS
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 4249 7807 4289 7831 4296 7760 4276 7759
      4276 7761 4268 7760 4267 7759 4258 7758
      4258 7766 4253 7766 4253 7772 4247 7772
TIME...MOT...LOC 1147Z 267DEG 32KT 4270 7783 

$$

NYC003-037-051-055-121-111215-
/O.CON.KBUF.SV.W.0098.000000T0000Z-210811T1215Z/
Wyoming NY-Livingston NY-Allegany NY-Genesee NY-Monroe NY-
747 AM EDT Wed Aug 11 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 815 AM EDT
FOR EASTERN WYOMING...LIVINGSTON...NORTH CENTRAL ALLEGANY...
SOUTHEASTERN GENESEE AND SOUTH CENTRAL MONROE COUNTIES...

At 747 AM EDT, a severe thunderstorm was located over Mount Morris,
or near Geneseo, moving east at 35 mph.

HAZARD...60 mph wind gusts.

SOURCE...Radar indicated.

IMPACT...Expect damage to trees and power lines.

Locations impacted include...
Geneseo, Dansville, Letchworth State Park, Perry, Warsaw, Avon, Mount
Morris, Honeoye Falls, Attica and Pavilion.

This includes Interstate 390 between exits 4 and 10.
 
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 4249 7807 4289 7831 4296 7760 4276 7759
      4276 7761 4268 7760 4267 7759 4258 7758
      4258 7766 4253 7766 4253 7772 4247 7772
TIME...MOT...LOC 1147Z 267DEG 32KT 4270 7783 

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

$$

Apffel

967 
WWUS51 KBUF 111210
SVSBUF

Severe Weather Statement
National Weather Service Buffalo NY
810 AM EDT Wed Aug 11 2021

NYC003-037-051-055-121-111220-
/O.EXP.KBUF.SV.W.0098.000000T0000Z-210811T1215Z/
Wyoming NY-Livingston NY-Allegany NY-Genesee NY-Monroe NY-
810 AM EDT Wed Aug 11 2021

...THE SEVERE THUNDERSTORM WARNING FOR EASTERN WYOMING...
LIVINGSTON...NORTH CENTRAL ALLEGANY...SOUTHEASTERN GENESEE AND SOUTH
CENTRAL MONROE COUNTIES WILL EXPIRE AT 815 AM EDT...
        
The storm which prompted the warning has moved out of the area.
Therefore, the warning will be allowed to expire.

LAT...LON 4249 7807 4289 7831 4296 7760 4276 7759
      4276 7761 4268 7760 4267 7759 4258 7758
      4258 7766 4253 7766 4253 7772 4247 7772
TIME...MOT...LOC 1210Z 267DEG 32KT 4271 7757 

$$

Apffel

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 10, 9:29 PM EDT	Special Weather Statement	BUF	Jefferson	31 min
Aug 10, 10:04 PM EDT	Special Weather Statement	BUF	Lewis	41 min
Aug 10, 10:47 PM EDT	Flash Flood Warning	BUF	Jefferson, Lewis	5 hr
Aug 11, 4:38 AM EDT	Special Weather Statement	BUF	Chautauqua, Erie, Niagara	52 min
Aug 11, 5:37 AM EDT	Special Weather Statement	BUF	Chautauqua	53 min
Aug 11, 5:41 AM EDT	Special Marine Warning	BUF		64 min
Aug 11, 6:09 AM EDT	Severe Thunderstorm Warning	BUF	Cattaraugus, Chautauqua, Erie	51 min
Aug 11, 6:27 AM EDT	Special Marine Warning	BUF		93 min
Aug 11, 6:40 AM EDT	Severe Thunderstorm Warning	BUF	Erie, Genesee, Wyoming	65 min
Aug 11, 6:48 AM EDT	Special Marine Warning	BUF		42 min
Aug 11, 7:39 AM EDT	Special Weather Statement	BUF	Genesee, Monroe	81 min
Aug 11, 7:46 AM EDT	Severe Thunderstorm Warning	BUF	Genesee, Livingston, Monroe, Ontario, Orleans	50 min
Aug 11, 7:55 AM EDT	Severe Thunderstorm Warning	BUF	Livingston, Monroe, Ontario, Wayne	50 min
Aug 11, 8:09 AM EDT	Special Marine Warning	BUF		96 min
Aug 11, 8:25 AM EDT	Special Weather Statement	BUF	Wayne	65 min
Aug 11, 9:18 AM EDT	Special Weather Statement	BUF	Oswego	27 min
Aug 11, 1:44 PM EDT	Small Craft Advisory	BUF		6 hr
Aug 11, 6:52 PM EDT	Special Weather Statement	BUF	Chautauqua	38 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.