Alert archive / New York / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 88, NWS Buffalo, NY

July 20, 2021Allegany County, Cattaraugus County, New York

NWS Buffalo, NY issued this severe thunderstorm warning at Jul 20, 2021, 8:28 PM EDT for Allegany County, Cattaraugus County, New York. It was in force for 62 min. 4 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, 8:28 PM EDT (00:28 UTC)
Expired
Jul 20, 2021, 9:30 PM EDT
In force
62 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

The radar

The Buffalo radar (KBUF), 100 km from the middle of the area, began a volume at 00:30 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

TimeReportWhereRemark
Jul 20, 8:36 PM EDTTSTM WND DMGOlean, NYMULTIPLE REPORTS OF TREES DOWN IN OLEAN.
Jul 20, 8:42 PM EDTTSTM WND DMGPortville, NYMULTIPLE REPORTS OF TREES DOWN IN PORTVILLE.
Jul 20, 8:57 PM EDTTSTM WND DMGBolivar, NYTREES DOWN IN BOLIVAR.
Jul 20, 9:16 PM EDTTSTM WND DMGWellsville, NYTREES 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, 0.5 hours before the alert went out and 97 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-pSkew-T log-p diagram, Buffalo Intl Airport, NY at 00:00Z on 2021-07-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Buffalo Intl Airport, NY at 00:00Z on 2021-07-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -176 square meters per square second.193958Sfc1 km3 km6 km9 kmRMLM
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.

144 
WUUS51 KBUF 210028
SVRBUF
NYC003-009-210130-
/O.NEW.KBUF.SV.W.0088.210721T0028Z-210721T0130Z/

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

The National Weather Service in Buffalo has issued a

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

* Until 930 PM EDT..

* At 828 PM EDT, a severe thunderstorm was located near Bradford,
  moving east at 40 mph.

  HAZARD...60 mph wind gusts.

  SOURCE...Radar indicated.

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

* Locations impacted include...
  Olean, Salamanca, Wellsville, Allegany State Park, Allegany, Cuba,
  St. Bonaventure, Weston Mills, Hinsdale and Friendship.

 This includes Interstate 86 between exits 23 and 27, and near exit
29.
 
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 7872 4217 7870 4227 7790 4200 7786
TIME...MOT...LOC 0028Z 260DEG 35KT 4201 7854 

HAIL...<.75IN
WIND...60MPH
 
$$

Reynolds
2 follow-up statements
406 
WWUS51 KBUF 210054
SVSBUF

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

NYC003-009-210130-
/O.CON.KBUF.SV.W.0088.000000T0000Z-210721T0130Z/
Cattaraugus NY-Allegany NY-
854 PM EDT Tue Jul 20 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 930 PM EDT
FOR SOUTHEASTERN CATTARAUGUS AND SOUTHWESTERN ALLEGANY COUNTIES...

At 853 PM EDT, a severe thunderstorm was located near Shinglehouse,
or 11 miles east of Olean, moving east at 40 mph.

HAZARD...60 mph wind gusts.

SOURCE...Radar indicated.

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

Locations impacted include...
Olean, Wellsville, Allegany, Cuba, St. Bonaventure, Weston Mills,
Hinsdale, Friendship, Scio and Bolivar.

 This includes Interstate 86 between exits 25 and 27, and near exit
29.
 
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 7850 4218 7850 4227 7790 4200 7786
TIME...MOT...LOC 0053Z 260DEG 35KT 4205 7821 

HAIL...<.75IN
WIND...60MPH
 
$$

Reynolds
944 
WWUS51 KBUF 210110
SVSBUF

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

NYC009-210120-
/O.CAN.KBUF.SV.W.0088.000000T0000Z-210721T0130Z/
Cattaraugus NY-
910 PM EDT Tue Jul 20 2021

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHEASTERN 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 4200 7828 4220 7827 4227 7790 4200 7786
TIME...MOT...LOC 0110Z 260DEG 35KT 4208 7798 

$$

NYC003-210130-
/O.CON.KBUF.SV.W.0088.000000T0000Z-210721T0130Z/
Allegany NY-
910 PM EDT Tue Jul 20 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 930 PM EDT
FOR SOUTHWESTERN ALLEGANY COUNTY...

At 910 PM EDT, a severe thunderstorm was located near Wellsville,
moving east at 40 mph.

HAZARD...60 mph wind gusts.

SOURCE...Radar indicated.

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

Locations impacted include...
Wellsville, Friendship, Scio, Bolivar, Belmont, Alma, Richburg, West
Clarksville, Stannards and Little Genesee.

 This includes Interstate 86 near exit 29.
 
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 7828 4220 7827 4227 7790 4200 7786
TIME...MOT...LOC 0110Z 260DEG 35KT 4208 7798 

HAIL...<.75IN
WIND...60MPH
 
$$

Reynolds

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 20, 8:07 PM EDTAreal Flood WarningBUFLivingston, Monroe, Ontario, Wayne81 min
Jul 20, 8:39 PM EDTSevere Thunderstorm WarningBUFAllegany, Cattaraugus, Erie, Livingston, Wyoming53 min
Jul 20, 9:16 PM EDTSevere Thunderstorm WarningBUFAllegany36 min
Jul 20, 9:45 PM EDTSpecial Marine WarningBUF60 min
Jul 20, 10:14 PM EDTAreal Flood WarningBUFNiagara9 hr
Jul 20, 10:19 PM EDTSevere Thunderstorm WarningBUFChautauqua56 min
Jul 20, 11:10 PM EDTSpecial Weather StatementBUFCattaraugus35 min
Jul 20, 11:29 PM EDTSevere Thunderstorm WarningBUFAllegany, Cattaraugus, Chautauqua61 min
Jul 21, 12:31 AM EDTSpecial Weather StatementBUFAllegany44 min

Nearby

Severe Thunderstorm Warnings in New York, 2021Every 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.