Alert archive / New York / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 91, NWS Buffalo, NY

July 20, 2021Chautauqua County, New York

NWS Buffalo, NY issued this severe thunderstorm warning at Jul 20, 2021, 10:19 PM EDT for Chautauqua County, New York. It was in force for 56 min. 2 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, 10:19 PM EDT (02:19 UTC)
Expired
Jul 20, 2021, 11:15 PM EDT
In force
56 min
Issued by
NWS Buffalo, NY
Area
Storm-based polygon
Hail
0.75 in
Wind
60.0 mph

County Chautauqua County, NY

The radar

The Buffalo radar (KBUF), 94 km from the middle of the area, began a volume at 02:17 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, 10:40 PM EDTTSTM WND DMG1 Se Brocton, NYTREES DOWN ON ROUTE 380.
Jul 20, 10:52 PM EDTTSTM WND DMG1 Ssw Cassadaga, NYTREES AND WIRES DOWN ON PUTNAM RD.

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, 2.3 hours before the alert went out and 94 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.

918 
WUUS51 KBUF 210219
SVRBUF
NYC013-210315-
/O.NEW.KBUF.SV.W.0091.210721T0219Z-210721T0315Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Buffalo NY
1019 PM EDT Tue Jul 20 2021

The National Weather Service in Buffalo has issued a

* Severe Thunderstorm Warning for...
  Chautauqua County in western New York...

* Until 1115 PM EDT..

* At 1018 PM EDT, a severe thunderstorm was located 9 miles northwest
  of Westfield, or 18 miles west of Fredonia, moving southeast at 45
  mph.

  HAZARD...60 mph wind gusts.

  SOURCE...Radar indicated.

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

* Locations impacted include...
  Jamestown, Dunkirk, Fredonia, Westfield, Lakewood, Falconer,
  Mayville, Clymer, Long Point State Park and Jamestown West.

 This includes the following highways...
 Interstate 90 between exits 61 and 59.
 Interstate 86 between exits 4 and 14.

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 4244 7950 4252 7941 4254 7935 4234 7906
      4200 7906 4200 7976 4227 7976 4228 7973
      4231 7977
TIME...MOT...LOC 0218Z 314DEG 37KT 4243 7969 

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

Reynolds
2 follow-up statements
508 
WWUS51 KBUF 210258
SVSBUF

Severe Weather Statement
National Weather Service Buffalo NY
1058 PM EDT Tue Jul 20 2021

NYC013-210315-
/O.CON.KBUF.SV.W.0091.000000T0000Z-210721T0315Z/
Chautauqua NY-
1058 PM EDT Tue Jul 20 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 1115 PM EDT
FOR CHAUTAUQUA COUNTY...

At 1058 PM EDT, a severe thunderstorm was located near Lakewood, or
near Jamestown, moving southeast at 45 mph.

HAZARD...60 mph wind gusts.

SOURCE...Radar indicated.

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

Locations impacted include...
Jamestown, Fredonia, Lakewood, Falconer, Mayville, Long Point State
Park, Jamestown West, Chautauqua Institution, Frewsburg and
Chautauqua.

 This includes the following highways...
 Interstate 90 near exit 59.
 Interstate 86 between exits 6 and 14.

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 4234 7906 4200 7906 4200 7952 4222 7969
      4249 7927
TIME...MOT...LOC 0258Z 314DEG 37KT 4214 7929 

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

Reynolds
557 
WWUS51 KBUF 210315
SVSBUF

Severe Weather Statement
National Weather Service Buffalo NY
1115 PM EDT Tue Jul 20 2021

NYC013-210322-
/O.EXP.KBUF.SV.W.0091.000000T0000Z-210721T0315Z/
Chautauqua NY-
1115 PM EDT Tue Jul 20 2021

...THE SEVERE THUNDERSTORM WARNING FOR CHAUTAUQUA COUNTY WILL EXPIRE
AT 1115 PM EDT...
                
The storm which prompted the warning has moved out of the warned 
area. Therefore, the warning will be allowed to expire.  However 
gusty winds are still possible with this thunderstorm.

LAT...LON 4234 7906 4200 7906 4200 7952 4222 7969
      4249 7927
TIME...MOT...LOC 0312Z 314DEG 37KT 4205 7916 

$$

Welch

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, 8:28 PM EDTSevere Thunderstorm WarningBUFAllegany, Cattaraugus62 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, 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.