Alert archive / New York / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 77, NWS Buffalo, NY

July 17, 20214 counties in New York

NWS Buffalo, NY issued this severe thunderstorm warning at Jul 17, 2021, 3:46 PM EDT for 4 counties in New York. It was in force for 44 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
Jul 17, 2021, 3:46 PM EDT (19:46 UTC)
Expired
Jul 17, 2021, 4:30 PM EDT
In force
44 min
Issued by
NWS Buffalo, NY
Area
Storm-based polygon
Tornado
Possible
Hail
0.75 in
Wind
60.0 mph

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

The radar

The Buffalo radar (KBUF), 62 km from the middle of the area, began a volume at 19:51 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.

The nearest sounding before it

Buffalo Intl Airport, NY (KBUF), launched 12:00Z, 7.8 hours before the alert went out and 58 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 12:00Z on 2021-07-17Temperature 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 12:00Z on 2021-07-17The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 32 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
558 m above ground
0-6 km bulk shear
45 kt
0-1 km storm-relative helicity
32 m²/s²
0-3 km storm-relative helicity
137 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

349 
WUUS51 KBUF 171946
SVRBUF
NYC003-009-029-121-172030-
/O.NEW.KBUF.SV.W.0077.210717T1946Z-210717T2030Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Buffalo NY
346 PM EDT Sat Jul 17 2021

The National Weather Service in Buffalo has issued a

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

* Until 430 PM EDT..

* At 346 PM EDT, a severe thunderstorm was located near Arcade, or 22
  miles south of East Aurora, moving east at 20 mph.

  HAZARD...60 mph wind gusts.

  SOURCE...Radar indicated.

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

* Locations impacted include...
  Arcade, Rushford, Houghton, Yorkshire, Sardinia, Eagle, Pike,
  Delevan, Gainesville and Short Tract.

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 4251 7860 4268 7811 4254 7805 4253 7806
      4243 7800 4235 7852
TIME...MOT...LOC 1946Z 251DEG 19KT 4246 7848 

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

Mitchell
2 follow-up statements
815 
WWUS51 KBUF 172016
SVSBUF

Severe Weather Statement
National Weather Service Buffalo NY
416 PM EDT Sat Jul 17 2021

NYC029-172024-
/O.CAN.KBUF.SV.W.0077.000000T0000Z-210717T2030Z/
Erie NY-
416 PM EDT Sat Jul 17 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 4268 7811 4254 7805 4253 7806 4243 7800
      4239 7829 4258 7840
TIME...MOT...LOC 2014Z 244DEG 15KT 4252 7830 

$$

NYC003-009-121-172030-
/O.CON.KBUF.SV.W.0077.000000T0000Z-210717T2030Z/
Wyoming NY-Cattaraugus NY-Allegany NY-
416 PM EDT Sat Jul 17 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 430 PM EDT
FOR SOUTHWESTERN WYOMING...NORTHEASTERN CATTARAUGUS AND NORTHWESTERN
ALLEGANY COUNTIES...

At 414 PM EDT, a severe thunderstorm was located near Arcade, or 18
miles southwest of Letchworth State Park, moving northeast at 20 mph.

HAZARD...60 mph wind gusts.

SOURCE...Radar indicated.

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

Locations impacted include...
Houghton, Eagle, Pike, Gainesville, Short Tract, Rossburg, Hermitage,
Fillmore and Bliss.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Heavy rainfall is occurring with this storm, and may lead to flash 
flooding. Do not drive your vehicle through flooded roadways.

&&

LAT...LON 4268 7811 4254 7805 4253 7806 4243 7800
      4239 7829 4258 7840
TIME...MOT...LOC 2014Z 244DEG 15KT 4252 7830 

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

Welch
368 
WWUS51 KBUF 172032
SVSBUF

Severe Weather Statement
National Weather Service Buffalo NY
432 PM EDT Sat Jul 17 2021

NYC003-009-121-172041-
/O.EXP.KBUF.SV.W.0077.000000T0000Z-210717T2030Z/
Wyoming NY-Cattaraugus NY-Allegany NY-
432 PM EDT Sat Jul 17 2021

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHWESTERN WYOMING...
NORTHEASTERN CATTARAUGUS AND NORTHWESTERN ALLEGANY COUNTIES HAS
EXPIRED...
                
The storm which prompted the warning has weakened below severe 
limits. Therefore, the warning has been allowed to expire.  However 
gusty winds and heavy rain are still possible with this thunderstorm.

LAT...LON 4268 7811 4254 7805 4253 7806 4243 7800
      4239 7829 4258 7840
TIME...MOT...LOC 2031Z 251DEG 19KT 4255 7819 

$$

Welch

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 17, 4:15 AM EDTBeach Hazards StatementBUFChautauqua, Monroe, Niagara, Orleans, Wayne32 hr
Jul 17, 4:42 AM EDTSpecial Weather StatementBUFChautauqua48 min
Jul 17, 6:12 AM EDTAreal Flood WarningBUFErie, Genesee, Livingston, Monroe, Niagara, Orleans and 1 more13 hr
Jul 17, 7:39 AM EDTSpecial Weather StatementBUFChautauqua36 min
Jul 17, 7:59 AM EDTFlash Flood WarningBUFChautauqua3 hr
Jul 17, 9:11 AM EDTAreal Flood WarningBUFChautauqua3 hr
Jul 17, 1:48 PM EDTSevere Thunderstorm WarningBUFAllegany42 min
Jul 17, 2:10 PM EDTAreal Flood WarningBUFMonroe40 hr
Jul 17, 3:15 PM EDTFlash Flood WarningBUFCattaraugus, Erie6 hr
Jul 17, 3:15 PM EDTTornado WarningBUFCattaraugus, Erie30 min
Jul 17, 4:30 PM EDTSpecial Weather StatementBUFLivingston45 min
Jul 17, 4:35 PM EDTRiver Flood WarningBUFCattaraugus, Chautauqua, Erie, Wyoming10 hr
Jul 17, 5:15 PM EDTAreal Flood WarningBUFLivingston, Ontario3 hr
Jul 17, 5:28 PM EDTAreal Flood WarningBUFAllegany, Cattaraugus5 hr

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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.