Alert archive / New York / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 18, NWS Buffalo, NY

June 20, 2021Cattaraugus County, Chautauqua County, New York

NWS Buffalo, NY issued this severe thunderstorm warning at Jun 20, 2021, 6:40 PM EDT for Cattaraugus County, Chautauqua County, New York. It was in force for 35 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
Jun 20, 2021, 6:40 PM EDT (22:40 UTC)
Expired
Jun 20, 2021, 7:15 PM EDT
In force
35 min
Issued by
NWS Buffalo, NY
Area
Storm-based polygon
Hail
0.75 in
Wind
60.0 mph

Counties Cattaraugus County, NY, Chautauqua County, NY

The radar

The Buffalo radar (KBUF), 62 km from the middle of the area, began a volume at 22:42 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, 10.7 hours before the alert went out and 61 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 2021-06-20Temperature 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 2021-06-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 88 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
926 m above ground
0-6 km bulk shear
38 kt
0-1 km storm-relative helicity
88 m²/s²
0-3 km storm-relative helicity
188 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

584 
WUUS51 KBUF 202240
SVRBUF
NYC009-013-202315-
/O.NEW.KBUF.SV.W.0018.210620T2240Z-210620T2315Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Buffalo NY
640 PM EDT Sun Jun 20 2021

The National Weather Service in Buffalo has issued a

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

* Until 715 PM EDT..

* At 639 PM EDT, a severe thunderstorm was located 11 miles southeast
  of Fredonia, moving northeast at 25 mph.

  HAZARD...60 mph wind gusts and penny size hail.

  SOURCE...Radar indicated.

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

* Locations impacted include...
  Gowanda, Silver Creek, Stockton, Dayton, Ellington, Leon,
  Arkwright, Forestville, Cassadaga and South Dayton.

 This includes Interstate 90 near exit 58.
 
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 4232 7940 4257 7913 4257 7911 4254 7906
      4254 7903 4253 7900 4249 7896 4248 7896
      4245 7892 4244 7888 4241 7884 4216 7918
TIME...MOT...LOC 2239Z 220DEG 21KT 4231 7921 

HAIL...0.75IN
WIND...60MPH
 
$$

Mitchell
2 follow-up statements
195 
WWUS51 KBUF 202305
SVSBUF

Severe Weather Statement
National Weather Service Buffalo NY
705 PM EDT Sun Jun 20 2021

NYC009-013-202315-
/O.CON.KBUF.SV.W.0018.000000T0000Z-210620T2315Z/
Cattaraugus NY-Chautauqua NY-
705 PM EDT Sun Jun 20 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 715 PM EDT
FOR NORTHWESTERN CATTARAUGUS AND NORTHEASTERN CHAUTAUQUA COUNTIES...

At 704 PM EDT, a severe thunderstorm was located 7 miles west of
Gowanda, or 12 miles east of Fredonia, moving northeast at 25 mph.

HAZARD...60 mph wind gusts and penny size hail.

SOURCE...Radar indicated.

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

Locations impacted include...
Gowanda, Silver Creek, Dayton, Leon, Arkwright, Forestville, South
Dayton, Cherry Creek, Perrysburg and Hamlet.

 This includes Interstate 90 near exit 58.
 
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 4257 7913 4257 7911 4254 7906 4254 7903
      4253 7900 4249 7896 4248 7896 4245 7892
      4244 7888 4241 7884 4225 7905 4238 7934
TIME...MOT...LOC 2304Z 220DEG 21KT 4242 7908 

HAIL...0.75IN
WIND...60MPH
 
$$

Mitchell
806 
WWUS51 KBUF 202314
SVSBUF

Severe Weather Statement
National Weather Service Buffalo NY
714 PM EDT Sun Jun 20 2021

NYC009-013-202323-
/O.EXP.KBUF.SV.W.0018.000000T0000Z-210620T2315Z/
Cattaraugus NY-Chautauqua NY-
714 PM EDT Sun Jun 20 2021

...THE SEVERE THUNDERSTORM WARNING FOR NORTHWESTERN CATTARAUGUS AND
NORTHEASTERN CHAUTAUQUA COUNTIES WILL EXPIRE AT 715 PM EDT...
                
The storm which prompted the warning has weakened below severe
limits, and no longer poses an immediate threat to life or property.
Therefore, the warning will be allowed to expire.

LAT...LON 4257 7913 4257 7911 4254 7906 4254 7903
      4253 7900 4249 7896 4248 7896 4245 7892
      4244 7888 4241 7884 4225 7905 4238 7934
TIME...MOT...LOC 2313Z 220DEG 21KT 4246 7903 

$$

Mitchell

The office that day

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

IssuedProductOfficeCountiesLasted
Jun 19, 8:52 PM EDTSpecial Weather StatementBUFOswego53 min
Jun 19, 9:51 PM EDTAreal Flood WarningBUFOswego2 hr
Jun 19, 10:00 PM EDTSpecial Weather StatementBUFOswego60 min
Jun 20, 2:44 PM EDTWind AdvisoryBUFErie, Genesee, Niagara, Orleans25 hr
Jun 20, 3:30 PM EDTSpecial Weather StatementBUFCattaraugus45 min
Jun 20, 3:57 PM EDTSpecial Weather StatementBUFCattaraugus48 min
Jun 20, 4:30 PM EDTSmall Craft AdvisoryBUF57 hr
Jun 20, 6:23 PM EDTSpecial Weather StatementBUFChautauqua52 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.