Alert archive / New York / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 87, NWS Buffalo, NY

July 20, 20214 counties in New York

NWS Buffalo, NY issued this severe thunderstorm warning at Jul 20, 2021, 7:38 PM EDT for 4 counties in New York. It was in force for 31 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, 7:38 PM EDT (23:38 UTC)
Expired
Jul 20, 2021, 8:09 PM EDT
In force
31 min
Issued by
NWS Buffalo, NY
Area
Storm-based polygon
Hail
0.75 in
Wind
60.0 mph

Counties Livingston County, NY, Monroe County, NY, Ontario County, NY, Wayne County, NY

The radar

The Binghamton radar (KBGM), 125 km from the middle of the area, began a volume at 23:41 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, 7:55 PM EDTTSTM WND DMG2 W Clifton Springs, NYTWO TREES DOWN ON COUNTY ROAD 13.
Jul 20, 8:03 PM EDTTSTM WND DMG2 Se Clifton Springs, NYTREE DOWN ON WHEAT ROAD.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The watch it was issued in

The SPC watch in force over the same counties when this warning went out.

IssuedProductOfficeLasted
Jul 20, 3:05 PM EDTSevere Thunderstorm WatchSPC8 hr

The nearest sounding before it

Buffalo Intl Airport, NY (KBUF), launched 12:00Z, 11.6 hours before the alert went out and 123 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 2021-07-20Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 574 joules per kilogram.LCLLFCEL10008507005003002001001 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 2021-07-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 38 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
574 J/kg
Mixed-layer CIN
-62 J/kg
Mixed-layer LCL
893 m above ground
0-6 km bulk shear
23 kt
0-1 km storm-relative helicity
38 m²/s²
0-3 km storm-relative helicity
56 m²/s²
Significant tornado parameter
0.1
Supercell composite
0.7

Open this sounding in Storm Lab

The text

As transmitted.

614 
WUUS51 KBUF 202338
SVRBUF
NYC051-055-069-117-210045-
/O.NEW.KBUF.SV.W.0087.210720T2338Z-210721T0045Z/

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

The National Weather Service in Buffalo has issued a

* Severe Thunderstorm Warning for...
  Southern Wayne County in western New York...
  Northeastern Livingston County in western New York...
  Southeastern Monroe County in western New York...
  Ontario County in western New York...

* Until 845 PM EDT..

* At 737 PM EDT, a severe thunderstorm was located over Honeoye
  Falls, or 11 miles south of Brighton, moving east at 15 mph.

  HAZARD...60 mph wind gusts.

  SOURCE...Radar indicated.

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

* Locations impacted include...
  Geneva, Canandaigua, Newark, Lyons, Palmyra, Victor, Honeoye Falls,
  Bristol, Lima and Clifton Springs.

 This includes the following highways...
 Interstate 390 near exit 11.
 Interstate 90 between exits 46 and 42.

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 4280 7767 4305 7768 4309 7685 4302 7686
      4301 7696 4287 7696 4286 7698 4276 7698
      4276 7723
TIME...MOT...LOC 2337Z 268DEG 15KT 4295 7757 

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

Reynolds
2 follow-up statements
068 
WWUS51 KBUF 202359
SVSBUF

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

NYC051-055-069-117-210045-
/O.CON.KBUF.SV.W.0087.000000T0000Z-210721T0045Z/
Wayne NY-Livingston NY-Monroe NY-Ontario NY-
759 PM EDT Tue Jul 20 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 845 PM EDT
FOR SOUTHEASTERN WAYNE...NORTHEASTERN LIVINGSTON...SOUTH CENTRAL
MONROE AND ONTARIO COUNTIES...

At 758 PM EDT, a severe thunderstorm was located over Victor, or 9
miles northwest of Canandaigua, moving east at 15 mph.

HAZARD...60 mph wind gusts.

SOURCE...Radar indicated.

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

Locations impacted include...
Geneva, Canandaigua, Newark, Lyons, Victor, Honeoye Falls, Bristol,
Lima, Clifton Springs and Clyde.

 This includes Interstate 90 between exits 45 and 42.
 
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 4280 7767 4298 7767 4309 7685 4302 7686
      4301 7696 4287 7696 4286 7698 4276 7698
      4276 7723
TIME...MOT...LOC 2358Z 268DEG 15KT 4295 7745 

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

EAJ
144 
WWUS51 KBUF 210009
SVSBUF

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

NYC051-055-069-117-210019-
/O.CAN.KBUF.SV.W.0087.000000T0000Z-210721T0045Z/
Wayne NY-Livingston NY-Monroe NY-Ontario NY-
809 PM EDT Tue Jul 20 2021

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHEASTERN WAYNE...
NORTHEASTERN LIVINGSTON...SOUTH CENTRAL MONROE AND ONTARIO COUNTIES
IS CANCELLED...
                
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 has been cancelled.

A Severe Thunderstorm Watch remains in effect until 1100 PM EDT for
western New York.

LAT...LON 4280 7767 4298 7767 4309 7685 4302 7686
      4301 7696 4287 7696 4286 7698 4276 7698
      4276 7723
TIME...MOT...LOC 0007Z 268DEG 15KT 4295 7739 

$$

Reynolds

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 20, 2:13 PM EDTSpecial Marine WarningBUF62 min
Jul 20, 2:57 PM EDTSpecial Weather StatementBUFNiagara48 min
Jul 20, 3:14 PM EDTSpecial Marine WarningBUF61 min
Jul 20, 3:23 PM EDTSevere Thunderstorm WarningBUFNiagara67 min
Jul 20, 3:39 PM EDTSpecial Marine WarningBUF81 min
Jul 20, 3:48 PM EDTSpecial Marine WarningBUF87 min
Jul 20, 4:08 PM EDTSevere Thunderstorm WarningBUFJefferson, Lewis67 min
Jul 20, 4:23 PM EDTSevere Thunderstorm WarningBUFErie, Genesee, Niagara, Orleans67 min
Jul 20, 4:42 PM EDTSevere Thunderstorm WarningBUFNiagara48 min
Jul 20, 4:46 PM EDTSpecial Marine WarningBUF59 min
Jul 20, 4:49 PM EDTFlash Flood WarningBUFNiagara6 hr
Jul 20, 4:55 PM EDTSpecial Marine WarningBUF48 min
Jul 20, 4:58 PM EDTSpecial Marine WarningBUF92 min
Jul 20, 5:00 PM EDTSpecial Weather StatementBUFGenesee30 min
Jul 20, 5:10 PM EDTSpecial Marine WarningBUF2 hr
Jul 20, 5:13 PM EDTSevere Thunderstorm WarningBUFJefferson, Lewis, Oswego62 min
Jul 20, 5:28 PM EDTSpecial Weather StatementBUFOswego47 min
Jul 20, 5:30 PM EDTSevere Thunderstorm WarningBUFErie, Genesee, Niagara, Orleans60 min
Jul 20, 5:43 PM EDTSpecial Marine WarningBUF92 min
Jul 20, 5:43 PM EDTSevere Thunderstorm WarningBUFOswego62 min
Jul 20, 5:56 PM EDTSpecial Weather StatementBUFGenesee, Monroe, Ontario, Orleans34 min
Jul 20, 6:07 PM EDTSevere Thunderstorm WarningBUFCayuga, Jefferson, Lewis, Oswego, Wayne38 min
Jul 20, 6:21 PM EDTFlash Flood WarningBUFErie, Niagara4 hr
Jul 20, 6:26 PM EDTSpecial Marine WarningBUF34 min
Jul 20, 6:30 PM EDTSpecial Weather StatementBUFErie, Genesee30 min
Jul 20, 6:37 PM EDTSevere Thunderstorm WarningBUFErie, Genesee, Niagara46 min
Jul 20, 6:46 PM EDTSpecial Weather StatementBUFLewis29 min
Jul 20, 6:52 PM EDTSpecial Marine WarningBUF67 min
Jul 20, 7:24 PM EDTSpecial Weather StatementBUFErie, Genesee, Livingston, Ontario, Wyoming36 min
Jul 20, 7:58 PM EDTSpecial Weather StatementBUFLivingston, Wyoming92 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.