Alert archive / New York / Severe Thunderstorm Warnings in 2017

Severe Thunderstorm Warning 75, NWS Buffalo, NY

July 20, 20178 counties in New York

NWS Buffalo, NY issued this severe thunderstorm warning at Jul 20, 2017, 12:21 PM EDT for 8 counties in New York. It was in force for 54 min. 1 report 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, 2017, 12:21 PM EDT (16:21 UTC)
Expired: Jul 20, 2017, 1:15 PM EDT
In force: 54 min
Issued by: NWS Buffalo, NY
Area: Storm-based polygon
Hail: 0.75 in
Wind: 60.0 mph

Counties Erie County, NY, Genesee County, NY, Livingston County, NY, Monroe County, NY, Niagara County, NY, Ontario County, NY, Orleans County, NY, Wayne County, NY

The radar

The Buffalo radar (KBUF), 68 km from the middle of the area, began a volume at 16:25 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

Time	Report	Where	Remark
Jul 20, 1:24 PM EDT	TSTM WND DMG	Lima, NY	TREE DOWN - RADAR ESTIMATED TIME

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 12:00Z, 4.4 hours before the alert went out and 65 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 2004 m above ground
0-6 km bulk shear: 52 kt
0-1 km storm-relative helicity: 122 m²/s²
0-3 km storm-relative helicity: 131 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

943 
WUUS51 KBUF 201621
SVRBUF
NYC029-037-051-055-063-069-073-117-201715-
/O.NEW.KBUF.SV.W.0075.170720T1621Z-170720T1715Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Buffalo NY
1221 PM EDT THU JUL 20 2017

The National Weather Service in Buffalo has issued a

* Severe Thunderstorm Warning for...
  Western Wayne County in western New York...
  Northeastern Erie County in western New York...
  Northern Livingston County in western New York...
  Eastern Niagara County in western New York...
  Orleans County in western New York...
  Monroe County in western New York...
  Genesee County in western New York...
  Western Ontario County in western New York...

* Until 115 PM EDT.

* At 1221 PM EDT, a severe thunderstorm was located near Albion,
  moving east at 45 mph.

  HAZARD...60 mph wind gusts. 

  SOURCE...Radar indicated. 

  IMPACT...Expect wind damage to trees and power lines. 

* Locations impacted include...
  Rochester, Greece, Irondequoit, Chili, Lockport, Batavia,
  Canandaigua and Brockport.

This includes the following highways...
 Interstate 390 between exits 8 and 12.
 Interstate 90 between exits 48A and 43.

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 4312 7891 4342 7840 4333 7765 4328 7754
      4331 7744 4325 7702 4267 7739 4284 7796
      4286 7796 4286 7803
TIME...MOT...LOC 1621Z 289DEG 40KT 4321 7823 

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

Mitchell

3 follow-up statements

960 
WWUS51 KBUF 201648
SVSBUF

Severe Weather Statement
National Weather Service Buffalo NY
1248 PM EDT THU JUL 20 2017

NYC029-063-201657-
/O.CAN.KBUF.SV.W.0075.000000T0000Z-170720T1715Z/
Erie NY-Niagara NY-
1248 PM EDT THU JUL 20 2017

...THE SEVERE THUNDERSTORM WARNING FOR NORTHEASTERN ERIE AND EASTERN
NIAGARA COUNTIES IS CANCELLED...
    
The severe thunderstorm which prompted the warning has moved out of 
the warned area. Therefore, the warning has been cancelled.

LAT...LON 4298 7844 4334 7808 4327 7769 4323 7756
      4321 7740 4312 7712 4267 7739 4284 7796
      4286 7796 4286 7803
TIME...MOT...LOC 1647Z 289DEG 40KT 4311 7785 

$$

NYC037-051-055-069-073-117-201715-
/O.CON.KBUF.SV.W.0075.000000T0000Z-170720T1715Z/
Wayne NY-Livingston NY-Orleans NY-Monroe NY-Genesee NY-Ontario NY-
1248 PM EDT THU JUL 20 2017

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 115 PM EDT
FOR SOUTHWESTERN WAYNE...NORTHERN LIVINGSTON...EASTERN ORLEANS...
MONROE...GENESEE AND WESTERN ONTARIO COUNTIES...

At 1247 PM EDT, a severe thunderstorm was located over Churchville,
or near Chili, moving east at 45 mph.

HAZARD...60 mph wind gusts. 

SOURCE...Radar indicated. 

IMPACT...Expect wind damage to trees and power lines. 

Locations impacted include...
Rochester, Greece, Irondequoit, Chili, Batavia, Canandaigua,
Brockport and Geneseo.

This includes the following highways...
 Interstate 390 between exits 8 and 12.
 Interstate 90 between exits 48A and 43.

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 4298 7844 4334 7808 4327 7769 4323 7756
      4321 7740 4312 7712 4267 7739 4284 7796
      4286 7796 4286 7803
TIME...MOT...LOC 1647Z 289DEG 40KT 4311 7785 

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

Apffel

037 
WWUS51 KBUF 201705
SVSBUF

Severe Weather Statement
National Weather Service Buffalo NY
105 PM EDT THU JUL 20 2017

NYC069-073-117-201714-
/O.CAN.KBUF.SV.W.0075.000000T0000Z-170720T1715Z/
Wayne NY-Orleans NY-Ontario NY-
105 PM EDT THU JUL 20 2017

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHWESTERN WAYNE...EASTERN
ORLEANS AND WESTERN ONTARIO COUNTIES IS CANCELLED...
    
The severe thunderstorm which prompted the warning has moved out of 
the warned area. Therefore, the warning has been cancelled.

LAT...LON 4327 7770 4323 7756 4321 7740 4316 7739
      4288 7765 4294 7789 4298 7797
TIME...MOT...LOC 1704Z 288DEG 31KT 4306 7770 

$$

NYC037-051-055-201715-
/O.CON.KBUF.SV.W.0075.000000T0000Z-170720T1715Z/
Livingston NY-Monroe NY-Genesee NY-
105 PM EDT THU JUL 20 2017

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 115 PM EDT
FOR NORTH CENTRAL LIVINGSTON...SOUTHERN MONROE AND EAST CENTRAL
GENESEE COUNTIES...

At 104 PM EDT, a severe thunderstorm was located near Scottsville, or
near Chili, moving east at 35 mph.

HAZARD...60 mph wind gusts. 

SOURCE...Radar indicated. 

IMPACT...Expect wind damage to trees and power lines. 

Locations impacted include...
Rochester, Greece, Irondequoit, Chili, East Rochester, Webster,
Fairport and Brighton.

This includes the following highways...
 Interstate 390 between exits 10 and 12.
 Interstate 90 near exit 46.

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 4327 7770 4323 7756 4321 7740 4316 7739
      4288 7765 4294 7789 4298 7797
TIME...MOT...LOC 1704Z 288DEG 31KT 4306 7770 

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

Apffel

218 
WWUS51 KBUF 201718
SVSBUF

Severe Weather Statement
National Weather Service Buffalo NY
118 PM EDT THU JUL 20 2017

NYC037-051-055-201727-
/O.EXP.KBUF.SV.W.0075.000000T0000Z-170720T1715Z/
Livingston NY-Monroe NY-Genesee NY-
118 PM EDT THU JUL 20 2017

...THE SEVERE THUNDERSTORM WARNING FOR NORTH CENTRAL LIVINGSTON...
SOUTHERN MONROE AND EAST CENTRAL GENESEE COUNTIES HAS EXPIRED...
                
The storm which prompted the warning has weakened below severe
limits, and no longer pose an immediate threat to life or property.
Therefore the warning has been allowed to expire.

A severe thunderstorm watch remains in effect until 800 PM EDT for
western New York.

LAT...LON 4327 7770 4323 7756 4321 7740 4316 7739
      4288 7765 4294 7789 4298 7797
TIME...MOT...LOC 1717Z 289DEG 40KT 4302 7753 

$$

Apffel

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 20, 11:44 AM EDT	Special Marine Warning	BUF		31 min
Jul 20, 11:47 AM EDT	Special Weather Statement	BUF	Genesee, Monroe, Niagara, Orleans, Wyoming	58 min
Jul 20, 12:11 PM EDT	Special Marine Warning	BUF		34 min
Jul 20, 12:31 PM EDT	Severe Thunderstorm Warning	BUF	Allegany, Cattaraugus, Erie, Genesee, Livingston, Niagara and 1 more	59 min
Jul 20, 12:36 PM EDT	Tornado Warning	BUF	Cattaraugus, Erie, Wyoming	24 min
Jul 20, 12:55 PM EDT	Tornado Warning	BUF	Allegany, Cattaraugus, Erie, Wyoming	35 min
Jul 20, 1:23 PM EDT	Severe Thunderstorm Warning	BUF	Allegany, Cattaraugus, Wyoming	52 min
Jul 20, 1:35 PM EDT	Tornado Warning	BUF	Allegany	40 min
Jul 20, 1:44 PM EDT	Special Weather Statement	BUF	Erie	31 min
Jul 20, 2:07 PM EDT	Severe Thunderstorm Warning	BUF	Allegany, Cattaraugus, Erie, Wyoming	38 min
Jul 20, 2:46 PM EDT	Severe Thunderstorm Warning	BUF	Allegany	59 min

Nearby

Severe Thunderstorm Warnings in New York, 2017 Every severe thunderstorm warning in 2017

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.