Alert archive / New York / Severe Thunderstorm Warnings in 2009

Severe Thunderstorm Warning 86, NWS Buffalo, NY

August 20, 2009Erie County, Niagara County, New York

NWS Buffalo, NY issued this severe thunderstorm warning at Aug 20, 2009, 7:56 PM EDT for Erie County, Niagara County, New York. It was in force for 79 min. 3 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
Aug 20, 2009, 7:56 PM EDT (23:56 UTC)
Expired
Aug 20, 2009, 9:15 PM EDT
In force
79 min
Issued by
NWS Buffalo, NY
Area
Storm-based polygon

Counties Erie County, NY, Niagara County, NY

The radar

The Buffalo radar (KBUF), 13 km from the middle of the area, began a volume at 23:58 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
Aug 20, 8:25 PM EDTTSTM WND DMGNorth Tonawanda, NYNUMEROUS TREES DOWN
Aug 20, 8:27 PM EDTTSTM WND GST 65Buffalo, NYBUFFALO CHARTER SCHOOL OF APPLIED TECHNOLOGY
Aug 20, 8:28 PM EDTTSTM WND DMG2 Ne North Tonawanda, NYNUMEROUS TREES DOWN IN WHEATFIELD

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
Aug 20, 6:54 PM EDTSevere Thunderstorm WatchSPC5 hr

The nearest sounding before it

Buffalo Intl Airport, NY (KBUF), launched 12:00Z, 11.9 hours before the alert went out and 16 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 2009-08-20Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1149 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 2009-08-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 94 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
1149 J/kg
Mixed-layer CIN
-36 J/kg
Mixed-layer LCL
810 m above ground
0-6 km bulk shear
27 kt
0-1 km storm-relative helicity
94 m²/s²
0-3 km storm-relative helicity
110 m²/s²
Significant tornado parameter
0.4
Supercell composite
2.2

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

000 
WUUS51 KBUF 202356
SVRBUF
NYC029-063-210115-
/O.NEW.KBUF.SV.W.0086.090820T2356Z-090821T0115Z/

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE BUFFALO NY
756 PM EDT THU AUG 20 2009

THE NATIONAL WEATHER SERVICE IN BUFFALO HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  ERIE COUNTY IN WESTERN NEW YORK
  NIAGARA COUNTY IN WESTERN NEW YORK

* UNTIL 915 PM EDT

* AT 753 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  LINE OF SEVERE THUNDERSTORMS CAPABLE OF PRODUCING DESTRUCTIVE WINDS
  IN EXCESS OF 70 MPH.  THESE STORMS WERE LOCATED ALONG A LINE
  EXTENDING FROM 11 MILES WEST OF GRAND ISLAND TO 20 MILES WEST OF
  LAKE ERIE BEACH...OR ALONG A LINE EXTENDING FROM 9 MILES NORTHEAST
  OF PORT COLBORNE TO 7 MILES NORTHWEST OF DUNKIRK...AND MOVING
  NORTHEAST AT 45 MPH.

* SEVERE THUNDERSTORMS WILL BE NEAR...
  NIAGARA FALLS AND LEWISTON BY 810 PM EDT...
  YOUNGSTOWN AND GRAND ISLAND BY 815 PM EDT...
  SANBORN AND LAKE ERIE BEACH BY 820 PM EDT...
  BUFFALO AND TONAWANDA BY 825 PM EDT...
  NORTH COLLINS BY 825 PM EDT...  
  PENDLETON BY 830 PM EDT...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

THESE ARE DANGEROUS STORMS. IF YOU ARE IN THE PATH...PREPARE
IMMEDIATELY FOR DAMAGING WINDS...DESTRUCTIVE HAIL...AND DEADLY CLOUD
TO GROUND LIGHTNING. PEOPLE OUTSIDE SHOULD MOVE TO A SHELTER...
PREFERABLY INSIDE A STRONG BUILDING BUT AWAY FROM WINDOWS.

A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL 200 AM EDT FRIDAY
MORNING FOR WESTERN NEW YORK.

&&

LAT...LON 4270 7905 4275 7892 4279 7887 4295 7893
      4297 7902 4301 7904 4307 7899 4309 7908
      4314 7905 4326 7907 4335 7871 4338 7846
      4288 7846 4287 7848 4270 7846 4255 7908
      4257 7913 4259 7915
TIME...MOT...LOC 2354Z 240DEG 38KT 4299 7917 4255 7945

$$

ZAFF
3 follow-up statements
000 
WWUS51 KBUF 210032
SVSBUF

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE BUFFALO NY
832 PM EDT THU AUG 20 2009

NYC029-063-210115-
/O.CON.KBUF.SV.W.0086.000000T0000Z-090821T0115Z/
NIAGARA NY-ERIE NY-
832 PM EDT THU AUG 20 2009

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 915 PM EDT
FOR ERIE AND NIAGARA COUNTIES...

AT 828 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR CONTINUED TO
INDICATE A LINE OF SEVERE THUNDERSTORMS CAPABLE OF PRODUCING
DESTRUCTIVE WINDS IN EXCESS OF 70 MPH.  THESE STORMS WERE LOCATED 
ALONG A LINE EXTENDING FROM RANSOMVILLE TO PENDLETON TO 
BUFFALO...MOVING NORTHEAST AT 45 MPH.

* SEVERE THUNDERSTORMS WILL BE NEAR...
  WEST SENECA BY 835 PM EDT...
  WILSON BY 840 PM EDT...
  WALES CENTER BY 845 PM EDT...
  OLCOTT BY 850 PM EDT...
  MIDDLEPORT BY 855 PM EDT...
  THIRTY MILE POINT BY 900 PM EDT...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

THIS IS A PARTICULARLY DANGEROUS SITUATION MOVE INTO A STRONG 
SHELTER AND REMAIN INDOORS IN THE LOWEST FLOOR OF YOUR HOME. STAY 
AWAY FROM WINDOWS AND EXTERIOR WALLS IF POSSIBLE.

THESE ARE DANGEROUS STORMS. IF YOU ARE IN THE PATH...PREPARE
IMMEDIATELY FOR DAMAGING WINDS...DESTRUCTIVE HAIL...AND DEADLY CLOUD
TO GROUND LIGHTNING. PEOPLE OUTSIDE SHOULD MOVE TO A 
SHELTER...PREFERABLY INSIDE A STRONG BUILDING BUT AWAY FROM WINDOWS.

&&

LAT...LON 4270 7905 4275 7892 4279 7887 4295 7893
      4297 7901 4301 7904 4307 7899 4309 7908
      4314 7905 4326 7907 4335 7871 4338 7846
      4288 7846 4284 7848 4270 7846 4255 7908
      4257 7913 4259 7915
TIME...MOT...LOC 0030Z 238DEG 39KT 4321 7892 4309 7877
          4291 7887

$$

HITCHCOCK
000 
WWUS51 KBUF 210051
SVSBUF

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE BUFFALO NY
851 PM EDT THU AUG 20 2009

NYC029-063-210115-
/O.CON.KBUF.SV.W.0086.000000T0000Z-090821T0115Z/
NIAGARA NY-ERIE NY-
851 PM EDT THU AUG 20 2009

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 915 PM EDT
FOR ERIE AND NIAGARA COUNTIES...

AT 848 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR CONTINUED TO
INDICATE A LINE OF SEVERE THUNDERSTORMS CAPABLE OF PRODUCING
DESTRUCTIVE WINDS IN EXCESS OF 70 MPH.  THESE STORMS WERE LOCATED 
ALONG A LINE EXTENDING FROM OLCOTT TO GASPORT TO SLOAN...MOVING 
NORTHEAST AT 45 MPH.

* SEVERE THUNDERSTORMS WILL BE NEAR...
  MIDDLEPORT BY 855 PM EDT...  
  BUFFALO AND AMHERST BY 855 PM EDT...
  CLARENCE AND LANCASTER BY 905 PM EDT...
  AKRON BY 915 PM EDT...

ANOTHER LINE OF SEVERE THUNDERSTORMS NEAR SILVER CREEK WILL MOVE 
INTO SOUTHWEST ERIE COUNTY AND IMPACT AREAS FROM BRANT TO EDEN AND 
ANGOLA THROUGH 910 PM EDT.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

THESE ARE DANGEROUS STORMS. IF YOU ARE IN THE PATH...PREPARE 
IMMEDIATELY FOR DAMAGING WINDS...AND DEADLY CLOUD TO GROUND 
LIGHTNING. PEOPLE OUTSIDE SHOULD MOVE TO A SHELTER...PREFERABLY 
INSIDE A STRONG BUILDING BUT AWAY FROM WINDOWS.

A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL 200 AM EDT FRIDAY
MORNING FOR WESTERN NEW YORK.

&&

LAT...LON 4270 7905 4275 7892 4279 7887 4295 7893
      4297 7901 4301 7904 4307 7899 4309 7908
      4314 7905 4326 7907 4335 7871 4338 7846
      4288 7846 4284 7848 4270 7846 4255 7908
      4257 7913 4259 7915
TIME...MOT...LOC 0049Z 237DEG 40KT 4334 7867 4322 7852
          4288 7881

$$

HITCHCOCK
000 
WWUS51 KBUF 210115 RRA
SVSBUF

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE BUFFALO NY
915 PM EDT THU AUG 20 2009

NYC029-063-210125-
/O.EXP.KBUF.SV.W.0086.000000T0000Z-090821T0115Z/
NIAGARA NY-ERIE NY-
915 PM EDT THU AUG 20 2009

...THE SEVERE THUNDERSTORM WARNING FOR ERIE AND NIAGARA COUNTIES HAS
EXPIRED...

AT 915 PM EDT NATIONAL WEATHER SERVICE RADAR SHOWED THAT THE SEVERE
THUNDERSTORM THAT PROMPTED THE WARNING HAD EXITED THE WARNED AREA...
THUS THE WARNING HAS BEEN ALLOWED TO EXPIRE.

A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL MIDNIGHT EDT 
TONIGHT FOR WESTERN NEW YORK.

LAT...LON 4270 7905 4275 7892 4279 7887 4295 7893
      4297 7901 4301 7904 4307 7899 4309 7908
      4314 7905 4326 7907 4335 7871 4338 7846
      4288 7846 4284 7848 4270 7846 4255 7908
      4257 7913 4259 7915
TIME...MOT...LOC 0051Z 237DEG 40KT 4335 7864 4323 7849
          4289 7878

$$

HITCHCOCK

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 20, 6:31 PM EDTSpecial Marine WarningBUF119 min
Aug 20, 7:15 PM EDTSpecial Marine WarningBUF2 hr
Aug 20, 7:47 PM EDTSevere Thunderstorm WarningBUFChautauqua73 min

Nearby

Severe Thunderstorm Warnings in New York, 2009Every severe thunderstorm warning in 2009

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.