Alert archive / New York / Severe Thunderstorm Warnings in 2009

Severe Thunderstorm Warning 91, NWS Buffalo, NY

August 20, 2009Allegany County, New York

NWS Buffalo, NY issued this severe thunderstorm warning at Aug 20, 2009, 10:06 PM EDT for Allegany County, New York. It was in force for 54 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: Aug 20, 2009, 10:06 PM EDT (02:06 UTC)
Expired: Aug 20, 2009, 11:00 PM EDT
In force: 54 min
Issued by: NWS Buffalo, NY
Area: Storm-based polygon

County Allegany County, NY

The radar

The Buffalo radar (KBUF), 109 km from the middle of the area, began a volume at 02:08 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 watch it was issued in

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

Issued	Product	Office	Lasted
Aug 20, 6:54 PM EDT	Severe Thunderstorm Watch	SPC	5 hr

The nearest sounding before it

Buffalo Intl Airport, NY (KBUF), launched 00:00Z, 2.1 hours before the alert went out and 106 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: 828 J/kg
Mixed-layer CIN: -14 J/kg
Mixed-layer LCL: 1273 m above ground
0-6 km bulk shear: 42 kt
0-1 km storm-relative helicity: 232 m²/s²
0-3 km storm-relative helicity: 306 m²/s²
Significant tornado parameter: 0.8
Supercell composite: 6.5

Open this sounding in Storm Lab

The text

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

000 
WUUS51 KBUF 210206
SVRBUF
NYC003-210300-
/O.NEW.KBUF.SV.W.0091.090821T0206Z-090821T0300Z/

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE BUFFALO NY
1006 PM EDT THU AUG 20 2009

THE NATIONAL WEATHER SERVICE IN BUFFALO HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  SOUTHERN ALLEGANY COUNTY IN WESTERN NEW YORK

* UNTIL 1100 PM EDT

* AT 1005 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM CAPABLE OF PRODUCING DAMAGING WINDS IN EXCESS
  OF 60 MPH.  THIS STORM WAS LOCATED 12 MILES SOUTHWEST OF
  WELLSVILLE...AND MOVING NORTHEAST AT 35 MPH.

* THE SEVERE THUNDERSTORM WILL BE NEAR...
  WELLSVILLE BY 1025 PM EDT...
  ALFRED BY 1050 PM EDT...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

DOPPLER RADAR HAS INDICATED SOME WEAK ROTATION WITHIN THIS STORM.
WHILE NOT IMMEDIATELY LIKELY...A TORNADO MAY STILL DEVELOP. IF A
TORNADO IS SPOTTED...ACT QUICKLY AND MOVE TO A PLACE OF SAFETY IN A
STURDY STRUCTURE...SUCH AS A BASEMENT OR SMALL INTERIOR ROOM.

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

&&

LAT...LON 4200 7815 4211 7822 4226 7801 4234 7772
      4209 7774
TIME...MOT...LOC 0206Z 238DEG 28KT 4204 7815

$$

ZAFF

1 follow-up statement

000 
WWUS51 KBUF 210255
SVSBUF

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE BUFFALO NY
1055 PM EDT THU AUG 20 2009

NYC003-210305-
/O.EXP.KBUF.SV.W.0091.000000T0000Z-090821T0300Z/
ALLEGANY NY-
1055 PM EDT THU AUG 20 2009

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHERN ALLEGANY COUNTY WILL
EXPIRE AT 1100 PM EDT...

AT 1055 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 4200 7815 4211 7822 4226 7801 4234 7772
      4209 7774
TIME...MOT...LOC 0255Z 238DEG 28KT 4224 7771

$$

HITCHCOCK

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 20, 8:31 PM EDT	Special Marine Warning	BUF		44 min
Aug 20, 8:31 PM EDT	Severe Thunderstorm Warning	BUF	Orleans	59 min
Aug 20, 8:52 PM EDT	Areal Flood Advisory	BUF	Allegany, Cattaraugus, Chautauqua, Erie, Genesee, Niagara and 2 more	3 hr
Aug 20, 8:59 PM EDT	Severe Thunderstorm Warning	BUF	Cattaraugus, Chautauqua	61 min
Aug 20, 9:16 PM EDT	Special Marine Warning	BUF		89 min
Aug 20, 9:52 PM EDT	Severe Thunderstorm Warning	BUF	Allegany, Cattaraugus	53 min
Aug 20, 10:04 PM EDT	Severe Thunderstorm Warning	BUF	Genesee, Monroe, Orleans	56 min
Aug 20, 10:19 PM EDT	Special Marine Warning	BUF		86 min
Aug 20, 10:25 PM EDT	Tornado Warning	BUF	Allegany	35 min
Aug 20, 11:28 PM EDT	Special Marine Warning	BUF		92 min

Nearby

Severe Thunderstorm Warnings in New York, 2009 Every 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.