Alert archive / Pennsylvania / Tornado Watches in 2003

Tornado Watch 357

May 11, 20035 states

The Storm Prediction Center issued this tornado watch at May 11, 2003, 11:45 AM EDT for 5 states. It was in force for 5 hr.

The area

The outline as issued.

The facts

Issued: May 11, 2003, 11:45 AM EDT (15:45 UTC)
Expired: May 11, 2003, 5:00 PM EDT
In force: 5 hr
Issued by: the Storm Prediction Center

All 50 counties

Garrett County, MD, Allegany County, NY, Cattaraugus County, NY, Chautauqua County, NY, Erie County, NY, Genesee County, NY, Livingston County, NY, Monroe County, NY, Wyoming County, NY, Ashtabula County, OH, Belmont County, OH, Carroll County, OH, Columbiana County, OH, Guernsey County, OH, Harrison County, OH, Jefferson County, OH, Mahoning County, OH, Monroe County, OH, Noble County, OH, Trumbull County, OH, Allegheny County, PA, Armstrong County, PA, Beaver County, PA, Butler County, PA, Cambria County, PA, Cameron County, PA, Clarion County, PA, Clearfield County, PA, Crawford County, PA, Elk County, PA, Erie County, PA, Fayette County, PA, Forest County, PA, Greene County, PA, Indiana County, PA, Jefferson County, PA, Lawrence County, PA, McKean County, PA, Mercer County, PA, Somerset County, PA, Venango County, PA, Warren County, PA, Washington County, PA, Westmoreland County, PA, Brooke County, WV, Hancock County, WV, Marshall County, WV, Monongalia County, WV, Ohio County, WV, Wetzel County, WV

The radar

The Pittsburgh radar (KPBZ), 55 km from the middle of the area, began a volume at 15:46 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.

Warnings issued inside it

2 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.

Issued	Product	Office	Counties	Lasted
May 11, 1:46 PM EDT	Severe Thunderstorm Warning	BUF	Genesee	44 min
May 11, 2:54 PM EDT	Severe Thunderstorm Warning	BUF	Monroe	51 min

Discussions around it

SPC mesoscale discussions over the same counties from four hours before the watch to its end.

The nearest sounding before it

Pittsburgh, PA (KPIT), launched 12:00Z, 3.8 hours before the alert went out and 67 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: 1410 J/kg
Mixed-layer CIN: -36 J/kg
Mixed-layer LCL: 703 m above ground
0-6 km bulk shear: 25 kt
0-1 km storm-relative helicity: 188 m²/s²
0-3 km storm-relative helicity: 137 m²/s²
Significant tornado parameter: 0.6
Supercell composite: 4.0

Open this sounding in Storm Lab

The text

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

000 
WWUS20 KWNS 111545
SEL7  
SPC WW 111545
MDZ000-NYZ000-OHZ000-PAZ000-WVZ000-LOZ000-LEZ000-112100-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 357 
NWS STORM PREDICTION CENTER NORMAN OK 
1145 AM EDT SUN MAY 11 2003

THE NWS STORM PREDICTION CENTER HAS ISSUED A
TORNADO WATCH FOR PORTIONS OF 

       EXTREME WESTERN MARYLAND
       WESTERN NEW YORK
       EASTERN OHIO
       WESTERN PENNSYLVANIA
       NORTHERN WEST VIRGINIA
       LAKE ONTARIO
       LAKE ERIE

EFFECTIVE THIS SUNDAY MORNING AND AFTERNOON FROM 1145 AM UNTIL 500
PM EDT.

TORNADOES...HAIL TO 2 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS
TO 80 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.

THE TORNADO WATCH AREA IS ALONG AND 75 STATUTE MILES EAST AND WEST
OF A LINE FROM 25 MILES NORTH NORTHWEST OF BUFFALO NEW YORK TO 25
MILES WEST SOUTHWEST OF MORGANTOWN WEST VIRGINIA.

REMEMBER...A TORNADO WATCH MEANS CONDITIONS ARE FAVORABLE FOR
TORNADOES AND SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH AREA.
PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR THREATENING
WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS AND POSSIBLE
WARNINGS.




DISCUSSION...SCATTERED THUNDERSTORMS ARE EXPECTED TO DEVELOP SOON
OVER EASTERN OH AND TRACK ACROSS WESTERN NY/PA.  RAPID
DESTABILIZATION AHEAD OF COLD FRONT COUPLED WITH STRONG DYNAMIC
FORCING SHOULD PROMOTE DAMAGING WINDS AND LARGE HAIL IN STRONGER
CELLS.	VERTICAL SHEAR PROFILES ALSO SUPPORT A RISK OF SUPERCELLS
AND ISOLATED TORNADOES IN THIS REGION.

AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 2 INCHES. EXTREME TURBULENCE AND SURFACE WIND
GUSTS TO 70 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 500.
MEAN STORM MOTION VECTOR 26040.


...HART

431,0772 392,0785 392,0814 431,0802

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
May 11, 2:52 PM EDT	Mesoscale Discussion	SPC	Garrett	113 min
May 11, 3:18 PM EDT	Mesoscale Discussion	SPC	Anne Arundel, Baltimore, Calvert, Caroline, Carroll, Charles and 14 more	117 min
May 11, 10:07 AM EDT	Mesoscale Discussion	SPC	Allegany, Broome, Cayuga, Chemung, Chenango, Cortland and 19 more	113 min
May 11, 10:30 AM EDT	Mesoscale Discussion	SPC	Allegany, Cattaraugus, Chautauqua, Erie, Genesee, Orleans and 1 more	2 hr
May 11, 12:32 PM EDT	Mesoscale Discussion	SPC	Broome, Cayuga, Chemung, Chenango, Cortland, Jefferson and 13 more	118 min
May 11, 1:50 PM EDT	Tornado Watch	SPC	Broome, Cayuga, Chemung, Chenango, Cortland, Herkimer and 14 more	5 hr
May 11, 3:54 PM EDT	Mesoscale Discussion	SPC	Broome, Cayuga, Chemung, Chenango, Cortland, Herkimer and 14 more	2 hr
May 10, 11:40 PM EDT	Mesoscale Discussion	SPC	Williams	2 hr
May 11, 12:00 AM EDT	Tornado Watch	SPC	Defiance, Paulding, Van Wert, Williams	6 hr
May 11, 12:28 AM EDT	Mesoscale Discussion	SPC	Adams, Allen, Ashland, Auglaize, Brown, Butler and 44 more	2 hr
May 10, 9:28 PM EDT	Mesoscale Discussion	SPC	Boone, Clay, Fayette, Kanawha, Lincoln, Logan and 6 more	62 min
May 11, 5:16 AM EDT	Mesoscale Discussion	SPC	Wayne	59 min
May 11, 6:05 AM EDT	Severe Thunderstorm Watch	SPC	Wayne	4 hr

Nearby

Tornado Watches in Pennsylvania, 2003 Tornado Watches in Ohio, 2003 Tornado Watches in New York, 2003 Every tornado watch in 2003

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.