Alert archive / Pennsylvania / Tornado Watches in 2001

Tornado Watch 759

September 24, 2001Sullivan County, New York; 25 counties in Pennsylvania

The Storm Prediction Center issued this tornado watch at Sep 24, 2001, 4:15 PM EDT for Sullivan County, New York; 25 counties in Pennsylvania. It was in force for 6 hr.

The area

The outline as issued.

The facts

Issued
Sep 24, 2001, 4:15 PM EDT (20:15 UTC)
Expired
Sep 24, 2001, 10:00 PM EDT
In force
6 hr
Issued by
the Storm Prediction Center
All 26 counties

Sullivan County, NY, Adams County, PA, Berks County, PA, Bradford County, PA, Carbon County, PA, Columbia County, PA, Cumberland County, PA, Dauphin County, PA, Lackawanna County, PA, Lancaster County, PA, Lebanon County, PA, Lehigh County, PA, Luzerne County, PA, Monroe County, PA, Montour County, PA, Northumberland County, PA, Perry County, PA, Pike County, PA, Schuylkill County, PA, Snyder County, PA, Sullivan County, PA, Susquehanna County, PA, Union County, PA, Wayne County, PA, Wyoming County, PA, York County, PA

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
Sep 24, 6:22 PM EDTSevere Thunderstorm WarningCTPAdams, York53 min
Sep 24, 6:53 PM EDTTornado WarningCTPYork67 min
Sep 24, 7:16 PM EDTFlash Flood WarningCTPAdams, York3 hr
Sep 24, 7:36 PM EDTFlash Flood WarningCTPColumbia, Dauphin, Lebanon, Lycoming, Montour, Northumberland and 4 more3 hr
Sep 24, 7:57 PM EDTSevere Thunderstorm WarningCTPLancaster, York63 min
Sep 24, 8:09 PM EDTSevere Thunderstorm WarningCTPLebanon66 min
Sep 24, 9:17 PM EDTSevere Thunderstorm WarningCTPColumbia, Northumberland, Schuylkill58 min
Sep 24, 9:43 PM EDTSevere Thunderstorm WarningCTPSullivan62 min

The nearest sounding before it

Phillips Aaf/Abe, MD (KAPG), launched 12:00Z, 8.3 hours before the alert went out and 132 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, Phillips Aaf/Abe, MD at 12:00Z on 2001-09-24Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 432 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Phillips Aaf/Abe, MD at 12:00Z on 2001-09-24The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 70 square meters per square second.19395878Sfc1 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
432 J/kg
Mixed-layer CIN
-35 J/kg
Mixed-layer LCL
541 m above ground
0-6 km bulk shear
37 kt
0-1 km storm-relative helicity
70 m²/s²
0-3 km storm-relative helicity
65 m²/s²
Significant tornado parameter
0.1
Supercell composite
1.4

Open this sounding in Storm Lab

The text

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

399 
WWUS9 KMKC 241956
SEL9  
MKC WW 241950
NYZ000-PAZ000-250200-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 759
STORM PREDICTION CENTER NORMAN OK
350 PM EDT MON SEP 24 2001

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

   EXTREME SOUTH CENTRAL NEW YORK                           
   EASTERN PENNSYLVANIA                       

EFFECTIVE THIS MONDAY AFTERNOON AND EVENING FROM 415 PM UNTIL 1000
PM EDT.

TORNADOES...HAIL TO 2 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS
TO 70 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.

THE TORNADO WATCH AREA IS ALONG AND 50 STATUTE MILES EAST AND WEST
OF A LINE FROM 35 MILES SOUTH OF HARRISBURG PENNSYLVANIA TO 45
MILES WEST NORTHWEST OF MONTICELLO NEW YORK.

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.

OTHER WATCH INFORMATION...  CONTINUE...WW 758...

DISCUSSION...SURFACE MESOLOW CONTINUES TO TRACK NORTHEASTWARD
ACROSS CENTRAL VA...AND IS EXPECTED TO MOVE INTO EASTERN PA IN THE
NEXT FEW HOURS.  SMALL SUPERCELL STORMS AND ISOLATED TORNADOES HAVE
ALREADY OCCURRED IN ASSOCIATION WITH THIS SYSTEM OVER VA.  MODEL
GUIDANCE INDICATES LOW LEVEL WINDS WILL STRENGTHEN THROUGH THE LATE
AFTERNOON...INCREASING VERTICAL SHEAR PROFILES AND THREAT OF
TORNADOES.

AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 2 INCHES.  EXTREME TURBULENCE AND SURFACE WIND
GUSTS TO 60 KNOTS.  A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 500. 
MEAN STORM MOTION VECTOR 21030.

...HART

415,0743 394,0755 394,0774 415,0763

Nearby

Tornado Watches in Pennsylvania, 2001Tornado Watches in New York, 2001Every tornado watch in 2001

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.