40th Anniversary of the Palm Sunday Outbreak

40th Anniversary of the Palm Sunday Outbreak: 

40th Anniversary of the Palm Sunday Outbreak How It Changed Tornado Preparedness & Forecasting Daniel McCarthy Warning Coordination Meteorologist NOAA/NWS/NCEP Storm Prediction Center Photo by Paul Huffman, Elkhart Truth

Slide2: 

Typical Parameters for OH Tornadoes > 80 kt Mid Level Jet over OK Coupled ULJ and LLJ Area underneath ULJ exit region Steep Lapse Rates over the Plains Advecting into area behind cold front or dryline BRN Shear > 80 Presence of Deep Layer Shear

Fujita Attributed Outbreak to Several Facets: 

Fujita Attributed Outbreak to Several Facets Decrease in Best Lifted Index Pressure of best lifting Strong differential thermal advection Occurring with respect to the juxtoposition of intersecting jets First comprehensive aerial damage survey Led to theory of suction vortices Enhanced Super Outbreak

April 11-12, 1965: 

April 11-12, 1965 ~47 Tornadoes 21 Killer Tornadoes 260 Fatalities 3,442 Injuries “Most significant outbreak since March 18, 1925.” -Fujita

Fujita’s Plot of Aerial Survey: 

Fujita’s Plot of Aerial Survey

850 mb 11APR65/1800 CST: 

850 mb 11APR65/1800 CST From Fujita, et. al, 1970

500 mb 11APR65/1800 CST: 

500 mb 11APR65/1800 CST From Fujita, et. al, 1970

200 mb 11APR65/1800 CST: 

200 mb 11APR65/1800 CST From Fujita, et. al, 1970

Surface Analysis 1200 CST: 

Surface Analysis 1200 CST From Fujita, et. al, 1970

Isotherm Analysis 1200 CST: 

Isotherm Analysis 1200 CST From Fujita, et. al, 1970

Dayton Sounding – 1200 UTC: 

Dayton Sounding – 1200 UTC

Flint, MI Sounding – 1200 UTC: 

Flint, MI Sounding – 1200 UTC

Dayton, OH Sounding – 0000 UTC: 

Dayton, OH Sounding – 0000 UTC

DAY NAM 24 HR FCST Sounding: 

DAY NAM 24 HR FCST Sounding

LAN NAM 24 HR FCST Sounding: 

LAN NAM 24 HR FCST Sounding

TOL NAM 24 HR FCST Sounding: 

TOL NAM 24 HR FCST Sounding

NAM40 Surface: 

NAM40 Surface

SFC Td & Mean RH: 

SFC Td & Mean RH

500 mb Vorticity: 

500 mb Vorticity

Upper Jet: 

Upper Jet

Low-Level Jet: 

Low-Level Jet

Composite : 

Composite

Supercell Parameter: 

Supercell Parameter Most Unstable CAPE (>1000 Jkg-1) BRN Shear (>40 kt) 0-3 km Storm Relative Helicity (>100 m2s-2) SCP = MUCAPE * BRN Shear * SRH(0-3km)

Supercell Parameters: 

Supercell Parameters

Differential Divergence: 

Differential Divergence After Uccellini and Johnson, 1980

Fujita’s Aerial Survey: 

Fujita’s Aerial Survey From Fujita, et. al, 1970

Storm Data: 

Storm Data

Storm Data: 

Storm Data

Toledo Tornado: 

Toledo Tornado From Fujita, et. al, 1970

Toledo Tornado: 

Toledo Tornado

IN into NW Ohio: 

IN into NW Ohio From Fujita, et. al, 1970

Bluffton Tornado: 

Bluffton Tornado From Fujita, et. al, 1970

Rockaway Tornado: 

Rockaway Tornado From Fujita, et. al, 1970

Strongsville Tornado: 

Strongsville Tornado From Fujita, et. al, 1970

Slide35: 

From Weather Bureau Survey Team Report

Problems Identified: 

Problems Identified Tornado “Forecast” issued for 6 hours Those interviewed didn’t know the difference between “forecast” and “warning” No real urgency until warnings were heard on radio and TV Radar coverage (WSR-57) inadequate Nothing in tornado-prone areas Poor communication with media sources

Lessons Learned: 

Lessons Learned Watch/Warning terminology began Before 1966 were “Tornado Forecasts” Watches area definition simplified Use 4 or less points to define Circles, Triangles, portions of states (Florida South of line from Tampa to Melbourne, etc. Parallelograms implemented in 1970 60 miles either side of a line 60 miles north and south of a line

Lessons Learned: 

Lessons Learned Hold Preparedness Meetings Spotter Talks now Saturate public with material on tornadoes Ready-Set-Go Outlook-Watch-Warning Doppler Radar Better coverage by NWS Private companies provide ability to local TV

It Must Work!: 

It Must Work!

Slide40: 

Thank You!! Any Questions? Web Site: www.spc.noaa.gov e-mail: Daniel.McCarthy@noaa.gov