New paper regarding the 1965 Palm Sunday Tornado Outbreak

[Hoosier]

Last year I mentioned that there was a new paper that would be coming out about the Palm Sunday outbreak, which would take a look at the outbreak using some of the modern severe weather parameters in use today.  Well, here it is.

 

http://www.weather.gov/media/crh/publications/TA/TA_1502.pdf

 

 

Some highlights:

 

Estimated MLCAPE (using lowest 50 mb) and 0-6 km bulk shear values using a synthetic forecast sounding for South Bend, IN, valid 23z were 1170 J/kg and 103 kt, respectively.  0-8 km bulk shear was around 110 kts.  0-1 km SRH exceeded 300 m2/s2 over a pretty large area.  Basically these shear values are on the extreme high end of what is necessary for long track strong/violent tornadoes.

 

The mean pattern prior to the outbreak with lack of deeply penetrating cold fronts into the deep South was favorable for efficient northward moisture transport once April 11 arrived, not unlike what happened prior to the April 1974 outbreak.

[andyhb]

CAPE rather unimpressive, but 103 kts of 0-6 km shear is just silly.

 

Basically the ultimate low/mod CAPE, high shear event. Going to add this to my recommended material for the article on US Tors.

[HillsdaleMIWeather]

Last year I mentioned that there was a new paper that would be coming out about the Palm Sunday outbreak, which would take a look at the outbreak using some of the modern severe weather parameters in use today. Well, here it is.

http://www.weather.gov/media/crh/publications/TA/TA_1502.pdf

Some highlights:

Estimated MLCAPE (using lowest 50 mb) and 0-6 km bulk shear values using a synthetic forecast sounding for South Bend, IN, valid 23z were 1170 J/kg and 103 kt, respectively. 0-8 km bulk shear was around 110 kts. 0-1 km SRH exceeded 300 m2/s2 over a pretty large area. Basically these shear values are on the extreme high end of what is necessary for long track strong/violent tornadoes.

The mean pattern prior to the outbreak with lack of deeply penetrating cold fronts into the deep South was favorable for efficient northward moisture transport once April 11 arrived, not unlike what happened prior to the April 1974 outbreak.

Thanks for posting this, the Meteorological insight is always appreciated. My mother remembers the aftermath of the Twin Hillsdale tornadoes vividly.

[Stebo]

What I would love to see for this event is a radar simulation maybe something based off of the wrf models we have now with the environmental conditions added.

 

As for the paper it is a really good read, the key to this event to me was the lower amplitude of the wave allowing to limited forcing so you ended up with supercells vs linear convection.

[Indystorm]

Thanks, Hoosier for sharing this research.  As I've said elsewhere in discussing this event I was a young teen in Hobart that day looking east that evening at towering cauliflower cumulonimbus backlit in white by the sun and knowing that all hell was breaking loose somewhere just to my east.  We fortunately only had a mild t storm at my location. I later did a master's thesis at I.U. on tornado disaster planning for public schools in Indiana based largely on this event.

[Hoosier]

CAPE rather unimpressive, but 103 kts of 0-6 km shear is just silly.

 

Basically the ultimate low/mod CAPE, high shear event. Going to add this to my recommended material for the article on US Tors.

 

 

Yeah, the shear was definitely the standout aspect of this event. 

 

Looks like instability was a bit better down toward central IN.  Would've been nice to see a sounding from IND or somewhere around there to better estimate the environment near the cells in central IN.

[RCNYILWX]

Excellent paper, thanks for sharing! Would be cool to do a comparison of all significant outbreaks across the region in terms of the CAPE/shear spectrum. That fairly low CAPE and extreme shear environment for the extrapolated SBN sounding is reminiscent of what was in place near the West Liberty KY tornado on 3/2/12.