Forecast Model Simulations for the 1965 Palm Sunday Outbreak

[Bob Hartig]

The 1965 Palm Sunday Tornado Outbreak has been a subject of focused research for me. I plan to write a book on the event, and in fact have got a prologue and first chapter already written. Chapter two has been on hold while I've worked on getting a handle on the meteorology of the event.

Yesterday, after a 500-mile drive to the WFO at State College, PA, I finally acquired some critical insights that will allow me to makes sense of an exhaustive set of model simulations I have for the event.

I'm not going to write all about my project here since I just completed a time-consuming post in my blog, complete with a couple samples--i.e. a map showing model CAPE and low-level shear, and a forecast sounding for KGRR. But I thought I'd let the Stormtrack community know. Anyone who has an interest in this historic tornado outbreak, click here to read my writeup.

 

[Mike Smith]

Amazing how low the CAPE was for an F4 tornado.

 

[Robert Dewey]

It doesn't really look like a case of "large CAPE in the bottom" either...

 

[rdale]

...but at 22 hours, in a low resolution model with limited input, and a warm front that's still not handled well by models today, can that low CAPE be considered accurate?
Looking at Dan McCarthy's presentation on the event, CAPEs in Lansing were 1500+.

http://www.authorstream.com/Present...65-Fu-of-the-as-Entertainment-ppt-powerpoint/

 

[Bob Hartig]

John (Janis) Laurens at KGRR coauthored a Powerpoint presentation on synoptic setups for Michigan/Great Lakes tornado outbreaks. He and his research partner (don't know that person's name offhand) identified three patterns. The first, "Type A," for which John used the Palm Sunday Outbreak as a case study, occurs in a high shear/low CAPE environment. With the PSO, the 500 mb jet was absolutely screaming over the outbreak area. The hand-analyzed chart for 7 p.m. that evening showed 135 knots over north-central Illinois--weaker to the east, but still mighty potent.

It is interesting to see that the CAPE is skinny overall, not fat at the bottom, as Dewey points out. The charts/soundings aren't perfect, obviously, particularly given the relatively limited data that was available to produce them. But this is the first I'm aware that anyone has produced anything like them for the Palm Sunday Tornadoes. They're bound to engender some questions.

Remember, though, that with early spring events, once you start tipping over 500 j/kg in the presence of whopping shear, strange things seem to become possible. You can get nothing, or you can get Palm Sunday.

 

[Chris Vagasky]

Bob -

That presentation was from Laurens and Graham. If you need a copy of it, I've got it.

 

[Bob Hartig]

Bob -

That presentation was from Laurens and Graham. If you need a copy of it, I've got it.

Thanks, Chris. I do in fact have it, just was too lazy to download the disk and look up the second author. KGRR is just 7 miles up the road from me, and Janis has been extremely helpful to me in pulling material together.

 

[Bob Hartig]

I should add, since I've let the cat out of the bag about it, that the book will not be a meteorological treatise (which I'm not equipped to write), but a historical/human interest tome written in a popular voice. However, me being a storm chaser, it's natural for me to want to gain as thorough an understanding of the outbreak's meteorology as I can.

Initially, what I hoped to get was just a basic set of maps that would help me trace the genesis of the system that produced the tornadoes. What I obtained was beyond anything I ever expected, and I believe it warrants an appendix which I think the storm chasing community will take an interest in. It will take me time to sift through the material, and I'll need to have my results vetted by heads more knowledgeable than mine. In the end, my hope is to provide something of interest and value to my fellow chasers.

 

[rdale]

But this is the first I'm aware that anyone has produced anything like them for the Palm Sunday Tornadoes.

Click the link again Dan did this several years ago, with SCP / BRN / etc plotted along with many model and real soundings from MI/IN/OH. He is now the MIC at Indianapolis and I'm sure has much more info if you'd like, he's great to work with.

 

[Bob Hartig]

Click the link again Dan did this several years ago, with SCP / BRN / etc plotted along with many model and real soundings from MI/IN/OH. He is now the MIC at Indianapolis and I'm sure has much more info if you'd like, he's great to work with.

Rob, I appreciate your supplying the link. I had seen Dan's Powerpoint before, but it was a while ago and it has been vague in my mind as I've dealt with the material I've got, which has been a ponderous output. Dan sounds like a stellar resource, and your suggestion to contact him is well taken. I'll refresh myself on his presentation and then give him a shout. Thanks, and know that your input is welcome and valued.