Tornado warning dilemma...

[Jay McCoy]

Originally posted by Mike Peregrine
By the way - just one more little scenario that comes up sometimes that really affects a choice you will make this way:

Last year on May 29th we were initially on a storm that went severe fairly early on over highway 36 to the west of Belleville, Kansas ... HOWEVER, a cell to the south grew rapidly and also became severe - and we could visually determine that the anvil of the southern storm was moving dangerously close to the updraft of the northern, severe storm. This caused us to decide to quickly head south - the best decision we could have possibly made - because the storm to the south soon dominated - the original cell we were on became seeded by the southern anvil and subsequently was absorbed into the new supercell, which then produced the tornadoes. If we had stuck with the northern cell, we would have probably been disappointed and missed a lot of the opportunities to the south.

Just thought I'd add it for the sake of discussion -

Nice observation Mike. I saw the same and decided as you did which made our chase instead of busting a big day.

Things I notice when deciding between storms can be very apparent or little things like even the shadow from an anvil can cool surface temps and limit another storms growth. Road network is also a major factor. A storm may be better than another one but if you cant realistically chase it then work the other.

 

[David Drummond]

My gut feeling, developed from years of living and chasing on the southern plains....not very technical I know, but it works more times than it doesn't....

When in doubt....go with the southern storm! :wink:

 

[Kurt Hulst]

As David was saying some times you just gotta rely on your gut. take June 12, 2004 for instance. I found my self getting off at 160 in Kansas the storms had just initiated. I saw my target cell which was the south most cell closest to me. I was astonished to see how elevated it was. I later met up with Keith Minor. You may not know him but oh well. We were seeing on his threat net a cell with good rotation about 50 miles north tornado warned shortly after. He thought about heading that way as we knew a few were already on the way. Mainly since our cell was looking sick. I told him he could go but there was something inside me that said be patient. The winds were at first just barely out of the south some what SW. Then we headed east down 160 twoard wellington KS. and the winds were SE. The storm had hit a very potent and potential atmoshpere. We were some what watching a LP structured storm just to the south of our main supercell. which finally our cell Devoured. Our cell became suface based and well the rest is history. 6-7 tornadoes

 

[Shane Adams]

For years I too lived by the "southern storm" rule, but after a while it proved itself to be a crapshoot at best on any given day. Jim Leonard once told me "stay with the storm you're on," and I think that's pretty wise. For me, the wisdom in this approach is that you really don't know what will happen, and going out of your way to miss something good makes a lot less sense than missing something good because you stuck to your guns.

Of course sometimes there are situations where you just "know" what to do. You might not get a tornado, but the decision ends up bagging you the better storm. Certain situations will deictate my decisions, based on storm behavior "rules" or "for sures" such as a splitting cell.....I'll take the right mover (southern storm) every time. Other situations where there are two discrete cells, that's always a gut call for me. If I think one storm is better than the other, I'll go for it regardless of roads or distance. The only factor that will make me choose the "other storm" (the one I don't want) is darkness.

May 31, 1999 we had targeted Shattuck, OK and had been there all afternoon. We saw what was the beginnings of the Meade/Sitka cell and headed north for it. A glance over my shoulder showed a fully-developed supercell, much further away to the distant southwest. I didn't even think about it, that was our storm. Later that evening we intercepted three tornadoes in SW OK, while the circus was raging in SW KS. I think I can count the other chasers who saw those SW OK tornadoes with us on one hand.

May 3, 2003 we came into Paducah, TX with a storm bearing down on us from the south. I called Dwain and he told me the storm near us was a left split, and that the right split was about 50 miles south of us, and the only thing on radar that looked worth going after. Without even considering it, we blasted south for a storm we couldn't even see yet. As several other chasers were parked south of Paducah with vidcams mounted, pointed at the storm, we blasted right into the core and out of town. Some of the looks on their faces have made me wonder to this day if they knew about the southern split. Eventually we came into visual range of the southern storm, and before the day was over we'd seen five tornadoes, along with one of the top-three storms I've ever witnessed.

May 5, 2001 we had been on the north storm since the first cumulus, and had tracked it for well over an hour as it moved towards Rocky and Cordell. A new storm blew up to the south, and we pulled over to analyze. The northern storm was due north od us, the southern storm SW of us. We had cool inflow feeding the north storm, while chunks of cloud were being ripped away from it's southern flank and pulled into the southern storm. Looking due south, we could see rainbands bowed nearly 90 degrees, riding inflow into the southern storm. We sat and debated all this and the decision was made to go for the southern storm. later that evening the north storm produced a pair of beautiful purple tornadoes while all we got was a linear mess. The northern storm had encountered a boundary shortly after we'd abandoned it, something we hadn't been aware of prior.

It goes both ways, and no one can predict which storm will tornado from one moment to the next with exact certainty. This is just one of the things that makes chasing so much fun, the little challenges we're faced with every step of the way.

 

[Mike Peregrine]

I also agree with a point that Shane makes about staying with the storm you are on ... a personal rule that I have is that if it has been rotating, stay with it. It may cycle through some unimpressive stages at times, but I've left more than one storm going through one of those cycles that later turned out to be the storm of the day.

 

[Justin Turcotte]

In the ideal world, you are already on a cell when it becomes tornado warned. Using the initial example of a cell north and a cell south and you're in the middle questioning which way to go... you will want to take into account which cell is on the preferred boundary (best combination of shear and instability). Visual appearance can be a large factor but the old addage does apply here: never judge a book by its cover which brings you back to synoptic and mesoscale knowledge. Already brought up and I agree that accessability is just as critical as anything else. Can you get to the cell in a reasonable time (without doing 90?). Another idea to consider is the accessibility and proximity to other storms thatr may be chaseworthy should your cell not get tp to par. I have even chased cells simply because they were closer to or on the way home. With gas at $2 a gallon this will unfortunately be factored in my chases this year, though I will not sacrifice a cyclical beast for the sake of a few gallons of gold. If you're on the cells early you will have more options (which could go better or worse) than if you arrive at the last second.