Determining Which Storm to Chase

[ScottCurry]

This is my first chase season, and I have another question about chasing... I'm getting pretty good at picking target areas, but I'm confused which storm to chase once I get there (assuming there is more than one, and there usually is).

If you don't mind, I'd like to throw out a scenario based loosely on today's storms in NE CO to better understand how you pick which storm to chase.

Let's say you just reached your target area and there are three storms nearby. You are at an intersection with two roads. One road goes north / south, the other road goes east / west. Both roads have 65mph speed limits. Which storm do you pick and why? Here are your options:

Storm A) located 60 miles to your east, moving east at 30 kts. This storm is tornado warned with a confirmed tornado on the ground.
Storm B) located 60 miles to your north, moving north at 10 kts. This storm is severe warned and producing 1" hail. It also has radar indicated rotation.
Storm C) located 60 miles to your south, moving NE at 20 kts. This storm is not warned, but is growing stronger with every radar pass.

Just to let you know, today I chose option A and failed to ever catch up to the storm. I just saw Bob Schafer's report that he did the same thing and barely caught up with it. Based upon Bob's report, he was about 30-40 minutes ahead of me. What would you have done and why?

 

[NealRasmussen]

Cell B, moving north, would seem to be a 'left mover'. Perhaps it came off as a split from the tornadic cell, not sure. But left movers might have anticyclonic shear or rotation, but are generally just big hailers.

Cell A at 60mi away and a closing speed of 30mph. Maybe 35, but let's count on 30. So 2 hrs to intercept. It might last that long, but only if the environment it's going through is very even. Little cape or shear or vent gradient. Even if the gradients 'get better', since it is tornadic, any change might cause it to morph.

Cell C is my prey. Depending on roads, I would either go east, then south, or south and then east, squirting any hooks. Also making sure Cell C has good air to go through, and is not behind the RFD OFB left behind by Cell A. A fineline trace from Cell A swinging back SW might tell ya. Or a cu line on satellite indicating a cast out OFB.

Unless Cell A is going towards home and it's late, or near sunset and I'll get in between the two for increased lightning pic chances.

 

[Dan Robinson]

It depends on the environment the storms are in, the radar trends, and what type of mesoscale features each storm is working with. "Tail-end charlie" is usually a safe bet *if* all storms are in an identical environment, as the southern storm has unimpeded, uncontaminated inflow. But if one of the storms is tracking along an outflow boundary, usually that is the one you want, no matter which one it is. Or if the northern/southern storm is in line for a glancing blow of better upper support, you'd choose that one. A storm heading for a warm frontal interaction is the better choice if the others are heading out into open warm sector. Capping is also a concern. Will the southern storm get killed by a strengthening cap? You really need to know your synoptic and mesoscale environment to be able to make a good choice.

In Colorado, there are topographical features that would dictace which areas to stick with (DCVZ). I'm not familiar with the subtleties of Colorado forecasting, so I'll let others chime in who are.

 

[Joshua Nall]

I would definitely drop down to storm C, to answer your question, but the idea is to not be in that position. Sometimes you can't help it because the good stuff just fires up further east than you thought it would, but I always play downstream a ways to lessen the odds of getting caught behind. Too far East is always better for me than being just a little too far west. Sure don't like chasing storms down. How far downstream depends on storm speed and how fast storms will mature, etc... This is why guys/gals who know their stuff and can better predict this are more successful. I miss tornadoes sometimes, for example, on storms that just explode, spin and start spitting them out.

 

[Bob Schafer]

No matter how complicated you create the scenario in a hypothetical case like this, in a real situation it's always ten times more complicated than one can even describe it. That's not to say that a chaser can even comprehend everything that's in play. You just do the best you can.

The best advice, IMO, is to do your homework. If you can tell me what's going on with moisture, wind speeds, wind directions, temperatures, outflow boundaries, cloud cover, inhibition, and anything else that may be important, at any given moment in time throughout the day, and at every different level of the atmosphere, without looking at data, then you're gonna kick every other chaser's butt from here to Poughkeepsie, because nobody can do that. Oh, and throw in some considerations for the road network, orographic features, chaser congestion, and wooded areas while you're at it.

Whatever you do, have an escape route. Then, either get to the storm with the cleanest inflow, and that's going to continue to have the cleanest inflow, or the next best one you can reach. Don't chase warnings. Learn what kills storms, like bad hodos. And don't ever lose the passion, my friend.