Best position to be in when chasing a storm

[Chris Lott]

During a skywarn seminar I went to a couple of years ago, it was discussed that the best position to be in when chasing(or to observe a storm) would be 3-5 miles SE of the storm. If this for instance, is a classic or HP supercell, couldn't you be putting yourself in the storms path? Isn't it their nature to turn right?

 

[Chris Wilburn]

I may be wrong here (still a newbie), but I think LP, HP, and classic supercells can take a right turn and put you in harms way. I think SE of the storm is prefered because most storms move E or NE. Sorry, this may not help you at all and you probably know what I just explained. Anyway, I am curious to know too and will look for replies from people that are much more knowledgeable than I.

 

[Mikey Gribble]

Some storms do propogate to the right of the mean wind some times which is known as a right turn. I would think if you were 3-5 miles SE of the storm that was tracking NE and if it suddenly made a hard right turn you would probably still be far enough to the South of it that you would be OK. I don't know a whole lot about the topic, but you can usually anticipate that storms might have a tendancy to right turn on certain days. Storms propogate to the right because of how they are interacting with the environment they are located in. Vertical wind shear will influence where updrafts and downdrafts are located and this will influence where new updraft formation will be. I really don't want to attempt to explain momentum transport or any aspect of why storms deviate from the mean flow, but if you are interested in it you can find some things on the internet or PM me and I know of a couple good books that touch on this. Perhaps one of the mets who knows a little more about this could give a brief overview of it, if that is possible.
Anyway, you really should try to anticipate storm motion and whether they might deviate from the mean flow. Not only can it keep you out of trouble, it will help to anticipate where you need to be to have a good view of the storm. June 26 in South Dakota is a good example of this. A lot of people got stuck behind the storm because they didn't anticipate a right turn. In my experience, storms typically make a right turn shortly after reaching their mature stage (excluding when storms cross fronts and other boundaries). As long as you are paying close attention, you should be able to tell when the storm is right turning in time to get out of its way. If you stay 3-5 miles SE of the business end of the storm, I would think you would be far enough away to be safe even if it made a hard right turn.

 

[Shane Adams]

I have a hunch the 3-5 mile distance is suggested in anticipation of a possible right turn, so IMO you'd have plenty of time to realize the change of direction before the storm was on top of you. Also, with HP storms, many times the tornado will form on the forward flank side, which means the better viewing position would actually be the east/northeast flank of the storm, not neccessarily the southeast. One thing for sure, never expect a textbook behavioral pattern with a storm, always expect something new.

 

[Steve Miller TX]

One thing for sure, never expect a textbook behavioral pattern with a storm, always expect something new.

Ditto! I would add to also expect the unexpected. Always keep an escape route handy if you do need to hightail it out of there. I always know what my road options are to the east and to the south and adjust my position to the storm relative to my escape options.

But, back to the original question of this thread is the best position for chasing a storm, but Chris refers to a spotting position. These are two different strategies in my opinion with the need for a margin of safety greater for spotters in general. It also has alot to do with a storm's forward speed.

If a storm is hauling butt at 40mph or more, I've seen 3-5 miles get chewed up quickly. You gotta play leap frog alot and end up doing ALOT more driving than observing. Things change much more rapidly and you've got to stay on your toes.

If it is a slow mover like June storms usually are, then 3-5 miles is perfectly safe and probably too far away. Then I'd say 1-2 miles....but being very observant of the storm getting HP and becoming an HP bowling ball picking up forward momentum rapidly. Again...gott a have those escape routes.

I personally like to be at a 45 degree angle to the storm's movement. I use the angle measurement because a storm's motion isn't always going to be the same during it's life span, especially deviant moving supercells. Storms don't always move NE and can even move due S. A note here too...DO NOT TRUST the "indicated movement" of a storm by radar or what is heard in the warning text. That is only determined by the storms PREVIOUS motions. Use your own eyes by by watching the storm evolve or by watching a radar loop. I've heard a few frustrated chasers out there mumble about "well, the warning said it was moving NE at 20mph and I got cored while sitting SE of it!". LOL!!

Of course, if you are wanting the "safest" viewing angle, it should be a 90 degree angle to storm motion and 3-10 miles away depending on the storm's forward speed.

My $0.02

 

[Bill Tabor]

Originally posted by Chris Lott
During a skywarn seminar I went to a couple of years ago, it was discussed that the best position to be in when chasing(or to observe a storm) would be 3-5 miles SE of the storm. If this for instance, is a classic or HP supercell, couldn't you be putting yourself in the storms path? Isn't it their nature to turn right?

Good points made already by others. But yes there is no guarantee that SE of a storm is the appropriate position based on storm type or movement. SE is probably good if you have a NE or possibly E moving storm (using the 90 degree to 45 degree rule). However storms can move all different directions and different types of storms do require different strategies and distances to be safe. Take for instance the fact that the '97 Jarrell storm / tornado was backbuilding on a boundary to the SW.

Any supercell has the potential to right turn. This tendency is increased as they tap into more storm relative flow, meso strengthens. I've noticed when chasing that they usually do this as their radar echo initially gets very strong and they are potentially turning tornadic. This may coincide with the mature phase. They can turn on a boundary as well. The left member of a splitting supercell may also turn left.

Do not "chase" after (follow) a storm unless you have good roads, no towns, good visibility, and the storm speed is slow such as 15mph or less. Otherwise plan on staying ahead of (possibly at a slight angle to path) or wait in front of the supercell for it to come to you. For really fast moving storm systems you can't 'chase' them at all. You have to wait downstream and let the storm approach you. Of course if you get tired of waiting you can close the distance, but point being it is very difficult to catch up to a storm that has already passed you.

As others mentioned an HP tornadic position may be an occluded area closer to the forward flank. There may be no way to see the tornado unless you are directly in the storms path near the inflow notch.

As for distances from the storm / tornado...I'd say that entirely depends on your skill level, equipment, road options, conditions, the storm (including storm speed), and vehicle.

Here is a page that discusses some of this in an ok fashion:
http://spotterguides.us/advanced/advanced08.htm

 

[Robert Edmonds]

I have to agree stay in front of the direction of movement and to the south, generally. Usually you want to stay a few miles out in front of the storm so that you do not get over run when you come to a road network rough spot. Because like what someone else said it is very hard to catch up partly due to speed of the storm but I've found it will be hard to get the roads you want once it is in front of you. To remain in position you must also know the roads. Although I do not have the money for some really nice gps system with maps I found an alternative to help with this task. For 60$ you can get some nice road software. Load it into any crummy laptop, Velcro it to the dashboard. Every few minutes just re-center the map and this will really help with keeping track of where you are and where the roads are. This as far as I know the cheapest alternative and most logistical with out getting $$$. With paper maps I've found them not detailed enough and annoying when flipping & flapping around. Anyhow I’m sure that could be for another thread but it was just something to mention for staying in position.

 

[Mike Johnston]

Checking the mean storm vector in your target area - speed and direction - is a good thing to remember on a last minute checklist, along with putting rainex on the windshield, camera batteries, etc. A quick way to check out: the SPC mesoanalysis helicity maps show the mean storm motions for the latest analysis (based on observations, RUC forecast, etc.) - always subject to change when out on the storm, but at least it gives you a starting point to plan positioning.

[BTW: this is my first post after updating my new location. I've moved back to Virginia now. I'll probably spend time back in the Kansas City area next spring, at least during the heart of chase season. Hopefully will get at least a little taste of the tropical season back here this year!]