Loaded Gun Storm Chasing
website of storm chaser Mikey Gribble
This page is meant to be educational and will have a wide variety of tools, information and insights to storm
chasing and forecasting. Any feedback would be appreciated. Just go to the
Contact Me page or email me at
I just got these Help Pages started, so
there really isn't much on them yet. To
see what I have done so far scroll down
the list of links until you get to the
"Help Pages" section. I will work on
them when I have time and eventually I
would like for it to be kind of an
overview on the topics that gives advice
and rules of thumb. I'm basically writing
down my notes and some of the things
I've learned over the years. If anybody
has any feedback or suggestions I
would be glad to hear it. Just go to the
contact me page or email me at  
About Chasing
New Help Pages
I have had a lot of people ask me if chasing is anything like the movie Twister and the answer is no. 98% of
chasing is forecasting, driving, and seeing a whole lot of nothing.

these computers take initial atmospheric conditions, run thousands of equations, and produce atmospheric
these computers take initial atmospheric conditions, run thousands of equations, and produce atmospheric
conditions for later dates. There are several different models, but for forecasting severe weather in the plains I
primarily rely on the NAM, GFS, and RUC. I'll use other models too though, just not as much.
primarily rely on the NAM, GFS, and RUC. I'll use other models too though, just not as much.

For a typical spring tornado outbreak, the forecasting process will start about a week out. Synoptic scale (large
scale) forecasting is the primary focus at this point. What kind of airmass is over the Gulf of Mexico, is the
moisture fetch going to be adequate, what kind of tilt does the trough have, are the wind fields such that you
will have good directional shear, etc. As the chase day approaches and you get two or three days out you
begin to focus in on mesoscale (smaller scale) details and start to consider targets for your chase. What will be
the focusing boundaries for convection (warm front, cold front, dryline), where are these boundaries going to
be located when convection is anticipated, what convective mode is favored at each area of anticipated
convection, and so on until you narrow down the range of possible targets. Then on the last twenty four hours
leading up to an event you focus in on mesoscale features that could locally enhance the tornado potential,
such as outflow boundaries, mesolows, anomalies in the wind fields, and countless other slight differences
between different locations. Some time in the last day you pick a target. Basically you work on your forecast
daily and zoom in closer and closer on a target area as the chase day approaches. Of course there are
exceptions and this isn't always the way it works. Some times you know where you want to chase three days
out. The triple point may be the obvious target if the cap is going to be an issue. A warm front or surface low
may be the obvious target if it is the only location with sufficient low-level shear for tornadoes due to backed
surface winds. There are a million different scenarios and every chase is unique.

There is an art to targeting, especially in the earlier part of the season. The jet stream is stronger during the
winter than it is in the summer. As a result, the earlier months of storm season have stronger wind fields and
storm motions are much faster as a result (storms pretty much move at the mean wind speed throughout the
layer they are located in). Forecasted storm motions are a huge part of picking a target  early in the season.
When storm motions are going to be >40kts, you need to setup down stream of where storms are going to
fire. When there is going to be fast storm motions I like to setup about 30-40 miles ahead of where I expect a
storm to form. That way the storm has a chance to mature before it gets to me and is hopefully going tornadic
about the time I get on it. Storms typically take at least an hour to mature and they don't start to put down
tornadoes until they have matured. There are exceptions. The fastest I have ever seen a storm tornado was
the Hallam, Nebraska storm in 2004. It produced the largest tornado ever recorded (a 2.5 mile wide F4). That
storm tornadoed about 30 minutes after it showed up on radar. That is fast.  Anyways, the reason for setting
up ahead of where storms will form on fast storm motion days is because when a storm moves that fast you
can't keep up with it for long. If you get on a storm right after if forms (like you would with slower storm
motions) the storm will outrun you and you will loose it before it goes tornadic. Lots of chasers make this
mistake. I know I have several times. A storm may only be moving at 40kts, but that is as the crow flies, which
means you need to maintain an average speed of 60kts if you are driving on square mile grid roads, which is
usually the case in the plains. It is very stressful and difficult to keep up with fast moving storms and you need
to pick a target that is going to allow you to maximize your residence time on the storm during the most
optimal time for tornadogenesis.

Next comes the driving. I like to get to my target at least two or three hours before I expect storms to fire,
but this doesn't always happen. I am late a lot more often than I care to admit. I like to be at my target early
so that I can do last minute forecasting, which usually takes at least an hour, then fine tune my target and
move if necessary. You need that extra time to allow for flexibility in targeting. It is nothing to move a hundred
miles one way or another after you reach your original target. Storm chasers drive extreme distances to see
tornadoes. Most chases for me average over 600 miles.

Finally comes the storm. In twister they pretty much skip everything up to this point. In the movie they watch
radar and then haul ass after a storm when a hook echo forms. It doesn't work that way in real life. You have
to be there before it happens. That is why forecasting is so critical to being a good chaser. If you chase
warnings you are going to be too late the vast majority of the time.

Once I'm on a storm I like to position myself straight East of the updraft base, which is where tornadoes form.
Typically the storm is moving NE or E. This gives me the ability to put myself in front of the tornado when it is
forming so that I can get good up close video of the tornado as it approaches me. I typically stay about a mile
ahead of where a tornado would form and move in closer when I start to see rapid vertical motion and rotation,
which usually proceeds a tornado.
Very rarely do chasers get as close to tornadoes as they do in Twister. I like to get closer than most, but I still
have my limits. I will not put myself directly in front of a violent tornado (EF 4-5). If you do put yourself directly
in the path of a major tornado like that then you are in very serious trouble if your car gets stuck or breaks
down. Roads are usually muddy because the precipitation part of the storm has already passed through and
that needs to be considered. You can outrun a tornado, but not if the roads are in bad shape. The closest I like
to get to stronger tornadoes is about a quarter to a half mile away. In twister they get closer than that and
they do it on a regular basis. I don't think you would last long if you chased that way.

And finally, with all the forecasting, driving, and busts (days where you don't get a tornado) there is a whole lot
more boring times than exciting ones. You don't see nearly as many tornadoes as they show in the movie. I
like to think that I am a fairly good chaser and over the course of a season (April, May, and June) I consider
myself lucky if I see twenty plus tornadoes.  I probably go on about 20-30 chases each year and drive about
20,000 miles. Early in the year, March and April, I will typically see a tornado on about 20-25% of the chases I
go on. In the peak of the season I get a tornado about 50-75% of the time. And then towards the end of the
season the percentage drops back down to 20-25%. Personally I think it is pretty damn good if you are hitting
about 50% of the time during peak season. Tornadoes are extremely rare and difficult to predict. You have to
earn them. I didn't get a tornado in my first two years of chasing and that mostly had to do with me not
knowing how to forecast. There is a huge learning curve with chasing if you are doing it on your own. It is a lot
of fun, but you have to work hard at it to be successful on a regular basis.
Q: Is storm chasing like the movie Twister?
troposphere and a sounding is the end result.
troposphere and a sounding is the end result.

A loaded gun sounding is a slang term for a sounding that is typical on tornado outbreak days in the plains.
With a loaded gun sounding there is extreme instability ready to be released, but it is being suppressed by a
cap. A cap is a temperature inversion in the atmosphere that works like a lid on boiling water. It allows
instability to build and build until finally it breaks the cap. When  this happens explosive storms are usually the
result and with the right conditions in place tornadic supercells will form.
Q: What is "loaded gun" supposed to mean?