Storm Chasing 101

As we go along I’ll attempt to highlight our route on maps on this blog to show where we end up on chase (or bust) days. But first of all, it may help those who were dozing at the back of the class during O level Geography to take a look at the states of the USA, and where “Tornado Alley” actually is:

The area highlighted in yellow is (roughly) the area where severe storms and tornadoes can occur at this time of year in the USA. The “Chase Season” (i.e. when storm chasers think its worth their while heading out and trying to track down severe storms) usually starts in April and lasts through to mid/late June. As a rule of thumb, the later in this period you chase, the further north the storms are likely to be. That is not to say that storms and tornadoes don’t occur outside this period – they can occur virtually at any time of year – for example, there was a big outbreak back in February this year. In early to mid May, the favoured states tend to be Texas, Okalahoma, and up into Kansas.

How will we know where to go to chase the storms? The $1m question! I think this side of chase planning falls into pre-chase day and on the day itself. Looking at computer forecast models and the SPC’s advanced warnings will give a good indication of the general area you will want to be in a couple of days beforehand. The night before you’ll pick a hotel to stay in that’s pretty much at the “bullseye” of your chosen area. On the day itself, you’ll study the latest real-time data (soundings, satellite, radar etc) and model predictions and see what adjustments to your position you want to make – unfortunately these can be long distances if your pre-chase-day analysis hasn’t quite come off! When you’re on the road on chase day you will constantly re-analyse this data and make use of Doppler radar, but also I think simply looking out of the window at what the sky is actually doing is also a very valuable tool!

You can’t be everywhere at the same time, so you’ll miss out on some storms simply because its just too far to relocate for the next day’s chasing. Some days the prognosis will just be too poor to warrant an 8 hour drive to chase congestus that’s capped to the hilt – but that’s what hotel pools and State Parks were invented for. Sometimes the prognosis looks good, and you make the 8 hour drive only to find diddly-squat. That’s what’s known as a Bust Day. Let’s hope we don’t get too many of those…