May 012016

Sunday 1 May, 2016

It’s interesting being both a meteorologist and a storm chaser. I mean, the whole reason I ever wanted to pursue a degree in meteorology in the first place was driven by a passion for severe weather. It’s something that was always in my DNA, and triggered anytime I saw a thunderstorm as a kid. So I always knew I would end up studying weather in some capacity as an adult. And what drove that home was an intense fascination with tornadoes. As a young child, I remember my grandparents would talk about having tornado warnings from bad storms in Illinois. I never saw any pictures or video, so my imagination would go wild. It wasn’t until I was almost a teenager that I saw actual footage of a tornado from a TV special. I just wanted to see one myself. But rooted within that desire was also an interest in how tornadoes form.

Image above: Gust front on a supercell from April 29, 2003 in northwest Kansas near the Nebraska border. (Photo by Jim Bishop)

I spent years studying tornadoes while at the University of Oklahoma. And this wasn’t just in the classroom – I chose to independently (along with Simon Brewer and Tom Santillo) go storm chasing. And storm chasing back then wasn’t easy, and neither was forecasting! It’s funny to think what storm chasing and forecasting was like back then, and what little I knew then compared to what I know now. At any rate, throughout my college career, I learned how to apply my knowledge from the classroom into the field. I had become an experienced storm chaser, a forecaster and meteorologist.

But every spring there were always the same questions. When will the pattern become active? Is a death ridge going to develop and put an early end to the chase season? When will the Gulf moisture return to the southern plains? This is where climate science and meteorology begin to converge, and it’s an area of study I didn’t know I would get into. It really wasn’t a focus after graduating from OU. My focus was getting a job forecasting the weather, and going storm chasing in the spring.

I ended up in a career in the energy industry, where I’ve spent the last twelve years forecasting medium and long range weather patterns. I sorta fell backwards into a field of climate science mixed with all the short term, day to day weather forecasting you would expect from any degreed meteorologist. But it’s very interesting as a storm chaser to spend so much time studying and forecasting weather patterns, because it gives me the ability (at least to a degree) to forecast weather patterns conducive to producing tornadoes across the U.S.

Living in Boston, about as far away as you can get from the Great Plains while still living in the U.S., I have to take storm chasing trips to see tornadoes. There are two ways to go about this. The first way is the most obvious – plan a vacation. You pick the dates, request the time off of work, etc., and when the time comes you go storm chasing. The one major downside to that is you are 100% at the mercy of the prevailing weather pattern. If the patter is quiet, you’re out there making the best of it. The upside is you were probably able to make this vacation budget friendly.

The second way is more difficult to implement, and it’s called spot chasing. Basically, when you see a series of 2-3 good setups, go storm chasing. You end up paying a premium for a plane ticket, but you are not out there for that long and you are much more likely to see a tornado. Of course, if you are not familiar with the current state of the weather pattern, you might get suckered into going chasing by favorable looking setups on the computer models, only to see the setups look much less favorable as the event draws closer. So how do you about spot chasing?

Rozel Tornado
Image above: Jim Bishop shooting video of the Rozel, Kansas tornado on May 18, 2013. (Image by Simon Brewer)

I’ve found having an understanding of how the weather pattern is likely to evolve over the course of the month can be very useful in choosing when to go storm chasing. And it’s funny saying that now, because back in the early days of my storm chasing career, I was at the mercy of a single medium range computer model and the setups it would forecast over the next ten days or so. At the beginning of May, even if nothing looked favorable for severe storms for the next ten days, there was still plenty of hope being early in the chase season. It wasn’t until the calendar turned to early June that we would become concerned the season might be over soon if not much had happened yet. We were basically chasing in a day to day, week to week type of outlook with open wonder in the weeks beyond that.

At any rate, it’s just interesting to me that today I apply what I’ve learned while forecasting medium and even long term weather patterns (climate), to storm chasing. Every year by the early spring I find myself diagnosing the ocean-atmosphere system (El Nino, La Nina) for clues as to when the weather pattern will become active for storm chasing. And when you have an understanding of how the pattern should evolve or how it should act, you should be able to pick a good time to find tornadoes. Or at least, that’s the best I can do right now!

Image above: Two supercells off in the distance over southern Kansas on April 17, 2002.

So cutting to the chase (no pun intended), our current ocean-atmosphere system remains complex. I guess if it wasn’t, this blog post would have gone a different direction! But we still have El Nino forcing over the western Pacific, despite the fact that it does appear we will see the demise of El Nino later this month (there are numerous indications we will be in a La Nina this summer). Nevertheless, there are small atmospheric waves over the western Pacific, interfering with a new MJO (Madden-Julian Oscillation) signal over the Indian Ocean. This interference is one of the reasons why we keep getting cold fronts over the eastern U.S., closed upper lows over the Southwest to Plains, and why the pattern won’t be conducive for numerous severe storm setups (particularly tornadoes) over the next several days. We should see a significant closed upper low the weekend of May 7 over the plains, but low level moisture return will be a concern given the previously mentioned issues.

What I believe will occur, is the MJO will grow in intensity over the Indian Ocean over the next 10 days or so and progress slightly east. This usually sends a series of troughs into the southwestern U.S., and would promote a pattern conducive for severe storms and possibly tornadoes. But western/central Pacific tropical forcing (likely tied to the last gasp of El Nino as it fades) needs to go away. If that forcing weakens or dissipates (which is suggested by the European Weekly model), the warmer phases of the MJO will probably have more of an impact on the weather pattern and May 14 (ish) to May 25 (ish) should prove to be quite active for severe storms and tornadoes across the southern and central Great Plains of the U.S.


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