Apr 282013
 

Sunday, 28 April 2013

 

It must be a combination of a busy work schedule and a slow weather pattern. But whatever the actual reason, somehow time has just flown by and all of a sudden it’s almost May! It feels like just the other day I was writing a post about how my favorite month is actually April, since you still have the whole month of May in front of you. Now here we are and April is almost over.

I mention May with such gusto because it’s the climatological peak in the southern plains tornado season. And most storm chasers are well aware that there are usually good tornado setups during some part of May. That’s why every year hundreds to perhaps over a thousand storm chasers from across the U.S. and from around the world have been waiting for the month of May to begin. Of course the same number or more storm chasers wait until June to take their storm chasing vacation. But that’s the topic for another discussion.

So right now is the time when all the preparation is basically done. Storm chasers have their camera equipment, gps/maps, laptops and vehicles all set for storm chasing. Some plan their trips well in advance, and some wait until the weather pattern is favorable for significant severe weather events until taking their trip. Unfortunately for a lot chasers, especially the ones overseas, taking a chasing trip on the fly isn’t practical. Thus, many chasers have to kinda roll the dice and plan their trip out months in advance. And that’s why a lot of chasers from all over the world choose their storm chasing vacation during the month of May, because it is the climatological peak in the southern plains tornado season. Essentially, they are playing the odds.

So here we are. It’s only a few days before the start of May and the tornado season has been and continues to be very, very slow. Forecasts for the next several days don’t really bring much hope or excitement to the upcoming season. We had a very cold late winter that didn’t want to let go in March. Things quickly turned around in Mid April, but too much of mother nature’s grip from winter held on and the severe weather setups that unfolded had significant issues with both the CAP as well a bit too much cold front involvement. Basically, it just wasn’t meant to be.

Unfortunately, the weather pattern continues to be stubborn. We’ll call it the high latitude blocking ‘hangover effect’ from late winter, but whatever phrase or word you want to use, it just doesn’t want to let go. Not yet. Sorry, not today, and not anytime soon. It’s partly due to the MJO (Madden Julian Oscillation) returning to the wrong side of the northern hemisphere, coupled with a Pacific pattern that favors a ridge over western North America. Any systems that break through the ridge are forced under another blocking ridge over eastern Canada, bringing troughs to the Southeastern U.S. In essence, the pattern we are headed towards over the coming weeks does not look great for active severe weather events or tornadoes across the Great Plains of the U.S. It doesn’t mean nothing will happen, because the atmosphere — even in terrible chase patterns — almost always finds a way to produce supercells and at least a few tornadoes during the month of May. But it certainly appears that mother nature has other things on her mind for May besides tornadoes. Perhaps she’s more interested in drought recovery through heavy rain events instead of supercells and tornadoes? From that angle, things could be much worse.

So where do we go from here? I mean what usually happens when the peak month for tornadoes is, for lack of a better word, a dud? Well in some of the worst years on record the season never really picked up, it just sorta never got going. Sometimes a ridge just expands and summer sets in by June, and there are not many significant severe weather events during the season.

Ok, you can step away from the ledge and relax! Take a deep breath. This year doesn’t seem quite like that, at least not yet. It doesn’t look good, but we’re not to the point where we need to start waiving a white flag or anything like that. There is hope, and it has my full undivided attention.

I’ve been watching the sea surface temperature trends across the Pacific and have found some interesting similarities to recent years. While I don’t think this season is going to be good at all as whole, it’s far too early to write off as a complete dud. We may be headed towards a summer where El Nino tries to develop. Sometimes when this occurs the MJO steps up to the plate and brings a large extension to the Pacific jet stream all the way to North America. It doesn’t happen for very long and it only happens as a sorta transition from the spring to the summer pattern. But when it does occur, it can bring with it a period (a week or two) of significant severe weather outbreaks including tornadoes to the Great Plains and central U.S.

So don’t despair, don’t lose hope. May is upon us. Sure the weather pattern is depressing and forecasts for the next few weeks probably won’t look that encouraging. There will be setups that may not be ideal. But keep hope alive, stay positive. Mother nature is brewing the Pacific just right so that by late May or June, the jet stream will come roaring across the Pacific Ocean towards the west coast and chasers from around the world will get excited. They’ll be rejoicing because their patience has paid off and a series of severe weather events will be poised to unfold across the Great Plains. And they will say to themselves, “This is what I’ve been waiting for. This is what I live for.”

Until next time…

 

Jim

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