Will this be a good year for tornadoes

[Vicky Redwood]

I hope 2009 brings lots of isolated, well structured supercells with photogenic tornadoes for us all, there seemed to be lots of MCS and HP stuff in the period I chased this year. As last year and this year are La Nina episodes, it would be interesting to see how they measure up against each other - mind you every year is totally different....

 

[Chris Nuttall]

Some nice dryline storms in the TX panhandle sure would be nice this year. I think the panhandle has been void of its usual spring weather so hopefully it lights up this year, and if so, I plan on being there.

La Nina years generally lead to below normal tornado activity in the Texas Panhandle. They usually correspond to drought years. 2008 was a La Nina year, but with a lack of moisture for so long, cloud bases were generally pretty high. That's why we wound up with a lot of landspout activity last year.

 

[Chris Lott]

I see people saying this will be a La Nina year, and I'm reading things on the internet that we are going into an El Nino event. So which one is it?

 

[Jason Boggs]

Chris, I believe this is a La Nina year. If I were you, I wouldn't count on many storms in the TX panhandle this year. We haven't had any substantial moisture here in a long time. We've only had 6 tenths of an inch of snow all season along with very, very little rain. Hence, the dryline will move east very rapidly with daytime heating due to the shallow moisture layer. Central OK may be getting the "goods" this year. Now, if we get some moisture, things may change, but were still in a La Nina pattern which isn't good.

 

[rdale]

So which one is it?

I'll tell you at the end of the year

People need to realize that predicting LN or EN is -- a prediction. Two people can look at the data and come up with different predictions.

The NWS says.... drumroll please... La Nina.

http://www.cpc.ncep.noaa.gov/

You might read on the Internet of people that predict El Nino though.

 

[Chad Cowan]

I see people saying this will be a La Nina year, and I'm reading things on the internet that we are going into an El Nino event. So which one is it?

See this ENSO analysis and forecast .pdf by the CPC issued a few days ago: http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/lanina/enso_evolution-status-fcsts-web.pdf

Slide 8 shows La Nina patterns strengthening over the last month.

Outlook: Nearly all ENSO forecasts indicate below-average SSTs in the central equatorial Pacific through Northern Hemisphere Summer 2009. Many models suggest La Niña conditions through April 2009.

2009The CFS ensemble mean (heavy blue line) indicates La Niña conditions through mid-2009.

•Atmospheric and oceanic conditions reflect La Niña.
•Recently, negative equatorial SST anomalies have strengthened across portions of the central and eastern Pacific Ocean.
•Based on recent trends in the observations and model forecasts,La Niña conditions are likely through early 2009.

A couple other sources forecasting a weak-moderate La Nina through the Spring:

EDIT: To add my opinion, as I have stated in similar previous threads, I believe El Nino and La Nina have more of an impact on the geographical concentration of tornadoes than the frequency. This is due to the impact of SSTs on the positioning of the subtropical and polar jet streams. A typical La Nina pattern features a weaker subtropical jet further north than normal, while a typical El Nino pattern features a polar jet further south. There may indeed be a correlation between SSTs and tornado numbers, but with only a few cycles of solid numbers to work with there is too much uncertainty in ascribing El Nino or La Nina as the bigger tornado producer.

This is a mashup I made last year of the SST anomalies and tornado numbers. La Nina is blue (top for some reason) and El Nino is red. As we are forecast to move from a strong La Nina to weak/neutral, I went back and marked these areas where we made a similar transition in the past. It should be noted, however, that the tornado numbers from over twenty years ago are not nearly as accurate as today's numbers. When looking at the 1950's-80's tornado numbers in this graph I only make a comparison to the years around it, as they should have similar tornado/reports ratios.

Higher-res: http://img210.imageshack.us/img210/3356/enso1st4.jpg

 

[Greg McLaughlin]

It is impossible to accurately say whether or not this is going to be a good tornado year. It is always nice when you get a longwave trough to hang up over the western US in the late spring spitting out disturbances day after day over a broad warm sector. That is something I hope for every spring. Even if we get a below normal year as far as tornado numbers go, it only takes one good day, one slow moving cyclic supercell to make for a great year.

 

[Chris Lott]

Chris, I believe this is a La Nina year. If I were you, I wouldn't count on many storms in the TX panhandle this year. We haven't had any substantial moisture here in a long time. We've only had 6 tenths of an inch of snow all season along with very, very little rain. Hence, the dryline will move east very rapidly with daytime heating due to the shallow moisture layer. Central OK may be getting the "goods" this year. Now, if we get some moisture, things may change, but were still in a La Nina pattern which isn't good.

Hey, I'll take the La Nina event then. We seemed to have some pretty good severe weather events closer to my area last year, a little more than normal anyway. A lot of them were hail events but I will take what I can get. I might have to settle for Oklahoma instead.

 

[STurner]

I dont know much about La Nina's but how do they play a role on how good a tornado year might be. On average how often do La Nina's occur. It seems that a lot of things play into factor on how good a tornado year might be. Could an La Nina year also be good for like September-November tornado outbreaks? An example would be like Crosstown, Missouri, Nappanee, Indiana, Evansville, Indiana, and Madisonville, Kentucky. Is it even reasonable to say that EF5 tornadoes could occur during the months of September-November for there have been several tornadoes rated F4 on the old fujita scale.