Winter Tornadoes, is 2012 another 2008?
With last nights and this mornings terrible news of yet another tornado outbreak. Combined with the tornadoes here in North Carolina and the outbreak early last week. The questions and comments are pouring in to me.
- Brad…. these winter tornadoes I’ve never heard of such a thing.
- Isn’t this extremely rare?
- Winter tornadoes aren’t supposed to happen…right?
Well yes and now is my first answer. While tornadoes are most common in the spring and summer months it’s not unheard of for large winter time outbreaks especially in La Nina years. Which like last year we under the influence again.
When I was doing my winter forecast this year which has bombed horribly thanks to the lack of a negative phase of the NAO/AO. (That’s a whole other blog in and of itself). The one thing I did nail was the late winter severe weather pattern and the comparisons to 2008. Like this year 2008 was an election year and like this year we have a very similar set-up going on.
So first things first, what’s normal or average compared to this year? Even with last nights tornadoes we aren’t that far ahead of average with still a week left in the month. I should note these are reported tornadoes or LSR reports the actually number always comes in lower once confirmation and assessments are done. Tornado reports are often doubled to tripled because of the same tornado being reported multiple times.
So how many tornadoes are normal in January and February? Since records have been kept here are all the tornadoes from 1950-2010
January tornadoes 1950-2010 1223 have occurred(confirmed) about 21 per year in Jan.
February Tornadoes 1950-2010 1441 have occurred, about 24 on average.
The other thing about winter to remember is wind shear is actually much high in the winter. You have stronger jet streams and deeper low pressure areas in the mid-latitudes. What you lack is the surface instability of the spring and summer, ie.. heat & moisture. This disconnect with the surface air keeps severe weather for happening….normally. Even in the biggest blizzards and nor’easters you have way more wind shear than a spring storm or dry-line set up in the southern plans. When you combine these strong jet streams and low pressure areas with surface based instability you get big problems. It doesn’t take much either just temperatures in the upper 50s to low 60s and dew points in the 50s and you have trouble. That’s exactly what happened in 2008 and last night.
You had similar tornado outbreaks like this year in January 2008 as well, but the worst was yet to come in February 2008.
The February 5-6, 2008 Super Tuesday Outbreak:
When people were focused on voting in the presidential primaries many never thought they’d see a horrendous tornado outbreak that killed 57 people. Before last years deadly outbreaks in Alabama, Mississippi, North Carolina and Missouri. This February 2008 outbreak was at the time unheard of for so many deaths with modern technology. Societal impacts played a huge role in the death toll. People just weren’t paying attention to the weather due to the primary and it being February. Also like most winter outbreaks these tornadoes occurred at night when people aren’t tuned into their sources of weather information. If you want to read more about this outbreak NOAA did a detailed post assessment. The PDF can be found by clicking here.
So there is some precedent for these types of outbreaks. What we learned from 2008 and from last years outbreaks was people need days of warnings. It may sound repetitive but repeated warnings given to people over the days leading up can raise awareness for when an actual tornado is on the ground. You should also know that many myths of tornadoes still persist and have been proven untrue the hard way. Tornadoes can and will strike any time of the year and in any place. Sure there are places that get more than others but it only takes one where you live to be devastating.
Let’s hope things turn cold and snowy fast because I don’t want tom see a repeat of 2008.
