Tornado in northwest Oklahoma on April 14, 2012. (Zachary Biggs via Flickr)
Meteorological spring is upon us, and it is time again to take a look at the spring tornado forecast. Are we going to see a repeat of the last two years with low tornado numbers? Or are we finally going to turn things around in 2015?
Not much is expected in the way of tornado activity through the first chunk of March. It’s early for much in most years anyway, but we do usually see an uptick as the month goes.
Looking at some of the teleconnection indices mentioned in the 2014 outlook and the 2013 outlook, it would seem that the near term would provide a shot or two for tornadoes. In this case, any activity is either too far north or too strung out to really get tornadic storms going.
Heading into the middle of March, the pattern looks mercilessly harsh for tornadoes, though maybe the West Coast could score a few tornadoes. After all, March is the peak climo month for tornadoes in California.
The pattern starts getting even more jumbled around once we hit the middle of March.
An +EPO/+WPO/+AO setup is expected around that time will be slightly more conducive to tornado potential.
This type of pattern generally supports troughs and digging storm systems in the western U.S. while warmer temperatures develop over an upper-level ridge in the eastern half of the country. However, it is still far from ideal. The core of the upper-level ridge of high pressure will likely be centered over the Great Lakes, which creates easterly/northeasterly flow across the Southeast. This type of low-level wind pattern struggles to tap into the Gulf moisture.
The El Niño-Southern Oscillation (ENSO) is not expected to be a major player in the overall pattern. It is anticipated to hold onto weak El Nino or fall into neutral positive territory.
Given that fact, I focus most of my forecast off of the strongly positive Pacific Decadal Oscillation (PDO), which has kept a persistent upper-level ridge over the western U.S. through most of the winter. While December was abnormally wet in the Southwest, January and February have been fairly dry. That’s generally not a good sign for getting tornadic storms in the U.S. The PDO will likely remain positive (perhaps strongly positive) through spring.
The ongoing drought conditions in the western U.S. helps promote a positive feedback of warmer and drier conditions across that region. A lot of the big tornado-producing storm systems move across the Southwest before ejecting into the Plains and eastern U.S. So, a tendency towards drier than normal conditions, with less disturbances in the Southwest, is expected to keep the tornado numbers down a bit.
The warmer and drier conditions in the Southwest helps keep the upper-level ridge over the western U.S., forcing many systems to drop down from the Northwest and western and Canada into the Plains. Not the best storm track for tornadoes.
We may be looking at another late season for more continual instances of tornado producing systems, unless we can get disturbances to cut underneath the prominent upper-level ridge in the western U.S. Of course, last year was relatively quiet early and still had several large killer tornadoes during that time.
My spring 2015 temperature and precipitation anomaly analogs:
The only notable caveat I would add to these analogs is I think the western U.S. will end up warmer and drier than the analogs indicate.
Bottom line…
I am expecting the tornado count for meteorological spring to be below normal again this year.
However, I do think we are in for a few good systems that move across the Southwest despite the drought and ridging. It probably won’t be enough to bring the tornado count up to near normal levels, but the season should still offer a handful of dangerous tornado days and probably some memorable periods for chasers as well.
Odds of the tornado count ending up below/near/above normal for meteorological spring:
Below normal: 50%
Near normal: 35%
Above normal: 15%
Long term forecasts, while generally providing added value to climatology, are still very broad-brush outlooks and do not offer a very consistent level of skill. This forecast only hopes to capture some of the most reliable information available to provide a best guess as to what spring may bring.
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Fun to hear your thoughts. One thing for sure - seems we are following a similar weather pattern as past 2 years which would make it reasonable to assume a repeat performance this year. However, "patterns" are subject to change at anytime and there are enough unforeseen variables that could dash the best predictions going forward. So we wait and hope for things to change to our liking. Maybe we will all be pleasantly surprised.
I live in Ohio, do you think we will still have a normal amount of thunderstorms this spring, regardless of tornados?!
Kyle,
Given the pattern I expect with storm systems dropping in from the northwest, in addition to the drier than normal conditions indicated by the analogs, I would lean towards lower than normal thunderstorm activity this spring.
Can you characterize how accurate your previous seasonal forecasts have been, using the same parameters as shown above?
David,
The 2014 forecast performed well, with a below normal tornado count in spring and a 50% chance that we would end up below normal (the highest of the three categories). The spring of 2013 was another below normal season, and I had a forecast for near normal numbers. That ended up incorrect, but I did think that there was more of a risk of it ending up quieter than normal vs. being more active than expected.
So the seasonal forecasts have gotten off to a decent start, with one accurate prediction and one "not accurate but not that bad" prediction. Since spring tornado forecasts are still in their early stages (both for this site and for anywhere, really), it is hard to determine how well these kinds of forecasts perform over the long term. However, this being my third year of making a seasonal tornado forecast, I'll have better confidence in the accuracy of such forecasts if this spring verifies as expected.
"Meteorological spring is upon us, and it is time again to take a look at the spring tornado forecast. Are we going to see a repeat of the last two years with low tornado numbers? Or are we finally going to turn things around in 2015?"
Turn things around ? TURN THINGS AROUND? You want Tornadoes to happen so you can get your adrenalin rush storm chasing? Real nice attitude with all he death and destruction caused by mother natures most fearsome phenomenon.. Stay classy dude..
Tornadoes are a natural part of the world. No one wishes they hit population. This is a site about tornadoes.. Obviously we think they are neat. ;)
I love these comments from people that don't get what it's like to enjoy tornadoes. We like what we like. It's nature. It's beautiful. We can't stop them. We wish all tornadoes formed in open fields and never did any damage. We despise death and destruction, but a tornado's going to do what a tornado's going to do. Deal with it.
"... with all he death and destruction caused by mother natures most fearsome phenomenon.."
That phenomenon is most certainly NOT tornadoes. We are all part of mother nature. I submit the carnage caused by people who condemn and demonize others for seeing things differently. Begins small with negative attitudes, lack of understanding, and leads to Syria, Somalia, Germany's death camps, Stalin, Mao. What were you saying about death and destruction?
Stay classy dude. Try to understand we don't love carnage. We love weather. Peace
How's montana looking for this spring/summer
Like this: http://upload.wikimedia.org/wikipedia/commons/c/c8/Montana_Relief_1.jpg
I live in northeast ill and was very pleased with 2014s thunderstorms ...had some tornadoes as well ..I'm understanding it will be a slow start this year...do u think late spring things will change for me?
http://www.accuweather.com/en/weather-news/accuweather-spring-forecast-2015/41636471
Also check out my page West Tennessee Storm Responders on fb.
I don't know if I do feel things right but I feelththis year the tornadoes are going to be more than what we get in a year. God knows I hope I'm wrong on how I feel about this year. I live in central Illinois but it also says I like in southern Illinois and east about 50 miles from In. and do you think it's going to be up or down in my part of Illinois.
With your expectation of drier conditions in the west and southwest would it be fair to assume that the dryline might move farther east than usual and be a factor in the Midwest when we finally get good moisture and dews coming up from the Gulf into a system?
Moving a dry line further east still keeps it in the Plains most of the time. I don't anticipate the typical dry line to be any further east than it was last year. To get a dry line in the Midwest, it typically has to be attached to a low pressure system, which is not a terribly common occurrence.
Mr. Ellinwood…We live on the gulf coast in MS. (Gulfport) What about the tornado activity here? this year? I realize God is in control but doing what you do you have a good idea?
Eddie
Hey Guys, you are so right.They are beautiful if they are in a field and not destroying people lives.I live in Arkansas and last April's Tornado changed people lives forever. I Pray we never see a day like that again. Be Safe out there. Timothy.
For some reason, I am a feeling a repeat of (or close to ) the 3/1966 Jxn weather event; not just that one in particular, but also a repeat of last year's event -for Hinds, Rankin, Madison, Scott, Smith and possibly Warren, Yazoo and Copiah counties. Seems like a repeating cycle. I'm just an amateur but there's something about the history details I keep going over.