Record low tornadoes

As 2012 comes to a close, this will likely go down as a year with some of the fewest tornadoes on record. This can closely be tied to the drought that has been ongoing for a few years in Kansas and a stubborn high pressure system that was difficult to move for most of the summer.

It can be hard to pin down an exact number of tornadoes, but as a rough estimate, there have been just over 800 tornadoes through the end of September. Official tornado numbers for October, November, and December have not been released yet, but even when those numbers come out, we will likely still have a low number of tornadoes. Last year, there were 1700 tornadoes and a significant death toll too, just over 500 fatalities around the nation. The Joplin tornado alone had a significant loss of life, with over 150 people killed by the EF-5 tornado.

In Kansas, we average about 60-70 tornadoes a year, and across the nation, the average is closer to 1200. One important contribution to thunderstorms and thus tornadoes, is moisture. In a year that has had very little subsoil moisture and little rainfall, it is not a huge surprise the number is down significantly.

Mobile, AL tornado from Christmas Day

The outbreak of severe weather on Christmas Day in the southeast US will go down in history as the largest on record. It's not unheard of to have tornadoes in December, but because the air over much of the US is colder, they are not as frequent as in the spring and summer months.

Winter Forecast 2012-2013

If you are interested in what the winter may have in store for Kansas, you've come to the right place. After weeks of studying the weather pattern and gathering as much information as possible, I've come up with a forecast that will make some happy and others disappointed.

Last year was almost a year without winter as much of Kansas had very little snowfall. Wichita would normally get 15 inches of snow in a winter season, while western Kansas would expect amounts much higher. Goodland, for example, averages close to 40 inches in a winter season.

Two of the factors that were considered in the forecast is El Nino/La Nina and the Arctic Oscillation. The last two winters have been influenced by La Nina, which is unusually cool water along the equator in the Pacific. La Nina has contributed to the drought over the last few years too, but it has finally diminished. El Nino is the opposite of La Nina, when the water temperatures are warmer than normal along the equator. We had anticipated El Nino coming back for the winter season, but it has not developed yet, so this will be a neutral winter (no El Nino and no La Nina)

The other factor I looked at closely is the Arctic Oscillation. It is an index that shows when cold air will dislodge from Arctic region and move south. When the number is negative, it is more likely cold air will move south. Positive numbers represent a pattern that will favor the colder air to stay farther north. The winter of 2010-2011 was a snowy and cold winter, when the Arctic Oscillation numbers were dropping to -4 or -5. Last winter, the numbers were as high as 4 and 5, so it turned out to be a very mild winter. This year, I expect we will have several fluctuations, but in this map here, notice has the red lines are dipping back below 0, which will indicate colder weather for the last week of November and into December. Between Nov. 1 and Nov. 16, the numbers are positive, which correlates nicely with our unseasonably warm weather we've had so far in November.

I expect the dominant pattern this winter will be northwest flow in the upper atmosphere, which will favor cool and dry weather for the central US. With this setup, we'll have a series of cold fronts coming through, but moisture will be lacking and therefore, not much snow when the pattern sets up like the one you see below.

There will be cases of the pattern buckling to the southwest, and that's when the weather should be more exciting around the central US. Moisture from the Gulf of Mexico is more likely to return to Kansas when a storm develops in the southwest. Our chances for rain and snow will dramatically increase when we see this type of setup, but I call it a secondary pattern because I don't think it will happen that often this winter. We'll probably see it at least 3 times, and that's when we can hope for some drought relief.

So putting this altogether, here's what I've come up with. If I had to make a prediction on snowfall for Wichita, I'd say between 5-10 inches for the season, which is below normal, but more than last winter. Expect warm stretches this winter too, that could be 2 weeks in length. Highs in that time could be in the 60s. But there will be, when the Arctic Oscillation goes negative, cold weather showing up in Kansas, with highs in the 30s. Unfortunately, the drought will persist into spring of 2013. The drought has been so bad and intense that it will take a long time for us to climb out of this dry situation we are in, so maybe spring rains will help, but winter moisture just won't be enough.

You can also view our story on KWCH: http://www.kwch.com/news-ckt-winter-track-what-to-expect-this-winter-20121120,0,2147850.story

We will all know the answer by March or April of 2013, right? All of us can agree... bring on the moisture!!

Pressure & the Northeast Storm

We reference it in every weathercast we do, but barometric pressure is sometimes a hard thing to understand. The pressure reading really refers to the weight of the atmosphere above us, and we measure it with a barometer to see if it's going up or down. When a storm is approaching, the pressure goes down (hence, "low" pressure). Just because the pressure goes down, it doesn't necessarily mean rain or snow will soon follow, but it does give you an idea that something could be changing soon. Higher pressure is generally associated with calm weather because the air is sinking and exerting more force down toward the ground.

Watching the fluctuation in pressure with Sandy has been interesting, and once it comes on shore, it will have one of the lowest pressure readings and cause significant flooding and storm surge. Consider for a moment that most people sensitive to changes in the weather will notice the pressure when it drops to around 29.70". Sandy, even as a category 1 hurricane, has had pressure readings down around 28.00", but because it is merging with another system over the US, the pressure will likely drop to around 27.90 before it begins coming back up (or the storm starts weakening)

It's a big deal because so many people will be hit by the storm and power outages will be widespread. It could be several days before things get back to normal, even after the storm is long gone.