WINTER COME, WINTER GO
It is a topic of interest everywhere I go. On social networks like Twitter and Facebook, informed weather fans want to know. Even around the water cooler here at WSAZ the casual observer is asking. IS THIS ALL WINTER HAS TO OFFER?
So far most areas have recorded a few ground coverings of snow and most porch thermometers have barely managed to dip toward 10 or 12 degrees on a few occasions. The ponds where I live have only measured 1 inch of ice with the water around the fountain never freezing. Kids in my neighborhood have not been able to use their sleds and toboggans but boy are those Christmas bikes getting a workout!. Are these signs of an early spring? Will the snow and cold curse of the WSAZ Wrestling invitational be broken?
To help us to understand the motis operandi of long range forecasting and why I believe we will still garner our fair share of snow this winter, I am introducing you to the spaghetti plots we use in meterorology. Let’s have some fun.
Click on this link and do the following.
1. Identify 2 locations, say West Virginia and North Dakota (ND is in the dead middle of the maps).
2. Hit the slow down button on the left so the animation doesn’t seem like it is a train wreck about to happen.
3. Where you see blues and purples, the air is cold, the darker the colder. Where the greens, yellows and oranges reside, the air is warmer.
4. Allow the animation to recycle, then start counting…day 1,day 2, day 3….day 16
Note how over time (16 frames), the cold and warm air masses ebb and flow toward and away from our region, neither securing sole dominance. The cold air colors do stay locked in Canada while the warmer shades love to hug the Gulf and Florida.
Now think about it! When we hawk big winter storms armed with snow, ice and wind, we always seem to talk about the conflict of cold arctic air to the north and warm tropical air to the south. In the seam between the two air streams, big storms tend to form. And that my friend is where we are likely to reside in the next 6 weeks and if we are unlucky, all the way until April Fools Day!
If one thinks of the spaghetti plots as strands of spaghetti that wrap themselves around the globe, you can get a feel for the slinky nature of the atmosphere. The strings of spaghetti represent wind flow patterns around the globe. With each twist and turn, with each dip and rise, a new storm is born, some weak, some strong.
Now using a mathematical technique called smoothing, an ensemble mean adds all the strands of spaghetti together and averages it out to help us produce a credible forecast for the weather trends over the next 16 days and beyond. And that average mean spells a stormy back half of winter with our fair share of rain and high water, snow and cold and yes Binky at least one healthy ice storm.