Another Winter Forecast Ingredient
Don’t forget our 2012-13 Winter Forecast is slated for Tuesday Night during FOX 4 News @ 9PM.
We do our forecasts a little different compared to other local TV Winter Forecasts. We look at this more as a team effort. We all make our predictions/guesses individually then we average ALL of them together to form our FINAL Winter Forecast. That snowfall forecast and lowest temperature is what we run with.
Last year, as I’ve talked about numerous times before, was just awful. I think I predicted something like 27″ of snow or close to it. We all went on the higher side and well we had a record low total of 3.9″! Needless to say not good. In our defense, as I talked about before, we were asked to do the forecast a day or two after Halloween. Way too early, and by late November we could already start to see how that original forecast was going to be too high. We then reissued our forecast on the 1st day of winter and brought those numbers way down. I think to about 15-16″. Still though way too high but at least we got the trends a bit better.
Not sure if that will be needed again or not this forecast year but if so, I’m sure we’ll look at that potential in about a month or so.
I’ve talked about the NAO aspect of the forecast, and last week I talked about the US/Canadian snowcover aspect of the forecast. In that vein I want to expand the snowcover discussion and cover more geography by taking a look at the Eurasian snowcover situation. There is some correlation between increased fall season snowcover in that part of the world and a tendency for more cold air to be a factor in our part of the world. It’s not a 100% correlation, but it’s something that, I think, at least bears some watching. So let’s look at the month that we finished and compare to last year and then the year before (record little snow [2011-12] and well above average snow [2009-10]) This data is from Rutgers University.
First lets look at October 2012. It’s important to look for the BLUISH shadings as that indicates above average amounts of snowcover.
Now let’s go back to last October (2011) leading up to our lowest snow total winter and also one of the warmest.
Notice on the image above all the brownish colors…indicating BELOW average amounts of snowfall. Now let’s go back to October 2010…again the blues make an better appearance (increased cold/snow for us).
OK just for the heck of it, we know that 2009-2010 was a crazy snow season (44″+). Here is a look at the October 2009 snow trends for that part of the world.
Again a LOT of blue colors.
Just so I’m clear here, all this extra snow per say, doesn’t mean it’s going to be snowy here, what it does indicate though is the better potential for building cold airmasses up towards N Canada and across the Pole area. This bitterly cold air usually finds a way down towards the USA in some form. When certain other factors are involved, i.e. more atmospheric blocking etc, that cold air can be delivered towards our area. So in a nutshel, IF there is more snowcover up there, it makes sense that we have the potential to be colder down here as opposed to a lack of snowcover up there. Hopefully that makes sense.
So what can we take from the current situation? Well there was definitely more snow up there and as a result, more snowcover. Now that the nights are so long and the daylight is so little towards the Northern Territories, that snow melts less and less and the coverage of the snow increases more and more. The airmasses have a better chance of getting growing colder.
So let’s wrap this up…I talked last week about how the atmosphere has tended to be more “blocked up” this fall. The NAO index has been mostly negative since July. This index plays a bigger role in Winter forecasting than in Summer forecasting. Last week I also talked about how the snowcover was higher for the US/Canadian areas compared to last season. Today I talked about how the Eurasian snowcover is also above average compared to last season. That’s now 3 things that I look towards to create my winter guess. The 4th item is something called the Arctic Oscillation or AO for short. This is another parameter that in conjunction with the NAO can lead to more turbulent and cold weather for parts of the USA. I will blog about that tomorrow. Also there is another wildcard to my winter forecast thoughts and that would be the ongoing drought. When you are in a drought it can be VERY difficult to break as we’ve seen. We’ve had two good rainmakers in the last 2+ months and very little in between. The summer and most of last Spring was miserable for precipitation and with dry weather expected till at least near the end of the month, the drought will persist for awhile at least. Yesterday the GFS gave us 1/10th over the course of 16 total days. The early AM run this morning gives us about 4/10″ in the same time span. So again no real drought relief and my concern in forecasting a lot of snow/precipitation this winter is the ongoing drought.
So we’ve got not a total of 5 ingredients into my winter forecast thoughts (so far). Over the last few years however most of these ingredients have led me into making some really bad guesses as far as the upcoming winter snowfall amounts. That’s why, in my opinion there is little to no skill in these forecasts. I think if another ingredient is added into the mixture the skill levels would be better and that would be the potential for a tremendous strong La Nina (cooling) or El Nino (warming of the equatorial Pacific waters). There are strong correlations in what those aspects bring to the winter season but alas, this season will be a “La Nada” winter where there is not really an influence from the Equatorial Pacific water anomalies.
More on these thoughts in tomorrow’s weather blog.