Bill's 6th Annual Winter Outlook for Johnson County

Issued Oct. 9, 2009

Winter ‘09-’10: "A Harsh, Snowy Winter On The Way"

Well it’s that time of year again.  The days are growing shorter, the leaves are beginning to put on “their show,” and temperatures are growing cooler.  Perhaps it’s a combination of the three, or more so the latter, but for whatever reason, it’s always this time of year that wondering minds really begin to think ahead to the wintry months just around the corner, and just how much snow they may deliver. 

Folks that are regulars to the site know that I’ve been dropping hints for the past few months regarding just how cold and snowy I think this upcoming winter will be.  We have three main drivers in this year’s winter, and they are as follows. 

1. Fading weak El Nino
2. High Latitude Blocking
3. Low Sun Spot Activity

Now of course there are several other factors that will lead to what I think is going to be one of the colder and snowier winters in quite some time, but for the purpose of this year’s winter forecast, I want to concentrate on the “big three.”

Fading Weak El Nino:  We’ve officially been in an El Nino since the summer (and to be honest, since late last spring).  This has already lead to a wetter than normal summer and early fall season.  What should continue into the winter is a more active than normal southern stream of the jet.  However, unlike with stronger El Ninos, a weak El Nino like the one we’re currently in will not flood the country with warmer than normal Pacific air.  In addition, I expect the signal to be neutral by the time we’re getting ready to pull out of this winter, and weak fading El Ninos are notorious for producing big time first class winter events late in the season.  This is something we’ll have to keep a close eye on.

High Latitude Blocking:  I’ve shown several graphics over the past few months hinting at the coming colder than normal winter.  One of the primary factors in what appears to be a moderately to significantly colder than normal winter season is the increased amount of high latitude blocking.  This will keep strong high pressure over Canada, forcing the coldest of the air (relative to the means) south, into the Lower 48.  In addition, as we progress into the latter half of the winter season, I anticipate ridging to develop out in the West, which will promote more in the way of “troughiness” here in the East.

Low Sun Spot Activity:  This is something we mentioned back in our Summer Outlook, and it’s something still relatively new in terms of how it impacts the immediate region, but it is something I’m finding myself researching more and more.  The very low sunspot activity should coordinate directly with the cooler temperature pattern we’ve seen not just here across our great country, but all over the globe for that matter.  Admittedly, this is something I’m still doing great research over, but it has caught my attention for the cooler temperature pattern that has developed in widespread fashion over the past few years.  In fact, last March we reached an 11 year low for sun spot activity.

The Numbers Please…55 inches of snow in Mountain City (nearly 200% of normal when compared to the average of 30 inches).  Now, this is from first flake to last flake, not just the meteorological winter months of Dec., Jan., and Feb.  Keep in mind that “prime” upslope regions typically see higher snowfall amounts while extreme southern areas of the county, such as Butler, typically see lower snowfall amounts.

Temperatures that end up 2 degrees colder than normal for the meteorological winter months of Dec., Jan., and Feb.

*Special thanks to http://www.cpc.noaa.gov/products/people/wwang/cfs_verif/verif.html for the graphics.

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