The Winter Outlook
November 19th, 2008, 5:03 pm · 20 Comments · posted by dglenn
The early chill of November may have many of you wondering what is in store for the upcoming winter. Well, I have been wondering about that over the past few weeks as well working on my winter forecast. This is something that I enjoy doing. As a Tennessee valley native, I am always wondering if we will see snow and just how cold it might be. Long range forecasts are always going to have its flaws, but as I learned in climatology courses we look to the past to look to the future.
So, I have compared data from 2008 so far to other years with similar patterns. I can then look at similar winter patterns or “analogs”. These analog years can give you an idea of how other past winters have played out. Keep in mind that no 2 winters are the same. And, even if all of the past winters have a similar pattern, if doesn’t mean that the next winter will follow the same pattern. So, you can see the challenge and understand that the skill level involved is still in its infancy. But, I like a challenge, so here is my take on what we might expect for the winter.
Watch the Video, or read the Text version below:
Let’s start with 2 other outlooks that have already been released. The NOAA December through February outlook for the Tennessee Valley continues the trend of slightly above normal temperatures and possibly near normal precipitation. Here is a link to that NOAA Outlook. The 2009 Old Farmers Almanac is projecting a wetter and cooler than normal winter for the Tennessee Valley. Click here for the Almamac’s web site. So, we have 2 totally different views of the season ahead. The Almanac uses a secret formula, but is loosely linked to the solar cycle and sunspot activity which does have a degree of accuracy for seasonal trends. The NOAA outlook is based on the influence of the La Nina or El Nino patterns. NOAA is projecting a neutral pattern where neither the La Nina or El Nino has a major influence. Typically, a neutral pattern tends to lead to slightly milder than normal conditions. The solar cycle/sunspot activity has been something that has to be looked at carefully. We are experiencing a prolonged period of minimal sunspot activity, which in the past has led to colder than average conditions.
My forecast based on looking at past seasons can be summed up in one word….Average. I am projecting a winter that might exhibit average temperatures and average precipitation. Keep in mind, that an average winter will be cooler than the past few winters that have been above normal. I see the chance for some prolonged periods of very cold conditions only to be countered by upswings in temperature to follow.
Past winter patterns or analogs to this past year suggest that rainfall might be near normal to above normal. However, none of these analogs were during a drought, so I am little cautious with my forecast and am keeping the rainfall outlook to near normal (hoping it goes above). Past patterns also suggest that the local snowfall potential should be about normal and I will go with that as well. Locally, we average 4.8 inches of snow per year. That amount has come down during the past 10 years from 5.0 inches. So, I do believe that there will be some snow potential. And, as it often goes, there are usually 2 snow events in the mountains for every 1 event in the valley. That ratio should continue this year. Past similar patterns have yielded 2-3 small events in the valley, and that looks sufficient in my forecast for this winter.
As with any season, the threat of an ice storm always lingers. Snow can be fun, but ice is not. 2 of our most devastating ice storms occurred during the winters of 1960 and 1973. With the chance that rainfall might be a little higher this winter, I am concerned about our chances for having an ice event.
So, there you have it! Only time will tell what will transpire this winter. You can always depend on the Storm Track 9 Team to keep you updated on any winter weather situations which might develop.
David Glenn
Storm Track 9 Chief Meteorologist
November 22nd, 2008 at 11:21 pm
we had 20 inches of snow in chattanooga TN 1993 the largest snow
20 inches with 1 storm
and it was in the 70s the week before it came lol
what are the chances of that
November 23rd, 2008 at 8:54 pm
Hi David,
Oh yes….I remember the 93 storm very well. I was here for that one and I remember that week as well being very warm and some folks calling me crazy for predicting snow after such a warm week….As for whether it will ever happen again, anything is possible on any given year. There is just no way to see this far out as to what will happen.
David
November 24th, 2008 at 5:39 pm
Hey David I know this is all hype at this point but I noticed earlier that the GFS model showed the possibility of snow for us and the Carolinas the first week of December. I know this is really far out but what are your thoughts about that?
November 24th, 2008 at 5:57 pm
Hi Matt,
The GFS has tried to stir up some systems in the long range for about a week now. I do not put much weight on computer model data past 84 hours or so. But, we are at the time of year where we have to carefully watch these systems for any “tricky” situations. I will be posting here on the blog when and if some threats develop.
Thanks for reading and for your input!
David
November 24th, 2008 at 6:51 pm
One thing is for sure though…we have one heck of a cold shot coming down South just beyond a week from now (around 10 days)…Looks like the entire arctic (literally) is getting prepared to plow on Southward. Perhaps highs near freezing (valley) with twenties for mountains? Yikes! Lows will be mighty chilly too…
I have liked some of the storms the GFS has been showing, but as you said, it’s always impossible to know that far out…and with colder weather, it’s harder to get the moisture. But we shall see! Fingers crossed…we have a snow drought, so I’m ready for us to get caught up.
November 24th, 2008 at 6:55 pm
BTW: did you see the NAO teleconnections forecast? Holy cow! Talk about an insane amount of blocking! Makes sense with the cold shot coming soon.
November 24th, 2008 at 9:12 pm
Hey Jordan,
I enjoy analyzing and using teleconnections especially in longer term patterns as opposed to the model data. Yeah, keep and eye on the polar jet and those blocks can lead to a pattern lock that can persist for long periods.
David
November 24th, 2008 at 9:47 pm
“tanking” might be a good word to describe the NAO projection. We shall see……..!
David
November 24th, 2008 at 10:36 pm
I hope we have an encyclopedia definition of a snow storm this winter .
November 24th, 2008 at 11:00 pm
David you also worked at WRCB in the 1990s ???
I forgot that was you on WRCB
I found a very old VHS tape and you are on Wrcb forcasting the weather in the early 1990s .
brings back old memories
November 24th, 2008 at 11:07 pm
Hi David,
I was at WRCB from 1991-1998 as weekend and morning meteorologist. I then served as Chief Met. at WPMI in Pensacola/Mobile from 1998-2006. I have been here are WTVC since late 2006. I actually started my career here at WTVC. I was a weather watcher in the 1980s and interned here in 1990-91. I am a native, so I love living here!!!!
I bet that VHS tape shows me with far fewer gray hairs on my head
David
November 24th, 2008 at 11:43 pm
Thanks for the input guys. I am getting the feeling this winter may be far more interesting than those in the past. We now have to sit back and pay the waiting game. Please let me know of any updates! Thanks!
November 25th, 2008 at 5:54 pm
Good observations by all! You can see why I am forecasting a winter that might be cooler than the past few winters. It should be fun as always, with some forecast challenges!
I will say this about the GFS. Long range daily forecasts (days 7-16) tend to be less reliable. But, the model may be “seeing” something in the long range “trend”. So, sometimes you have to look away from the fine details and look at the broader picture with the long range output.
David Glenn
November 25th, 2008 at 10:14 pm
Good point David the GFS even seems to be backing off of its trend of showing anything interesting. The Texas panhandle might be in for some fun and games in another week or so. However, it does seem pretty obvious that we are going to get an artic shot sometime in early December and the question then becomes will there be any moisture to work with? Some models are showing a second gulf low developing while there is some very cold air in place. This is again like I stated last night really far out and completely unreliable. Just something to keep an eye on for you snow lovers out there. All we can do is hope something comes together for us. There sure are a lot of variables!
November 26th, 2008 at 1:51 am
*arctic
November 26th, 2008 at 1:09 pm
I check the 7 day forecast every 50 minutes to see if it changes.
I wish i could go back to the 1990s and enjoy those storms more than I did.
I figured that we would keep on having snows every other year .
we had a number of storms in the 90s .
Blizzard in 1993 has its own category tho and will be always known as the KING of snow storms in chattnooga .
Its those snows in late or mid 1990s and the ice storms we had in the 1990s I also miss .
November 26th, 2008 at 1:13 pm
I know its just my Perception.
The 1990s winters to me was more fun than from the year 2000 - 2008.
lol maybe im wrong but the last 4 years for sure has not been fun for winter around chattanooga.
November 27th, 2008 at 9:35 pm
Hi David,
First let me thank you for hepling us with the MDA telethon.
what is the chances of us having a big snow and what month & day was the ice storm in 1973.
Thanks
Jon
November 27th, 2008 at 11:24 pm
Thanks Jon!!!
No way to tell if or when a big snow could occur during the season, only time will tell.
The 1973 Ice Storm happened on January 7-8 of that year.
David
November 30th, 2008 at 11:58 am
Thank you David. The reason I was asking i was born on March 1 ‘73