Walker's Winter Outlook 2012-2013
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Transcript of Walker's Winter Outlook 2012-2013
This year’s winter outlook once again took many hours of research and many factors were
considered. Unlike last year when we had a La Nina in the Pacific Ocean, this year we will have a
weak to very weak El Nino. Here's just a small part of the items I considered this year and how I think
they will play out with our winter of 2012-2013.
El Nino: When looking at the El Nino, you must look at how strong it is, when will it peak, how fast
will it fade and where in the Pacific Ocean is it strongest. This year's El Nino is forecast to be weak to
neutral. Here's a chart of the forecast of the El Nino and as you can see it is forecast to stay weak at
best.
Pacific Decadal Oscillation ( PDO ): I'm a firm believer in the Pacific Ocean having a major impact
on our winter weather. Let's face it, oceans cover about 3/4 of the earth so we must pay close attention
to what certain ocean currents and sea surface temperatures are worldwide when doing long term
seasonal forecasts. This oscillation as the name implies, tends to last for a decade or longer, actually
around 20 - 25 years. We were in the "cool" phase of the PDO from about the middle 1940's till the
late 1970's. We then went into the "warm" phase of this oscillation from the late 1970's until about
2000. Since around 2000, we have gone back into the "cool" phase and this had to be factored in when
looking at the El Nino. El Ninos of the 80s and 90s will not act the same as current El Ninos because
of the change in the PDO. I believe this is going to keep us in colder winters for probably the next 10-
15 years. To give you an example, during the decade of the ‘90s all our winters were above
normal. Since 2000, we’ve had 12 winters and 8 of those have been colder than normal. There’s an
obvious change that has happened since 2000.
Here's a graph of the PDO trends since 1900:
Atlantic Ocean and Gulf of Mexico temperature profiles: Depending on what the temperature
profiles look like in these areas will help determine where storms may be more likely to form and
where the will track. Will a high pressure be more likely to form in the southeast or will low pressure
be more likely there during the winter, this can greatly impact temperatures and storm tracks for us in
this area. This year it does not look favorable for a “ridge” of high pressure to set up over the southeast
part of the country for any long period of time. In the graphic below notice lots of warm water in the
Gulf of Mexico and in the Atlantic. The cool area off the southeast coast was colder water churned up
by hurricane Sandy in late October.
North Atlantic Oscillation ( NAO ): Just like the PDO, this also will oscillate but on a much shorter
time period. The NAO is very difficult to predict much more than a couple of weeks in general and
then it's not always predicted well. When the NAO goes into a negative value, we generally have
colder than normal temperatures and when it's positive, we normally have warmer than normal
weather. The NAO has been mainly running mainly negative the past few months ( it was positive
much of last winter ) so the question here is, will that trend continue. My feeling is that we will remain
in a negative phase much of the time but there will be swings to positive and this will give us some
pretty large temperature swings from cold to warm.
Here's the NAO chart since 1950. Notice the very positive values for last winter but very negative for
the two winters before that and those winters were cold.
Arctic Oscillation ( AO ): This works similar to the NAO and when negative, we have colder weather
and positive brings warmer weather. It was running mainly positive until around October 1st and then
went negative and stayed there for the entire month and we ended October 3 degrees colder than
normal. It has been bouncing around the last few weeks as you can see from the chart. Once again, I
think we are looking at mainly a neutral to negative value here. When the AO and NAO are both
negative, we should experience some pretty cold weather and look for that for some of the winter.
Atlantic Multidecadal Oscillation (AMO) This is based on the sea surface temperatures mainly in
the northern Atlantic Ocean. It’s currently in the “warm phase” and is running the warmest we’ve seen
since back in the 1950s. We are still learning about the AMO but we tend to see more of a “blocking”
pattern when it’s in the warm phase and this brings shots of colder weather into the eastern part of the
United States during the winter months.
Snowpack in Canada and the US: This helps to show how much modification air masses will have
when coming down from the cold far northern reaches of Canada and Alaska. The snowpack here in
late November is a little more than normal and about 30% more in southern Canada as compared to this
time last year. Notice the difference in snow cover from November 2011 to this November. Lots more
snow cover in southern Canada and less in the Rockies this year.
Volcanic activity worldwide: You may say what does a volcano half way around the world have to do
with our weather? That's a good and reasonable question but remember that the "weather" travels
worldwide and is impacted by things many thousands of miles away ( such as La Nina way out in the
Pacific Ocean ). Let me give you an example: On April 10th, 1815 there was a major eruption of the
volcano Tambora in Indonesia. The year that followed ( 1816 ) is known as "the year without a
summer." That summer there was frost here in the Midwest and even snow in the Great Lakes and
New England and this was caused by a volcano eruption thousands of miles away. We did have a
couple of notable eruptions in the last three years. One was in Iceland back in 2010 and then later in
2010 a pretty major eruption happened in Indonesia. I believe a volcano eruption in the southern
latitudes such as in Indonesia will have a bigger impact on weather patterns than one in the more
northern latitudes. Depending on the amount of ash being thrown into the atmosphere and depending
on how high into the atmosphere it reached, will determine any impact on weather patterns. The
impacts from those eruptions can be felt for around 3 – 5 years so this needed to be factored into the
outlook.
Sun activity: The sun had been pretty inactive for a few years but as become much more active
recently. There are still many questions on what impact we see with long term temperature predictions
and solar activity but another factor looked at again this year. Here's a chart of the solar activity since
2000 and as you can see we reached a low around 2009 and we've seen an increase in the last couple of
years but has seen a drop in the last several months and is running lower than forecast and closer to
what we had in 2003 and 2004 and both of those years were used in the winter outlook.
Fall trends: I look at how weather patterns in October and November from the past compare to this
year and how past winters in those years turned out. Many times we find that a warm November brings
a warmer than normal winter and a colder November will many times bring on a colder than normal
winter.
After taking all those things into consideration along with a few others, I came up with what we call
"analog years." These are years when things like El Nino, PDO, hurricane season, volcanic activity
and so on are similar. I came up with the following analog years that I used: '51-’52, '76-’77, '78-'79' ,
'79-’80, '90-’91, '93-'94, '94-'95, ‘03-’04, '04-'05, '06-'07, '09-'10. Some of you may have noticed
something in those years and that being 1976-1977 and 1977-1978. Those are the two coldest winters
ever on record in this area and produced the last blizzard for the area back in January of 1978! I’m not
expecting a winter that extreme but it was the first time in all the years of doing a winter outlook that
those years came up in my analog years.
I then give each analog year a weight value based on how close I think it is and come up with a formula
to produce some numbers to be used in my winter outlook.
So after much work on it this year, here is my winter outlook.
Walker's Winter Outlook 2012-2013
1. Colder than last winter
YES...36.1 degrees last winter/34.3 so far this winter
2. More snow than last winter
YES...9.4” last year/11.3” so far this winter
3. Colder start to winter than last year
YES...1st 1/2 last year was 36.3 degrees/1st 1/2 this winter was 34.8 degrees
4. First measurable snow not till after December 15th
YES...Happened on December 26th
5. More windy days this winter
YES...21 days so far with winds of 25mph or grater (almost every other day!)
6. Large temperature swings this year (60+ degree swings)
YES...66 degrees so far
7. The coldest part of the winter will be the second 1/2
YES...34.8 for 1st 1/2...29.0 so far in second half and won’t get as high as 34.8 degrees
8. There will NOT be a white Christmas (at least 1 inch of snow on the ground Christmas morning)
YES...NO white Christmas this year
9. There will be 4 sub zero days (we had 0 last year!)
None yet...
10. December will be ABOVE normal temps
YES...was + 6.2 degrees
11. January will be BELOW normal temps
NO...was +1.6 degrees
12 .February will be BELOW normal temps
Don’t know yet
13. Slim chance of any major ice this year
YES...Nothing major so far
14. At least 1 record or near record high temperature
YES...on December 3rd and January 28th
15. At least 1 record or near record low temperature
None yet
16. Biggest snowfall will be from middle January to early February
Not looking likely but too early to say for sure
17. “Snow Days” (days with 1”+ snow) will be below normal with less than 9
YES...only 3 through January and we will not reach 9
18. Temperature will be BELOW normal
Forecast is 29.5 This is my coldest forecast ever!
Normal is 31.2
Don’t know yet
19. Precipitation will be BELOW normal
Forecast is 9.25"
Normal is 8.88"
NO...has been above normal already
20. Snowfall will be BELOW normal
Forecast is 15.5"
Normal is 16.5"
Don’t know yet but so far only 11.3” at the TV station
Record so far is 12-2 86%