So you want more more clues on what we might see this upcoming winter? Well sit right down, because meat is back on the menu!
There is an old saying that says you find what you shine your light on, meaning you find what you are looking for. But I am not just out there looking for cold weather forecasts or clues; I am looking for everything. On Wednesday, I came upon a tantalizing clue that could lead to cold things for this year.
This blog post begins with this confusing (yet awesome) tweet:
Jul AO 2nd most neg. since '50
10 most neg. Juls all followed by -ve AO in DJF
3 most neg. Julys followed by "mega-blocking" DJF (09/62/68)
— Todd Crawford (@tcrawf_nh) August 5, 2015
It was commented on by the following tweet from WSI Energy Weather, a company that sells their weather expertise to energy companies to help them plan for weather changes, forecasts, etc
Big blocking in July portends blocking/colder risks following winter – throws "cold water" on warm Nino winter idea https://t.co/7DkuFCl5Vj
— Weather Co Energy (@WxCoEnergy) August 5, 2015
WOW! This is fantastic. Wait…you’re confused, right?
OK, we need to lay down some explanations and for you longtime readers of The Propane Buzz (and my emails), a refresher.
The ‘AO’ referred to in this tweet stands for ‘Arctic Oscillation’. Here is a definition of the Arctic Oscillation:
“The Arctic Oscillation (AO) is a large-scale mode of climate variability, also referred to as the Northern Hemisphere annular mode. The AO is a climate pattern characterized by winds circulating counterclockwise around the Arctic at around 55°N latitude. When the AO is in its positive phase, a ring of strong winds circulating around the North Pole acts to confine colder air across polar regions. This belt of winds becomes weaker and more distorted in the negative phase of the AO, which allows an easier southward penetration of colder, arctic air masses and increased storminess into the mid-latitudes.”
Now, let’s ‘translate’ the first tweet to illustrate the possible ‘good news’ and clues that it holds:
“Jul AO 2nd most neg. since ’50. 10 most neg. Juls all followed by -ve AO in DJF. 3 most neg. Julys followed by “mega-blocking” DJF (09/62/68)”
Here is my translation for you: “This recently concluded July saw a significant negative phase of the Arctic Oscillation. In there is only one other July since 1950 where there was a deeper negative phase than what we just experienced. When you take a look at the 10 most negative AO’s in July, the subsequent December, January and February time frames experienced a negative Arctic Oscillation as well, compared to the average. The three most negative July Arctic Oscillation levels were followed by ‘mega blocking’ events during the December, January and February. Those years were 2009, 1962 and 1968.”
Let me continue with some translating and explaining.
Do you remember the term ‘Polar Vortex’ that was all the rage two years ago? The term has been around forever, by the. When the Arctic Oscillation is in its positive phase, the Polar Vortex (or extremely cold air) stays trapped around the Arctic circle by strong winds and we have milder winters in the United States. But when it goes into the negative phase during the winter months, it causes the winds to weaken. When they weakens, the Vortex is like a herd of cattle (maybe bison as this is too cold for cattle!) spooked by a rattle snake; it breaks free of its confines and heads south, to the USA. When blocking is involved, typically over Greenland, the cold air has nowhere to go so it settles in and sticks around for a while. ‘Mega Blocking’ would mean the cold air can travel farther south and stick around a good long while, respectively. It’s blocked from getting back to the north from where it came.
The image below shows some of this. The photo on the left is from December 2009, when there was an outbreak of the Polar Vortex due to a negative Arctic Oscillation. Notice the reds and yellows over Greenland; that is warm air, or a ridge. It ‘blocks off’ the possible avenues of retreat to the Arctic for the cold air, the Polar Vortex, that has made its way to the USA. The image on the right gives you a visual explanation as well. The graphic is from North Carolina State University.
The image on the left gives also you an example of Mega Blocking. There is just nowhere for that cold air to go. You will typically see Europe embraced in cold during something like this as the vortex splits, as was the case in December 2009 and January 2010. All of Great Britain was covered in snow and ice in early January 2010, something that is rare.
The winter of 2009-2010 was also cold and snowy for much of North America.
January and February of 2010 may ring a bell to you if you are a faithful reader of this blog and my missives. I actually wrote something a few weeks back when some 2009-2010 winter analogs were beginning to show up in my daily scouring of news and notes pertaining to weather and energy. If you missed that one, here it is:
In that item, I looked at combined heating degree days for January and February 2010 and 2003 to see how they ranked in terms of being colder than usual, warmer than usual or average going back to 1996.
What I found was encouraging, or at least encouraging to someone who works in a business where we hope for cold winters.
Many of the higher ranking Jan-Feb combined HDD years came in either Jan-Feb 2003, Jan-Feb 2010 or both. The image on the left from the above graphic came from December 2009. December 10th, 2009 was the starting point of that image with the Polar Vortex and the mega blocking. I recall it well as I was snowed in at a radio station in Des Moines Iowa for 48 hours as there was 15 inches of snow, driving winds and below zero temperatures. The rest of the country had it pretty bad that winter, too. The only areas that saw milder temps that year were along the northern tier of the country, such as Minneapolis.
Why would 2002-2003 and 2009-2010 have an even greater interest to me when I wrote that item back on July 10th, and why is that rammed home to me now in light of the tweet/info that started this blog post?
Because those were El Nino years…just like the one we are in in right now. How about them apples?
So what we have right now, on August 6th, 2015 are several key winter weather teleconnections setting up…we have discussed the warm Sea Surface Temperatures over the Gulf of Alaska that tend to lead to colder American winters (the last two winters have had this element in place) and how computer models have recently projected those warmer waters to stay in place for November, December and January. We have a renowned meteorologist in Joe Bastardi whose historic analogs pointed to 2002-2003 and 2009-2010 back on July 10th before he had any idea of the negative AO that was to come the rest of the month. Those years were also El Nino years, though not as strong os the El Nino that is presently building. Now, we have historical support for years where we saw steep negatives in the Arctic Oscillation in July that led to excellent winters for us in the United States.
None of this guarantees a cold winter for us, but these are THE CLUES the pros look for and look at when putting together their projections and prognostications. The more historically supported teleconnections that exist, the more confidence they place in their forecasts. When you apply current conditions to past years where the same conditions were in place at the same time, that’s how you arrive at comparative winter analogs…and those things do have some merit.
So far, so good…and we march onward.