I believe a good chunk of the country will have a heat index north of 100 degrees at some point in time this week, so it may feel like an odd juncture to talk about winter weather. NEVER!
Yesterday, I reached out to Michael Clark of BAMWx.com, the Meteorological partners of The Propane Buzz, and asked if he had any early thoughts on climate drivers relative to the upcoming winter. As coincidence would have it, he and his team had been starting to work on that earlier in the week, so Michael had some data in hand to share with us.
PLEASE NOTE, and I cannot stress this enough, these are PRELIMINARY thoughts. In fact, they are the preliminary to the preliminary thoughts. BAM will fine-tune their winter forecast and release their official winter forecast sometime in mid to late October and we will share that with you as well.
Let’s start with this simple (yet complex) premise: what happens in the oceans (water temperatures) has everything to do with the type of winter weather we will have. Think of having a fan in your house, and think of that fan being turned on and in front of the fan, you have a block of ice. Think of the ice as the ocean and the wind generated by the fan as the jet stream and other surface area winds. Now think of the same thing but instead of a block of ice, you have water heated up that is warmer than room temperature and can remain at that warmer state for extended periods of time. This is a simplistic way of thinking about how the oceans impact North American winters….if the ocean waters are cooler in some areas, it’s going to have a cooling effect. If they are warmer in some areas, it can have a warming effect….but not always…let me explain that a bit more below.
So the first thing Michael share was that the climate driving forces they are favoring right now for this winter, meaning the aspects to climate that seem most likely to be present with us this winter are a La Nina state as well as a negative QBO. QBO stands for Quasi-Biennial Oscillation. What this is is an oscillation in the wind direction in the stratosphere within roughly 15 degrees of the equators. A La Nina state is when equatorial waters in a region just west of South America are colder than normal. When Clark plugged these two climate drivers into the history comparison machine (analogs), this is the resulting overlay of what has been experienced in the past:
There are also the Sea Surface Temperatures (SST) to take into consideration. Remember that fan/ice/hot water analogy from above? Let me share a current Sea Surface Temperature map that I have drawn on to explain more below:
The circled area in the Gulf of Alaska with the H in the center….this is an area where SST’s are much warmer than they normally are. When winds aloft, as well as the jet stream, encounter this ‘blob’ of warm water, they are forced over the top of the high pressure system, as evidenced by the arrow going up and over the Golf of Alaska. That air gets cooled as it travels through the Arctic and can also lead to a negative state of the Arctic Oscillation, which can perturb the Polar Vortex, weaken it and ‘set it free’ from its north pole moorings. We had this type of SST set up in the Gulf of Alaska in the winter of 2013-2014, for instance. (no, this is not a prediction of the repeat).
The narrow rectangle along the equator is the Nina/Nino region and the waters are cooler than normal there, which shows the likelihood of a La Nina state. The waters in the Maritime region, Australia, are also warmer than normal.
So according to Clark, if we just looked at historic analog years where the SST set up was similar to what we have now and what is expected to carry through for the next several months, this is the resulting mix of analogs:
If you look at the dates at the top of that map, you will see some ‘All Timer’ winters listed in there.
Now, I asked Clark which climate drivers he was favoring, or weighting, more for this winter as well as considering the current state of our climate, which is warmer than the baseline state from decades past. He told me they are putting heavier weight on there being a strong La Nina and a -QBO state with the PDO factored in, which is the Pacific Decadal Oscillation….they are putting MORE weight on these ‘warmer’ climate impacting factors than they are the SST set up, which as you saw from above would, on their own, be a very cold look. As such, here is BAM’s Preliminary Preliminary thought:
I was surprised to see that much below normal, considering that Clark told me he placed more weight on the warmer drivers…it’s just that the current and expected SST set up is so monstrous relative to cold winters from the past when similar set ups were in place, that the warmer drivers couldn’t wipe everything out.
One final reminder; this is a preliminary look. We are a long ways out from winter and the forecast that BAM issues in October will be on the doorstep of winter and therefore the clues about what may lie ahead will be clearer at that time. But there is absolutely a science to all of this and what the folks at BAMWx.com do, and I greatly appreciate their time and sharing this with us so that we can share with you.