WINDS OF CHANGE

POST # 58

Last week, somewhere south of the Hawaiian island chain in the mid Pacific ocean, a collection of air molecules started off on a journey. In previous years, this air mass in some cases would continue to flow in a direction that would send it across the ocean to the Pacific Northwest, in what is known in Vancouver at least as the "Pineapple Express". Blowing from the direction that it had come, the air was warm, and would have the effect of not only increasing the temperature on the west coast, but at the same time it would usually bring with it a fair amount of rain as well. From there, the air mass would continue its journey in an easterly direction over the prairies, across to the east coast and beyond, over the Atlantic ocean, then onwards to Europe and beyond, eventually circling the globe.

But last week, this air mass charted a different course. Instead of heading in a primarily easterly direction, it instead veered way up northwards over the high latitudes of Alaska and the Yukon, before it made a sharp turn south, down the entire length of British Columbia, crossing the border into the USA, eventually arriving here in Yuma as a cold northerly wind.

In one respect, I found this quite amazing. It was incredible to think that the same air that had started off its journey south of Hawaii had travelled such a huge distance in a matter of days. Probably in round numbers, 10,000 kms or 6250 miles. Incredible.

It was troubling as well. What made it so, was its trajectory, and for this part of the discussion we need to mention something about the jet stream. The easiest way to think of the jet stream is to imagine an invisible barrier of air that circles around the planet from west to east at high altitude. In general, in the northern hemisphere, this jet stream shifts north or south dependiing on the season, and the air mass north of it is colder than the air mass south of it. So far so good. What has been normal up until recent times was that the jet stream would flow at a rather rapid speed, and meander along its course. However now, as the satellite images show, the meanderings have become much more exaggerated and the speed of the jet stream has slowed relative to what has been the norm. This has primarily caused two things to happen. The first is that warmer tropical air now flows up into more northerly latitudes, and cold polar air sinks farther south towards the equator. The second effect is that these weather systems can now be "stuck" in a type of holding pattern longer than normal. As a result many things can come about from heavy downpours to the other extreme of drought conditions during the summer season, to large snowfalls followed by cold air masses in the winter. This is now becoming the new normal.
But why is this happening? Well it's beginning to look like the primary reason is due to the loss of ice in the polar region. It is now disappearing at such a rapid rate, that it is now estimated that the Arctic Ocean could be ice free as early as this coming September, but many scientists are now saying that by September of 2015 it will be ice free at the very latest. The Arctic hasn't been ice free for over three MILLION years, so this is signifcant. As a result of the melting ice, the temperature difference between the areas of the planet north and south of the jetstream is now less than before, and this is what has impacted the speed and direction of the jet stream. Or at least that is what is widely believed at this point in time.

So this brings me back to the cold days we had here in Yuma last week. I am quite sure I wouldn't be getting any sympathy from my friends in the Yukon, as the degree of cold is relative. But it was chilly enough here to make it difficult to want to get out from under the covers in the morning. Thankfully I had my little bed heater in the form of one Mr. Watson the dog, to help.

Things have warmed up significantly since then, however when I looked at the satellite images today from out in the Pacific Ocean, I can see a similar pattern setting up. Whether we see some cold temperatures again soon, only time will tell, but for now at least, Watson and I will take advantage of the summer like weather and make sure to get out for a few walks, because he likes to, and because my right leg needs the work out.

Happy birthday mom.
Happy birthday Troy.

Happy trails.

Paul

The Thoughtful Wanderer