It’s been a while since we’ve looked at what has been happening, weather-wise, around the world, so I figured we should do that. To start off, we don’t have to go further than our own backyard.
The global temperature anomalies for October have all come out and nearly all of the different reporting agencies agreed October 2019 was the second warmest on record, coming in just behind October 2015. For those who are interested, the agencies that reported the second-warmest October were NASA, NOAA, the Japan Meteorological Agency and the University of Alabama Huntsville. The one agency that didn’t agree was the EU Copernicus group, which recorded this last October as the warmest on record. These differences arise from the way the different agencies handle data-poor areas such as deserts, oceans and the Arctic.
The top five warmest Octobers have all occurred in the last five years and, according to NOAA, you would have to go all the way back to 1976 to find an October that was cooler than the 20th-century global average.
Now, if you live in Western Canada or somewhere in the western or west-central United States, you are probably questioning these numbers; after all, October was a cold month — record cold for some regions. If you look at this issue’s weather map, you’ll quickly see an anomalous blob of blue or colder-than-average temperatures centred over the western U.S. and extending into Western Canada. Exactly why this pattern set up like this in October is not exactly known, but there is some indication that excess heat entering the atmosphere from the large amount of open ocean in the Arctic helped to alter Arctic weather patterns, pushing the cold air southward. This just goes to remind us that you can’t judge what is happening to our planet by just looking outside of your own back door.
This leads to our next story, the state of the planet’s polar ice. After an Arctic melt season that saw ice extent drop to the second lowest level on record on Sept. 18, sea ice extent started to grow rapidly for the rest of the month. This pace continued into early October before falling off rapidly by the middle of the month. This slowing of sea ice growth allowed for ice levels to fall below the previous record low for October, on the 13th, and then stay at record lows until the 30th. This resulted in October’s average sea ice extent coming in at a record low of 5.66 million square kilometres, which is 2.69 million square km below the 1981-2010 average. Ice growth has naturally increased during November but is still running near record lows. Over the South Pole the melt season is now well underway, with Antarctic sea ice extent running well below average.
The next big weather story must be the fires that have been devastating a large part of eastern Australia. Australia is noted for its swings from wet to dry periods, and lately it has been in a particularly strong dry period, supported in part by an increase in global temperatures. As the global warming/climate change models point out, dry periods will become increasingly drier and warmer. This latest dry period in Australia has been the second hottest and driest year on record in over 100 years, which contributed to what has been characterized as one of the most dangerous fire hazard periods ever seen across this part of Australia. One way to picture just how dangerous the fire conditions were earlier in November was a statement made by the Australian Broadcasting Corporation, which pointed out that embers from existing fires could travel upward of 30 km ahead of the fire line, starting new fires. I just can’t imagine the conditions that would be necessary for burning embers to travel over 30 km and remain hot enough to start a fire.
Finally, we have the persistent flooding that has been going on in Venice, Italy and across parts of southern Florida. Fall is unofficially known as “king tide” season, where a combination of factors regarding the orbits of the sun and the moon help to contribute to higher-than-average tides. Fall can also be a stormy time of the year as cold air begins its winter journey southward. When these above-average high tides happen to coincide with strong storm systems blowing inland, you can get prolonged periods of exceptionally high tides that bring about widespread minor flooding. Venice made the news earlier this month with videos showing both tourists and residents wading through calf- to knee-high waters. Across southern Florida, minor but long-lasting tidal flooding is becoming a nuisance. Of particular interest is that over the years, this type of flooding has been slowly moving from what used to be the odd occurrence to what’s now seen as normal expected events.
Well, that’s about it for this week. If you have any weather topics you are interested in, please feel free to email me at [email protected].