More on Lightning

Here are a few more charts from my analysis of regional lightning activity; some interesting results are already emerging.

First, the Upper Yukon Valley zone of Alaska (i.e. the northeastern interior) remains the most unusually inactive of Alaska's fire management regions in terms of lightning strikes so far this season.  The number of cloud-to-ground lightning strikes is the lowest since at least 2012, and time is running out to add to the total - although it can happen (like last year).

Across the eastern border, Canada's Yukon Territory is also having a very inactive year for lightning, at least as reported by the Alaska detection network.  The chart below reveals a "striking" change to lower lightning activity in 2018, compared to 2012-2017; this would be a remarkable result if correct, but the sudden and sustained drop-off seems a bit implausible to me.  However, the dataset documentation does not indicate any change in the detection network in recent years.

A similar change is obvious in the detected lightning activity over the Beaufort Sea and Arctic Ocean, as defined by the IHO boundaries (see below).  More investigation will be required to see if a sensor change might explain this.

Finally, it's interesting to note that detected lightning over the North Pacific (excluding the Bering Sea) is the highest on record so far this year (of course this only pertains to a small area of the North Pacific within range of the lightning sensors):

Notice how much later the lightning season is over the waters south of Alaska: with a long seasonal lag in ocean temperatures, the most favorable conditions for lightning occur much later in the year than farther north.  I'll illustrate this more clearly in a future post.