Today’s Hurricane Observations; Is the season half over?

There is a reasonably high probability that tropical storm force winds from what is now Hurricane Igor will affect the Maritime provinces in Canada. Look for that to start happening Tuesday and later. Igor could actually be weaker than a hurricane is supposed to be (or close to it) over the next few hours, technically, but is still organized like a hurricane and is expected to restrengthen one more time before being absorbed into the extrapolar system.

Meanwhile, say hi to Lisa.

Lisa does not exist yet, but at present a zone of low pressure and storminess 400 miles west of Cape Verde is getting its act together. and this seems to be the most likely candidate for a named storm. This would happen some time Tuesday or Wednesday, most likely.

Regarding the question, “Is the season half over?” … You may not have even been thinking this, but I was, so let’s look at it.

The Atlantic season runs from June 1st to November 30th (though sometimes storms extend past that date). That’s six months, so in terms of calendar time we are about 61% into it. In terms of the total number of storms, this seems about right.

If we are more than half way through, we will not likely use up the full list of named storms, as has happened now and then in the past, causing us to go to Alpha, Beta etc for the remaining storms.

The following table based on data from the Hurricane Prediction Center gives the number of Atlantic Hurricane Season named storms to date for September 20th (including those in progress) in each of several years, the total number of name storms each year, and the percentage of storms that had at least started by September 20th.

So, for last year, there was a total of 9 named storms, 67% of which had started (and some completed) by the present date (September 20th) in that year. Overall, about 66 percent of the total number of storms to occur in a given year are in progress or done by now, however, this may vary across years based on how many total storms there are. (This would depend on whether more storms = an earlier season start, a later season end, or a shorter interval between named storms.)

Year NTD Total % Pre 09/20
2009 6 9 67
2008 10 16 62
2007 9 15 60
2006 9 10 90
2005 17 28 61
2004 12 15 80
2003 9 16 56
2002 10 12 83
2001 7 15 47
2000 8 15 53
1999 8 12 67
1998 9 14 64
1997 5 8 62
1996 8 13 62
1995 13 18 72

If we use this as a guide, one might expect that we have between five and seven more named storms to go this season. Any bets on what the name of the last storm will be? I’m thinking Richard.

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