Wednesday, August 11, 2010

It's August, Where Are the Hurricanes?

Back at the end of May, I commented on the NHC predictions of a busier than normal hurricane season.  Here we are in August - still about a month from the statistical peak of the season, and those predictions have not been borne out.  It would take a record-breaking September and October to come close to the NHC predictions.

Back in May, if you recall, people were predicting hurricanes would rip the repair ships off the BP Deep Water Horizons well, and throw that oil up onto the land.  Some speculated lightning strikes would ignite the oil and the coast would experience a flood that carried fire!  Epic disasters of Biblical proportions. 

We are up to tropical depression #5, which fizzled this afternoon and was pronounced dead without ever making tropical storm strength and getting a name.  This is the IR satellite photo from this morning.  Frankly, my cats have barfed up scarier looking things than that.
It shouldn't be a surprise that some of the leading hurricane research centers are in Florida: the National Hurricane Center in Miami and Florida State University.  At FSU, researcher Dr. Ryan Maue has been tracking the total amount of tropical cyclone activity (Accumulated Cyclone Energy - ACE) around the world.  He reports findings so far removed from the hype that it should make your head spin.

Global TC Activity remains at 30-year lows at least -- The last 24-months of ACE at 1090 represents a decrease from the previous months and a return to the levels of September 2009...Since Hurricane Katrina (August 2005) and the publication of high-profile papers in Nature and Science, global tropical cyclone ACE has collapsed in half. This continues the now 4-consecutive years global crash in tropical cyclone activity. While the Atlantic on average makes up about 10% of the global, yearly hurricane activity, the other 90% deserves attention and has been significantly depressed since 2007.

and the zinger that got me:

Northern Hemisphere year-to-date ACE is nearing 50% below normal. The Western North Pacific is at 17% of normal (or the past 30-year average).

17% of normal?  That's amazing!  If anything, we should be standing around wondering what happened to the tropical cyclones.  No one I know enjoys getting hit by one (well, no one enjoys the preparation and clean up although the storms can have some entertainment value) but they are a vital part of the global weather system, distributing heat and moisture from the tropics into the northern parts of the globe when summer tends to shut down circulation from higher latitudes to lower.  It is not entirely a joke when I say one of our main exports is humidity.

Dr. Maue's plot of ACE.  Note we are at levels not seen since the 1970s.  
I find this quite interesting.  I "grew up" as a homeowner in south Florida before the left end of that plot.  I don't recall any hurricanes in the early 1970s - I remember going through a few while growing up in Miami (Donna, Cleo, Betsey) and I remember David in 1979 - which was just a brush for us.  Betsey was in 1965, so that was 14 years with no storms.

In 2004, we had two direct-hit hurricanes here and a couple of swipes.  In 2005 we had a couple of brushes.  I don't count tropical storms, although the one we had last year, Fay, dropped more rain than all of the 2004 hurricanes combined.  2005 is just about the last peak of that chart.  The possibility of getting back to a decade or 15 year quiet time sounds good.  I suspect, though, that somewhere on Dr. Maue's website there's one of those disclaimers the stock brokers use, "past performance is no guarantee of future results".

Edited  8/12 for a dumb-o error.

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