Hurricane season 2007 is near the record low of 1977

ACE Plot 2007

Florida State University’s COAPS (Center for Ocean-Atmospheric Prediction Studies) says that hurricane season 2007, which ends November 30th, is looking well below normal, in fact they are calling it “historic inactivity”.

According to COAPS: “Unless a dramatic and perhaps historical flurry of activity occurs in the next 11 weeks (ACE is based on calendar year, not traditional June-November hurricane season) , 2007 will rank as a historically inactive Tropical Cyclone year for the entire Northern Hemisphere. During the past 30 years, only 1977, 1981, and 1983 have had less activity to date (Jan-December). For the period of June 1 – October 19, 2007, only 1977 experienced LESS tropical cyclone activity.”

ACE Departure from Climatology thru October 24th, 2007

Northern Hemisphere  -31% **** 316 (458) (Historic inactivity, 16% of season to go)

North Atlantic  -28% **** 63 (87) (Bill Gray wants 4 more (huh?, Season 91% over)

Eastern Pacific  -59% **** 52.2 (128) (Kiko helping out a little, Season 95% over)

Western Pacific  -25% **** 179 (237) (Still 21% of yearly activity to go)

PDI Departure from Climatology thru October 24th 2007

(PDI = Power Dissipation Index)

Northern Hemisphere  -24% **** 29687 (39101)

North Atlantic  -8% **** 6533 (7095) Effects of the Category 5’s

Eastern Pacific  -63% **** 3875 (10510) Includes Kiko

Western Pacific  -18.3% **** 17189 (21037) Includes Kajiki

Here are the named storms so far and their PDI:

Andrea 2.3 (Subtropical)

Barry 3.4

Chantal 2.5

Dean 386

Erin 1.3 (weak weak weak)

Felix 215

Gabrielle 4.0

Humberto 8.2

Ingrid 2.8

Jerry 2.4

Karen 17.2

Lorenzo 6.7

Melissa 1.9

There are some caveats:

Climatology based upon ACE (Bell et al. 2000) from 1970-2006 for each basin. ACE is not a perfect metric and does not account for storm size. Northern Hemisphere includes Northern Indian Ocean after 1976, which accounts for less than 3% of the yearly total. Data quality is a tremendous issue. The NHC declared extratropical observations were not included, which can account for up to 20% a year in additional ACE. The JTWC only started keeping track of EX phases in 2004, so there are literally 1,000 observations since the 1950s that are likely extratropical in the database (as phished out from the JMA database).

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21 thoughts on “Hurricane season 2007 is near the record low of 1977

  1. Precisely the same question comes up here as elsewhere: what do we think ‘normal’ variability limits are? When should we get alarmed? The mean seems to be, if read correctly, 483. Are we saying that anything between about 200 and 900 is simply in the noise from the point of view of climate? It is just weather fluctuations?

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  3. BTW AlphaOr, you linked to NOAA’s North Atlantic prediction, which they were very close on. Predicted 13-16 named storms, actual was 13.

  4. I believe that NOAA prediction was updated mid-year and they dropped their estimated number of hurricanes from something much higher (18+ ?) to 13-16. One of the problems with relying on data online… it’s easily changed.

  5. Predicted 13-16 named storms, actual was 13.
    In all UN-fairness, Matt, they were “naming” storms that were so weak they wouldn’t normally have been named, just so their prediction wouldn’t appear to be so far off.
    One of the problems with relying on data online… it’s easily changed.
    John, reminds me of the headline on MarketWatch a week or so ago. At 8AM it said “Stocks to open higher”. When, an hour and a half later, stocks opened lower, the headline was changed to “Stocks to open lower”. IIRC, the same economic data was used to explain both headlines — not at all unlike what we frequently see in the Climate debate. Ya just gotta chuckle and say (my 13-year-old granddaughter’s favorite phrase) WHATEVER!

  6. Has that median/mean been increasing? Because as with all things AGW, it’s always “observe the trend”…
    Also, just to hit the mean, we only need 1 more hurricane with 1/2 of Dean’s strength.

  7. There’s a discussion over at Climate Audit about the effects of storms on the Southwest’s weather and the relationship to fire dangers. It’s pretty good and a couple of responders are dead on the money. Whether wet or dry, we get the fires. My home is in Santa Clarita. The only difference this year from our 2004 fires is a dang better response. Given the few deaths in the San Diego fires, it appears that the response is also much better down there.
    Question: Does the PDI relate to a named storm? Asked another way, do they have a cut off point in regards to storm intensity where they don’t name a storm?

  8. I know that they changed the forcast mid-year. I simply mean if we can not determine what will happen in one year how do we know what will happen in 100?

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  10. Larry the minimum requirement for a named storm is a 35 knot wind for 6 hours, which I believe equates to a PDI of 0.4

  11. “So. Global Warming leads to more frequent and more intense hurricanes, huh?”
    Call it an outlier. (Or maybe some other kind of liar.)

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  13. Has this lobe of the “figure 8” hysteresis loop completed? Are we now going through the great 1976 – 1977 climate shift in reverse?

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