Climate Donkey

May 29, 2008

Atlantic Hurricane Seasonal Forecasts — Politics and Hype Part 1

Filed under: Hurricanes — climatedonkey @ 5:01 am
Tags: , ,

With the focus on climate change and media fascination with natural disasters, considerable coverage has recently been afforded to seasonal forecasts of Atlantic hurricane activity. However, when NOAA holds a press conference to announce their forecast, as they did on May 22, 2008, weather weenies come out of the woodwork to react to the prognostications. In general, the mainstream media will report the typical preparation entreaties by Conrad C. Lautenbacher, NOAA administrator, somewhere in the middle of an article. First, you have to get past the haunting and daunting headlines, which during the past 7 years have been exasperating in their portents for destruction. Then, for 2008, the numbers came fast and furious, 12-16 tropical storms, 6-9 hurricanes of which 2-5 will become intense or major. What you get is an inch deep and a mile wide in terms of precision – and also accuracy. Yet, seasonal forecasts, with all of the examples of ineptitude, are still official government issued products, with a bunch of other competing outfits.

Rather than bore the pants off of everyone with fancy correlations and confidence testing, we can simply look at the forecasts themselves and judge them based upon how a few end-users will react. These end-users can include Big Oil, the State of Florida, the tourism industry, and Betty who enjoys her retirement in a Bradenton trailer park.

Since 1995, hurricane activity when measured using the Accumulated Cyclone Energy Index, or known affectionately as ACE, has been above the previous 50-year historical mean/median/whatever. Some claim a multidecadal signal while others blame global warming or climate change; the wordage depends on the season. Whatever the reason, the Atlantic has been active since 1995, while the Eastern Pacific has been depressed (no need for Zoloft).

ACE ATL

By 2001, climatologists experienced with hurricane activity and the Atlantic’s history expected a prolonged period of “enhanced activity”. This is endemically referred to as “above normal” activity. This is a bad description since a quick look at North Atlantic hurricane history shows peaks and valleys; normal really is not a state that exists for a long time period (10-20 years). Generally the situation is feast or famine, 1997 or 2005, depressed or enhanced. You get the picture.

Above average activity is now the forecast for the next decade or maybe longer because we have entered the “enhanced activity period”. Okay, Betty in her trailer does not care about the next 10-20 years, but wants to know about this year – not if the season is going to be above normal, but is she going to get blown sideways in September? We’ll get back to this in a bit…

The following information is a compilation of several sources including archived online articles, seasonal verifications from NOAA, Dr. Bill Gray’s group, as well as Tropical Storm Risk.

2001: 15 TROPICAL STORMS – 9 HURRICANES – 4 MAJOR – ACE = 108

Look at those big numbers! Out of those storms, a grand total of zero, fortunately made landfall in the US as a hurricane (most hurricanes without a US landfall in 50 years).
Dr. Gray’s outfit in April, June, and August predicted 10, 12, and 12 tropical storms, with 6, 7, and 7 hurricanes, with 2, 3, and 3 being intense. While the prediction was considerably underdone, no harm no foul – no hurricane landfalls.

2002: OBSERVED 12 TROPICAL STORMS – 4 HURRICANES – 2 MAJOR – ACE = 68
Yet, the next May, “federal experts” at NOAA unleashed their seasonal forecast. Headlines presaged a “heavy hurricane season ahead” with a “bit above average” activity.

NOAA: May 20, 2002 9-13 TROPICAL STORMS – 6-8 HURRICANES – 2-3 MAJOR
GRAY: May 31, 2002 11 TROPICAL STORMS — 6 HURRICANES — 2 MAJOR

Here we see an example of headline writers in the media totally blowing out of proportion what scientists or experts are telling them – for whatever reason. Throughout the hurricane season, which runs from June to November, the forecasters get a chance to “amend” their predictions or “hedge their bets”. Maybe the activity is gangbusters or perhaps non-existent: time to update that forecast midstream. Now, if the forecast change is in the right direction, meaning a true refinement, can we really say that is “adding skill” to the previously made forecast? Not really – but if the forecast goes in the wrong direction, now that looks bad!

UPDATE August 8, 2002 CNN STORY

El Nino’s reappearance in the United States will reduce the number of estimated Atlantic hurricanes from eight to six this year, according to the National Oceanic and Atmospheric Administration. NOAA revised its outlook for the 2002 Atlantic hurricane season, which runs from June 1 to November 30, to include between seven and 10 tropical storms with four to six developing into hurricanes.

NOAA Aug 8, 2002 7-10 TROPICAL STORMS – 4-6 HURRICANES – 1-3 MAJOR
GRAY Aug 7, 2002 9 TROPICAL STORMS — 4 HURRICANES — 1 MAJOR

El Nino’s unexpected emergence highlights a reality in long-term seasonal predictions: the autumn phase of El Nino is poorly predictable in the spring. The forecasts were rightly downgraded but did not anticipate a record 8 storms that developed in September. Betty is happy. Big Oil is happy. Insurance underwriters did good. However, the overly excited headlines may have scared a few tourists from piling into their station wagons and driving down to Florida. The sense of urgency for hurricane preparedness and expectation of a major disaster likely is at the lowest point — until the 2004 season changes the rules of the game.

First, 2003 …

OBSERVED: 14 TROPICAL STORMS – 6 HURRICANES – 3 MAJOR – ACE = 168

This season had a couple of long lasting and intense storms, which fortunately did not affect the US at anywhere near their maximum strength. Fabian and Isabel traveled for more than week criss-crossing the far Atlantic, with one making landfall in the Carolinas (Isabel). NOAA’s press release predicted above normal activity on May 19, 2003

NOAA 2003

James R. Mahoney, assistant secretary of commerce for oceans and atmosphere and deputy NOAA administrator said, “This year the Atlantic hurricane outlook calls for a 55 percent chance of an above normal season, a 35 percent chance of near normal, and only a 10 percent chance for a below-normal season such as last year.”


NOAA: May 19, 2003 11-15 TROPICAL STORMS – 6-8 HURRICANES – 2-4 MAJOR
GRAY: May 30, 2003 14 TROPICAL STORMS — 8 HURRICANES — 3 MAJOR

Forecast look familiar? Well it is basically a repeat of 2002’s. It would be hard to take either of those forecasts without knowledge of what happened and predict whether 2002 or 2003 would see more activity. So, Betty has a good memory, especially when it comes to clipping coupons and her neighbor’s business. She remembers than 2002 wasn’t too bad, and sees no reason to really believe the 2003 seasonal forecast. Perhaps, when Betty reads the USA Today at Denny’s, she notices that the hurricane season is “racing along” as reported July 18, 2003 (USA TODAY).
Fortunately, Max Mayfield, National Hurricane Center director is reassuring —

…Max Mayfield, says he isn’t worried.
“It certainly doesn’t mean the world is coming to an end,” he says.

Whew…

The August update keeps the activity at about the same levels: slightly overdone but not too bad.


NOAA: Aug 7, 2003 12-15 TROPICAL STORMS – 7-9 HURRICANES – 3-4 MAJOR
GRAY: Aug 6, 2003 14 TROPICAL STORMS — 8 HURRICANES — 3 MAJOR

NOAA also predicts the ACE for the season, and expected 95-155 in May and 103-146 in August as the likely range of 2003 activity. An ACE of 168 was observed, well outside their expected range, which highlights the longevity and intensity of Fabian and Isabel. This metric is very hard to get right because you need to know how long the storms will last, at what intensity, and of course, how many. Pretty tough standard.

So, Part I discusses 2001-2003. During the first three years of the Bush administration, the focus has hardly been on hurricane activity, climate change, or seasonal forecasts. The media publish the articles as “a matter of fact” and really do not exasperate the coverage for any agenda purposes. The run-up to the war in Iraq has led Katie Couric to bemoan the media’s acquiescence to the Bush Administration’s intelligence as a “one of the most embarrassing chapters in American journalism“. Part II and following posts in this blog will take this nugget of wisdom from the “Perky One” and extend the logic to coverage of Katrina and global warming. There is an agenda at play here, and it all is part of a neatly woven together amalgamation of “scientific experts”, disasters, Bush Derangement Syndrome, and a new technocratic ideology of environmentalism, which some have described as a new Stalinism.

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