Most of the well-known forecasters have weighed in with their 2007 forecasts now, so let’s take a look at what is being predicted.

• NHC/NOAA Hurricane forecast summary:
13 to 17 tropical storms
7 to 10 of them becoming hurricanes.
75% chance of above normal hurricane activity according to the NOAA’s NHC.

Other people are predicting:
• William Gray from Colorado State predicts 17 named storms with 9 hurricanes.
• AccuWeather calls for 13-14 tropical storms with 9 becoming hurricanes.
• Tropical Storm Risk (back in March) expected to bring 17 tropical storms, of which nine will strengthen into hurricanes.

Essentially all within the same ball-park.

What does this MEAN? It means that the experts think that we’ll have a busy season – we may or we may not, see below. So what should you do now? You have two choices: prepare now and be ready if a hurricane hits your area or don’t prepare and have no options. Preparation is a pretty simple matter when you have time to prepare, so the smart choice is to be ready.

In our view, these forecasts are an educated guess based on statistical analysis of previous seasons as applied to current seasons’ weather patterns. There is currently no magic box (or even sophisticated computer program) that can provide an accurate forecast for the number of storms. That said, the annual predictions are a worthwhile exercise in order to advance our knowledge. Studying current weather patterns, comparing these patterns with previous years, and then attempting to forecast based on the intersection between the two advances our knowledge incrementally and advancing knowledge is very worthwhile.

When the actual number of storms falls near the long term average, the forecasts are general correct since the forecasters generally end up predicting trends near the average while adjusting for various well known factors. The way forecasting works (usually) is you start with a long term average as your prediction and then you adjust it up or down based on various factors. For example, El Nino or La Nina’s presence or lack thereof will cause forecasters to adjust their predictions up or down. Patterns over the Atlantic, dust or lack of dust from Africa work similarly. Sea surface temperatures impact the forecasts also. It is merely a matter of how much each factor will impact storm formation and whether the impact will be up or down.

Let’s recall previous year predictions compared with the actually events. Please remember, the forecasters do their best with the knowledge they have.

****2006****
2006 ended with 10 named storms (one between Alberto and Beryl that was unnamed during the season and only identified in the post-season analysis).
CSU had predicted 17 storms
AccuWeather: 6 tropical cyclones (3 major) will strike US coast (none did), with a total number “above average”
NHC/NOAA predicted:
* 13-16 named storms (hurricanes and tropical storms)
* 8-10 of which will become hurricanes
* 4-6 of which will be major hurricanes (category 3 or higher)

In summary, the number of storms was well below predictions.

****2005*****
Actual: 28 tropical storms, 15 hurricanes, 7 major
CSU’s May forecast, predicted 13 named storms for 2005, which was obviously well off.
NOAA: 12-15 Storms, 7-9 hurricanes, 3-5 of them major

In short, the number of storms greatly exceeded pre-season predictions.

****2004****
Actual: 15 storms, 9 hurricanes, 6 major
NOAA: 12-15 Storms, 6-8 hurricanes, 2-4 major
CSU: 14 storms, 8 hurricanes, 3 major (May 2004 forecast)

The number of storms in 2004 fell in the average range and consequently pre-season predictions were quite accurate, only fall well below actual numbers in the “major storms” category.

In an “average” year, by today, August 21st between 1944 and 2005 and *average* of 1.5 hurricanes have formed. Likewise in an average year, 3 tropical storms have formed by August 20th. So far 2006 has had zero hurricanes and 3 tropical storms.

Therefore, compared with an average year 2006 is now below average in not only hurricanes formed, but tropical storms formed.

One reason? Cooler sea surface temperatures which are below (or just at) long-term averages depending upon the location of course. A paper to be published in next month’s Geophysical Research Letters, shows that between 2003 and 2005 *global* average upper ocean temperatures have *cooled* significantly. (for a PDF version of the draft paper, see http://www.pmel.noaa.gov/people/gjohnson/lyman_heat_v2.pdf. Please note that this is a very technical paper.)

In fact, the 3 years erased 20% of the warming that occured over 48 years! Yes, 3 years (2003, 2004, and 2005) have erased 20% of 48 years of warming, effectly removing nearly 10 years of sea surface temperature warming.

Will these facts make the major news outlets after last year’s hype?

Time will tell.

For more information:
Lyman, J. M., J. K. Willis, and G. C. Johnson. (In preparation). Recent cooling of the upper ocean. Geophysical Research Letters, http://www.pmel.noaa.gov/people/gjohnson/lyman_heat_v2.pdf [http://www.pmel.noaa.gov/people/gjohnson/publications.html]

Florida offers a new hurricane home evaluation service – My Florida Safe Home. See http://www.mysafefloridahome.com/. It provides some good tips on protecting your home from hurricane damage and perhaps being able to reduce your insurance premiums.

While it is a good idea and we urge people to use the service, unfortunately as so much provided by the government there are significant problems:
1. The 800 number 800-342-2762 is no accessible from many areas of Florida, including the Jacksonville area – “You have dialed a number that is not available from your calling area 126 D” (126 T? 126 P?). If you are setting up a service to evaluated a home’s resistance to hurricanes and offering it to Florida residents, at least make it accessible to all of Florida. Particularly coastal counties on the east coast of Florida, not just 22 selected counties – which counties are not listed anywhere that we could find. Tom Gallagher needs to get his act together on improving the My Safe Florida Home Hurricane evaluation. (Verfied over the course of several days, last: August 17, 2006).

2. There is no list of people who are doing the inspections and recommendations. Since the options are only available to residences that are primary residences and with an insured value of under $500,000 people that do not fit those categories are out of luck. At minimum provide a list of appropriate people so that others can pay for the hurricane home inspection service.

While the program is nice in principle, Florida’s implementation still leaves much to be desired.

Christian Riley

The Final report from the National Hurricane Center on Hurricane Katrina has been issued.

The highlights on Hurricane Katrina are as follows:

1. Hurricane Katrina was a category three (3) storm when it made its closest approach to New Orleans, although it had been a category five (5) storm previously.

2. “The strongest winds corresponding to that [Category 3] intensity were likely present only over water to the east of the eye.” This means that the category 3 winds were well east of New Orleans.

3. “The sustained winds over all of metropolitan New Orleans and Lake Pontchartrain likely remained weaker than Category 3 strength.” New Orleans was experiencing a Category 2 hurricane. A majority of the damage was due to flooding, not winds. Flooding was caused by political failures in terms of 40-50 years of neglect and political games.

4. Surge was signficant and pentrated miles inland along bays and rivers. In some cases up to 12 miles inland. It was worse east of the eye, but still significant to the west of the eye – e.g. in the New Orleans area.

The facts on Katrina and Wilma should illustrate several important points that must be remembered.

a. Storm strength can change quickly. In 24 hours Hurricane Wilma went from a small tropical storm to the most powerful hurricane (measured by low central pressure) ever measured in the Atlantic Basin (to that point). Likewise Hurricane Katrina strengthened rapidly.

b. There is no such thing as “only a Category 1 or 2” hurricane – let alone “only category 3.” When both Hurricane Wilma and Hurricane Katrina made landfall neither was a Category 4 or 5 storm and New Orleans only experienced Category 2 force winds. In both cases the damage was significant. Much damage was due to neglect of flood control systems over 40 years due to political neglect and political game playing.

In short, there is no such thing as a minor hurricane. Evacuation is always your safest option – get out of the path of the storm. Following hurricane preparation guidelines – for water, food, yard etc. Too often we hear people blaming others for their own failure to prepare. Your own safety is your own responsibility first. Simple steps will help you to ensure that you do remain safe, but they do require planning.

Likewise, when the City, State, and Federal governments are assuring you that levees (or buildings or any structure) can survive a category 3 (or higher) storm do not always believe them. The National Hurricane Center will provide extremely accurate facts and information. However, politicians will use that information for their own political gain – look at the Hurricane Katrina hearings and the finger pointing in Hurricane Katrina’s aftermath. Politicians who are quick to assign blame to anyone they can in order to cover themselves are people to whom you should not look to for advice. They’ll take credit when they can, and deflect blame for everything else. No one who behaves that way is a leader, they are a disgrace.

Christian H F Riley

You can read the entire Hurricane Katrina report on the web. Hurricane Katrina Report

You can read the entire Hurricane Wilma report on the web.

A great satellite image of Katrina

Hurricanes are categorized by several methods, the most well known being the Saffir-Simpson Hurricane Scale. The Saffir-Simpson scale, developed in 1969, is based on the wind speed of the hurricane. The various categories are listed below in their traditional form:

Category 1: 74 to 95 mph
Category 2: 96-110 mph
Category 3: 111-130 mph
Category 4: 131-155 mph
Category 5: greater than or equal to 156 mph

The amount of damage between each category does not increase linearly. Each increase in category greatly increases the damage potential. The original scale included no Category 6 hurricane. Robert Simpson has stated that there was no reason to include an additional category because the damage would be severe no matter the wind speed over 155 mph. Improvements in building engineering over the past roughly 35-40 years may have changed that dynamic and might necessitate the addition of a category 6 hurricane.

In our view, if the Saffir-Simpson scale were adjusted to include another category, it would likely be as follows:

Category 1 hurricane: 74 to 95 mph
Category 2 hurricane: 96-110 mph
Category 3 hurricane: 111-130 mph
Category 4 hurricane: 131-155 mph
Category 5 hurricane: 156-175 mph
Category 6 hurricane: greater than or equal to 176 mph

The current Saffir-Simpson scale has the following wind speed bands for its categories:

Category 1: 21 mph band
Category 2: 14 mph band
Category 3: 19 mph band
Category 4: 24 mph band
Category 5: unlimited band since there is no upper limit besides atmospheric limitations

A Category 5 band would likely be a 19 or 24 mph band and therefore a category 6 hurricane would have winds greater than or equal to 176 mph (or 181 mph). The 176 mph figure seems to make the most sense based on wind speeds and engineering.

On a related note, the question has come about, what about a storm that has winds of 95.5 mph or 110.5 mph or 131.5 mph or 155.5 mph etc? It would seem that the scale does not provide for those wind speeds. A continuous mathematical restatement of the Saffir-Simpson Scale should be made with the addition of an additional category.

The Saffir-Simpson scale should be restated as:

Category 1 Hurricane: 74 to 95 mph
Category 2 Hurricane: > 95 to 110 mph
Category 3 Hurricane: > 110 to 130 mph
Category 4 Hurricane: > 130 to 155 mph
Category 5 Hurricane: greater than 155 mph

Or, alternatively:

Category 1 Hurricane: 74 to less than 96 mph
Category 2 Hurricane: 96 mph to less than 111 mph
Category 3 Hurricane: 111 mph to less than 131 mph
Category 4 Hurricane: 131 mph to less than 156 mph
Category 5 Hurricane: 156 mph or greater

Or with an additional category:

Category 5 Hurricane: >155 to less than 175 mph
Category 6 Hurricane: 175 mph or greater

or

Category 5 Hurricane: 156 mph to less than 176 mph
Category 6 Hurricane: 176 mph or greater

Precision is important in the sciences and hurricane forecasting is nothing if not a science. Likewise taxonomies assist in the classification and therefore the study of any phenomenon. Our view is that the Saffir-Simpson scale has a few minor areas that need correction.

For more information on the Saffir-Simpson scale, see this page.