Tag: NOAA

The 2011 Hurricane Forecast Is Out

This forecast gets a lot of attention (including from me). I’m just not sure how useful it is

The seasonal hurricane forecast came out from the Weather Service today. No surprises. The call is for another busy year.

This forecast gets a lot of attention (including from me). I’m just not sure how useful it is. More on that in a moment.

Across the entire Atlantic Basin for the six-month season, which begins June 1, NOAA is predicting the following ranges this year:

  1. 12 to 18 named storms (winds of 39 mph or higher), of which:
  2. 6 to 10 could become hurricanes (winds of 74 mph or higher), including:
  3. 3 to 6 major hurricanes (Category 3, 4 or 5; winds of 111 mph or higher)

Each of these ranges has a 70 percent likelihood, and indicate that activity will exceed the seasonal average of 11 named storms, six hurricanes and two major hurricanes. – NWS press release

Let’s say for a second this forecast is perfect (though it never is). What would/could we do differently? It’s a little late to move New Orleans, Miami or New Haven even if this forecast was geographically specific (and it isn’t).

Besides, a busy season doesn’t necessarily mean a deadly season. Look back at last year.

“The United States was fortunate last year. Winds steered most of the season’s tropical storms and all hurricanes away from our coastlines,” said Jane Lubchenco, Ph.D., under secretary of commerce for oceans and atmosphere and NOAA administrator. “However we can’t count on luck to get us through this season. We need to be prepared, especially with this above-normal outlook.” – NWS press release

This incongruity works better when reversed. 1992 was a light hurricane season. The “A” storm didn’t come until late August (my earlier citation of September was incorrect). It was Hurricane Andrew!

You would be hard pressed to convince the people of South Florida ’92 wasn’t a bad year.

Hurricanes, like real estate, are best analyzed by checking location, location, location.

Seasonal Hurricane Forecasts: Why Bother?

A nameless friend, well known in the small world of tropical weather experts, likens NOAA’s wide range of potential storms to a gambler betting every number at roulette then bragging when he hits!

The 2010 NOAA seasonal hurricane forecast is out. The prediction is for a banner year or in government speak: “active to extremely active.”

14 to 23 named storms (top winds of 39 mph or higher), including:
8 to 14 hurricanes (top winds of 74 mph or higher), of which:
3 to 7 could be major hurricanes (category 3, 4 or 5; winds of at least 111 mph)

This would be a very valuable thing if

  • There was a history of accuracy in this forecast
  • The numbers meant anything

The number of storms is inconsequential unless one hits you. Even then only one counts. Human tragedy doesn’t parallel the number of storms. 1992 was a very light season and the year of Hurricane Andrew!

Beyond that top wind speed is only one piece of the equation. As with real estate ‘location, location, location’ is the critical factor. A poorly placed tropical storm can do lots more damage than a monster out to sea.

A nameless friend, well known in the small world of tropical weather experts, likens NOAA’s wide range of potential storms to a gambler betting every number at roulette then bragging when he hits! He went on:

“14-23 storms are you kidding me? That must be 75% of the full distribution. I thought the point of a forecast was to narrow the possibilities from the full range.”

Usually an ensemble of computer models is run to produce a forecast like this. Then the outputs are pared to the most likely results. He’s complaining too many possible scenarios have been left in. The forecast deck is stacked so the forecaster can’t lose!

The Numbers Guy at the Wall Street Journal is similarly complaining.

It is possible that NOAA is keeping its estimates loose to avoid having egg on its face later: In the past nine years, NOAA’s May storm-count predictions have proved accurate about 40% of the time.

Why do they even produce these forecasts? Who benefits?

NOAA and the Hurricane Center do great public good when they forecast individual storms. However, these dubious long range projections only cause skepticism down the road. Just what we don’t need!