Atlantic hurricane season predictions fall flat

Despite dire predictions to the contrary, the 2013 hurricane season is turning out to be a dud.

With a little over a month left in the North Atlantic hurricane season, it's now clear that the long-range U.S. forecasts issued in the spring — all calling for a high level of storm activity — weren't even close.

In May, the U.S. National Oceanic and Atmospheric Administration predicted unusually warm ocean temperatures would spawn between seven and 11 hurricanes, and that three to six could become major hurricanes churning out winds in excess of 178 kilometres an hour.

So far this year, there have been only two hurricanes — Ingrid and Humberto in early September — both of which were relatively weak storms, rated at Category 1 on a scale that reaches up to 5. Ingrid, however, brought heavy rain to parts of Mexico, where flooding and landslides claimed dozens of lives.

I think it hurts the credibility of these long-range forecasts- Chris Fogarty, Canadian Hurricane Centre

In all, there have been 12 named storms, including tropical storm Lorenzo, which is expected to weaken to a tropical depression as it moves east over the Atlantic.

A dozen named storms is about average for a season, which spans from June 1 to Nov. 30. But the number of hurricanes and major hurricanes is well below average. The last time a season passed without a major hurricane was 1994.

In Halifax, where the Canadian Hurricane Centre keeps track of tropical cyclones, forecasters have issued bulletins for only two storms this year, Andrea in June and Gabrielle in September. Both had little impact on the Atlantic region.

Chris Fogarty, the centre's program supervisor, says the spring predictions were so far off base that U.S. meteorologists should consider issuing seasonal forecasts without hard numbers.

"We haven't had such poor pre-season forecasts since the early 1990s," he said, adding that unlike meteorologists in the U.S., Environment Canada forecasters do not issue long-range predictions for the number and severity of North Atlantic storms.

"I think it hurts the credibility of these long-range forecasts."

Dennis Feltgen, a meteorologist with the National Hurricane Center in Miami, said the season isn't over yet.

"However, the odds that the season will produce the expected numbers of hurricanes and especially major hurricanes are rapidly decreasing," he said in an email.

As for the credibility of the long-range forecasts issued by the U.S. Climate Prediction Centre, he said these predictions should never be used as guides to decide whether or not to prepare for hurricane season.

"Anyone living in a hurricane-vulnerable area can be affected, regardless of whether the season is quiet or busy... It only takes one storm hitting your area to make it a bad year. And storms do occur in November."

Fogarty said there are a number of reasons why the predictions were a bust.

Scientists have recorded an unusually low level of moisture in the tropics and the oddly persistent downward motion of air masses. Together, these phenomena have kept the tropics relatively cloud free.

No clouds, no hurricanes.

"There's something going on globally at a larger scale that was causing a general downward motion in the Atlantic," said Fogarty. "It seemed to be kind of stuck in one position. There's a lot of little questions there."

As well, unusually strong winds in the upper atmosphere have been tearing apart emerging storms.

"We know where to start looking, but there's not a smoking-gun answer," he said.

Still, he says the season could end with a bang, even though a NOAA study found that in the past 100 years only 10 per cent of recorded Atlantic hurricanes have formed after Oct. 25.

Sandy, described as a superstorm, was a massive post-tropical storm when it roared ashore near Atlantic City, N.J., last Oct. 29, causing widespread flooding and wind damage along the entire eastern seaboard and farther inland.

The 1,600-kilometre-wide storm killed 72 people in the Caribbean before making its way up the Atlantic Coast, where it killed more than 100 people in 10 states, and left more than 8.5 million people without power.