NOAA's forecast: a very active, possibly hyperactive Atlantic hurricane season

maquiladora

From Dr Jeff Masters :

The National Oceanic and Atmospheric Administration (NOAA) issued its 2010 Atlantic hurricane season forecast today. NOAA forecasts a very active and possibly hyperactive season. They give an 85% chance of an above-normal season, a 10% chance of a near-normal season, and just a 5% chance of a below-normal season. NOAA predicts a 70% chance that there will be 14 - 23 named storms, 8 - 14 hurricanes, and 3 - 7 major hurricanes, with an Accumulated Cyclone Energy (ACE) in the 155% - 270% of normal range. If we take the midpoint of these numbers, NOAA is calling for 18.5 named storms, 11 hurricanes, 5 major hurricanes, and an ACE index 210% of normal. A season with an ACE index over 175% is considered "hyperactive." An average season has 10 named storms, 6 hurricanes, and 2 intense hurricanes.


http://www.wunderground.com/blog/JeffMasters/show.html


:eek:

I get the feeling we are going to see some interesting named storm threads here on the forum this summer...

Su Campu

Ever since 2005 hyperactivity they've been predicting above-average seasons, and yet every one of them's been a flop, so I wouldn't get too carried away just yet.

maquiladora

Su Campu wrote: »

Ever since 2005 hyperactivity they've been predicting above-average seasons, and yet every one of them's been a flop, so I wouldn't get too carried away just yet.

I'm sorry but...

In 2009 they didn't predict an above-average season.

In 2008 they predicted an active season and there was an active season with sixteen named storms, eight hurricanes and five major hurricanes.

In 2007 they predicted and active season and there were 15 tropical storms, 6 hurricanes, and 2 major hurricanes.

So 2006 was the only year since 2005 where they predicted an active season that didn't materialise.

Su Campu

Yes you are right. I was actually thinking about their forecast vs actual storms. While the number of actual named storms was within their (fairly wide) forecast range (except '06), the number of actual hurricanes was less than their forecast for '09, '07, '06.

Still, I suppose they have become much better than their total disaster in 2005, where there were twice as many storms as forecast. We live and learn.:)

peasant

wouldn't exactly call this a "flop"
http://en.wikipedia.org/wiki/Hurricane_Ike

Hurricane Ike (pronounced /ˈaɪk/) was the third costliest hurricane ever to make landfall in the United States. It was the ninth named storm, fifth hurricane, and third major hurricane of the 2008 Atlantic hurricane season.

In total, seven people were killed in Cuba from Ike.[72] The combined damage estimate from Ike and Gustav, and succeeding Paloma is about $9.7 billion (USD), with $7.3 billion of that from Ike, making Ike the most destructive hurricane in Cuban history.

M.T. Cranium

This idea of a very active season is quite widespread among American forecasters. The "eastern U.S." weather forum, which is similar to net-weather in size and has quite a few professional forecasters posting as well as knowledgeable amateurs, had a contest running before the NWS issued their numbers, and consensus on there from about 30 forecasters was for 19 named storms, 11 hurricanes and 5 major storms.

Very few people are expecting numbers even as low as 14,8,3 which would still be a fairly active season and ahead of last year.

Now this may mean nothing but it does show you that whatever conventional signs people look at, and they are varied, most of them must be pointing towards the high end of the scale, because it's pretty unusual for consensus in a large forecast contest to be somewhere around a 5% upper end outcome. If 19,11,5 verifies, this will represent about the fourth most active season on record. If we got to 23 it would be second only to 2005.

The active forecasts are mainly based on the rising easterly index in the subtropics, the dying El Nino, high sea surface temperature anomalies in the formation zones, and the observation that it has been a very warm spring in the eastern U.S. which often precedes an active season.

They didn't run this competition last year but a few people who did issue forecasts on the same forum tended to over-predict the numbers slightly; the average of about five forecasts was something like 13,6,2. The NWS came a bit closer although their possible range was quite large, as it turns out their forecast mid-point was just about right. I remember back in 2005 there were some forecasts out for a very active season, it's a long time ago and I don't recall too many details on forecasts, but I seem to remember at least one person saying near-record season ahead.

maquiladora

Updated hurricane season predictions from the CSU team :

June 2 (Bloomberg) -- Colorado State University researchers boosted their forecast for the 2010 Atlantic hurricane season, calling for 18 named storms, 10 of them becoming hurricanes.

The researchers also said there is a 76 percent chance that a major hurricane, with winds of 111 mph (178 kph) or greater, will strike the U.S. The past-century average is 52 percent.

The forecast comes less than a week since the U.S. National Hurricane Center predicted an above-average season with 14 to 23 named storms forming before Nov. 30. The most active season on record was 2005, when 28 storms formed, including Hurricane Katrina, which caused New Orleans levees to fail, flooding the city and killing more than 1,800 people.

The CSU team predicts tropical cyclone activity in 2010 will be 195 percent of the average season. By comparison, 2009 activity was about 69 percent of the average season....

http://www.businessweek.com/news/2010-06-02/colorado-state-increases-its-prediction-for-atlantic-hurricanes.html