Philip J. Klotzbach/Dr Gray's Verification of 2006 forecast

[cycloneye]

http://typhoon.atmos.colostate.edu/fore ... 6/nov2006/



ABSTRACT


This report summarizes tropical cyclone (TC) activity which occurred in the Atlantic basin during 2006 and verifies the authors’ seasonal and monthly forecasts of this activity. A forecast was initially issued for the 2006 season on 6 December 2005 with updates on 4 April, 31 May, 3 August, 1 September and 3 October of this year. These forecasts also contained estimates of the probability of U.S. hurricane landfall during 2006. The 3 August forecast included forecasts of August-only, September-only and October-only tropical cyclone activity for 2006. Our 1 September forecast gave a seasonal summary to that date and included individual monthly predictions of September-only and October-only activity. Our 3 October forecast gave a seasonal summary to that date and included an October-November forecast. Our 2006 seasonal hurricane forecast was not successful. We anticipated a well above-average season, and the season had activity at slightly below-average levels. We did catch this downward trend beginning with our early August update We attribute a large portion of this forecast over-prediction to a late-developing El Niño and increased mid-level dryness in the tropical Atlantic.




The 2006 hurricane season had the following special characteristics:

· Another early-starting season. Alberto formed on June 11. The climatological average date for the first named storm formation in the Atlantic, based on 1944-2005 data, is July 10.



· Nine named storms formed during the 2006 season. This is the fewest named storms to form in the Atlantic since 1997, when only seven named storms formed.



· Five hurricanes formed during the 2006 season. This is the fewest hurricanes to form in the Atlantic since 2002, when four hurricanes formed.



· Two major hurricanes formed during the 2006 season. 1997 was the most recent year to have fewer than two major hurricanes form (1 – Erika).



· 50 named storm days occurred in 2006. This is the lowest value of named storm days since 1997, when only 28.75 named storm days occurred.



· 20 hurricane days occurred in 2006. This is the lowest value of hurricane days since 2002, when 10.75 hurricane days were observed.



· 3 intense hurricane days occurred in 2006. This ties 2002 for the lowest value of intense hurricane days observed since 1997, when only 2.25 intense hurricane days occurred.



· Only one hurricane formed during August. This is the fewest hurricanes to form in August since 2002, when no hurricanes formed.



· September 2006’s NTC value was 66. This is the ninth straight September with NTC exceeding the climatological average of 48. The last September with below-average NTC was 1997, when only 28 NTC units were accrued.



· 18.25 hurricane days occurred in September 2006. This is more than were observed in September 2005 (16.75 hurricane days).



· No named storms formed in October. This is the first time that no named storms have formed in October since 2002. Prior to 2006, only eleven years since 1950 witnessed no named storm formations in October.



· Only two named storm days were observed in October (from Isaac which formed in late September). This is the fewest named storm days in October since 1994, when zero named storm days were observed.



· The season accumulated 85 NTC units. This is the lowest NTC value since the 2002 season which accrued 82 NTC units.



· No Category 4 or 5 hurricanes formed in the Atlantic basin this year. This is the first year with no Category 4-5 hurricanes in the Atlantic since 1997.



· Three named storms made United States landfall in 2006. This is the fewest number of named storms to make landfall in the United States since 2001 when three named storms (Allison, Barry and Gabrielle) made landfall.



· This is only the 11th year since 1945 that no hurricanes have made United States landfall.



· From Alberto-Helene, each tropical cyclone lasted as long or longer than the cyclone preceding it. For example, Alberto and Beryl lasted 2.75 named storm days, Chris and Debby lasted 3.25 named storm days, Ernesto lasted 6 named storm days, etc.



· Both Gordon and Helene accumulated 7.5 hurricane days. These two storms accrued as many hurricane days as Wilma, which was the longest-lived hurricane of the 2005 season


The Colorado team admits the big bust of their forecast.Also very interesting things occured after all even with the inactivity as you can read in the Special Caracterictics of the 2006 season.About the actual status of El Nino,they say it's a moderate el nino.

Any comments about this verification report are welcomed.

[HURAKAN]

Some 2006's pride:

18.25 hurricane days occurred in September 2006. This is more than were observed in September 2005 (16.75 hurricane days).


Of course it's a big bust to their forecast. I hope they have an exit plan!!! This just proves how Mother Nature can be, even in the 21st Century!!! Let see how the media and the public reacts to their 2007 forecast.

[cycloneye]

· This is only the 11th year since 1945 that no hurricanes have made United States landfall.

Well,that will depend on the Ernesto Tropical Cyclone Report that may have it as a hurricane landfall in North Carolina or not.

Yes HURAKAN,it will be interesting to see how the public follows the seasonal forecasts from now on after the busts in 2006 from all the experts.

[hurricanetrack]

Ernesto certainly had the pressure of a typical category one hurricane- I recorded 985.9 in the "eye" as it made its way through SE NC. However, I am not sure if the winds ever caught up to the pressure drop- perhaps ILM and MHX Doppler radar estimates can help in that area. We shall see....would be nice to have it classified as a hurricane if indeed it really was. This season was, as a few of us say, "rolled up".

[Stormcenter]

I hope we have more of these type "busts" forecasts in the future. I still can't believe it was so slow. We all deserved it especially those living along the battered western and northern GOM coastlines, including the good folks in Fl. who had to deal with the 2003 & 2004 seasons.

[brunota2003]

I like "bust" seasons too...but remember the folks here in NC too...we have had to deal with storms in 2002 (Kyle), 2003 (Isabel), 2004 (Alex, Bonny, Charley, Frances, Gaston, Ivan, Jeanne), 2005 (Dennis, Ophelia), and 2006 (Alberto, Ernesto)...I dont feel like looking to see if anymore affected NC...probably alot more there...now before you go and chew my head off, saying quite a few of the 2004 storms did not affect NC...remember that Western N.C. counts...as the rains can cause, and often do cause, serious problems in the mountains...

as for MHX radar helping, from what I've seen, it was well weaker when it finally entered into our area, remember when it was making landfall it was a long ways off and that the radar beam was most likely over shooting the areas of the storm we would be most interested in seeing: i.e. the low levels...however Mark, ILM is the one that ought to be real interesting...

[MGC]

From feast to famine....I'll take it after 2005. Hopefully the 2007 season mirrors 2006.......MGC