Klein maar taai, dat is een prima omschrijving voor “eppy” (cat.1 orkaan) die boven water van slechts een graad of 22-24 van geen opgeven weet. Waarschijnlijk als gevolg van lagere bovenlucht temperaturen daar zo noordelijk, west van de azoren. Nu gaat ie weer richting zuid en zoekt dus warmer water op. Als ie wat kou van boven mee sleurt kan ie wellicht nog wat versterken ook.
Verder: Volgend jaar 79% kans op weer een actiever dan normaal orkaan seizoen… ik kan nu al niet wachten op alle theorieën over actief seizoen versus easton07/ december kou/ winter verwachtingen… en ik doe zelf wel mee hoor. Hoe dan ook, als de easton cyclus nu viel/valt in 05/06/07, en actieve orkaan seizoenen vaak vervolgt worden door koudere winters, dan is met veel fanta. Wel een verband te zien. O.k. deze winter moet nog ff beginnen, maar 05 was in heel europa m.u.v. Nl. tamelijk sneeuwrijk en fris hoor. Ik zou zeggen: fantaseer er zelf maar op los.
:"Extended Range Forecast for Atlantic
Hurricane Activity in 2006
Issued: 6th December 2005
by Professor Mark Saunders and Dr Adam Lea
Benfield Hazard Research Centre, UCL (University College London), UK
Forecast Summary
After accurate long-range outlooks for 2003-5, TSR predicts another active
Atlantic hurricane season in 2006.
The TSR (Tropical Storm Risk) extended range forecast for Atlantic hurricane activity in 2006 anticipates
yet another active season. Based on current and projected climate signals, Atlantic basin and US
landfalling tropical cyclone activity are forecast to be 60% above the 1950-2005 norm in 2006. There is a
high (~80%) likelihood that activity will be in the top one-third of years historically. The forecast spans
the period from 1st June to 30th November 2006 and employs data through to the end of November 2005.
TSR’s two predictors are the forecast July-September 2006 trade wind speed over the Caribbean and
tropical North Atlantic, and the forecast August-September 2006 sea surface temperature in the tropical
North Atlantic. The former influences cyclonic vorticity (the spinning up of storms) in the main hurricane
track region, while the latter provides heat and moisture to power incipient storms in the main track
region. At present TSR anticipates both predictors having a moderate enhancing effect on activity.
Monthly updated forecasts will be issued through to August 2006.
Atlantic ACE Index and System Numbers in 2006
ACE Intense Tropical
Index Hurricanes Hurricanes Storms
TSR Forecast (±FE) 2006 162 (±60) 3.9 (±1.8) 8.5 (±2.8) 15.7 (±4.5)
56yr Climate Norm (±SD) 1950-2005 102 (±61) 2.7(±1.9) 6.2 (±2.6) 10.3 (±4.0)
Forecast Skill at this Lead 1996-2005 32% 21% 17% 5%
Key: ACE Index = Accumulated Cyclone Energy Index = Sum of the Squares of 6-hourly Maximum Sustained
Wind Speeds (in units of knots) for all Systems while they are at least Tropical Storm Strength.
ACE Unit = x104 knots2.
Intense Hurricane = 1 Minute Sustained Wind > 95Kts = Hurricane Category 3 to 5.
Hurricane = 1 Minute Sustained Wind > 63Kts = Hurricane Category 1 to 5.
Tropical Storm = 1 Minute Sustained Wind > 33Kts.
SD = Standard Deviation.
FE (Forecast Error) = Standard Deviation of Errors in Replicated Real Time Forecasts 1986-2005.
Forecast Skill = Percentage Improvement in Mean Square Error over Running 10-year Prior Climate Norm
from Replicated Real Time Forecasts 1996-2005.
There is a 79% probability that the 2006 Atlantic hurricane season ACE index will be above average
(defined as an ACE index value in the upper tercile historically (>113)), a 15% likelihood it will be nearnormal
(defined as an ACE index value in the middle tercile historically (67 to 113) and only a 6% chance
it will be below-normal (defined as an ACE index value in the lower tercile historically (<67)). The 56-
year period 1950-2005 is used for climatology.
Key: Terciles = Data groupings of equal (33.3%) probability corresponding to the upper, middle and lower onethird
of values historically (1950-2005).
Upper Tercile = ACE index value greater than 113.
Middle Tercile = ACE index value between 67 and 113.
Lower Tercile = ACE index value less than 67.
_
ACE Index & Numbers Forming in the MDR, Caribbean Sea and Gulf of Mexico in 2006
ACE Intense Tropical
Index Hurricanes Hurricanes Storms
TSR Forecast (±FE) 2006 136 (±60) 3.36(±1.6) 6.4 (±2.7) 11.3 (±4.2)
56yr Climate Norm (±SD) 1950-2005 79 (±60) 2.3 (±1.8) 4.3 (±2.5) 7.1 (±3.5)
Forecast Skill at this Lead 1996-2005 39% 35% 38% 17%
The Atlantic hurricane Main Development Region (MDR) is the region 10oN - 20oN, 20oW - 60oW
between the Cape Verde Islands and the Caribbean Lesser Antilles. A storm is defined as having formed
within this region if it reached at least tropical depression status while in the area.
There is a 78% probability that in 2006 the MDR, Caribbean Sea and Gulf of Mexico ACE index will be
above average (defined as an ACE index value in the upper tercile historically (>91)), an 18% likelihood it
will be near-normal (defined as an ACE index value in the middle tercile historically (35 to 91) and only a
4% chance it will be below-normal (defined as an ACE index value in the lower tercile historically (<35)).
The 56-year period 1950-2005 is used for climatology.
USA Landfalling ACE Index and Numbers in 2006
ACE Tropical
Index Hurricanes Storms
TSR Forecast (±FE) 2006 4.2 (±1.8) 2.3 (±1.3) 4.9 (±1.9)
56yr Climate Norm (±SD) 1950-2005 2.4 (±2.2) 1.5 (±1.3) 3.1 (±2.0)
Forecast Skill at this Lead 1996-2005 37% 23% 19%
Key: ACE Index = Accumulated Cyclone Energy Index = Sum of the Squares of hourly Maximum
Sustained Wind Speeds (in units of knots) for all Systems while they are at least
Tropical Storm Strength and over the USA Mainland (reduced by a factor of 6).
ACE Unit = x104 knots2.
Landfall Strike Category = Maximum 1 Minute Sustained Wind of Storm Directly Striking Land.
USA Mainland = Brownsville (Texas) to Maine.
USA landfalling intense hurricanes are not forecast since we have no skill at any lead.
There is an 81% probability that in 2006 the USA landfalling ACE index will be above average (defined
as a USA ACE index value in the upper tercile historically (>2.63)), a 15% likelihood it will be nearnormal
(defined as a USA ACE index value in the middle tercile historically (1.14 to 2.63) and only a 4%
chance it will be below-normal (defined as a USA ACE index value in the lower tercile historically
(<1.14)). The 56-year period 1950-2005 is used for climatology.
Caribbean Lesser Antilles Landfalling Numbers in 2006
ACE Intense Tropical
Index Hurricanes Hurricanes Storms
TSR Forecast (±FE) 2006 2.4 (± 2.4) 0.4 (±0.4) 0.7 (±0.6) 1.8 (±1.1)
56yr Climate Norm (±SD) 1950-2005 1.4 (±2.0) 0.3 (±0.5) 0.4 (±0.7) 1.1 (±1.0)
Forecast Skill at this Lead 1996-2005 26% 15% 29% 0%
Key: ACE Index = Accumulated Cyclone Energy Index = Sum of the Squares of hourly Maximum
Sustained Wind Speeds (in units of knots) for all Systems while they are at least
Tropical Storm Strength and within the boxed region (10oN-18oN,60oW-63oW)
(reduced by a factor of 6). ACE Unit = x104 knots2.
Landfall Strike Category = Maximum 1 Minute Sustained Wind of Storm Directly Striking Land.
Lesser Antilles = Island Arc from Anguilla to Trinidad Inclusive.
_
Key Predictors for 2006
The key factors behind the TSR forecast for an above-average hurricane season in 2006 are the
anticipated moderate enhancing effect of July-September forecast trade winds at 925mb height over the
Caribbean Sea and tropical North Atlantic region (7.5oN - 17.5oN, 30oW - 100oW), and of August-
September forecast sea surface temperature for the Atlantic MDR (10oN - 20oN, 20oW - 60oW). The
current forecasts for these predictors are 0.68±0.80 ms-1 weaker than normal (1976-2005 climatology)
and 0.24±0.30oC warmer than normal (1976-2005 climatology). The forecast skills (assessed for the
period 1986-2005) for these predictors at this lead are 27% and 33% respectively.
Further Information and Next Forecast
Further information about TSR forecasts, verifications and hindcast skill as a function of lead time may
be obtained from the TSR web site http://tropicalstormrisk.com. The first TSR monthly forecast update
for the 2006 Atlantic hurricane season will be issued on the 5th January 2006."
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