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Verification of 2005 Hurricane Forecasts and 2006
Hurricane Forecast
Phil Klotzbach Bahamas Weather
Conference 3/10/2006
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2005 Atlantic Basin Activity Summary
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2005 ATLANTIC BASIN TROPICAL CYCLONE ACTIVITY
Forecast Parameter and 1950-2000 Climatology (in parentheses) Observed Activity
Named Storms (NS) (9.6) 27
Named Storm Days (NSD) (49.1) 126
Hurricanes (H) (5.9) 15
Hurricane Days (HD) (24.5) 51
Intense Hurricanes (IH) (2.3) 7
Intense Hurricane Days (IHD) (5.0) 16.75
Net Tropical Cyclone Activity (NTC) (100) 273
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Source http//weather.unisys.com
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2005 United States Landfalls
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2005 United States Major Hurricane Landfalls
Name Date Landfall Location Landfall Intensity (kts) Insured Damage (Billions) Total Damage (Billions)
Dennis 7/10 Santa Rosa Island, FL 105 1.1 2.2
Katrina 8/29 Buras, LA 110 37.5 75.0
Rita 9/24 Cameron, LA 105 4.7 9.4
Wilma 10/24 Cape Romano, FL 105 6.1 12.2
Total 50 100
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2005 Atlantic Basin Hurricane Forecast
Verification
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2005 ATLANTIC BASIN SEASONAL HURRICANE FORECASTS
Tropical Cyclone Parameter Issue Date 3 December 2004 Issue Date 1 April 2005 Issue Date 31 May 2005 Issue Date 5 August 2005 Observed Activity
Named Storms (9.6) 11 13 15 20 27
Named Storm Days (49.1) 55 65 75 95 126
Hurricanes (5.9) 6 7 8 10 15
Hurricane Days (24.5) 25 35 45 55 51
Intense Hurricanes (2.3) 3 3 4 6 7
Intense Hurricane Days (5.0) 6 7 11 18 16.75
Net Tropical Cyclone Activity (100) 115 135 170 235 273
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AUGUST 2005 FORECAST VERIFICATION
Forecast Parameter and 1950-2000 Climatology (in parentheses) Forecast August Activity Observed August Activity
Named Storms (NS) (2.8) 5 5
Named Storm Days (NSD) (11.8) 20 21
Hurricanes (H) (1.6) 3 2
Hurricane Days (HD) (5.7) 10 7
Intense Hurricanes (IH) (0.6) 1 1
Intense Hurricane Days (IHD) (1.2) 3 2.5
Net Tropical Cyclone Activity (NTC) (26) 50 42
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SEPTEMBER 2005 FORECAST VERIFICATION
Forecast Parameter and 1950-2000 Climatology (in parentheses) Forecast September Activity Observed September Activity
Named Storms (NS) (3.4) 5 5
Named Storm Days (NSD) (21.7) 31 36
Hurricanes (H) (2.4) 4 5
Hurricane Days (HD) (12.3) 22 18
Intense Hurricanes (IH) (1.3) 2 2
Intense Hurricane Days (IHD) (3.0) 6 3.5
Net Tropical Cyclone Activity (NTC) (48) 80 73
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OCTOBER 2005 FORECAST VERIFICATION
Forecast Parameter and 1950-2000 Climatology (in parentheses) Forecast October Activity Observed October Activity
Named Storms (NS) (1.7) 3 6
Named Storm Days (NSD) (9.0) 13 18.5
Hurricanes (H) (1.1) 2 4
Hurricane Days (HD) (4.4) 6 10
Intense Hurricanes (IH) (0.3) 1 2
Intense Hurricane Days (IHD) (0.8) 1 5
Net Tropical Cyclone Activity (NTC) (17) 30 66
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2006 Atlantic Basin Hurricane Forecast
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December Forecast Predictors
November 500 mb Geopotential Height
October-November SLP
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September 500 mb Geopotential Height
2
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September-November SLP
5
QBO
6
4
EQ.
November SLP
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2006 FORECAST AS OF 6 DECEMBER 2005
Forecast Parameter Statistical Forecast Analog Forecast 6 December 2005 Forecast 1950-2000 Climatology
Named Storms (NS) 11.2 12.0 17 9.6
Named Storm Days (NSD) 64.5 73.1 85 49.1
Hurricanes (H) 7.7 7.6 9 5.9
Hurricane Days (HD) 36.7 40.5 45 24.5
Intense Hurricanes (IH) 3.2 4.2 5 2.3
Intense Hurricane Days (IHD) 8.4 13.6 13 5.0
Net Tropical Cyclone Activity (NTC) 142 170 195 100
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The number of years that our tropical cyclone
forecasts issued at various lead times have
correctly predicted above- or below-average
activity for each predictand over the past seven
years (1999-2005)
Tropical Cyclone Parameter Early December Early April Early June Early August
NS NSD H HD IH IHD 6/7 6/7 5/7 5/7 5/7 5/7 7/7 7/7 6/7 6/7 5/7 5/7 7/7 7/7 6/7 6/7 7/7 7/7 6/7 6/7 7/7 7/7 7/7 7/7
NTC 5/7 6/7 6/7 7/7
TOTAL 37/49 (76) 42/49 (86) 46/49 (94) 47/49 (96)
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2006 Updates Forecasts
Date 6 Dec. 4 Apr. 31 May 3 Aug. 1 Sep. 3 Oct.
Seasonal Forecast X X X X X X
Monthly Forecast X X X
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Current Tools Used to Issue U.S. Landfall
Probability Forecasts

• Net Tropical Cyclone (NTC) Activity Forecast
• Measure of North Atlantic Sea Surface
  Temperatures (SSTA)

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PROBABILITIES FOR AT LEAST ONE MAJOR (CATEGORY
3-4-5) HURRICANE LANDFALL ON EACH OF THE
FOLLOWING COASTAL AREAS FOR 2006

• Entire U.S. coastline 81 (average for last
  century is 52)
• 2) U.S. East Coast including Peninsula Florida -
  64 (average for last century is 31)
• 3) Gulf Coast from the Florida Panhandle
  westward to Brownsville - 47 (average for last
  century is 30)
• 4) Expected above-average major hurricane
  landfall risk in the Caribbean

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Revised 1 June Landfall Probability Forecasts

• Net Tropical Cyclone (NTC) Activity Forecast
• 500 MB Ht. and SLP Predictors

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East Coast Landfall Predictors
April - May 500 MB Ht.
3
1
April - May 500 MB Ht.
EQ.
2
April - May SLP
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Gulf Coast Landfall Predictors
May 500 MB Ht.
3
EQ.
1
2
May 500 MB Ht.
April-May 500 MB Ht.
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Landfalling Hurricane Prediction Skill
Landfall Region Correlation (1950-2005) Top 10 / Bottom 10
East Coast 0.71 23 / 3
Gulf Coast 0.65 17 / 4
U.S. Coast 0.63 37 / 8
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New Landfalling Hurricane Web Application

• Currently Available at the following URL

http//www.e-transit.org/hurricane
In partnership with the GeoGraphics Laboratory
Bridgewater State College, Bridgewater MA
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Recent Updates

• Historical Database Updated Through 2004 Season
• Historical Database Extended Back to 1851 with
  Revision of the HURDAT Database

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Areas for which Landfall Probabilities are Issued
U.S. 1
Sub U.S. 2
Regions 11
Sub Regions 55
Counties 205
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REGION 2 - TEXAS LOUISIANA
H
A
J
C
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C
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V
C
(c)
(b)
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Future Work

• Monthly Probabilities
• User-Selected Probabilities (Daily, Weekly
  Periods)
• Potential Damage

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We must stop GLOBAL WARMING!
LANDFALLINGHURRICANES
MACK