TM Weather Research Center

3227 Audley Houston, Texas 77098 Phone: 713-529-3076 Fax: 713-528-3538 E-mail: wrc@wxresearch.org

Press Release

For Immediate Release

July 15, 2003

For Information Contact: Jill Hasling 713-529-3076

HURRICANE CLAUDETTE HELPS VERIFY WRC’S

OCSI HURRICANE OUTLOOK MODEL

Also recent research reveals WRC’s OCSI model has better results than Gray’s Atlantic Seasonal Hurricane Activity Prediction Model

Houston – According to meteorologists Jill F. Hasling and Dr. John C. Freeman of Weather Research Center, the 2003 Atlantic storm season had a chance of experiencing a hurricane along the upper Texas Coast. Hurricane Claudette verifies this prediction. When reviewing the past years in this phase of the Orbital Cyclone Strike Index [OCSI], Ms. Hasling found that there were that two past years in this phase of the OCSI 1961 and 1983 had hurricanes, which significantly impacted the upper Texas coast, Hurricane Carla 1961 and Hurricane Alicia 1983.

The OCSI also indicated that there could be an early start of the Hurricane season. When you review the past years, which are in this phase of the OCSI [1874, 1885, 1896, 1908, 1920, 1930, 1940, 1951, 1961, 1971, 1983, and 1993], one of the years, 1908, had a hurricane which formed March 6. Ana verified this prediction when it formed on April 20 and lasted until April 24, 2003. Tropical Storm Bill made an early appearance by forming on June 29th and making landfall in Louisiana on June 30th.

The Orbital Cyclone Strike Index [OCSI] has been used by Hasling and Freeman since 1985 to make an outlook for the section of the US coast which has the highest risk of storm landfall. The OCSI also indicates that this year will be busy for the Atlantic Seaboard with a 64% chance of a tropical storm or hurricane making landfall.

Further research indicates that Weather Research Center’s [WRC’s ] Orbital Cyclone Strike Index’s [OCSI] secondary prediction elements verify better over the past nineteen years than Colorado State University’s Dr. Bill Gray’s Atlantic Seasonal Hurricane Activity predictions. WRC’s secondary prediction elements consist of the number of named storms in the Atlantic Basin, number of hurricanes in the Atlantic Basin, number of hurricane days and the number of storm days. The tables below give WRC’s prediction and Gray’s earliest prediction in April, May or June.

In Table 1 when you count the number of years when WRC’s forecast of the number of storms was within one storm, there were eight years out of the nineteen years forecasted. Gray’s forecast was only within one storm five of the nineteen years. WRC’s OCSI method forecasted the exact number of storms four of the nineteen years and Gray’s method forecasted the exact number of storms three out of the nineteen years.

Table 2 gives the number of hurricanes forecasted each year by both WRC and Gray’s method. WRC forecasted the number of hurricanes within one hurricane ten years out of the nineteen years and Gray’s method forecasted within one hurricane seven of the nineteen years.

Table 3 gives the number of hurricane days forecasted for each year. WRC forecasted the number of days within five days eight years out of the nineteen years. Gray’s method forecasted the number of hurricane days within five days five years out of the nineteen years.

Table 4 gives the forecast for both WRC’s and Gray’s model for the number of storm days in each year. WRC’s model forecasted the number of days within ten days for ten of the nineteen years. Gray’s model forecasted the number of days within ten days for six of the nineteen years.

This verification of the nineteen years of forecast demonstrates that the WRC’ OCSI model is as accurate if not more accurate than Gray’s model. The advantage of the OCSI model is that WRC’s model can make a prediction for the next ten years.

Table 1: Number of Named Storms in the Atlantic

Year

OBS

WRC FCST

WRC Error

Gray

APR FCST

GRAY APR Error

1984

12

7

-5

10

-2

1985

11

10

-1

11

0

1986

6

11

5

8

2

1987

7

7

0

8

1

1988

12

8

-4

11

-1

1989

11

10

-1

7

-4

1990

14

8

-6

11

-3

1991

8

9

1

8

0

1992

6

6

0

8

2

1993

8

7

-1

11

3

1994

7

7

0

9

2

1995

19

10

-9

10

-9

1996

13

11

-2

11

-2

1997

7

7

0

11

4

1998

14

8

-6

10

-4

1999

12

10

-2

14

2

2000

14

8

-6

11

-3

2001

15

9

-6

10

-5

2002

12

6

-6

12

0

Table 2: Number of Hurricanes in the Atlantic Basin

Year

OBS

WRC FCST

WRC Error

Gray Apr/Jun

Gray Error

1984

5

4

-1

7

2

1985

7

5

-2

8

1

1986

4

5

1

4

0

1987

3

4

1

5

2

1988

5

5

0

7

2

1989

7

6

-1

4

-3

1990

8

5

-3

7

-1

1991

4

6

2

4

0

1992

4

3

-1

4

0

1993

4

5

1

7

3

1994

3

4

1

5

2

1995

11

5

-6

6

-5

1996

9

5

-4

7

-2

1997

3

4

1

7

4

1998

10

5

-5

6

-4

1999

8

6

-2

9

1

2000

8

5

-3

7

-1

2001

9

6

-3

6

-3

2002

4

3

-1

7

3

 

 

Table 3. Number of Hurricane Days

Year

OBS

WRC FCST

WRC Error

Plus/Minus

Days

Gray Apr/Jun FCST

Gray Error

Plus/Minus

Days

1984

18

16

-2

30

12

1985

21

21

0

35

14

1986

11

24

13

15

4

1987

5

7

2

20

15

1988

21

25

4

30

9

1989

32

30

-2

15

17

1990

27

20

-7

30

3

1991

8

20

12

15

7

1992

16

15

-1

15

0

1993

10

21

11

25

15

1994

7

16

9

15

8

1995

62

21

41

25

37

1996

45

24

-21

25

-20

1997

10

7

-3

25

15

1998

49

25

-24

20

-29

1999

43

30

-13

40

-3

2000

32

20

-12

25

-7

2001

27

20

-7

25

-2

2002

11

15

4

30

19

 

Table 4: Number of Storm Days in the Atlantic

Year

OBS

WRC FCST

WRC Error

Plus/Minus

Days

Gray Apr/Jun FCST

Gray Error Plus/Minus

Days

1984

51

55

-4

45

6

1985

51

68

-17

55

-4

1986

23

83

-60

35

-12

1987

37

47

-10

40

-3

1988

47

57

-10

50

-3

1989

66

69

-3

30

36

1990

66

58

8

55

11

1991

22

64

-42

35

13

1992

39

41

-2

35

-4

1993

30

50

-20

55

25

1994

28

55

-27

35

7

1995

121

68

53

50

71

1996

78

83

-5

55

23

1997

28

47

-19

55

-27

1998

80

57

23

50

30

1999

77

69

8

65

12

2000

66

58

8

55

11

2001

63

64

-1

50

13

2002

54

41

13

65

-11

Table 5 is a summary of the forecast comparisons in Table 1 through 4. This table gives the number of years that each model was closest within the limits indicated.

Table 5: Summary of Model Comparison

# of Storms in Atlantic

within 1 storm

WRC OCSI

8 Years

Gray Atlantic Season

5 years

# hurricanes in Atlantic

within 1 storm

10 years

7 years

# of hurricane days

with 5 days

8 years

5 years

# of storm days

within 10 days

10 years

6 years

2003 OCSI FORECAST FOR THE ATLANTIC

COASTOCSICLIMATOLOGY
Mexico30%39%
Texas46%49%
Louisiana to Alabama46%59%
West Florida46%70%
East Florida30%39%
Georgia to N. Carolina64%54%
East Coast of US64%32%
Gulf Oil Blocks73%78%
Cuba64%

There is a chance of late storms with November having a 40% chance of a tropical storm or hurricane forming.

Secondary Predictions OCSI Atlantic Hurricane Outlook

Number of Named Storms8
Number of Hurricanes6
Number of Hurricane Days21
Number of Storm Days50

During this phase of the OSCI, storms form in the Gulf of Mexico or Bay of Campeche over 80% of the time. This has verified with Tropical Storm Bill forming in the Gulf of Mexico.

The OCSI model is based on the premise that there are orbital influences that are reflected in the global circulation pattern on the sun and subsequently the global circulation pattern of the earth. The sun's circulation is tracked by the sun spot cycle. Using this solar cycle to make an index, hurricane climatology has

been summarized into an index called the OCSI. This index has been used

since 1985 to make annual forecasts of which section of North America has the highest risk of experiencing a tropical storm or hurricane. In addition to its ongoing research, the Center also provides storm and hurricane information via the Internet through Storm Navigator®. This service helps people navigate weather information on the Internet as well as providing detailed storm updates and related information. All of the Center's projections including past predictions can be found on the Internet, http://www.wxresearch.com/outlook .

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