2. Objectively Chosen Analog Years
Seasonal Forecasts
using
Objectively Chosen Analog Years

3. Objectively Chosen Analog Years
Seasonal Forecasts
using
Objectively Chosen Analog Years
The Technique
Verification
Analogs for Upcoming Winter
The Forecast

4. Analog Seasonal Forecasting
Look at this year so far…

5. Analog Seasonal Forecasting
Look at this year so far…
Look for past years that are similar to this year …

6. Analog Seasonal Forecasting
Look at this year so far…
Look for past years that are similar to this year …
Use what subsequently happened in those past years as a forecast for what will happen this year.

7. Analog Seasonal Forecasting
Look at this year so far…
Look for past years that are similar to this year …
Use what subsequently happened in those past years as a forecast for what will happen this year.

8. Climate Indices
PNA (Pacific North American Index) NAO (North Atlantic Oscillation) Jones NAO EPO (Eastern Pacific Oscillation) TNH ONI NTA (North Tropical Atlantic Index) CAR (Caribbean Index) MEI BEST Nino 3 Nino 1+2 Nino 3+4 Nino 4 Pacific Warm Pool Tropical Pacific SST EOF TNA TSA WHWP WP (West Pacific Index) QBO (Quasi-Biennial Oscillation) PDO (Pacific Decadal Oscillation) PMM (Pacific Meridional Mode) NP (North Pacific Index)
NOI (Northern Oscillation Index)
AO (Arctic Oscillation)
AAO
TNI
Atlantic Tripole SST EOF
AMO
AMM (Atlantic Meridional Mode)
ACE (Atlantic Accumulated Cyclone Intensities)
Solar Cycle (Flux)
Monthly Hurricane Total
MDR Hurricanes SST Anomaly
MDR - Tropics SST Anomaly
Central India Monsoon Precipitation
Sahel Rainfall
Brazil Rainfall
SW USA Monsoon
Global Mean Temperature
ESPI
Globally integrated angular momentum

12. Not just the index…
But sensible weather…
IE Warm/Cool… Wet/Dry

13. Automate the Process Compare each previous year to this year…
Compute a “Goodness of Fit” number…
Sort “Goodness of Fit”…
Print/Save results…
Do this for multiple indices…
Find “Consensus” analog years

21. Last Year’s

22. 2012/13 Forecast Summary Near Near Above Near Near Near
Climate Division 2 – Willamette Valley
Dec Jan Feb Mar Apr May
Near Near Above Near Near Near
Temp:
Below Above Below Near Above Near
Precip:

23. 2012/13 Forecast Summary Near Near Above Near Near Near
Climate Division 2 – Willamette Valley
Dec Jan Feb Mar Apr May
Near Near Above Near Near Near
Temp:
Below Above Below Near Above Near
Precip:
Observed:
Climate Division 2 – Willamette Valley
Dec Jan Feb Mar Apr May
Near Below Near Above Near Above
Temp:
Above Below Below Below Near Above
Precip:

24. P P P 2012/13 Forecast Summary Near Near Above Near Near Near
Climate Division 2 – Willamette Valley P P
Dec Jan Feb Mar Apr May
Near Near Above Near Near Near
Temp: P
Below Above Below Near Above Near
Precip:
Observed:
Climate Division 2 – Willamette Valley
Dec Jan Feb Mar Apr May
Near Below Near Above Near Above
Temp:
Above Below Below Below Near Above
Precip:

25. 3 “Hits” 6 One-category errors 3 Two-category errors
2012/13 Verification
3 “Hits”
6 One-category errors
3 Two-category errors

26. On to Next Winter…

27. On to Next Winter…

28. On to Next Winter…

29. Last Year’s Indices CPC SOI, MEI, ONI,
BOM SOI, Nino 3.4 Anom, Nino 3 Temps, Nino 4 Temps, PNA, PDO, NAO, AO, WP, and the QBO.

30. This Year’s Indices
CPC SOI
MEI
ONI
PDO

32. Choosing Analogs Art or Science? Steve Pierce:
1959/ / / / / /09

33. Choosing Analogs Art or Science? Steve Pierce:
1959/ / / / / /09
Rod Hill:
1979/ / / / /06

34. Choosing Analogs Art or Science? Steve Pierce:
1959/ / / / / /09
Rod Hill:
1979/ / / / /06
George Taylor:
1970/ / / / /08

35. Choosing Analogs Art or Science? Steve Pierce:
1959/ / / / / /09
Rod Hill:
1979/ / / / /06
George Taylor:
1970/ / / / /08
Pete Parsons:
1967/ / /07

36. Choosing Analogs Art or Science? Steve Pierce:
1959/ / / / / /09
Rod Hill:
1979/ / / / /06
George Taylor:
1970/ / / / /08
Pete Parsons:
1967/ / /07
Jim Little:
1961/ / / / / /02

37. Choosing Analogs 1981/82 1959/60 1985/86 1985/86 1961/62 1988/89
Art or Science?
1959/60
1961/62
1962/63
1964/65
1967/ /68
1970/71
1973/74
1975/76
1979/80
1980/81
1981/82
1985/ /86
1988/89
1990/91
1996/ /97
2001/02
2005/06
2006/07
2007/ /08
2008/09

39. Composites November…

55. Composites December…

64. Composites January…

70. Composites February…

76. Composites March…

82. 2013/14 Forecast Summary Below Near Near Near Below Near
Climate Division 2 – Willamette Valley
Dec Jan Feb Mar Apr May
Below Near Near Near Below Near
Near Above Near Below Above Near
Temp:
Precip:

83. Cascades

84. 2013/14 Forecast Summary Below Below Near Near Near Below
Climate Division 4 – North Cascades
Dec Jan Feb Mar Apr May
Below Below Near Near Near Below
Temp:
Near Above Above Below Above Above
Precip:

85. Government Camp Snow November 21 13 12 11 10 8 6 1 22 28 18 14 24 26
23d
24th
25th
26th
27th
28th
29th
30th
1st
1961 21 13 12 11 10 8 6
1964 1 22 28 18 14
1967 24
1996 26 29 30 34
2001 7 M 27 48
2007 15 16 36
Snow Depth in Inches
Thanksgiving – Nov 28th

86. 5 out of 6 years: Government Camp Snow November Thanksgiving or
23d
24th
25th
26th
27th
28th
29th
30th
1st
1961 21 13 12 11 10 8 6
1964 1 22 28 18 14
1967 24
1996 26 29 30 34
2001 7 M 27 48
2007 15 16 36
5 out of 6 years:
Thanksgiving or
Thanksgiving Weekend Opening
Snow Depth in Inches
Thanksgiving – Nov 28th

87. Government Camp Snow December 28 26 31 40 36 30 29 27 6 4 10 16 22 33
24th
25th
26th
27th
28th
29th
30th
31st
1961 28 26 31 40 36 30 29 27
1964 6 4 10 16 22 33
1967 20 12 9 3 2 1
1996 53 65 64 67 68 71 52 50
2001 56 54 48
2007 43 59 61 74 70
Snow Depth in Inches

88. Questions? Below Near Near Near Below Near
Climate Division 2 – Willamette Valley
Dec Jan Feb Mar Apr May
Below Near Near Near Below Near
Near Above Near Below Above Near
Temp:
Precip:
Winter Forecast Graphics

89. Questions? Below Near Near Near Below Near
Climate Division 2 – Willamette Valley
Dec Jan Feb Mar Apr May
Below Near Near Near Below Near
Near Above Near Below Above Near
Temp:
Precip:
Winter Forecast Graphics

90. Questions? Below Near Near Near Below Near
Climate Division 2 – Willamette Valley
Dec Jan Feb Mar Apr May
Below Near Near Near Below Near
Near Above Near Below Above Near
Temp:
Precip:
Winter Forecast Graphics