Objective Techniques In Analog Seasonal Forecasts Objective Techniques In Analog Seasonal Forecasts Analog Forecasting Objectively Picking Analogs Tools for Interpretation The Forecast Future Developments

Analog Seasonal Forecasting Look at this year so far…

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

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. 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.

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. 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.

Southern Oscillation Index Pacific Decadal Oscillation Multivariate ENSO Index PNA Nino 3.4 Sahel Rainfall

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) 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 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

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

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

Objective Forecast

The Indices: MEI CPC SOI BOM SOI ONI NINO3 TEMPS MEI CPC SOI BOM SOI ONI NINO3 TEMPS NINO4 TEMPS PNA PDO WP NINO4 TEMPS PNA PDO WP Objective Forecast

Analog Composites

November Temperature Precipitation

December Temperature Precipitation

January Temperature Precipitation

February Temperature Precipitation

March Temperature Precipitation

April Temperature Precipitation

Highs Lows

Period of Record Average Analog Average

32F = K

Wind storm 9 th, 10 th or 11 th ? … Mild Thanksgiving 30dm 500H anomaly over Pacific Northwest Wind storm 9 th, 10 th or 11 th ? … Mild Thanksgiving 30dm 500H anomaly over Pacific Northwest

Flirt w/cold air ~12 th -14 th Cold 20 th -29 th …Possible Arctic Event(s)? Positive 500H anomaly ~ 800 west of Oregon Flirt w/cold air ~12 th -14 th Cold 20 th -29 th …Possible Arctic Event(s)? Positive 500H anomaly ~ 800 west of Oregon

Warm 2 nd -8 th (Early “January Thaw”?) Arctic event toward end of month? 500H/850T significant negative anomaly Warm 2 nd -8 th (Early “January Thaw”?) Arctic event toward end of month? 500H/850T significant negative anomaly

Cool Month Valentine’s Day Snow? 30dm 500H negative anomaly Cool Month Valentine’s Day Snow? 30dm 500H negative anomaly

Wind Event 17 th, 18 th or 19th? 500H anomaly positive/850T anomaly negative Wind Event 17 th, 18 th or 19th? 500H anomaly positive/850T anomaly negative

Active month. Wide swings in temperatures but averages out cool. Active month. Wide swings in temperatures but averages out cool.

Government Camp Snow

2008: 4 th and 5 th 16 inches total…gone by 11 th. 2000: Snow on 6 th, snow again on 8 th and continuous snow cover through the end of the month. 1999: 21 st and 22 nd eight inches total…all melted by 27 th. 1989: Six inches on 13 th … 24 th -27 th twenty-eight inches. 1974: 18 th through 27 th seventeen inches total. 1971: Twenty-one inches on ground to start month… snowed fourty-seven inches during month. Government Camp Snow November

Good Great! Good Great! 2008: 4 th and 5 th 16 inches total…gone by 11 th. 2000: Snow on 6 th, snow again on 8 th and continuous snow cover through the end of the month. 1999: 21 st and 22 nd eight inches total…all melted by 27 th. 1989: Six inches on 13 th … 24 th -27 th twenty-eight inches. 1974: 18 th through 27 th seventeen inches total. 1971: Twenty-one inches on ground to start month… snowed fourty-seven inches during month. Bad Marginal Good Bad Marginal Good Government Camp Snow November

23d24th25th26th27th28th29th30th31st T001TT Government Camp Snow December Snow Depth in Inches

23d24th25th26th27th28th29th30th31st T001TT Government Camp Snow December Snow Depth in Inches

23d24th25th26th27th28th29th30th31st T001TT Government Camp Snow December Snow Depth in Inches OK Bummer Dude

Further Development

More indices

Further Development More indices Write routine(s) to produce and verify historical forecasts

Further Development More indices Write routine(s) to produce and verify historical forecasts Index/time period weighting

Forecast Summary/Questions Climate Division 2 – Willamette Valley Nov Dec Jan Feb Mar Apr Temp: Precip: Above Near Near Below Near Below Near Near Above Near Below Near