1. Surf Forecasting Today In search of the perfect southern hemi session Nathan Cool www.NathanCool.com

2. Agenda The pebble in the pond, forecasting principle Tools of the trade: WAMs Data Mining Weather models WAMs in-depth Forecast Accuracy Dissecting data (automatic data mining) Forecasting examples, tracking SW swells Near-term swell verification Seasonal Surf Forecasting Q&A and web resources

3. The Pebble and the Pond Ripples across the ocean Wind (the pebble) Wind (the pebble) Transfers energy to water Transfers energy to water Waves are created Waves are created Travel outward Travel outward Eventually reaching shore Eventually reaching shore Track ocean storms Track ocean storms Measure energy Measure energy Measure distance to shore Measure distance to shore Wax your board Wax your board The Principle The Practice

4. The Tools of the Trade Wave Analysis Models (WAMs) Model Data Weather Models

5. Wave Analysis Models (WAMs) Your Tax Dollars at Work FNMOC FNMOC NOAA NOAA NWS NWS

6. Dissecting a WAM Wave Heights Heights Scale/Key Date Forecast Date

7. Dissecting a WAM Periods Periods Scale/Key Date Forecast Date

8. The WAM Crystal Ball A model look at the future Today Tomorrow 48 Hours 144 Hours Sacrificing Accuracy

9. Weather Models Your Tax Dollars, Still At Work FNMOC FNMOC NOAA NOAA NWS NWS

10. WAM Raw Data Grabbing the middle-man Monitoring Mechanisms Data Model Wind data (wind fields) Sea surface temperatures Ice concentrations Bathymetry/obstruction data

11. WAM Raw Data Number Crunching Behind the Scenes For any point on the planet (“Virtual” Buoys) Thus….

12. WAM Raw Data Making a near-shore chart Data Charts (Near-shore estimates) Monitoring Mechanisms Wind data (wind fields) Sea surface temperatures Ice concentrations Bathymetry/obstruction data

13. Tracking A Southern Hemi From the Southern Ocean to SoCal The essentials Distance Distance Angle Angle Trajectory Trajectory Wave Height Wave Height Period Period

14. Tracking A Southern Hemi From the Southern Ocean to SoCal Distance: ~5200 nm Distance: ~5200 nm Angle (A): ~210° Angle (A): ~210° Trajectory (T): ~45° Trajectory (T): ~45° Wave Height: ~36 feet Wave Height: ~36 feet Period: 15 seconds Period: 15 seconds To SoCal Trajectory 270 180 ~210 T A

15. Tracking A Southern Hemi The Numbers for SoCal Distance: ~5200 nm Distance: ~5200 nm Angle (A): ~210° Angle (A): ~210° Trajectory (T): ~45° Trajectory (T): ~45° Wave Height (Wh): ~36 feet Wave Height (Wh): ~36 feet Period (p): 15 seconds Period (p): 15 seconds To SoCal Trajectory T A Distance Decay (dd) = >85% Distance Decay (dd) = >85% Angular Decay (ad) = ~15% Angular Decay (ad) = ~15% Height (h) = ((Wh – dd) – ad) Face Height = h * (p * 0.1) Time = Distance / (p * 1.5) Height = (35’ – 85%) - 15% = 4.4’ Face Height = 4.4 * (15 * 0.1) = 6.6 feet Time = 5200 nm / (15 * 1.5) = 231 hours (~ 9 days)

16. The SW Next Week Originating 2/17/08, Hitting SoCal 2/27/08 Distance: ~5300 nm Distance: ~5300 nm Angle (A): ~220° Angle (A): ~220° Trajectory (T): ~30° Trajectory (T): ~30° Wave Height (Wh): ~40 feet Wave Height (Wh): ~40 feet Period (p): 16 seconds Period (p): 16 seconds To SoCal Trajectory T A Distance Decay (dd) = >87% Distance Decay (dd) = >87% Angular Decay (ad) = ~10% Angular Decay (ad) = ~10% Height (h) = ((Wh – dd) – ad) Face Height = h * (p * 0.1) Time = Distance / (p * 1.5) Height = (40’ – 87%) - 10% = ~4 - 5’ *Face Height = 4 to 5 * (16 * 0.1) = 6 to 8 feet (based on 24h projection) Time = 5300 nm / (16 * 1.5) = 220 hours (~ 9 days) Height = ( 35’ – 87%) - 10% = ~4’ Height = (35’ – 87%) - 10% = ~4’ *Face Height = 4 * (16 * 0.1) = 6 feet max (based on 0h projection) Time = 5300 nm / (16 * 1.5) = 220 hours (~ 9 days)

17. The SW Next Week Shoaling Considerations Face Height = Face Height = 4 * (16 * 0.1) = 6 feet max Face Height Approximations Steep Shoaling: h * (p * 0.1) Slow-sloped Shoaling: h * (p * 0.075) So… So… Steep Shoaling: = 4 * 1.6 = 6 foot face height Slow-sloped Shoaling) = 4 * 1.2 = 4-5 foot face Or… 4 to 6 foot face heights max (chest to head high max) 6’ 4’

18. The SW Next Week Energy as it moves across the Pacific Calculate Forerunners Calculate Forerunners Reaffirm ETA by distance Reaffirm ETA by distance Reaffirm angle Reaffirm angle

19. Indicators Near-term verification by buoys

20. Indicators Near-term verification by CDIP 9-Period Bands Buoy history Now-cast Model But, initialized at Pt. Conception

21. Seasonal Forecasting Jetstream (recent January swell) Low latitudeLow latitude StrongStrong But slight nudge northwardBut slight nudge northward By comparison though…

22. Seasonal Forecasting Jetstream (summertime pattern) Higher latitudeHigher latitude Weaker southWeaker south

23. Seasonal Forecasting Jetstream (the SW next week) Bending northward Bending northward

24. Seasonal Forecasting ENSO La Niña: weaker southern hemi jetstream La Niña: weaker southern hemi jetstream Better chance for storms to drift north Better chance for storms to drift north Fewer Pacific hurricanes Fewer Pacific hurricanes Better chance for Atlantic hurricanes Better chance for Atlantic hurricanes El Niño: stronger southern hemi jetstream El Niño: stronger southern hemi jetstream Less chance for storms to drift north Less chance for storms to drift north More Pacific hurricanes More Pacific hurricanes Blows out Atlantic hurricanes Blows out Atlantic hurricanes

25. Q&A FNMOC WAMs and Wx Models: https://www.fnmoc.navy.mil/public/ FNMOC WAMs and Wx Models: https://www.fnmoc.navy.mil/public/https://www.fnmoc.navy.mil/public/ NOAA WAMs: http://polar.ncep.noaa.gov/waves/main_text.html NOAA WAMs: http://polar.ncep.noaa.gov/waves/main_text.htmlhttp://polar.ncep.noaa.gov/waves/main_text.html Surf Forecast Guide: http://www.amazon.com/gp/product/059530365X Surf Forecast Guide: http://www.amazon.com/gp/product/059530365Xhttp://www.amazon.com/gp/product/059530365X Swell Distance Calculator: http://wavecast.com/guide/distance.shtml Swell Distance Calculator: http://wavecast.com/guide/distance.shtmlhttp://wavecast.com/guide/distance.shtml Distance formulas: http://www.meridianworlddata.com/Distance-Calculation.asp Distance formulas: http://www.meridianworlddata.com/Distance-Calculation.asphttp://www.meridianworlddata.com/Distance-Calculation.asp Resources Presentation available at: www.WaveCast.com/groundswell WW3 Raw Data: http://polar.ncep.noaa.gov/waves/products.html WW3 Raw Data: http://polar.ncep.noaa.gov/waves/products.htmlhttp://polar.ncep.noaa.gov/waves/products.html CDIP: http://cdip.ucsd.edu/ CDIP: http://cdip.ucsd.edu/http://cdip.ucsd.edu/ Jetstream Analysis: http://squall.sfsu.edu/crws/jetstream.html Jetstream Analysis: http://squall.sfsu.edu/crws/jetstream.htmlhttp://squall.sfsu.edu/crws/jetstream.html National Data Buoy Center: http://www.ndbc.noaa.gov/ National Data Buoy Center: http://www.ndbc.noaa.gov/http://www.ndbc.noaa.gov/ ENSO, Climate Prediction Center: http://www.cpc.noaa.gov/ ENSO, Climate Prediction Center: http://www.cpc.noaa.gov/http://www.cpc.noaa.gov/ Free Surf Forecasts: http://WetSand.com Free Surf Forecasts: http://WetSand.comhttp://WetSand.com