Surf Forecasting Today

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Surf Forecasting Today In search of the perfect
southern hemi session
Nathan Cool www.NathanCool.com
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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
• QA and web resources

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The Pebble and the Pond Ripples across the ocean
The Principle

• Wind (the pebble)
• Transfers energy to water
• Waves are created
• Travel outward
• Eventually reaching shore

The Practice

• Track ocean storms
• Measure energy
• Measure distance to shore
• Wax your board

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

• Your Tax Dollars at Work
• FNMOC
• NOAA
• NWS

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Dissecting a WAM Wave Heights
Date
Forecast Date
Heights
Scale/Key
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Dissecting a WAM Periods
Date
Forecast Date
Periods
Scale/Key
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The WAM Crystal Ball A model look at the future
Today
Sacrificing Accuracy
Tomorrow
48 Hours
144 Hours
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Weather Models

• Your Tax Dollars, Still At Work
• FNMOC
• NOAA
• NWS

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WAM Raw Data Grabbing the middle-man
Data
Monitoring Mechanisms
Model

• Wind data (wind fields)
• Sea surface temperatures
• Ice concentrations
• Bathymetry/obstruction data

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

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Tracking A Southern Hemi From the Southern Ocean
to SoCal

• The essentials
• Distance
• Angle
• Trajectory
• Wave Height
• Period

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Tracking A Southern Hemi From the Southern Ocean
to SoCal

• Distance 5200 nm
• Angle (A) 210
• Trajectory (T) 45
• Wave Height 36 feet
• Period 15 seconds

A
To SoCal
T
Trajectory
270
210
180
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Tracking A Southern Hemi The Numbers for SoCal

• Distance 5200 nm
• Angle (A) 210
• Trajectory (T) 45
• Wave Height (Wh) 36 feet
• Period (p) 15 seconds

A
To SoCal
T
Trajectory

• Distance Decay (dd) gt85
• 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)
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The SW Next Week Originating 2/17/08, Hitting
SoCal 2/27/08

• Distance 5300 nm
• Angle (A) 220
• Trajectory (T) 30
• Wave Height (Wh) 40 feet
• Period (p) 16 seconds

A
To SoCal
Trajectory

• Distance Decay (dd) gt87
• Angular Decay (ad) 10
• Height (h) ((Wh dd) ad)
• Face Height h (p 0.1)
• Time Distance / (p 1.5)

T
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 Face Height 4
(16 0.1) 6 feet max (based on 0h
projection) Time 5300 nm / (16 1.5) 220
hours ( 9 days)
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The SW Next Week Shoaling Considerations
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4
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 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)
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The SW Next Week Energy as it moves across the
Pacific

• Calculate Forerunners
• Reaffirm ETA by distance
• Reaffirm angle

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Indicators Near-term verification by buoys
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Indicators Near-term verification by CDIP
Now-cast Model But, initialized at Pt. Conception
9-Period Bands Buoy history
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Seasonal Forecasting Jetstream (recent January
swell)

• Low latitude
• Strong
• But slight nudge northward

By comparison though
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Seasonal Forecasting Jetstream (summertime
pattern)

• Higher latitude
• Weaker south

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Seasonal Forecasting Jetstream (the SW next week)

• Bending northward

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Seasonal Forecasting ENSO

• La Niña weaker southern hemi jetstream
• Better chance for storms to drift north
• Fewer Pacific hurricanes
• Better chance for Atlantic hurricanes
• El Niño stronger southern hemi jetstream
• Less chance for storms to drift north
• More Pacific hurricanes
• Blows out Atlantic hurricanes

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QA
Presentation available at www.WaveCast.com/ground
swell
Resources

• FNMOC WAMs and Wx Models https//www.fnmoc.navy.
  mil/public/
• NOAA WAMs http//polar.ncep.noaa.gov/waves/main_
  text.html
• Surf Forecast Guide http//www.amazon.com/gp/pro
  duct/059530365X
• Swell Distance Calculator http//wavecast.com/gu
  ide/distance.shtml
• Distance formulas http//www.meridianworlddata.c
  om/Distance-Calculation.asp

• WW3 Raw Data http//polar.ncep.noaa.gov/waves/pr
  oducts.html
• CDIP http//cdip.ucsd.edu/
• Jetstream Analysis http//squall.sfsu.edu/crws/j
  etstream.html
• National Data Buoy Center http//www.ndbc.noaa.g
  ov/
• ENSO, Climate Prediction Center
  http//www.cpc.noaa.gov/
• Free Surf Forecasts http//WetSand.com