Interpreting Coastal Forecasts

[FishDiver]

I need a tutorial on relating NOAA swell, wave and weather forecasts to actual diving conditions for the Monterey coast area.

I assume that high North winds and big swells are bad. I need to understand what numbers correspond to "high" and "big". Understanding combinations of wind and wave conditions with wind direction would be very helpful.

 

[Anti-Hero]

This HOWTO page written by Chuck Tribolet is pretty much the gold standard at this time for reading predictive models.

Monterey Bay Sea Conditions - Some Examples

 

[btroxell]

For a more quantitative view of waves, I have written a simple paper on wave mechanics:
Monterey Dive Infomation- Wave Dissertion

Ben

 

[FishDiver]

Great references guys, thanks. I don't know how I missed Chuck's, I have other sections of his site bookmarked.

Looks like the short answer to my question is swell <= 10 feet = acceptable diivng.

 

[FishDiver]

Is there any seasonality to the swell and waves? I know the water temp doesn't vary much.

 

[Chuck Tribolet]

Actually, the water temp varies by about 8F. Usually we see 44F in April,
52F in Nov.
We see the bigggest swells about now.

 

[Chuck Tribolet]

Great references guys, thanks. I don't know how I missed Chuck's, I have other sections of his site bookmarked.

Looks like the short answer to my question is swell <= 10 feet = acceptable diivng.

Direction is important. If it's a 10' NW swell, I stay home,
but I'd go 12' SW swell (which is really rare).

 

[btroxell]

Is there any seasonality to the swell and waves? I know the water temp doesn't vary much.

Water temp (and indirectly clarity) can vary with the wind direction. This web site shows the temp vs wind effect.
MBARI - M1 Contour CTD string Metsys plot - last 30 days
The wind (when blowing in the right direction) causes upwelling, bringing up cold water laden with nutrients which plankton like they will bloom if the sun is bright.

Ben

 

[FishDiver]

How you interpret swell and wind waves? Do you add the two figures together for total wave height or is there a more subtle interaction?

TODAY
SE 10 TO 20 KT. WIND WAVES 3 TO 6 FT.
W SWELL 8 TO 10 FT AT 12 SECONDS. CHANCE OF RAIN.

TONIGHT
W WINDS 5 TO 15 KT. WIND WAVES 3 TO 4 FT.
W SWELL 7 TO 9 FT AT 12 SECONDS. CHANCE OF RAIN.

SUN
S WINDS 20 TO 30 KT. WIND WAVES 4 TO 8 FT.
W SWELL 7 TO 9 FT AT 12 SECONDS. RAIN.

SUN NIGHT
S WINDS 20 TO 30 KT. WIND WAVES 4 TO 7 FT.
W SWELL 9 TO 11 FT. RAIN.

 

[Chuck Tribolet]

What's that the forecast for? It's not Monterey (I log the Monterey offshore
forecasts, and the Monterey Bay forecast will be smaller).

The wind waves and swells add up, but they have different effects. Wind
waves make for a nasty surface swim or small boat ride, but don't effect
the diving much. Swells affect the surface swim and small boat ride
a bit, but mostly create surge on the bottom and surf for beach entries.