Marine Weather Conditions
By: Skip Hellen
The following information was accumulated over the past 40+ years of hard knocks and the byproduct of thousands of hours at sea while constantly watching and studying the local offshore weather patterns. I put the last few bits of information into this formula a few years ago and I am now enjoying a 80-90% accuracy ratio.
This is a short advanced course on how to read California off shore marine weather patterns and conditions
With gas prices skyrocketing to over $3 per gallon knowing how and when to plan your offshore hunting adventures and boat trips can save you hundreds of dollars as well as minimize the wear a tear on your body class="w3-content" and equipment.
This course is set up to walk you through the key components of reading and accurately predicting the marine weather off southern California. The key tools are Internet web sites which contain information critical in determining the current off shore weather and upcoming weather trends. The following sequence of web sites/information is important as well.
The lynch pin or key to all our local Southern California marine weather is the wind pattern at Pt. Conception. It’s important to understand that the prevailing weather flow on the west coast of the USA is on shore from the north to northwest from 280-330 degrees.
So let’s start by looking at the web site below:
Again this buoy information is the key to all marine weather in southern California.
Note the wind direction and the speed. The prevailing on shore winds on west cost are NW. Two primary forces listed below drive this powerful NW wind pattern;
1. High altitude, high speed jet steam (Caused mainly by the rotation of the planet).
2. Warming air over the desert which pulls the cooler marine air on shore (relationship of the Pacific Ocean and the North American continent).
Identifying breaks in these pattern is simply a function of watching the NW wind flow off Pt. Conception. When the NW pattern breaks the total energy tends to slack depending on the direction of the wind after the break.
Any wind other than NW can produce favorable off shore conditions. Each wind direction has its own particular issues but the main thing to remember is a break in the NW pattern is the key to favorable off shore sea conditions.
The second information web site has information that will verify how the change in wind direction at Pt. Conception is transferring down into southern California waters. The Tanner Bank buoy web site will verify the break.
Pay close attention to the sea height and intervals, if the seas are over 5' and the interval is less than 10 seconds it will be very uncomfortable to travel offshore in any vessel less that 50’ in length. Smaller waves and longer wave intervals indicate calmer seas, I look for under 4' and over 12 seconds. Ideal seas would be less than 3' with the interval over 15 seconds.
This is the third and very important peace to the puzzle.
This web site gives the big picture and shows all the wind speeds and directions from Pt. Conception to the Mexican border. The top animation indicates the wind with arrows and the bottom animation illustrates wind with colors. Shorter arrows indicate lighter winds on the top animation. Blue indicates lighter winds on the bottom color animation.
One other feature on this web site is the 12-hour Jaza loop below each animation, which allows one to see the wind trend over the last 12 hours. South of Pt. Conception is a very unique area on the west cost of California; we get what is called, “Catalina eddies,” especially in the late summer and fall months.
What generally happens is a high pressure develops over land and pushes air against the normal flow no shore, we call them Santa Ana winds and they blow E to NE. When these winds blow opposite the normal W to NW on shore winds the off shore waters calm down.
Again what to look for is a break in the normal N to NW wind.
Of course there are many other web sites and indictors but this is the condensed advanced course. I have listed many of the other web site tools I use to gather more information relating to marine offshore weather below.
Scripps - Costal Data Imformation Program
Intellicast - Weather Forcast
NRL/FNMOC NOGAPS SLP, Winds and Precip Forecasts
NOAA - National Data Buoy Center
NOAA/NCEP- Wave Watch
Dept. of Atmospheric Sciences, Univ. of Washington - Infrared Satellite Imagery with NCEP-Analyzed Fronts
I have a more advanced course with comprehensive information on how to use the additional above web site and much, much more. For info about this advanced course, offshore weather seminars and
PowerPoint presentations contact me at firstname.lastname@example.org. Prices are
negotiable for large groups. Good luck and good hunting.