Please select your home edition
Edition
Ancasta Ker 40+ 728x90

How to predict combination afternoon breezes

by John Jamieson on 10 Oct 2012
Coastal sailing - how will I know what the wind will do this afternoon? .. .
How can you predict the effects of a sea breeze when combined with a coastal wind? Will this mean sail reefing this afternoon or a wind light enough to fly a spinnaker? Learn how to forecast coastal wind effect with these sailing secrets from John Jamieson (Captain John):

Winds caused by pressure differences create prevailing winds. After blowing for several hours, a prevailing wind aligns itself in a direction, parallel the coastline.

If local sea breezes are strong enough, they can modify the direction and speed of the prevailing coastal wind.

These effects might not be included in a marine weather forecast. Use these easy steps to make your own sailing weather forecast:

1. Listen to the forecast prevailing wind

Tune in to the closest weather channel on your marine radio. Copy down the forecast coastal winds direction and speed.

For example, let's say that a northerly wind has been blowing for several hours along the coast. The marine forecast calls for northerly winds at 15 knots this afternoon.

2. Estimate the afternoon sea breeze

Make a determination as to whether to modify the forecast based on cloud cover. Cloudless days mean stronger afternoon sea breezes. Partly cloudy or overcast days indicate lighter sea breezes. In our example, you observe a cloudless sky, so you should expect a strong easterly sea breeze to fill in by early afternoon.

3. Combine directions and speeds

In the afternoon, the prevailing wind and sea breeze will combine to produce an average direction--northeasterly in the example. The strong sea breeze could increase the prevailing wind speed by 50%, or up to 22 1/2 knots.

Whether the winds increase that much depends on meteorological conditions, but you and your sailing crew will be ready in any case.

John Jamieson (Captain John) with 25+ years of experience shows you the no-nonsense cruising skills you need for safer sailing worldwide. Visit his website at www.skippertips.com and sign up for his FREE highly popular Sailing Tip of the Week. Discover how you can gain instant access to hundreds of sailing articles, videos, e-Books and more!

Southern Spars - 100Naiad/Oracle SupplierMackay Boats

Related Articles

Bavaria Yachts to introduce Cruiser 34 and Nautitech 46
The Cruiser 34 will be on show at the Bavaria Yachts display at the Strictly Sail boat show at Bayside’s Miamarina The Cruiser 34 will be on show at the Bavaria Yachts display at the Strictly Sail boat show at Bayside’s Miamarina, from February 16th to 20th.
Posted on 13 Feb
Unique Transatlantic Sailing Event - Building friendship across oceans
Rendez-Vous 2017 Tall Ships Regatta, organised to celebrate Canada 150, 150th anniversary of the Canadian Confederation. Sailing in the wake of the great explorers, international friendship and understanding is at the core of this once in a lifetime adventure - The Rendez-Vous 2017 Tall Ships Regatta, organised to celebrate Canada 150, the 150th anniversary of the Canadian Confederation.
Posted on 10 Feb
Frigid flying – Coast Guard aircrews take on New England Winter
Freezing rain? Teeth-chattering temperatures? Limited visibility? Coast Guard aircrews are still ready to fly. Freezing rain? Teeth-chattering temperatures? Limited visibility? Coast Guard aircrews are still ready to fly. At Air Station Cape Cod, aviation maintenance and electronic technicians work around the clock to ensure the MH-60 Jayhawk helicopters are prepared and ready to launch. There is one thing the maintenance crews and pilots cannot control: winter weather.
Posted on 9 Feb
On board interview with Lisa Blair - solo Antartica circumnavigation
So far, Lisa is tracking very well in her attempt to become the first woman to sail solo around Antartica. So far, Lisa is tracking very well in her attempt to become the first woman to sail solo around Antartica. After the setbacks of a delayed departure due to gremlins in the electronics, we are delighted to have these answers from her on board. She is well and enjoying her time. Climate Action Now, her Hick 50, left Albany in Western Australia on January 22, 2017.
Posted on 8 Feb
Yachting cartoonist Mike Peyton dies at 96
“The World’s Greatest Yachting Cartoonist” died on January 25, 2017 just five days after his 96th birthday. Mike Peyton, dubbed “The World’s Greatest Yachting Cartoonist”, died on January 25, 2017 just five days after his 96th birthday. A modest, shy man, he eschewed the spotlight and seemed unaware of the esteem which in sailors all around the world held him.
Posted on 27 Jan
Zhik Xeflex® - your shield against cold environments
This radiant barrier mid-layer nearly defies description. This radiant barrier mid-layer nearly defies description. How do you make a water resistant garment that really breathes, yet reflects your own body heat back to you? Where do you find a compression resistant and extremely insulating filling that is nowhere near as bulky as the Michelin Man, yet gives you that kind of warmth and comfort?
Posted on 17 Jan
Sounds like a boat - Lisa Blair's departure delayed due to electronics
Final preparations of her yacht, Climate Action Now by Sydney-based sailor Lisa Blair have uncovered an electrical issue Final preparations and safety checks of her yacht, Climate Action Now by Sydney-based sailor Lisa Blair have uncovered an electrical issue.
Posted on 15 Jan
Lisa Blair starts Solo Circumnavigation of Antarctica
Over 3,500 people have climbed Mount Everest, only two men have sailed solo, non-stop and unassisted around Antarctica. Over 3,500 people have climbed Mount Everest, over 500 have rowed across the various oceans and 12 people have landed on the moon. Only two men have sailed solo, non-stop and unassisted around Antarctica. Sydney-based Lisa Blair, 32, intends to become the first woman, the fastest and the third person in history to conquer such a challenge.
Posted on 14 Jan
When whales meet sails
CAMPER helmsman Roberto ‘Chuny’ Bermudez found himself nearly face to face with whale in middle of North Atlantic Ocean. Currently the database for marine mammal strikes is very sparse. We are requesting sailors and boaters help to submit information on current and past incidents, however long ago that may be. By giving a location, date, identification if possible, and any other relevant information you can help scientists better understand where marine mammals are at risk for strikes
Posted on 8 Jan
Potential instability in Atlantic Ocean water circulation system
One of the world’s largest ocean circulation systems may not be as stable as today’s weather models predict One of the world’s largest ocean circulation systems may not be as stable as today’s weather models predict, according to a new study. In fact, changes in the Atlantic Meridional Overturning Circulation (AMOC) — the same deep-water ocean current featured in the movie “The Day After Tomorrow” — could occur quite abruptly, in geologic terms, the study says.
Posted on 6 Jan