A Wind (and other relevant conditions) Primer
Deciphering the Wind Forecast
Wind. It can either make a great paddle, like when it’s ripping toward the West Maui Mountains and the Maliko Downwind run is firing, or it can break us, like the 2016 version of Chattajack, when 25 mile per hour plus headwinds make those 32 miles hell. Or like when an onshore wind messes up a perfectly good sup surf session.
Let’s face it, sometimes meteorological terms can be confusing. Especially where the wind is concerned. Does offshore mean it’s blowing toward the beach, or away from it? What about Nor’easters – do they come from the north or are they heading heading north? Let’s sort it out so we can all be on the same page, shall we? And while we’re at it, we’ll throw in a few more definitions that might be useful.
Meteorologists will tell you that in an official weather forecast, wind direction is usually cited as the direction the wind is coming from. So, if you hear a weather person say the wind is southwest at five miles per hour, or you read in a forecast that the wind is SW at 5 mph, it means the wind is coming from the southwest, blowing toward the northeast at 5 mph. It does not mean the wind is blowing toward the southwest.
If you want to get geeky about it, wind direction is measured in degrees clockwise from due north and so a wind coming from the south has a wind direction of 180 degrees; one from the east is 90 degrees.
Where it gets tricky is when we talk about coastal winds. If you look at a surf site like MagicSeaweed.com you’ll find this for the definition of onshore winds:
“Onshore wind blows from the sea towards the beach…” and offshore wind is conversely described as coming from the land, blowing toward the sea. So, that’s the opposite of cited wind direction.
No wonder it’s confusing, right?
But, sites like Magic Seaweed and Surfline help mitigate that confusion by including arrows that show the direction the wind is blowing in, as well as indicating whether it’s onshore or offshore, and the cited direction. On Magic Seaweed, just hover your mouse over the arrow and you’ll get the complete wind data, as in this example for Crystal Pier at Wrightsville Beach:
So, as an example, looking at the 6:00 am conditions, we can see that the wind is projected to be a moderate, onshore, east wind. That means the wind will be coming from the east, blowing onshore, like this:
So just to review, cited wind direction means the wind is coming from that stated direction. Onshore means the wind is blowing ONTO land, offshore means it’s blowing OFF land toward the ocean.
Here are a few more helpful definitions:
Cross shore wind: Wind that blows more or less parallel to the shoreline
Tailwind: wind that is blowing in the direction you want to paddle, coming from behind you, giving you a good push, and working with you.
Headwind: Wind coming from directly in front of you, from the direction you want to paddle, head-on. Headwinds work against you.
Crosswind: Wind that comes from the side, across your direction of travel.
Downwind: In the direction the wind is blowing, with the wind, similar to tailwind.
Upwind: Against the direction of the wind, similar to headwind.
Nor’easter: According to NOAA, a Nor’easter is a cyclonic storm that can develop along East Coast of North America that features strong winds blowing from the northeast.
Kona Wind: Important to know if you paddle in Hawaii, a Kona wind is a wind blowing from the southwest or south-southwest, usually from the leeward (protected) side of the island toward the windward. Example: if a Kona wind comes up while you are paddling the Maliko Run on Maui’s North Shore, it could blow you out to sea. It’s the opposite of the tradewind.
Tradewind: The trade winds are the prevailing pattern of easterly (coming from the east -blowing toward to west) surface winds found in the tropics, within the lower portion of the Earth’s atmosphere, in the lower section of the troposphere near the Earth’s equator.
Easterly, Easterlies A wind, especially a prevailing wind, that blows from the east. The tradewinds in tropical regions and the prevailing winds in the polar regions are easterlies.
Prevailing Wind A wind from the direction that is predominant at a particular place or season.
Sources: NOAA, The Weather Channel, Hawaiilife.com, HowStuffWorks.com, WRAL.com
Handy Wind Apps:
This week in North Carolina, longshore currents combined with rip currents have been dangerously strong for swimmers along our coast. Here’s a refresher on what they are:
Longshore current An ocean current that moves parallel to shore. It is caused by large swells sweeping into the shoreline at an angle and pushing water down the length of the beach in one direction. Read more about them here.
Longshore currents can sweep swimmers and surfers into rip currents, piers, jetties, and other hazardous areas. In many cases, the longshore current is strong enough to prevent swimmers from being able to keep their feet on the bottom, making it difficult to return to shore.
According to the U.S. Lifesaving Association, “Rip currents are powerful, channeled currents of water flowing away from shore. They typically extend from the shoreline, through the surf zone, and past the line of breaking waves. Rip currents can occur at any beach with breaking waves, including the Great Lakes.” Paddle surfers and ocean paddlers often use rip currents to help get through shore break because of their power, but to swimmers, they can be deadly, especially when combined with longshore currents.
N.C. Sea Grant has a great brochure on rip currents.