Weather & Marathon Swimming

This day from near shore at Dover,
the Harbor looks calm
however mid channel it was force 4+ = big waves. 

Dear Friends,

Weather plays an important part in open water and marathon swimming contributing to your success and failure. at its most basic level of influence, even to the degree of difficulty.

Some weather situations drive resulting sea state and large lake conditions from hundreds of miles away in ways that befuddle most of us, frustrate the hope swimmer waiting to go. In the end you must consult and work with local captains, seamen, ports to determine and plan well these variables to minimize the risks and increase your chances of success.

This summer, like last for me, has seen significant weather related "no-go's"but like Mount Everest or any other endeavour of similar magnitude its part of the challenge.

Below, you will find excerpts from the English Channel Google Group from July 18-19th. This exchange from the venerable Captain Oram and others who pilot swimmers in the English Channels show just the sheer variability and sometimes confusion messages that come from mother nature to unknowing swimmers that may not be accustom to terminology.

For those of you who are not familiar with sea terminology, I strongly suggest before you plan a big open water swim especially in the ocean or great lakes to spend the time to learn the basics - what force means, sea state, tides and current mapping, etc. Words like "rough", "unsettled" usually are code for really tough swimming in 6-10ft swells, white caps, or worse waves one direction and wind the other copping up the seas. It might just make the difference or at least reduce your safety crew "puke factor" from rolling seas. Once you know the basics trust your pilot/captain and let it go.

In the USA NOAA has great resources for inner coastal areas, lakes and rivers and many web sites exist for shipping and sport fishermen that track similar conditions as well as some national parks that have open water as part of the boundary or lake shore.

July 19th 

Actual Weather Forecast from Captain Oram:

Looks like we can go swimming as of tomorrow. (not sure exactly when)
All we have to do is wait for the sea to settle.
 
Sandettie 0900BST is showing WSW 22.9 knots with a 1.6 foot sea 
Water temp is still 59.7°F (15.5°C)
 
Today's forecast is back to Tuesdays with no strong winds on Sunday 

Dover -- Shipping Forecast - Issued: 0405 UTC Thu 19 Jul
Wind -- West 5 or 6, veering northwest 4 later.
Sea State -- Moderate or rough.
Weather -- Showers.
Visibility -- Good
North Foreland to Selsey Bill - Inshore waters forecast
Strong winds are forecast
For coastal areas up to 12 miles offshore from 0600 UTC Thu 19 Jul until 0600 UTC Fri 20 Jul
24 hour forecast:
Wind -- Westerly or southwesterly 5 or 6 (Big stuff!), becoming variable 3 or 4 later (Swimmable)
Sea State -- Moderate, occasionally rough at first.
Weather -- Showers, thundery for a time.
Visibility -- Good, occasionally moderate.
Outlook for the following 24 hours:
Wind -- Variable, becoming westerly for a time, 3 or 4.
Sea State -- Moderate becoming slight.
Weather -- Showers, thundery for a time, then fair.
Visibility -- Good, occasionally moderate
Thursday 19th July lunchtime chart -- 
Strong wind gusts until late afternoon (25 to 30 mph) then everything should start to settle.
The Azores high has built in and the last part of the low pressure is leaving the Channel


Midnight 0000 UTC Friday 20th July
Dover HW 0020 BST 6.3 metres
Dover HW 1240 BST 6.5 metres
The Azores high is moving into the Channel and the winds are settling.
Watch the Sandettie light vessel to see how soon the sea settles down.
http://www.ndbc.noaa.gov/station_page.php?station=62304
Saturday 21st July 000UTC 
Dover HW 0055 BST 6.4 metres
Dover HW 1315 BST 6.6 metres
High pressure dominant in the Channel, just a small ridge over the French side.


Midday Sunday 22July 1200 UTC
Dover HW 0129 BST 6.5 metres
Dover HW 1351 BST 6.7 metres
High pressure still dominant in the Channel with the deep low moving up and through Scotland.
Need updates on the pressure charts to sort out Monday onwards.

July 18th

Dover Shipping forecast
Gale warnings - Issued: 0332 UTC Wed 18 Jul
Southwesterly gale force 8 expected soon

Shipping Forecast - Issued: 1625 UTC Wed 18 Jul
Wind -- Southwest 5 to 7, occasionally gale 8 at first.
Sea State -- Moderate or rough.
Weather -- Showers.
Visibility -- Moderate or good
--------------------------------------
North Foreland to Selsey Bill - inshore waters forecast
Strong winds are forecast
For coastal areas up to 12 miles offshore from 1800 UTC Wed 18 Jul until 1800 UTC Thu 19 Jul
24 hour forecast:
Wind -- Southwesterly 5 to 7, occasionally gale 8 in east at first, veering westerly or northwesterly 4 or 5 later.
Sea State -- Moderate or rough.
Weather -- Showers.
Visibility -- Moderate or good.

Outlook for the following 24 hours: 1800 UTC Thursday 19th July to 1800 UTc Fri 20 July
Wind -- West or northwest 4 or 5, becoming variable or west, 3 or 4.
Sea State -- Moderate or rough, becoming slight.
Weather -- Showers.
Visibility -- Good
-------------------------------------

Dover
Western entrance has South Westerly 30 to 35 knots blowing on it at 1600
Sandettie 1600 BST -- SW 24.1knots -- 2.3 foot seas -- 5 sec wave -- 59.7°F (15.4°C)

Sea temperature reached 59.9 °F (15.5°C) this afternoon for a short time.
Air temperature around 58°/ 59F (14.5 to 15°C)
Wind direction is South West - South South Westerly
Short wave pattern of 5 secs most of the time

Looks like it will take a little time to settle