Jim started by advising on “Vigorous Lows” These features driven by strong upper Jet Streams can at times deepen explosively. He told how, when on a sailing holiday with his wife and two young daughters and sailing towards the Isles of Scilly, he heard on the radio 4 Shipping Forecast a synopsis which changed his plans. As a BBC Shipping Forecaster on holiday he kept a listening watch on his colleagues in Bracknell and to hear “Low leaving the Eastern Seaboard of the USA expected Shannon…..,” was a shock. The speed at which that low was travelling meant that the upper jet stream must be very strong and could lead to the explosive deepening of that low. With safety very much in mind they headed for Falmouth and a very secure and safe mooring off the Yacht Club. And then the FASTNET STORM blew in. His knowledge of meteorology kept his family safe and the thought that such knowledge should be shared with other yachtsmen (and women) is the reason he was at the meeting.

Fast moving lows can be very challenging, moving rapidly (35 to 45 knots) or very rapidly (>45 knots) their central pressure can fall very rapidly (more than 6 millibars (mb) in 3 hours) indicating a rapid increase in their winds to Gale Force. With a fall of 10 mb in 3 hours one can expect Storm Force 10 winds. So remember to keep a close watch on the barometer, especially the 3 hourly trends.

Jim continued the theme of vigorous lows by telling of one in the Southwest Approaches. In the early morning aboard a yacht in Yarmouth (I.O.W) listening to the BBC Shipping Forecast he heard that the low in Sole was moving into Northern France and that winds in Wight and Portland would be “Variable 4” Him and his crew mates (all meteorologists) thought this was strange because the previous late night forecast had brought the low up the Channel with southerly 7 to severe gale 9 winds on its eastern flank: a very different story. What to do? Do we proceed towards Falmouth? The crew all agreed, “We stay put!” A good decision, the low came up the Channel and all hell broke loose, as did their boat in the night when a not very secure yacht took out their bow warp. The Yarmouth lifeboat went out in the middle of the night, too. These tales emphasise the need to keep a close watch on the weather and forecasts days before you set out and while at sea, especially when lows are approaching your area. Think about the consequences of a relatively slight change in track or a rapid change in pressure.

Jim’s next item was Line Squalls, these are squalls who’s arrival is indicated by a horizontal roll of low cloud associated with the approach of a large cumulous or cumulonimbus cloud which can deliver a significant blast of wind. Often as these clouds approach the existing wind falls calm and the arrival of the squall can be vicious. Many a yacht has been dismasted by such events. So, if you see one coming the best action is to drop the sails or at least turn towards the approaching roll of cloud, it’s a good idea to do both.

Lessons Learned: - Always keep your weather eye open and look for the signs.

In his years of sailing Jim has learned: