Weather Logic–BVI to Bermuda

Hi Steve, We were planning to leave for Bermuda tomorrow, but just received a WX report from Commanders that’s a bit scary. They are predicting the “largest storm of the season” over Bermuda this Thurs and Fri. Are suggesting we can get there before it hits, but I’m not sure about that. And even if we get in safely, will have to anchor in St. George’s sufficiently well to withstand 55 knots, according to them. We asked Herb about the storm tonight, but he refused to comment, saying Fri is too far off. I can’t see the warning signs on the 96hr 500mb (maybe they’re over the West Coast now?), but I confess I’m still not great at understanding the 500mb charts, your Mariner’s Weather Handbook notwithstanding. We have no deadlines, no pressure to leave, except for a fridge full of food! What do you think, O Great Seer of the 500mb charts? Commanders says if we don’t leave tomorrow, we should wait till Tuesday, and will be motoring most of the way. By the way, David Jones has not warned our friends about this at all (they’re using him for routing), and they’re expecting to arrive in Bermuda Thurs or Fri as well.

Sorry to trouble you, but I would appreciate your opinion. By the way, we’re in Virgin Gorda Yacht Harbor, and BEOWULF looks in great shape over there in the yard. Regards, Candace

Hi Candace: I have not been following the weather, so cannot give you any impression. However, weather, and small boat voyages, in my opinion, are about minimizing risks. If there is the potential for something brewing by six days from now, the questions I would ask are the following:

1-What are the expected conditions and where will you be on your boat for each 12 hrs if you leave first thing Sat. morning?

2-Can you make good progress in these conditions (i.e. is the wind angle/strength favorable for pushing hard)? Reaching or broad reaching would be best–and winds ahead of a frontal system when you are on your way to Bermuda are apt to be SE.

3-What are the risk factors that the system will speed up development and movement, and if this were to happen, where will it catch you?

4-If the system does speed up, will you have enough warning to heave to below the track of the storm? This gives you the option of just waiting it out for a few days.

5-What is the likely storm structure? If it is likely to be “baroclinic” in nature, the risk factors of under-predicting are much higher, than if it is a Norwegian front type of system.

6-Is there likely to be tropical or subtropical feeding of heat/humidity to a extra tropical development? Again, this increases the risks that the models will under-predict.

7-How much leeway do you have time wise/speed wise in the various scenarios? It is only an 800/900 mile trip. If you have favorable winds, and can maintain 200 miles/day by pushing, that means you are in Wed. But that gives you only a 48 hour cushion. For us, with the ability to make 300 miles a day happen, we are only out until Tuesday midday–a much bigger cushion.

Now–to answer your questions. The approach to Bermuda from the S is not difficult. Just the last few miles, working through the buoys is tricky. Not something to be done the first time at night, in bad visibility, if it is blowing like stink and you are running down on a lee shore!

But once inside Town Cut you will be protected. The holding is OK–not great, but if you have good sized ground tackle you should be OK.

Do you go or stay? The weather usually gets better until hurricane season starts. It is probably cold and rainy on LI Sound, so why rush? With no real information with which to make a decision, I’d probably be tempted to stay put and enjoy the warmth another week or two.

Re overall schedule–it is not unusual this time of year to have an upper level low cut off around Bermuda–creating lousy weather for a week or two. On the other hand–if you always wait for the perfect weather window, you would rarely get to go anywhere. But with this time of year, I think I would err on the side of caution. Steve

PS: We faced almost the same situation, early May last year, leaving Antigua. A 96hr 500mb chart came through which I really did not like, with potential to brew up something unpleasant. So we stopped in St. Barts for the night. The next AM the upper level models looked clear, so we took off again, figuring it was an anomaly. But we were rushing a bit because we had a friend aboard. The next AM it looked lousy again. We kept at it, pushing hard. But we could see the weather deteriorating to the west of us, and heard the boats getting hammered in the Bahamas, etc. The next day after we made Bermuda it was gusting 50/60. No big deal really, but the boats behind us coming up, and coming from the Bahamas, got hammered. It stayed unpleasant for a week before we got a shot for a couple of days that was clear to make our passage to Norfolk. Steve


Posted by Steve Dashew  (November 30, 1999)



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