Marine Weather Q & A

Dear Steve, I have just read your analysis of the Queens Birthday Storm 1994. First of all, I'd like to thank you for your efforts in producing such detailed analysis - they are a wonderful education for relative novices like myself. I do have a question you may be able to help me with.

I agree with your position that the best way to avoid bad weather is to get out of the way - by staying in shelter or sailing fast in a direction which avoids the storm track.

Avoiding the storm track has to rely on knowing which way the storm/low pressure system is likely to be moving. These days, with all the communication aids to obtaining recent surface charts obviously has made this vastly easier than it was 10 or 20 years ago.

However there may well be occasions when you have lost communication and you know, either from before your weather fax went down, or from increasing wind and the barometer going down, that there is potential for bad weather.

You can simply find in which direction the low lies and work out the quadrant you are in.

However, my question is, how reliably can you estimate the potential storm track if you are no longer getting comms? The latitude you are sailing in and in which ocean obviously has a strong bearing as most lows are likely to track NE, E or SE if you are below 25/30 degrees South. Is this true, or can you be more accurate than NE/E/SE, and how?

Cyclones can and do seem to go W - possibly more frequently than they track NE/E/SE? Why is this? And will tropical lows do the same?

There is probably a lot more to this than I realize, but I would be greatly interested in any comments you might have and how if possible can you predict the track.

Best regards, Peter

P.S. I have purchased Practical Seamanship - love it, so also just ordered the Cruising Encyclopedia.

If all outside sources are down, you still have a pretty good idea of what is going on by logging barometric pressure, wind direction and velocity, waves, and cloud type/direction. The trends in this data will usually enable you to forecast the low center and where you are in relation to it.

There are usually trends in how systems behave in various parts of the world, and these can be used to help figure out what is going on. But sometimes weather systems behave differently than the norm. So, you need to be alert to variations.

Tropical lows are usually steered by upper level winds. However, while there are sometimes patterns to how this occurs, there are plenty of atypical situations too.

Our preference is to reduce risk factors by choosing the best season to travel, and avoid being bound by schedules. Taking this approach, together with getting the passage over with as quickly as possible, substantially reduces weather risks. Keep in mind that prior to the last 20 years, very little accurate offshore weather data was available. Regards - Steve

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Steve, My question relates to how the sea and land temperatures influence wind patterns. If the sea temperature is warmer than the adjacent land, then what type of flow can I expect? This specifically relates to So. Calif. waters and down towards Ensenada. Thanks, John

At night the process often reverses, with the cooler land air descending and flowing out over the now warmer ocean.

So, in S. California and along the Baja coast this is why you get an afternoon onshore (sea breeze) flow - which often reverses some time after midnight through the early morning hours.

To the extent that there is a pressure gradient present exclusive of the temperature differential, the sea breeze or night time land breeze, will reinforce the gradient or reduce it.

There is an entire section in our Mariner's Weather Handbook which goes into this in great detail.

Steve

PS-differentials in sea temperature, especially in areas like the Gulf Stream or South Australian current also have a big impact on local weather.

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Hi folks - If you were a small Falmouth Cutter 22, heading around the world, on what date would you most like to leave Panama, in order to best avoid the South Pacific typhoon season? This is the only piece of essential cruising information I can't find on your marvelous web site. Thank you very much. Dr. Gene

The "season" is the opposite of the N. Hemisphere - so you start to get nervous by mid-October and keep a close eye on things. The slower the boat, the closer the eye.

On the other hand, leaving from Panama, through the Galapagos, and onto the northern Marquesas Islands is usually considered cyclone free.

So, when you leave Panama depends on how fast you push at sea, and how much time you want to spend enroute. In a non El Niño year I would be happy organizing my schedule so as to leave from the Marquesas by late March or early April. If El Nino is brewing, I'd push this back a month or six weeks.

But you have to watch the weather patterns carefully for anomalies- much easier to track these days with all the satellites and communications.

All of this is covered in great detail in our Mariner's Weather Handbook. Regards - Steve

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Our catamaran is being delivered to Ensenada just after Christmas. Can you point me to information regarding sailing north from Ensenada to San Francisco. Thanks, Steve

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I would like to see information for first time participants on rallies, races and regattas. I went on the NARC Rally thinking it was about safety and found myself in 30-35 kt. winds with gusts even higher. There was no reliable weather information after the weather briefing in Newport and trusted the coordinator to keep us safe and informed. We ended up calling the weather coordinator on our Gobalstar because he had no way of keeping updated on the weather. I would like to know what questions I should ask IF I EVER DO THAT AGAIN. What I should look for in a coordinator to judge the safety of the operation.

Hi There: Your question got passed to me.

First, you need to be responsible for your own weather decisions. This is critical. No weather router can make those decisions. They can advise, but the models are often off a bit on their timing, and none of them are very good on a micro basis--what is happening on your own patch of ocean. Then there is the issue of what the boat and crew are capable of handling.

Understanding weather, and the best tactics associated with it should be everyone's first priority on the learning curve. This is ahead of anything to do with equipping the boat, or any other aspect of seamanship.

And it is not that hard. There is some study involved, you might want to spend some time taking a class, and you will need to practice at home (but that's fun). With the internet, and some of the software now available, you can practice based on the current data, and then check out how your forecast is stacking up the next day. Regards--Steve

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Re sailing to Bermuda, what's the best weatherfax station for the trip--New Orleans? And for Bermuda--Newport, is it the Boston station? Anything we need to worry about weatherwise for the Virgin Gorda--Bermuda run or is it pretty straightforward this time of year? As for Bermuda--Newport, I am basically terrified and am quite tempted by American Airlines. This, from someone who's sailed 5800 miles, now! There's no reforming a worrier...

Hi Candace: Radio stations first--use both New Orleans and Boston from the Caribbean up, and start watching them two to three weeks ahead of time to get a feel for the weather patterns.

You will want to keep an eye on the 500mb charts from Boston right from the beginning--to keep an eye on the risk factors (re-read the risk factor stuff in Mariner's Weather Handbook, and pay particular attention the 500mb stuff). The 500mb troughs occasionally "dig" south and pick up moisture/energy from the sub-tropics--which can then affect you south of Bermuda.

The trip to Bermuda from the Islands is easier and has less to be concerned about, but the weather can still be unpleasant. So, keep your eyes open, and then push really hard to get the passage to Bermuda over as quickly as possible.

Bermuda to the East Coast is a question of how the season is shaping up. Don't be in a rush. Wait for the right conditions. This could mean hanging out in Bermuda for two or three weeks, if there is a cut off low messing things up--as it did last May. The fronts will be coming through in a pattern. Try to avoid frontal stuff in the Gulf Stream. It is often better to heave to on the Bermuda side and wait for a front to pass over the GS, then meet it mid-way.

You might want to try using a routing service like Commander's on both legs. And if you have MaxSea Routing on board start running practice routings now, to get a feel for what they are showing with the current "grib" files.

And don't worry about worrying--it is a healthy response to the sea and weather, and will keep you out of trouble (I still worry about weather!). Steve

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Hi--I took your advice (article on The New Way to Get Weather Faxes) and got weather faxes from Marine Prediction Center. When I opened them they were scrambled letters and numbers only. Is the TIF format something I need to have a program for in order to decode and read? Thanks, Frank

Hi Frank: You should be able to open the .tif files in any image viewer. Photoshop, Image Ready, or one of the new Windows OS viewers will work. But you do need a viewer of some form. Steve

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I am trying to find a source to get some pricing and technical info on the Gale Rider drogue. Can you help? Thanks. :-) Tom

These are made by Hathway Resier and Raymond--they advertise in the classified ads of various sailing magazines (we're afloat right now and don't have any handy). Steve

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Hi. I have purchased and completely read Mariner's Weather Handbook, and now I am reading Surviving the Storm. I would like to take a stab at weather prediction, say for my own area (Detroit, MI) as a way to build the skills you suggest are necessary to make the best possible passages. My problem is, after reading all this material I must be in info overload as I have no idea how to start. Could you suggest a simple recipe for doing prediction using the internet that I could try out? I tried looking at some of the marine sites mentioned in the book, but there are so many sites and so many links to info. I am lost. A recipe might look like...

Hi Scott: The answer is actually quite simple. Go to the Marine Prediction Center's website (in the SetSail links), and then chose one of the regions. Then, look at the long and medium range weather--say 48 to 96 hour data--and make some educated guesses on what you think will happen. To evaluate how these turn out wait 24-48 hours--and check the charts called "surface analysis" which show you what's actually happening at the present time. Steve

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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

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Where can I find more technical info on passages in El Niño years? I've been unable to find anything, even in your books and website. There's talk of reinforced trades, reversed trades, and as you say reduced trades. Is there any solid data or experience on the subject? Many thanks again...Jan

Hi Jan: From first hand experience I can tell you that in El Niño years in the S. Pacific the trades are much lighter, and there tend to me more convergence zones in between the trade wind flow. And of course, the cyclone season tends to affect French Polynesia (which it typically does not in "normal" years). Otherwise two suggestions for data: One is Bob McDavitt at the NZ Met Service (mcdavitt@met.co.nz). The second suggestion is to check out the Next-Generation Pilot Charts on SetSail.com. These have world wide weather data in grib format for the years 1990-99, in month-long chunks. Great for checking patterns in SetSail-MaxSea, and you can make movies, do sample routings, etc. Steve

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Merry Christmas Steve and Linda: We're planning an Atlantic Crossing via Bermuda, Azores, Portugal in June. We have a 1998 Valiant 42. I have Inmarsat C and SSB aboard. What is your advice for a daily routine for getting the weather forecast predictions as we cross? Also, I have your book on weather. Thanks and the best of New Year's to you. Thanks, Roy

HI Roy: If we stick with our present plans we'll be crossing at the same time. There are a series of weather sources. You have the updates on SatC which are frequent and free, and of course the usual faxes from the US and the UK. In addition, if you have Sailmail capability using the new Saildocs format you can get small grib files. You the need software which will read the grib files (we are using SetSail/MaxSea--see the MaxSea part of this website). You can also use Sat C for larger grib files. Another approach is using an Iridium phone for the grib files (which is what we'll be doing). See you out there--Steve

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Hi Roy: There are two potential reception problems when you are on the East Coast and unable to pick up weather faxes. The first is outside interference, which is sometimes quite strong along shore. The second is the frequency and/or time of day. You often need to adjust down to a lower frequency, or use a station further away as higher frequencies may be inside of the "slip" zone of the radio station's transmitter. This past summer we were always able to get NMF in Boston at least twice a day, but we had to do some experimenting with the frequencies. It is theoretically possible to use Inmarsat C for the FTP fax sever, however the cost would be horrendous! A much better bet would be a Globalstar phone, which would probably end up costing about 50 cents/fax (rough guess)--as long as you were in their coverage area. But you cannot beat the SSB for price--i.e. free! Regards, Steve

To read article about receiving weather faxes via email, click here.

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Good Morning Steve and Linda: I try to read everything that either of you write and have ALL of the books. However, in sailing TIMING is everything as you know. Vicki and I have a 1998 Valiant 42 built for us in Texas. We have dear friends, Joe and Pam Harris from Durham. They have the Sundeer 60. We are to meet them in Crete in the Fall of 2003.

WHEN SHOULD I LEAVE FOR CRETE AND WHAT IS THE BEST ROUTE? I'm retiring in June of 2003 and will have a lot of time to get there. This might be a good article to look into as I'm probably not the only one to run across this problem. Any books that you recommend will be read. Thanks and keep up the good work--GURU--you've never let me down. Roy

Hi Roy: That's a long trip, with lots of different weather patterns to traverse, so there are no pat answers. However, in the next few weeks SetSail will be announcing a new Navigation and Weather analysis software package, which will have the ability to read historic weather data (with data going back ten years being currently available). This would be the best bet we know of for planning. If you are on the SetSail e-mail list you'll be notified when the new site is up for viewing. Otherwise, check over the next couple of weeks--it is close to being ready to go. Steve Dashew

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Dear Steve, Thank you for your last article of weather charts by e-mail from NOAA. Any possibility to have the weather charts for my area River of the Plate (Buenos Aires and Uruguay coast) would be wonderfull. Thank you, and excellent your work for all the cruisers world wide. Best regards, Roberto

Hi Roberto: The FTP server at NOAA does not have charts for your part of the world available. However, you can of course get them from many of the model outputs (see Setsail.com weather links). Also, stay tuned to SetSail over the next few weeks for some very exciting weather developments--which will affect your ability to get a new type of weather data for your part of the world--and the rest of the world as well. Regards--Steve Dashew

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Steve: Just read your excellent article in the recent issue of Ocean Navigator, concerning heavy weather steering issues. We just placed an order for a 43' Hallberg-Rassy, and I'm curious to learn what you think of the "beefiness" of its steering system. It has Whitlock wheel steering, with Cardan linked rod steering. Do you think this meets your recommendation for "twice ABS specifications"? Thank you for your help! Mike B

Hi Mike: There is no way for me to answer your question without a complete design evaluation. However, the question could be easily answered by the yard. Keep in mind that the structural system starts with the rudder and the rudder shaft (and the skeg if you have one), then includes the bearing carriers in the hull and the hull to which these are attached. Regards--Steve Dashew

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Steve, Do you know of any good buys on a weather fax? Thanks, Don P

Hi Don: There are a bunch of software choices. One of the recent Practical Sailor issues had evaluations and mentioned a couple of "shareware" programs available on the www for under $100 which were highly rated. For hardware, you just have to do some shopping. You can usually pick up the Furuno fax--our favorite--for around $1600 at a discount. Regards--Steve Dashew

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Steve, We are planning a bareboat charter in Tonga Vava'u and the first thing we are doing is choosing the time of the year we want to go. That will depend on a chart of weather in the Tonga region, including precipitation, winds and temperature. Do you know where we can get that chart? Thank you, Mary and Pablo V, Florida, USA

Hi Mary and Pablo: The first thing to do is contact Moorings for their info on Tonga--which should have climate data. Next, you could order up a set of the S. Pacific pilot charts. In general, you will find that the "winter" season--which runs opposite the N. Hemisphere (i.e. June-October) is the dry season, with the coolest temperatures and best trade winds. Steve Dashew

Later e-mail from Mary and Pablo

Thank you! We made a reservation with the Moorings from July 3 till the 13, with their 46 footer (we are 4). We will fly there through LAX, to Nandi and then back to Nandi, Sydney (to go to the Great Barrier for some diving) and back to LAX. It is our first time there. Thanks again, Pablo V

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Hi--I was wondering if you could point me in the right direction to find general season / wind / current / climate information for sailing in the red sea on your site. I had a good look round, but could only discover the present conditions there, as opposed to information to help me plan a trip there. Is there another site/source of information I should use instead? Many thanks, Francis P. from the United Kingdom

Hi Francis: We are aware of nothing like what you are requesting. However, in about 60 days there will be a new navigational software product with fantastic weather planning capabilities--which is being developed for SetSail. So keep an eye on the site over the next two months. Steve Dashew

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Good day! I was wondering if you would be able to refer me to an online source for understanding weather in the Caribbean--rainy season and dry season, and what exactly triggers the onset of each. Any direction you could give would be much appreciated! Thanks, Tim

Hi Tim: Tropical weather works with the same mechanisms around the world--so, if you understand it for one area, you will know what's going on in others. At the risk of self promoting, our own book, Mariner's Weather Handbook, has a pretty good tropical weather section. You can also check out the Tropical Prediction Center web site (available in SetSail weather links) for specific fax charts. They also have articles from time to time on their sight about the Carib. Weather cycles. Regards--Steve Dashew

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I read recently of your joining Sail Mail. I, like you, have a dedicated wfax. Have you switched to ssb--computer weather , or do you still use the wfax primarily? I have a SEA235, didn't know about its duty cycle when I bought it, have a fast laptop with 400mb of ram, but am also told it will cost additional 1500-1700 dollars for the modem, cables etc. and additional software. So I desire your opinion as to its worth, primarily for weather. Thanks, Dave.

Hi Dave: I don't think you can beat a dedicated fax, especially if you already own one! Our Furuno has been a workhorse for years, and it is nice to be able to program it get what we want, and then forget about it (and not have a conflict with radio schedules).

However, if we were starting from scratch, I think we would seriously consider an SSB-based system, as long as we were going to have our Sailmail e-mail system anyway. You have all the bits, except for the software, and Jim Corenmen has a very good fax program bundled for free with the Sailmail software. Incidentally, I think the modem, cables, etc. run more like $900 or $1000--at least that is what it was a year-and-a-half ago for our Icom ham rig (Pactor 2E modem).

Depending on where you are cruising, another option is the Globalstar phone. We had really good luck with one we tested this spring--downloading five or six weather faxes from the internet in four or five minutes (we'll be writing more about this on SetSail shortly). Good Luck--Steve Dashew

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Steve, Do you know of a good display of Gulfstream temperature and current conditions available online (i.e. that shows eddies and current patterns)? Thanks.

Check out the links section of the Bermuda Race--www.bermudarace.com--they have an entire section devoted to the Gulf Stream. Good Luck--Steve Dashew

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You mention more than once in (your) books how pleased (you are) with your barograph. Some probably don't handle the motion of a sailboat very well. Which one (do you) recommend? Thanks, Neal

Hi Neal: We have a Weems and Plath barograph which has worked flawlessly for 15 years. My dad has a different model, also from Weems and Plath, which he's had for probably 20 years. The number I have for them is 410 263 6700 or fax 410 268 8713. Ours has seen some pretty severe shock loading over the years and seems none the worse for wear. Regards--Steve Dashew

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Dear Sailors:Last summer, I was reefing the sail, had my hand on my aluminum mast, and a thunderstorm that was a mile away sent an invisible charge my way and gave me quite a shock with a boom that I think was caused by the main bolt hitting a nearby ridge. What are the odds of getting a strong bolt through the mast? What will occur? We were sailing down in the Keys last month, and a lightning bolt hit a sailboat mast while the boat was on the trailer, out of the water. The mast glowed red for five minutes. I can't find any information on this subject. Does a lightning bolt destroy radios? Can it hurt the hull? Best regards, Chris

Hi Chris:The entire subject of lightning is not totally understood, and the odds of being hit difficult to quantify. I am by no means expert on the subject, but here is what I think is the case:

1. You want to make sure that all the metal aboard is bonded electrically, so that if you do take a direct hit, your body does not become the means of equalizing the charges between various bits on the boat--that can be a fatal experience!

2. It is better to avoid the strike in the first place by bleeding off the ion charge which precedes the bolt from the cloud. This is done with brush like devices, typically placed on the masthead, and proper grounding of the spars and rigging. On our fiberglass boats we typically fit a sintered metal bonding plate below the heel of the mast to help in this regard.

This is all covered in somewhat more detail in our Offshore Cruising Encyclopedia.

Good Luck.

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Steve, This may seem like a dumb question, but....How does the height above the water affect the anemometer readings? The reason I ask this is that my mast is 56ft off the water and it seems that the wind speed readings I get are consistently higher than mates of mine that have shorter (i.e. 35ft) masts. I have B&G gear so it should be accurate....is there a formula that we can apply to get surface wind speed, knowing the height of our instruments ? Thanks Cheers Alan

Hi Alan: The wind increases with height. However, the amount it increases varies with the type of air mass, water surface conditions, temperature differentials between water and air, etc. There have literally been millions of dollars spent on trying to figure this out, as all racing polars are based on true wind speed. In addition, there is upwash and downwash to consider. These kick in more when reaching, and vary from boat to boat. For example, on Beowulf, we can be running in 10 knots true, and then start reaching and the true wind speed will climb to 13 knots. The higher end B and G systems, like the 790, have correction tables to roughly zero out these factors--but they are only as good as the day's conditions are like those when you originally made up the table. Our solution--we look at the water and make our own estimate. Steve

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STEVE: HOW MANY ROLLS OF THERMAL FAX PAPER SHOULD I HAVE ON BOARD FOR A 6 MONTH CRUISE......HAVING THE FURUNO 207 FITTED THIS WEEK.--PHIL

Hi Phil: First, you can use good quality thermal fax paper (availale at any office supply store) for about a tenth the price of the "official" Furuno paper. You will have to tear off the first 15/20% of the roll, however, as otherwise it will not fit in properly (we just toss what we tear off).

As to quantity--this depends on where you are sailing and how often the weather fax will be used. I think we have about a dozen rolls right now aboard Beowulf. My guess is we will use half of this between the Carribean and Azores--and then a good chunk of the balance over the summer.

If you are going to Mexico you will not need as much as if you're headed to the Pacific Northwest and/or Canada or Alaska. However, fax paper is usually available just about anywhere you travel--just the cost will be higher than at a discount store in the US.--Steve

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Here (in new Zealand) it is difficult (read impossible) to get 500Hpa charts on weatherfax....what options can you recommend ? Thanks for your input. Best regards, Alan

Hi Alan: As to 500mb charts in New Zealand, they are broadcast from Australia--and once you get away frm local interference, if you have a god receiver, you should be able to pick them up. If not, check for onboard sources of radio interference (we have had problems in the past with computer noise, and micro processors used in various electronics and/or control circuits). Regards--Steve

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My wife Tina and I will be leaving California next October, taking a year trip and making our new home in the U.S. Virgin Islands to work the boat in Day-Charter. I have learned alot from your books.

At your recommendation, I am buying the Furuno 207 weather fax. My local dealer says that I should not buy the optional amplified antenna coupler, but use a Metz whip antenna. I also recently bought a Sitex Navfax 200 SSB receiver and he sold me the Metz whip antenna, rather than the optional active antenna. He told me the sales reps have told him they work better than the active antennas. I have not installed it yet--which antenna do you use and what would you suggest for best reception for both of these units? I would appreciate any guidance you can offer.Thanks again, Frank

Hi Frank: We have used both the passive and amplified antenna. At present we have the amplified version. However, since we have not tried this set without I cannot tell you scientifically if it makes a difference. However, it does work well at present.

From a non-technical standpoint I will say that I think antenna length is a major issue. If you can work out a long wire, rather than a short whip, you will get better reception. If you are forced to use a whip, longer is better in weak areas.

In the West Indies you will get the fax station in New Orleans without difficulty. But Boston will very much depend on signal propagation, and it is in the marginal conditions where the bigger antenna, and/or the amplifier will help. Hope this helps--Steve

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Hi Steve: What the TV folks are talking about is the surface weather features, and here they talk about pressure--i.e. high pressure ridges, etc.

At the 500 Mb level and above the discussion is in terms of heights of pressure. Hence the difference (and often confusion) in terms. Regards--Steve Dashew

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Gooday--Looking for a web site dedicated to info on offshore sailing. I am a novice thinking of sailing Victoria, Canada to Mexico then across the Pacific to New Zealand with all the stops. Need to to know the right time of year and all that stuff. Please respond. Regards, Gaz.

Hi Gaz: You're asking a mighty big question! The correct time of year depends on what the weather cycle for that year is doing, and how the weather systems are reacting when you get close to leaving.

In general, you travel at the edges of the hurricane season between tropics and temperate latitude. The tricky part is deciding if you go when the risks of a late/early hurricane are higher and of a large extratropical storm are lower, or the reverse.

While tropical storms get lots of play in the press, they are typically less of a threat at sea, and easier to dodge than the large extratropical storms which start usually in the spring/fall equinoctial gale seasons.

As to specific times, generally folks leave for Mexico toward the end of October/early November. The hop to the S. Pacific is made anywhere from Feb. onwards. You don't want to move onwards from the Marquesas Islands until around May, when the S. Pacific hurricane season is winding down.

The next hop, from Tonga, Fiji, or New Caledonia to New Zealand will take place in the S. Hemisphere spring. Usually folks start leaving around mid-November. The weather between the islands and New Zealand can get gnarly, so picking the right time to go, and having a well-found boat are important. Good Luck--Steve

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Hi, I'm unable to locate a weatherfax for the South African coastline and immediate area. Please advise. Martin.

Hi Martin: We don't have a direct link to any SA faxes. However, we've got some good general weather links on SetSail.com which you might want to check. Also, you can get computer model data from any of the computer model links for both surface and upper level data for the SA part of the world. If you find a specific link, let us know and we'll add it. Regards--Steve Dashew

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Dear Madam, Sir, Two years ago, I ordered your Mariners Weather Book and read it. A compliment to your book. It is one of the best books, to learn maritime weather by sailors. On page 366, you refer about the Dvorak Technique to understand hurricane forecasting. Please give me the detailed information about this book: Where can I order it? What's the price? Yours sincerely, A. Schroeder

Howdy: The Dvorak Technique manual used to be available from NOAA in the U.S. However, it is no longer in print. We are exploring a means of bringing this data to our readers, but have so far not yet found a solution. Regards--Steve Dashew

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I am hoping to make this trip starting in October of this year. Do you have an opinion regarding the "weather window" in mid October? From what I have read I should be OK although there are always exceptions. I thought I would keep an eye on the group of people in the Baja Ha Ha race that usually head south from San Diego to Cabo in late October. If there are no storms developing off the coast of Mexico that would eventually head northwest then I thought I would leave San Diego on a rhumb line for the "Islands." If you have an opinion or experiences contrary to mine, I would appreciate the input. Sincere and personal regards, Jim Alexander

Hi Jim: Regarding a "weather window" for going to the Islands: First, there is no way to tell today what will be happening in October. However, a few generalizations can be made about the odds. Number One is that October is one of the worst months, as the risks from hurricanes will be quite high.

The potential problems along the coast are less than something catching you on the way west. However, I think the Ha Ha starts a little early. So, my first advice would be to wait until mid-November, and keep an eye on what is happening with the weather patterns and water temperatures. You can do this by checking both the Marine Prediction Center weather faxes as well as the Hurricane Center data--web site addresses for both are in the weather links area of setsail.com.

I would not wait to see what the Ha Ha rally folks are doing. Their weather patterns will be quite different than yours. What you will need to be watching are storms, which form off the coast a ways, and then track west to northwest. If you watch the cloud patterns (also available on the web) and the easterly waves coming off the Sahara, these will all give you a feel for how active a Fall it is. If it appears quiet--no easterly waves, and not much convective (cloud) activity, then you might consider moving the date up.

Good luck--Steve Dashew

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Firstly, let me say how much I am enjoying your books, Mariner's Weather Handbook and Surviving the Storm. For anyone with the slightest interest in the weather around them and in taking a boat to sea, they are excellent reading. However, I do have a couple of queries:

On page 340 of the 'Mariner's Weather Handbook' you show three photographs of tropical revolving storms, when and where they should not be, one off Angola (West Africa) in April 1991 and two of one storm in the Eastern Mediterranean in January (no year mentioned). It is my understanding that no tropical revolving storms have ever been reported in the South Atlantic (until now) and that the sea temperatures in the Eastern Mediterranean in January are certainly not high enough for cyclogenesis nor is the ITCZ anywhere near the Mediterranean. Have you any explanation for these phenomena and/or a year for the Mediterranean storm (I would like to research past meteorological records to find what conditions actually existed in the latter case).

I look forward to your reply, Brent

Hi Brent: The pro's tell me that part of the reason there have never been any tropical storms in the S. Atlantic is that there's rarely anyone down there to report them. The point we were trying to make is that ANYTHING can happen with the weather--so, be prepared.

To get the cyclogenis cooking you all you need are a bunch of thunderstorms,and a quiet upper atmosphere to allow the T-Storms to cook. Once they begin to rotate...

As for the series in the Med--while the satellite images appear to confirm cyclogenisis, the storm actually developed over Africa where it might have been warm enough to start the initial development, they could also be an indication of a bent back warm front structure.

As we are cruising right now I don't have my notes, so I can't give you any pointers are where to get more data. Regards--Steve

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I have a compaq laptop (slow & old, but OK) and use weatherfax from J.E.Hoot to receive weathercharts and forecasts.

I have difficulties to find the best frequencies for the mediterreanean and I always seem to miss the timing. Any suggestions as to the software, or the emitting station?

Frederik

P.S. I enjoy your Mariners Weather Handbook and CD.

Hi Frederick:

Most fax stations these days also have a website, where they list the frequencies and schedules--many of these will be found under the weather links on setsail.com. Or, you can leave your radio tuned to one of the frequencies until you get a cycle which includes a broadcast of times, frequencies, and product. When we're cruising this is what we typically do. Then, once we've gotten the written schedule on the fax, we program the receiver for what looks at first guess to be the best frequencies. Next step is to leave the volume turned up, and when the station begins to broadcast, we switch frequencies and listen for the strongest signal. It usually ends up that there are a couple of times a day when we can get the faxes.

For example, sitting in the Caribbean right now, we primarily listen to the New Orleans (NMG) station. Typically 8 megs works in the early morning (around 0800 local time). In early evening we find that 12 megs works better. There is no automatic way to work this out, except by taking some time to listen to the various frequencies.

Good Luck--Steve

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Dear Dashews, I have been very impressed with all three books I have ordered and read, Surviving the Storm, Mariner's Wx Handbook, and Offshore Cruising Encyclopedia...I would really like to relate more to the weather and practice more with the reading of 500mb and surface charts. I am not very good in tracking these down on the Internet even with the use of the wx links in your web site. Could you please suggest which site will offer me the best data for the 500mb and surface charts? I really do not care if it covers one particular part of the world because I would like to be able to study areas around the world with the worst wx at that time so as to relate the forcast info with what is actually occuring. Thanks, Silas

Hi Silas: For 500mb weather you can go the Marine Prediction Center website--and then work down through their menu. Also, all of the world models output 500mb. Again, pick a site and look for the 500 mb output. Hope this helps. Steve

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Hello, I've been reading Mariner's Weather Weather (which I find very helpful and readable compared to several other weather books I've slogged thru, thanks!) and I was wondering what scale of 500mb and surface charts you recommend I study (as I try to get a hang of this theory before heading out sailing in a few years).

I've seen them ranging from very small areas to the world (particularly the 500 mb ones). Thanks, Glen

Hi Glen: You need to look at a lot of area to get a feel for long and short waves with 500mb charts. Typically the entire ocean basin in which you are interested plus a bit upwind. For the North Pacific you'd be watching the ocean itself plus some area over Russia.

The US Marine Prediction Center 500mb charts are quite good in picking out the right geography. You can find the URLs for their websites in our weather links. Good Luck with your studies. Steve

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We are due to leave Mexico at the beginning of April and spend the season sailing the Pacific Islands. From our reading and research we are unsure which weather and fax stations provide the best information for which areas. Is there is a source for this information or can you make recommendations? In addition we have heard that New Zealand and Fiji are newly co- operating on producing forecasts for cruisers and would like to know if this is correct, where the results are broadcast from, the schedules and the channels used for faxes and forecasts. Many thanks Dudley and Philippa

Hi Guys: We probably sailed right by you on our way to Panama. When you leave, the best charts will be from NMG in New Orleans (for Mexico coastline out a ways) and KVM in Honululu. As you get closer to the Marquesas KVM will be your best bet. Once in the S. Pacific ZKLF in Auckland will start coming in. As you get closer to Fiji you will get AXM in Australia. From Fiji it is usually best to work all three-the Kiwis, Aussies, and US, and then see what makes the most sense. For up to the minute data on the NZ/Fiji cooperation, I'd contact Bob McDaviit at mcdavitt@met.co.nz Have a good trip. Steve Dashew

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Hi, I am enjoying reading our book "Surviving the Storm". I know you could not cover all the topics, and I have not read the whole book yet, but I could not find data or reference to world storm patterns. If one was chicken, and wanted to avoid category two and three heavy weather storms (page 16), what cruising routes could be planned, and where not to be at what time of year? I recall some published charts that show wind direction and speed at various locations. What about information on routes and the best time of the year to avoid bad storms. Could you name a few good sources for me. I get the hint that New Zealand is risky at best. If I missed this information in your book, please let me know where it is located. Thanks, Mike

Hi Mike: There are no hard and fast rules about avoiding storm seasons and/or areas. The weather varies too much from year to year. The pilot charts and sailing directions will give you a general idea for planning, but you need to check out the pattern in the time period in which you are sailing.

You can do this by talking with local forecasters during the time frame you are getting ready to leave, or with some of the commercial routers who are also in this business. Or, get up to speed on the weather forecasting process yourself and keep an eye on what's happening on the internet for a couple of months before it is time to take off.

Check out the weather links on SetSail--they are a good start. Regards--Steve

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Greetings from Cartagena, Columbia. We purchased your Mariners's Wx Handbook in August and have enjoyed reading it as we sailed West from Curacao. This has been a very unusual year in the Caribbean with the late hurricane "Lenny" that tracked East from Jamaica to St. Martin and now all the rain on the coast of SA in the normally dry month of Dec. It looks like a La Nina event with the cold water off the coast in the Pacific. Your book talks about El Nino but not much about La Nina. We are planning a cruise to the South Pacific this Spring. Can you tell us how this might affect the wx patterns? Or can you give me some references of web sites etc. to check. Hope to hear from you soon and best wishes for the holidays, Tom and Maureen

Hi Guys: Generally speaking, La Nina means stronger trades in the S. Pacific, and a minimized hurricane season in French Polynesia. Beyond this, hard to speculate. But there is typically a pattern to it all. Maybe we'll see you all next month. We're headed to Panama the end of the year, and then working our way towards Antigua (starting with the San Blas Islands for awhile). Regards--Steve

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I'm starting to practice weather forecasting with the 500mb and surface charts. The NWS site has lots of different charts with different forecasts such as 12,24 or 36hr forecasts. Which one of these would you recommend that I use to practice?

These are the charts I download: 15.00Z Surface Analysis Chart Part 1 10E-45W Northern Hemisphere Size: 38.4K--Updated: Fri Nov 26 03:23:37 1999 UTC 16.00Z Surface Analysis Chart Part 2 40W-95W Northern Hemisphere Size: 32.5K--Updated: Fri Nov 26 03:33:36 1999 UTC 28.00Z 500MB Surface Chart Analysis 45W-85W Northern Hemisphere Size: 26.8K--Updated: Thu Nov 25 23:23:35 1999 UTC.

I'm "superimposing" the 500mb on the surface analysis charts to forecast what the weather will be like for the next 24 hrs. Am I on the right track?? Regards, Susan

Hi Susan: The best approach is to download the current analysis (i.e. surface analysis or 500mb analysis) which tells you what the forecasters/or aviation computer model thinks is happening right now. Then get the 24, 48, and 96 hour progs (forecasts) for surface and 500mb. Your approach at overlaying works well, as does looking at each level in sequence. You will find that there is a rhythm at the 500mb level which will become noticable after a while. I'd start with that, and then see if you can tell how it relates to surface conditions. Each day it helps to compare the current analysis with the forecasts from the previous days. This will give you a feel for how the forecasters and/or computer models are doing. For North America you can download either or both of the coasts. If you are planning on cruising in one area rather than the other, I'd concentrate there. Look at this as if you were aboard your boat with the fax running--in which case you will be looking at about eight charts, once or twice a day. Sounds like you are on the right track. Good luck. Steve

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New Wx book a bargain at twice the price. I am reading it for the third time. Do you know where I can download (from the web) wx fax for south pacific? I have friends at 16S 155W headed for Australia. I would like to watch their weather, but cannot find any source for that area. Any help will be appreciated. Best, Jamie

Hi Jamie: Thanks for the nice comments. Re: weather for the Australian area, check setsail.com weather links and you will find the Australian Met. Bureau. Also, any of the world computer models (such as the US Navy NOGAPS) will have data (there are also links to these on setsail.com). Regards--Steve

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Where can I find weather faxes for the Caribbean on the Internet?

There are a number of Carib sources, but the best will be found in the National Hurricane Center URLs in our list of weather links or go to http://www.nhc.noaa.gov/ for the National Hurricane Center web page.

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I bought the Mariner's Weather Handbook and find it helpful. I have a question, though. On page 123, you attempt to show divergence/convergence on a drawing (bottom of page). I have read it 10 times and don't understand what you are trying to tell me. It is early in your discussion of this subject and so I do not want to move on without an understanding. Can you elaborate on what that drawing is showing me? Thank you, George

Hi George: Sorry about the confusion. This is a difficult topic to get across. First