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The Care and Feeding of Hurricanes

The Care and Feeding of Hurricanes

Jun 30, 2019

Because once you how a tropical cyclone thrives, you know how to avoid one.

There are hundreds of rules for sailors, but Colin and I live by a single one that so dominates the others it deserves all caps: MOTHER NATURE IS IN CHARGE.

This means that if she doesn’t want us to sail in the direction we’d intended, we don’t, or if she warns us to stay in port, we do. But now that it’s hurricane season here in Baja, this rule ratchets up from ensuring our comfort to saving our bacon. In other words, sh*t just got real.

As I write this, we’re at anchor in Punta Chivato at Latitude 27, technically within the safe zone and with a wide variety of alternatives at our disposal, but that doesn’t mean we ever take our eye off the ball. Here’s what we’re watching for.

Five Easy Steps to Make a Hurricane

Start in an area near, but not directly on, the equator — around 10-15 degrees latitude. A suitable spot in this corner of the world would be the Gulf of Tehuantepec in far southern Mexico. Patiently wait for mid to late summer when tropical waters are at least 80 degrees F, but the warmer the better. Hot ocean water is hurricane food. Once your storm is born, it will need to convert all that heat energy into the kinetic energy that drives its motion.

But first, you need conditions benign enough that your baby hurricane can form its trademark circle shape (thus the term cyclone), so wait for winds to be relatively light and stable across all three dimensions of a wide area.

Now things can get more interesting. Nudge a trough of low pressure across the equator. When air gets warmer, it rises like a hot-air balloon and creates an area of lower pressure underneath. Since nature abhors a vacuum, the low pressure pulls in air from around it to fill what we’ll unscientifically call the void.* This builds the initial winds you need.

You and I may need reminding that the earth’s always spinning 1000 miles an hour, but physics doesn’t. The friction between the earth’s surface and the air above it imparts a spin to the winds, known as the Coriolus effect. As soon as all that spin creates a full circle of wind, congratulations! You’ve birthed a cyclone.

Now, sadly, your baby must leave home because if it stays in one place, it will eventually use up its supply of warm surface water and starve. So it heads off (usually west or northwest) on its own, moving slowly at about 12 knots as it seeks more warm water to gorge itself on, and grows in stages from a tropical depression (less than 33 knots sustained wind) to a tropical storm (34-63 knots) to a full-fledged hurricane (64+ knots).

*If you live in San Francisco, a similar vacuum scenario plays out all summer long with hot air rising in the Central Valley and pulling in cooler air from the coast. But since there are no other ingredients for a hurricane, the result that all San Franciscans grumble about is pea soup fog. However, if you’re a sailor, you adore this phenomenon as it causes those outstanding 20 knot summer westerlies you can set your watch to.

What it Means for Us

If it takes 80 degree sea temps to sustain a hurricane, the straightforward way to stay safe is to park your boat in colder water. While Mother Nature offers no money-back guarantees, the further north we go in the Sea of Cortez, the less chance of a close encounter of the cyclonic kind. In fact, hurricanes so rarely hit north of Latitude 27 that it became something of a line in the sand for insurance companies, many of whom declare boats must be north of that latitude during hurricane season to keep coverage.

There are a few other things in our favor in the northern sea as well. Since nearly every storm heads off in the general direction of Hawaii, we are off the common path. And if one did circle back from the Pacific, as they do occasionally in late fall, by the time it got to the norther Sea of Cortez, it would likely be greatly diminished.

But Still, What If...?

We’re north of Latitude 27 at the moment, but out of an abundance of caution, we always have plans B, C and D in mind this time of year — and stay topped up on fuel, water and food so we’re ready to vamoose on a moment’s notice. From where we are now, we could get to Bahía Concepción in a day, San Carlos in a day and a half, or Puerto Don Juan in two — all good places to hole up if things got interesting. But since hurricanes start 700 miles away and move at the speed of a bicyclist on a Sunday ride, we’d have a lot of time to analyze the storm tracks and position ourselves accordingly.

All of this, of course, requires knowing where a storm is and where it’s likely going. Most of the time we don’t have cell coverage, Wi-Fi or cable TV to tell us what to prepare for, but we have tons of resources at our disposal that sailors of old could only dream of. Between our sat phone, iPad and SSB radio, we get informed daily (or hourly if necessary). For those who are interested in details, you’ll find our go-to forecast sources below.

What We've Been Up To

Despite all this talk about hurricanes, the weather in the Sea of Cortez has been beautiful of late, with warm water and cloudless skies — if a bit on the warm side. We spent time in Puerto Escondido, Isla Carmen and Loreto, had some idyllic days in deserted anchorages along the coast, and more recently visited Bahía Concepción and Mulegé. 

Just to round out the picture so you know it’s not all mangoes and margaritas down here, we’ve been on the move a lot to get ourselves far enough north for comfort. We also had an iPad tech meltdown that was extra frustrating to solve over glacial Wi-Fi, lugged a half-dozen water cooler jugs from beach to dinghy and dinghy to deck to keep our fresh water tanks full, got invaded by hundreds of honey bees, spent countless hours cleaning the hull and polishing the stainless (like the Golden Gate Bridge, by the time you get from one end to the other it’s time to start over), and passed three exhausting days stocking up on provisions for a summer with increasingly limited grocery access. But that’s all part of the game.

Meanwhile, much about this lifestyle is feeling happily routine. While we will always have tons to learn, it’s also fun to look back on our progress — especially the things that used to cause us anxiety that no longer do. We’re three times faster at getting the boat prepared for departure, better at patiently choosing weather windows so we do far more sailing than motoring, practiced at figuring out how to get supplies every time in a different place, and choosing cozy anchor spots. As the weather’s warmed, we’ve learned to unzip our dodger’s windshield for air flow, cover the eisenglass side panels for shade and to hang the hose from the lifelines so the melting rubber won’t leave marks on the deck (yep, it gets that hot down here).

So we’ll keep watching the weather, and doing our best to stay cool, but for now, all is well. :)

Fair winds and following seas, dear friends.

Dusty Loreto was charming

I grew up a few blocks from El Camino Real in Palo Alto. The missionaries built the 1300 mile long road so they could lug supplies by mule from one mission to the next. I knew it as a four-lane traffic nightmare during Stanford football games and as the spot where I learned that if you take a left turn too hard on a rainy day, your car may just spin in a great big circle in the middle of the intersection. (Ok, never doing that again). Anyway, while missionary history is far from simple, it was fun to visit the very beginning of the road as it exists in Loreto — a lovely, tree-covered amble.

Why are we always so happy in all the restaurant selfies we post? Living a life completely without takeout, a freezer or pre-prepped meals to fall back on means a lot of time in the galley. While we love to cook, having someone else do it for us is an enormous treat. Plus, bomber ceviche!

Dolphins off the bow

Needlefish off the stern 

We were told that Pristine’s original owner named her after the quest for pristine waters. If so, consider her aims achieved. Colin, Pristine, and I had this bay all to ourselves except for one panga, who came in just long enough to trade us two fish for three cokes.

I was a geology major in college until I realized I actually loved hiking more than I loved science, but Baja is paradise for rock nuts like us. I did at least learn enough to tell you that white stuff is a conglomerate ash, evidence of a massive volcanic event that would have been pretty amazing to witness if it wouldn’t have been your last sight. (The folks in Pompeii probably glimpsed something like this too.)

We’re not the first people to explore these shores, but man, it’d easy to sustain that fantasy.

We pulled the dinghy up over the beach to play Lewis & Clark in the mangroves

We may not have Netflix, but Mother Nature’s pretty good at drama too


Boat chores never end but they do get much more Zen in warm, clear water

Colin’s happy place, scrubbing the decks topsides. Seriously, am I lucky or what? This man loves a clean boat even more than I do.

I’m not sure you can call this a boat chore — Colin looks way too blissed for that — but his efforts resulted in a delicious triggerfish

Sometimes the safe anchorage is too far away to walk into town, but it just gives us the opportunity to meet awesome people. Ole was kind enough to give us a ride from Bahía Concepción to Mulegé.

Since missionaries found many of these Baja towns, it’s no surprise that the missions feature highly

Since Mulegé is fed by a natural spring, it has a totally different vibe than Loreto. Palm trees and greenery make for a lush sight after so much stark desert beauty.

If you ever wonder why we do something so crazy as sail away on a small boat, see exhibit A above.

How Do We Get Weather Forecasts?

There are lots of ways cruisers do this, but here’s our method. I’m sure it will evolve as we learn more, but we feel great that we get the core information we need from two different sources and can augment it with lots of options.

1) Iridium Go + Offshore (by PredictWind)

Every day we fire up our sat phone and pull down weather data via the Offshore app on our iPad.

Different weather charts and files can get really confusing, but it’s pretty critical to understand the sources because the devil is very much in the details.

Since satellite data speeds are to broadband what a cocktail straw is to Victoria Falls, this first process gives us GRIB (aka gridded binary) files — a download-friendly file of text-based code that would look like gobbledygook to you and I, but can be read effectively by a software application and displayed over a map.

While the graphics of the app are colorful and compelling, the catches here are 1) GRIB files are purely computer-driven estimates with no human interpretation, 2) wind is the hardest weather phenomenon to predict, and 3) the most important inputs are voluntary surface reports made by a tiny fraction of ships at sea so the source data driving the models is extremely limited — especially in places with little shipping traffic.

So while four different models of wind forecasts for our part of Baja may sound like a goldmine of information, our experience has been that only one (the ECMWF gust model) is reasonably accurate for the Sea of Cortez, and even that has its limitations.

Apparently, NOAA is updating their core GFS model, so hopefully the accuracy of GRIB forecasts will continue to improve. But quoting from NOAA’s own press release, “This is the first major upgrade to the dynamic core model in forty years,” which is great, but if you think about how far data science has come in four decades, it may give you a peek behind the curtain of the Great and Powerful Oz’s weather model. Hint: It ain’t nearly so great or so powerful as you might expect, especially given the pretty pictures.

But the other thing we can get via Offshore is an ugly, text-only weather bulletin from the GMDSS (Global Maritime Distress and Safety Service.) These cover a wide area (i.e. the Eastern North Pacific = Region XII) but unlike GRIB files, GMDSS bulletins are so directly crafted by experienced human beings that every prediction gives the forecaster’s name at the end. Computer models are still part of their process, but they know how best to weight various data sources and are still much better than any algorithm yet developed at filling certain gaps. These reports may not be pretty, and they may not be hyper-local, but we have far greater confidence in their overall accuracy. This is the first thing we look at when we wake up to find out if there’s a tropical disturbance 700 miles south with the potential to make our lives interesting. Unfortunately, it’s also the buggiest part of the Offshore app and often refuses to pull down a single byte of information. 

So — far from perfect. Still, it’s a heck of a lot more information than sailors of old had to work with — all from a device the size of a sandwich. And while I find it amazing that I can communicate with satellites regularly, Colin is utterly baffled that for all that I call this state-of-the-art technology, we still have no simple way to get baseball scores.

The colorful — and sometimes accurate — Offshore animated map driven by GRIB files

The uglier but far more reliable GMDSS weather bulletin

2) SSB + Chubasco Net

The second thing we do every morning is turn on the SSB radio. Out here in the Wild West of Baja, we’re too far from civilization to get line-of-sight VHF broadcasts, but that’s where the single side band comes into its own. Remember CB radios, good buddy? That’s just one set of frequencies covered by the SSB. Essentially, the same old school but still very trick radio waves get bounced off the ionosphere and propagate hundreds and even thousands of miles depending on atmospheric conditions. The sound is usually akin to 60s-era AM radio, but this process feels as magic as the sat phone, and when we hear familiar voices from places like Ensenada and Tucson make their way clearly out of the static, we feel a little like Apollo-era astronauts.

The frequency we listen to most often is the Chubasco net, where the weather is delivered every morning by an amateur volunteer (thank you amazing sailor communities!), based on all the best, human-tweaked NOAA reports. These forecasts get no more local than, say, the Central Sea of Cortez, but we feel good about their relative accuracy. It’s also hugely comforting to have a calm voice, with decades of experience in what matters to sailors, relating this information.

As an example, when the GMDSS report first noted “24 hr possible cyclone near 13.5N 101W at 1006 MB. 48 hours at 16N 105W 1004 MB,” we were soon covering the salon in charts and plotting positions. This was a good exercise, but we felt much better when the Chubasco broadcaster said the exact conclusion we’d come to ourselves: “The system bears watching but is moving primarily west so nothing to worry about in the Sea of Cortez at this point.”

Most of the time, between those first two sources, we have everything we need. But when we want more detail, or Offshore chokes at providing GMDSS bulletins, or we have any trouble hearing the Chubasco net (or waking up in time, or writing things down as fast as they’re spoken) or if one of our communication devices was to go on the fritz, it’s really helpful to have alternative sources in our toolbox.

3) SailDocs

One might think we could just go to NOAA and sign up for text-based weather bulletins to be emailed to our sat phone account. One would be wrong. For whatever reason, NOAA provides endless weather options on the web (that we can’t access without internet) and via specific radio broadcasts but not via sat phone-friendly email.

Enter SailDocs, a sidearm of Sail Mail, a popular SSB & sat phone email provider to cruisers. We don’t use their mail service, but they’re cool enough that they’ll send us weather text files for free, as long as we send them an email and ask nicely in computer code, i.e. send FZPN02.KWBC. Plug and play it is not, but it works fabulously in a pinch.

4) Weatherfax

Here’s another throwback that still has relevance to sailors. Remember old school fax machines that spit out rolls of slick, curly paper with images based on sounds transmitted over phone lines? The same SSB radio that broadcasts voices also transmits fax sounds over special weatherfax frequencies. The new age difference is that an app on our iPad interprets them (HF FAX), not a separate machine. Colin, the iPad and I all get to listen to the squeals and beeps that come through the speaker while the image gets drafted line by line. (One day, when we’re really cool, we’ll get the right jack to connect the two directly).

What comes through are NOAA synoptic and forecast charts. Again, unlike the GRIB files we get through Offshore, these charts start with computer models but are then carefully tweaked by human beings with real-world experience. These visual charts are too hefty in file size to come easily via satellite, but this SSB-based solution gives us the chance to see pressure systems for the whole Pacific region — where the lows are developing, whether the Pacific High has finally filled in, what we might want to keep an eye out for. If we are in a place with internet access, we can get these straight from the NOAA website, but when that’s not an option, weatherfax is super cool. (Thank you Chris from SV Gypsy for turning us onto this!)


5) The Environment

Everything above is based on good theory, but there is no substitute for actual, on-the-ground conditions. We check our barometer several times a day and monitor wind shifts and the progression of cloud patterns. Even ocean swells can give clues about systems hundreds of miles away. Also, the mountain formations of Baja make for hyper local wind funnels that nail one area where another nearby is totally protected. So in this place, we keep a good eye out for valleys as well.

Overall, we’ve learned a lot about reading the signs, but still have a long way to go before we can reach that old salt state we dream of — where we just feel in our bones what’s a-comin.

6) But Wait, There’s More!

With internet access, our options grow enormously. does a great job of summarizing weather forecasts for cruisers, NOAA has a thousand charts and Windy is another good weather app, it just doesn’t work with satellite.

Outside of that, there are lots more SSB-based weather sources, including hourly storm updates were that ever to prove necessary.

One additional note: If you’re looking for further reading, we’ve found most weather study aids are page-turners as much as advanced physics textbooks are. But David Burch’s books and Lee Chesneau’s classes are both brilliant at providing the details, but also cutting to the chase for sailors.

We’re still studying them too! Thank goodness this sailing thing has enough to learn that we could feed our curious minds for a lifetime. Let us know if you have anything that works well for you. We’re all ears.

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