weather forecast for the inside passage

At the end of May I will be heading to SE Alaska from Vancouver area. I have made this trip many times before. The weather forecasts that are via VHF radio, especially in Alaska, cover a wide area and sometimes you have to listen for about 20 minutes before it hits your specific area. A real PITA. I have an Iridium Go phone that I have used with Predict Wind when I cruise Mexico. Although the Predict Wind forecasts have a 50km resolution, that is fine in Mexico because the ocean and even the Sea of Cortez are large and open. However, for the Inside Passage a 50km resolution is not too useful because even the major straits are only about 15 miles across.

My question: has anyone on the Forum found a more suitable source of local wind/wave weather for the Inside Passage to Alaska? I know it is possible to call NOAA and get the forecast for one specific area. However, the Iridium Go minutes are rather expensive.

I find Windy to be very useful. Much more granular than NOAA. Windy has often helped me make a go-nogo decision when NOAA did not provide enough info.

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It’s been a long time since I played with an Iridium Go, but I believe you can access web sites with limited graphics. I have bookmarked the NOAA text marine forecast pages and observations pages to make them easier to get with only a bar or two of cell service using an amp and external antenna. It’s a big help as NOAA doesn’t spend much money fixing VHF sites.

Tom

I spent a week between Cape Caution and Kitimat 3 summers ago and found very little VHF service and almost zero cell service in the whole area. Your problem is deeper than which service has the best forecasts. You will need to accept what you can get.

If all were present on your boat, which you may have with Ham, Iridium Starlink or whatever, I prefer Windy. Use it a lot and you will find that its forecasts are much better than the very generalized Coast Guard weather.

The default weather model on Windy is ECMWF, with "E" standing for "ensemble." It is a composite of several models, including GFS, the U.S. model. Other stand alone models available on Windy are HRRR, NAM, ICON. They vary in how "granular" the models are and also in their forecasts. It is a little disconcerting to switch from one to another and (rarely) find that one model meets your standard for "go" and another model is "no go". Easiest to just play the numbers and use ECMWF. Of course you need cell phone coverage otherwise NOAA may be the only game in town.

If you have a reliable land based individual, what we use is asking them for a Windy report via InReach.

Marco Flamingo said:

The default weather model on Windy is ECMWF, with "E" standing for "ensemble." It is a composite of several models, including GFS, the U.S. model. Other stand alone models available on Windy are HRRR, NAM, ICON. They vary in how "granular" the models are and also in their forecasts. It is a little disconcerting to switch from one to another and (rarely) find that one model meets your standard for "go" and another model is "no go". Easiest to just play the numbers and use ECMWF. Of course you need cell phone coverage otherwise NOAA may be the only game in town.

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Pretty sure that's not correct. ECMWF stands for European Centre for Medium Range Weather Forecasts, and their model is independent of others.

Here's what Windy says about the ECMWF: "Very accurate model provided by the European Centre for Medium-Range Weather Forecasts. Clear winner compared to other forecast models. Since the model is commercial, only a few companies in the World offer it."

For a journey like that, especially with uncertain internet access, I would suggest learning to use a grib viewer to access multiple models directly and keep them in storage until refresh is available. On an iPad, I like LuckGrib.

However working with grib is much less intuitive that apps like Windy. A good weather course like the one from Starpath will teach how to use them.

As for forecast accuracy, it's a good practice to compare several. The HRRR model is superb but limited to about 16 hours in the future. ECMWF is the "best" on average among longer range models but the gap is closing. I feel better when I compare several and they agree.

The following post is a good place to start digging into all the available options and features both LuckGrib and David Burch (marine weather book and Starpath course author) :https://luckgrib.com/tutorials/2020/04/27/cca-gfs-ecmwf.html

One caution about Windy in SE Alaska. Its models don’t seem to factor in the terrain’s affect on winds. For example any wind with a southerly component will blow directly up Clarence or Chatham Straits. For the same reason the velocity is sometimes understated. NOAA’s forecast of 10kts/2ft backed up by Windy is a go. A forecast of 15/3 is a look see and a forecast of 20/4 is a stay put unless the prediction is 10/2 later in the day and then a look see is in order.

The place I have been surprised the most is Peril St when southerly winds turn out of Chatham and blow up Peril making it a slog just to get to Appleton Cove and Appleton sees winds of 15 kts.

Tom

tpbrady said:

One caution about Windy in SE Alaska. Its models don’t seem to factor in the terrain’s affect on winds. For example any wind with a southerly component will blow directly up Clarence or Chatham Straits. For the same reason the velocity is sometimes understated. NOAA’s forecast of 10kts/2ft backed up by Windy is a go. A forecast of 15/3 is a look see and a forecast of 20/4 is a stay put unless the prediction is 10/2 later in the day and then a look see is in order.

The place I have been surprised the most is Peril St when southerly winds turn out of Chatham and blow up Peril making it a slog just to get to Appleton Cove and Appleton sees winds of 15 kts.

Tom

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I think TOm nailed it. Narrow channels, Fjord like inlets can amplify the neighbouring winds and "channel" into much stronger and maybe concerning winds that the more open areas won't see. We see this in our inlets, Indian Arm, Howe Sound, and of course further up the coast.
Many times we have seen strong inlet winds where once out of the inlet there is only a mild breeze.

Up the coast/inlets those local winds will not be accounted for. At least not yet untill weather stations are installed.

I guess I'm the outlier here, the Canadian weather data via marine radio, cell phone or shore Internet has proven quite helpful. Then with InReach other data can be pulled up - for a fee. With InReach we found that contacting fellow cruisers (with great GRIB files etc) for information fills in a lot of blanks.

But, nothing beats a well found vessel, safe anchorages and schedule flexibility for those WTF times.

tpbrady said:

One caution about Windy in SE Alaska. Its models don’t seem to factor in the terrain’s affect on winds. For example any wind with a southerly component will blow directly up Clarence or Chatham Straits. For the same reason the velocity is sometimes understated. NOAA’s forecast of 10kts/2ft backed up by Windy is a go. A forecast of 15/3 is a look see and a forecast of 20/4 is a stay put unless the prediction is 10/2 later in the day and then a look see is in order.

The place I have been surprised the most is Peril St when southerly winds turn out of Chatham and blow up Peril making it a slog just to get to Appleton Cove and Appleton sees winds of 15 kts.

Tom

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Very true. We came up Clarence Strait today. Winds forecast to be 10-15kts from the north. It was 20-30kts for a stretch, then averaged 20kt the rest of the way.

TT,

Probably 3-4 ft depending on tides judging by the observations at Ship And Lincoln Is. The Lincoln Island site measures north winds pretty well but is partially shielded from the south. Where are you overnighting?

Tom

rpackard said:

However, for the Inside Passage a 50km resolution is not too useful because even the major straits are only about 15 miles across.

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PredicWind carries the ECMWF which is 9 km worldwide. They also have their own 8 Km and 1Km models, initialized two different ways (GFS and ECMWF data). Their models typically do a better job of predicting the influence of terrain. The 1Km model has limited coverage, basically around Puget Sound and Salish Sea. The 8 Km models are run all the way up to Glacier Bay and down to southern Mexico, but missing a tile inshore from Ketchikan to about Juneau.

I've just put in a SiriusXM weather receiver, supposed to get coverage for NOAA marine forecasts and Environment Canada marine forecasts north to Juneau. An advantage of that is you also get real time buoy reports. This is all the info you get from VHF, but captured and displayed as your leisure.

DDW,

My experience with Sirius XM weather was abysmal in SE Alaska. I think most of the problem was Lowrance on the first try and Garmin on the second. Lowrance took Sirius at their word that Ak service was limited so just followed a limited delivery by not displaying all the data. Garmin with their older GXM-52 could not reliably deliver the Ak marine forecasts, but I knew quickly about lightning in Florida. I would be interested in what your experience is and whose system you are using.

Tom

tpbrady said:

TT,

Probably 3-4 ft depending on tides judging by the observations at Ship And Lincoln Is. The Lincoln Island site measures north winds pretty well but is partially shielded from the south. Where are you overnighting?

Tom

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That's about right.


We are in Exchange Cove.

SE Ak weather

Richard- there are very few navigators out there with more SE AK experience than you! One thing for sure that we both know is that cell and internet service is considerably better then we had in the past. I’ve noticed that “Puffin” is still on the dock in Anacortes. Are you taken her or Lilian north this year. We’re still running Lady Anne but she’s a KK42 based out of La Conner, WA.