• Sailing is all about the Weather.

    Big into the exploration of Atlantic Hurricanes since Katrina came uninvited into his world, James (Jim) Gurley (JamesG161) has followed every Tropical Storm birthed in Atlantic, Gulf and Caribbean waters since. Being a boater, he knows that we often need more time to prepare than we get from the TV weather folk. Jim relies on the science of storm development to share early warning info with friends and fellow boaters.

    Early in 2018, Jim and John Shepard, (JSSailem) started to chat about the weather data available. John asked Jim to help forecast Pacific NW storms, and this morphed into discussions on weather forecasting.

    For John, sailing in the PNW is sometimes hit and miss. One day is ugly, then a string of beautiful days but no wind, followed by a series of blue-sky days and 12 knot breezes. Being ready for those great sailing days means you need to look to the Pacific Ocean and what is brewing. John has been into Pacific NW Weather since the 1970’s when his first PNW November storm hit bringing more than 40 days and 40 nights of continual rain.

    Together we want to share information, new APPs, safety, and thoughts about letting the weather help you. Identify some of the resources for sailors and help prepare you for your next sailboat outing.

    It is far better to go out on the water knowing what to expect in weather terms, than to be out on the water and see dark ominous clouds suddenly appear, unprepared.

LUCKGRIB and developing ideas in Weather Forecasting for Passage making.

jssailem

jssailem

SBO Weather and Forecasting Forum Jim & John
Oct 22, 2014
24,454
CAL 35 Cruiser #21 moored EVERETT WA
If you have followed our weather observations, you will have seen my comments about LuckGrib as a tool to plan your sailing. It is an Apple-based app, at present. There is work being done to make this software available on multiple platforms. Stay tuned for the future release information as it is published.

For the experimenters using LuckGrib to help them enjoy the wind forecasting, there are some new weather models being introduced. This is the recent update from Craig, the inventor of LuckGrib.

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Feb 9, 2026. | By: Craig McPheeters
On Feb 9th, 2026, five new GRIB models were added to the collection. Two of these are new operational models offered by NOAA, and three provide early access to an exciting new model being worked on, that is part of the UFS.

All of these models should be evaluated by all users of LuckGrib.

AIGFS and HyGEFS are both global models. AIGFS and AI ECMWF are both Artificial Intelligence / Machine Learning forecast models. There are indications that these models may be more skillful than the traditional deterministic models.

HyGEFS is a new global ensemble which contains the 31 GEFS ensemble members along with 31 members from a new AIGEFS model. The Hybrid GEFS offers data describing the ensemble average, along with the standard deviation. These two parameters offer a simple way to study the likely forecast outcome, along with a measure of its confidence.

The three RRFS models should be evaluated by everyone using LuckGrib in North America, Alaska, Hawaii and the Caribbean. This model has some similarities to HRRR in that it:

  • has high resolution (3km)
  • is rapidly refreshed (updated every hour)
  • has forecast data every 15 minutes for surface wind (and now simulated radar)
  • has four longer term forecasts over the day, at 0Z, 6Z, 12Z and 18Z - out to 3 1/2 days which is an improvement over HRRRs 48 hours.
In addition to the above, RRFS has a huge high resolution domain, covering all of North America, the Caribbean, Hawaii, Alaska - its a little astounding. This is going to be an extremely valuable weather model for sailors in these waters.

While RRFS is not yet operational, my understanding, as of Feb/26, is that its version 1 is frozen and being evaluated. RRFS is planned to become operational sometime in 2026.

The plan appears to be to discontinue many of the older regional models, such as HRRR, NAM Conus, RAP and others, at the time RRFS is made operational, or soon afterwards.
 
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colemj

.
Jul 13, 2004
1,036
Dolphin Catamaran Dolphin 460 Mystic, CT
I've been using the AI models AIGFS and AIECMWF and they have been performing better than all the others. They pick up weather systems days before the other models, and their predictions of direction and strength have been more accurate.

One example is two days ago, where the AI models have been showing strong W winds a week in advance where we are. West winds are rare here, and one needs to move their boat a considerable way to be protected by them. The other models continued to predict E winds, and didn't pick up the W winds until the day before the winds arrived. That was a 7 day heads up AI models gave us.

I have found the HyGEFS only slightly useful. I suspect I don't have enough knowledge yet of what it tells me and how to access that info.

We don't sail where the RRFS models have coverage, so no experience with them. Likewise, I've never used any of the models that are being discontinued.

Luckgrib is incredibly powerful routing software that is almost free ($60 for the weather routing lifetime license), but I find almost nobody out here with us using it. 100's of boats doing long passages, and the majority have bought into very expensive Predictwind packages ($600/yr) that do less than Luckgrib, but I guess have prettier interfaces and animations. It isn't completely the mac-only aspect, as many of these boats have macs.

Mark
 
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jssailem

jssailem

SBO Weather and Forecasting Forum Jim & John
Oct 22, 2014
24,454
CAL 35 Cruiser #21 moored EVERETT WA
I have found that there is a learning curve involved in developing reliable results.

Once you understand the structure of the application, reproducing the data for a series of days is lightning quick.

In the inside passage waters of the Pacific Northwest and the Salish Sea, it provides terrific surface results. One needs to separately consider the tidal currents happening beneath the surface to successfully navigate the passage.

I suspect that is less of an issue in the waters you sail, Mark.
 
MikeHoncho

MikeHoncho

.
Dec 28, 2015
1,944
Laser, Hunter H30 Cherubini Tacoma
I was getting some weird routing last time I used it. I think it was having issues calculating with all of the shorelines. Maybe I'm missing the option but I can't get it to locate on the chart using the GPS option. It always shows a wrong location by dozens of miles.
 
jssailem

jssailem

SBO Weather and Forecasting Forum Jim & John
Oct 22, 2014
24,454
CAL 35 Cruiser #21 moored EVERETT WA
Do you have an avoid a shoreline selected? You can choose a distance to avoid tracking through land.
What type of GPS is providing the location?
 
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colemj

.
Jul 13, 2004
1,036
Dolphin Catamaran Dolphin 460 Mystic, CT
Is this GPS option a mobile version thing, or available on the computer version? I've never seen it on the computer version, but would very much like to have it there.

Mark
 
jssailem

jssailem

SBO Weather and Forecasting Forum Jim & John
Oct 22, 2014
24,454
CAL 35 Cruiser #21 moored EVERETT WA
I use LuckGrib on my boat. LuckGrib is not a chartplot tool. It is a sailing weather tool. I enter my position (Longitude & Latitude) in the app as I progress on the passage. I updated GRIB files each day. The program then solves for the weather on the identified route using the new GRIB data.
 
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colemj

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Jul 13, 2004
1,036
Dolphin Catamaran Dolphin 460 Mystic, CT
colemj said:
Is this GPS option a mobile version thing, or available on the computer version? I've never seen it on the computer version, but would very much like to have it there.

Mark
Click to expand
I wrote the developer about this. His answer: "Yes, this is on my list. I agree it would be very useful."

Of course Luckgrib isn't a chartplotter tool, but having it know one's current position is convenient for weather routing. Two immediate conveniences come to mind: 1) I don't have to look at my position and then zoom in and move the start point around until it matches my position. 2) As one progresses during the passage between runs, it would be nice to see the difference from the predicted position vs actual position. This latter is actually important to weather routing.

Mark
 
jssailem

jssailem

SBO Weather and Forecasting Forum Jim & John
Oct 22, 2014
24,454
CAL 35 Cruiser #21 moored EVERETT WA
I agree with the thinking. I was stating the current state of the software.
There is a complete rewrite in the works (announced on the sites Blog Feb 2026). New features will be likely. I hope he does not detract from the original focus of elegant tight code work that produces results.
 
MikeHoncho

MikeHoncho

.
Dec 28, 2015
1,944
Laser, Hunter H30 Cherubini Tacoma
MikeHoncho said:
I was getting some weird routing last time I used it. I think it was having issues calculating with all of the shorelines. Maybe I'm missing the option but I can't get it to locate on the chart using the GPS option. It always shows a wrong location by dozens of miles.
Click to expand
It turns out it was my settings. It worked great on our recent race. With any routing software, it uses forecasts, and you need to scale the weather you have and use the routing as potential. It got us into several positions, allowing us to get out of becalmed conditions before others.
 
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jssailem

jssailem

SBO Weather and Forecasting Forum Jim & John
Oct 22, 2014
24,454
CAL 35 Cruiser #21 moored EVERETT WA
Great application of the tools.
 
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