Robert, great assessment of this group of apps. My understanding is that essentially all the apps provide the raw model output. In some cases only the GFS model, usually for the free apps. The more sophisticated apps, and usually those that charge a fee, may include a number of other models as options for viewing. But in any case, the raw model output. Forecasters always warn against using raw model data alone. When on the ICW I daily read the NOAA discussion provided by the meteorologist at the local forecast office. They regularly point out major disagreements among the various models and often use their own judgement to interpolate or choose among them. They are obviously not always correct in their judgements, but I'd rather rely on their experience than try to use my own judgement. Of course, the models differ the most when the systems we are all trying to predict are at their most unpredictable - and this Spring had been very complicated, with constant change. In other words, when we most need a good forecast, it is most difficult to predict. I suspect that in settled weather, all these apps would be in general agreement and in sync with NOAA marine forecasts as well. But with rapidly moving fronts, highs and lows, I doubt any of the raw models will be consistently accurate, hence the same result for the apps reporting the data.

PocketGrib show gust data on the Meteogram view.

Bob, I question the southwesterly boat heading of 208° of the 23kt wind screen shot if you are heading northerly to clear Wolf Trap. Usually, York Spit NOAA buoy is on a rhumb line of about 8° leaving Back River for Wolf Trap.

Bob: Another good article. Thanks. Here are my comments about Chesapeake Bay. I was waiting for you to get to the Chesapeake Bay to see how you dealt with the forecasts and other details here on my home cruising grounds. NOAA’s zone forecasts and marine forecasts consistently underpredict. I don’t know why. I started adding 5-8 kts to their zone forecasts about 15 years ago and still do today. And I always look at the Marine and Aviation forecasts for important details. However, I only adjust their forecasts after assessing the regional situation specific to frontal passage, location of pressure systems and any associated gradients. I also evaluate temperature (diurnal heating) and what side of the Bay I’m cruising on. Finally, I look at the zone forecasts all around me to see if there are large variances, which helps me understand where the boundaries may be. The Chesapeake Bay OFS Wind Forecast Guidance animation (link here) is my go-to when looking out a day, or so. I don’t depend on apps because I don’t know what logic or evaluation is being conducted by the people behind the curtain (say Wizard of Oz.) I think I have NOAA figured out by adding 5-8 kts. The one factor that I see on Chesapeake Bay during cruising season is what I loosely call “thermals.” That is, air that is moving from warm or cool areas to cool or warm areas, respectively. There are so many slots on the Bay (rivers on the western shore) in the landmass that as the heated air rises and creates seabreezes and landbreezes those are simply are not forecast by NOAA very effectively. Basically, I can count on sailing in the morning and in mid-afternoon as the energy from the thermals manifests itself. Not every day – but when there’s other energy (front passage, shortwave along a frontal boundary, a far-away storm system, etc.) I factor that in to the wind equation. And while I enjoy a good North breeze when sailing, I don’t even think of taking the Trumpy out in the Bay if the forecast is for N or NE. There’s too many miles of fetch and that wind direction often bodes discomfort.  Although I hankered for it with my Tartan 33 for the dozen years I sailed her.  

Hi Robert.  I tried to find an email for you and my googling skills are failing me, drat.  A review which included LuckGrib in the fall would be fantastic. NOAA provides an amazing amount of forecast data for our waters, some long term, some short, some high resolution, statistical blends of many models - what they offer is very impressive.  CMC up in Canada also provides some great data.  Europe is less fortunate, but the German DWD is providing a lot of public domain data.  In LuckGrib I'm trying to provide convenient access to as much of it as I can (although there is so much I need to be a little selective.)    In around mid July, NOAA is planning on upgrading their RAP and HRRR models - they expect the upgrade to improve the 10m wind forecasts.  Also worth checking out is the 'simulated radar' parameter in some of the models which help forecast convection (find this in HRRR, NAM, RAP.)  Feel free to contact me for more info.

Tim, I was hoping the apps would help, they seem to do so some but but not as much as I hoped.

Craig, when I first looked at LuckGrib after a suggestion for the Round 1 event, it appeared to be just another GFS grib file. I didn't realize it had all the other models, especially the finer resolution ones for Chesapeake Bay. That, plus the $20 buy-in price deterred me from including it.  I'll spring for the bucks and include it in the future but the testing will be in the fall on my next trip down the ICW. Thanks for explaining the details of the app.

Jim, I was using the name displayed under the icon when shown in the iPad choice of apps which is just "Windy". However, you are right. When I accessed the iTunes store under "Windy", the "Windyty, SE" shows up next to the Windy icon. That's the one I downloaded.  https://itunes.apple.com/us/app/windy-wind-and-waves-forecast/id1161387262?mt=8

Hi Bob, Just to clarify, the app to which you refer as "Windy" is , by Windyty, SE, right?   There is an app called , by Windy Weather Worldwide Inc.   The only difference between them is not the names, it's the Icon for the program... Jim

You should add LuckGrib to your app list!  It presents the weather model information in a very clear and informative manner.  It also supports many weather models, which you can download directly via the app.  For the Chesapeake Bay, it has four global models (GFS, GDPS, CMC ensemle, GFS ensemble) as well as five regional models, all much higher resolution than the global models (NAM, RAP, HRRR, HRDPS, NDFD.)  NAM and HRRR are available with a 1.62nm resolution.  LuckGrib is available on macOS, iPhone and iPad.

Great article. I have seen the same inaccuracies often.  Anecdote: Prior life as a airline pilot, made numerous arrivals over eastern Long Island and watched the development of the sea breeze, specifically over Gardiner's Bay. Tried to see the pattern of wind development, to be the fastest sailor on the bay. Retired after 29 years and still don’t have a clue other than in the most general sense!