We’re back in planning mode and waiting for a weather window in Charleston to jump down to San Francisco which made for a perfect opportunity to play around with weather Apps for the iPad.

A first rate weather application should allow you to see both wind and sea state information simultaneously. Air Temp, Water Temp, Cloud Cover, Precipitation are nice but not super critical for my needs, but may be for others. I’ll first go over some of the common functionality of these applications and then review how each app did at implementation.

All of the apps use public weather data either directly from NOAA, Saildocs or some other such relay service. If you’re familiar with receiving GRIB files through SSB or the web then you will be familiar with the way they are visualized in the apps. Each app adds a lot to the presentation of the data and making it easier to understand. Some of the apps support more than one data model (read about the GRIB data models on SailDocs). Since I don’t have a ton of experience interpreting data models, I am unsure which data model is better than the other or which is better suited for which route planning. It would be useful to look at more than one data model to see if and where they differ. The assumption that agreement between data models means a higher likelihood that the forecasted conditions are what you’ll actually see out there.

All of the apps allow you to visually select the area of the forecast model by selecting an area on a map. Additional selection information includes the following options: forecast to retrieve (and hence the file size), number of days in the forecast, number of forecasts per day, and the weather data to be retrieved (wind, wave, temps, cloud cover, precipitation, etc.). After selecting the data you want to include the GRIB file is then downloaded by the application.

All of the applications have the ability to play, or animate, the multi-day forecasts. This is similar to watching a time-lapse RADAR image on the web or on the local TV news, but in this case it shows the evolution of the forecast in your selected area.

Keeping the above information in mind and the disclaimer that I am at best an amateur neophyte weather forecaster, here are my reviews of the following applications.

WeatherTrack (iTunes) only allows you to see one weather data model at a time. Animating the data requires an extra step after download and there is some pause while it is generated. The other apps generate animations on the fly or by default; in this case the extra step makes the implementation feel less polished.

Weather 4D HD (iTunes) has some stunning graphics and not only are they are sexy, you can understand more information faster. With a two finger tap on the screen controls can be accessed that allow you to change the information displayed. For example, you can choose to mask forecast data over the land (or water) so it is hidden. You can also change wind display visualization from traditional wind barbs to color gradients. This can also be done for temperature data. Another nice feature allows you to visually display sunrise and sunsets data by changing the background display map from day to night making it obvious to tell if you’re looking at a day time part of the forecast or a night time forecast. This is VERY intuitive and when you’re trying to plan a multi-day passage it again makes understanding what will be happening at day or night on your projected route more obvious because you are visually prompted to see the end of each day.

This is by far the best app due to its visualization and its ease of use. However, it only supports the NOAA GFS Model which does not contain sea state information, which as I mentioned earlier was a must-have feature.

NOTE: I have spoken with the author of Weather 4D HD and he told me he just submitted an update which does include wave data. YAY!! I’ll update this review when I have actually used it.

PocketGrib (iTunes) is the only application that currently displays multiple types of data and does contain sea state information. Visually it is not as sexy as Weather 4D HD, but it is functional. Some things need work, like the date selection on the bottom takes all of the real estate on the screen and thus covers up the icons legend. This is especially problematic since I had a hard time deciphering the different sea state icon sizes. The red sea state icons are like carrots (or arrows) of differing sizes based on height pointing in the direction of the wave\swell. I don’t find the sizes of the icons to be considerably different. So if you have three icons represent three states the one in the middle isn’t different enough from the one above or below. Adding color gradients, wave gradient height would help, or even better, providing the option for both.

PocketGrib only supports one data model and the file name indicates it’s a GFS model. However, GFS models don’t contain sea state information. I contacted the author and they are merging in WW3 data, but don’t mention it. Probably not a big deal to an average user, but I think they miss out on getting credit for it.

Of the apps that I reviewed, PocketGrib is the only application that meets my primary requirements to allow me to visualize both wind and sea state information simultaneously. I am selecting it to use for future passage planning. Since I really liked Weather 4D HD, I will be using it when I in port and want to see normal land lubber weather.

I’m stoked for the new version of Weather 4D HD to come out, I keep checking for app updates looks like that will have to wait till we’re further down the coast.