Another new version of LuckGrib is now available.

This version of LuckGrib extends the improvements made in v2.0 in a number of ways.

The National Digital Forecast Database (NDFD)

The first major improvment in this version is that LuckGrib now supports viewing files from the National Digital Forecast Database (NDFD). This is a collection of GRIB files which are unique in that they are generated by a group of highly trained forecasters. Most GRIB models are the result of a computer simulation and receive no addition review before being published. The process used in the creation of the NDFD is entirely different: forecasters from each region review all of the resources as their disposal, which include GRIB models from the major weather centers; these forecasters then agree on a forecast for their region and submit the results to the NDFD; the NDFD creates a mosaic stitching together the regional results and presents it to the public.

The NDFD contains forecaster reviewed data. This is an exciting new addition to the weather information at our disposal.

Two NDFD models are provided on the LuckGrib server cluster: the contiguous USA (Conus) which is updated hourly and provides a variety of data at a 2.5km resolution. This model includes some new probability data, such as the probability of tornado, probability of hail, probabilty of storm force winds, and more.

The other NDFD model offered on the server cluster is the Oceanic model. This model only provides wind, wind gust and significant wave height. The domain for this model covers a huge area, however there is only data present in areas where NOAA is responsible for providing forecasts. More information is available at the page describing this model.

The oceanic model is updated every 6 hours and has data at a 10km resolution.

File compression

If you are using LuckGrib on either a slow internet connection, or a connection where you pay for data usage - both scenarios which are not uncommon among sailors, then this may interest you.

There is a new Experimental area in the Application Preferences window. Within this area is an option to turn compression on for files transmitted from the server.

The compression technique used is complex. Literally. The GRIB-2 format allows data to be encoded in a variety of ways. The simplest way of encoding data has the official name of simple. There is a JPEG encoder and lastly there is a complex encoding format. That’s what its called.

The complex encoding has the potential to greatly reduce file sizes, and there are examples of files being reduced by 90%. Some files are only reduced by 20% but 50% compression isn’t uncommon.

In the future, gzip compression may also be used to further reduce the file sizes. I would be interested in hearing from customers who would like to see more work in this area.

Feedback welcome

As always, the author welcomes feedback. If you have suggestions for changes you would like to see in this application, please let him know.

If you have used LuckGrib and enjoy it, please leave a comment on the Apple App store. Comments are read by people who are new to the software and are greatly appreciated.