Grib File Viewer For Mac
Wgrib2: wgrib for GRIB-2 Utility to read and write grib2 files wgrib2 v3.0.2 has been released (Windows) (3/2021) pywgrib2s been released for alpha-beta (Linux/MacOS) (wgrib2 v3.0.0, 9/2020) Introduction. Wgrib2 is not simple upgrade of wgrib for grib2 files. Wgrib can slice and dice grib1 files. We start with XyGrib because it is a free, easy to use Grib Viewer app that has both PC and Mac versions. It also has the advantage of providing very convenient GRIB file selection and download from right within the app, including a wide range of models, and several unique European sources.
A key aspect of modern weather work is the use of numerical weather model forecasts in Grib format. This should not be treated as a sole source of information, but it is extremely valuable once you have evaluated the forecast. Methods of doing that, along with an overview of models and available weather are covered in Background on GRIB Files and Numerical Weather Forecasts.
Here we jump straight into the process by looking at a couple options for downloading and viewing the files.
XyGrib
GRIB files are a self contained weather forecast that you can easily download. A GRIB file can include a forecast for one day, or for a longer time period. It can have wave info, or wind info, temperature info, cloud cover, precipitation, and other such weather data.
We start with XyGrib because it is a free, easy to use Grib Viewer app that has both PC and Mac versions. It also has the advantage of providing very convenient GRIB file selection and download from right within the app, including a wide range of models, and several unique European sources.
Get the app from https://opengribs.org/en in the Downloads section. Choose the online installer for Mac or PC. Install in the normal manner, and open the app. For the Mac install, you will need to open System Preferences / Security and give the app permission to be installed. During the installation process, be sure to check the option to install high-resolution maps. We need these for regional forecast work. Here is a short video on getting started. We will later add some with more details.
A review of the steps to download a file and a couple tips
Step 1. Default location of downloaded Grib files on a PC will be c:/users/username/xygrib/grib. This is similar in the Mac, but it is a hidden file, namely /.xygrib/grib. To see the contents of either one, use the folder icon in the menu bar, next to the quit button. The contents can be edited from within that window, or separate folders could be set up for different voyages or projects.
Step 2. Draw a box with the cross-hair tool in the main menu icon, then press the globe icon to select a model and other options, and download.
Step 3. After downloading, confirm the file storage location, which will display the data. If not already showing on the left, turn on the View Data panel ctrl+V (PC) or cmd +V (Mac). As you move the cursor over the map you will see the values showing in the panel. You can pull the panel off to the side. Once taken out, get it back in by restarting the program.
XyGribStart up tips
• In the window selection of window position, N and E are +, amd S and W are – numbers.
• On the menu/Weather map the top parts are closing what uses color overlay, and that overlay covers land and water. For inland work, maybe save that color for REFC or rain
• For a bigger view of time and date, click the slider bar at the bottom
• Note: the menu /File/New instance creates a new window of the program duplicating what was in the last instance. This can be valuable in some circumstances, ie for comparing different models or times side by side, but troublesome in others if you forget more than one is open.
• To update a file, use ctrl+d or cmd+d (Mac). This will fetch the existing file area and the same info that was left in the set up window. Note it will give the file marked with the UTC of the download time, but you will not know from the name if the file is same or different data for the region.
• In menu Options/Units: set speeds to kts and coordinates to ddº mm.mm' (note use of European comma for a decimal point.) One arc minute (1.0') is one nautical mile, so we can think through the extent of 12.2' more easily than 12' 24'.)
• To see true GRIB file resolution, use menu/Weather Map/Weather Options/Wind arrows on GRIB grid, then zoom in to see where actual data points are located. You can then measure the distance between grid points (tips of the wind arrows) with the the tool from menu/Earth/Great Circle Distance. Then shut this off when done. The true grid point display is awkward for normal use, so it then can be shut off for a scaled interpolation display.
• Caution, when you include higher altitude data, such as 500 mb or 850 mb surface, you do not get to choose parameters, so you are enhancing file size. There are several that get loaded: height, wind speed (the two main ones we need) plus you get RH, air temp, and theta-e temp, which is not a parameter we use in our weather course—it is a measure of stability, but we now have forecasts of simulated weather radar (composite reflectivity, REFC) which is a much easier and dependable way to forecast squalls.
• Models not yet in XyGrib but expected in the next build are HRRR (regional US weather) and RTOFS (global ocean currents and SST).
• The NAM CONUS available in XyGrib is only 12 km, not the 2.5 km version that would be preferred for regional route optimization. XyGrib does have the Arome data at 2.75 km that can be used for practice in Europe. The HRRR when available is 3 km which will serve US needs for regional work. (Note that the challenge the programmers face here is offering the hi-res data can overwhelm your delivery system if the user is not careful. Saildocs also limits NAM to 12 km. File size goes up as the square of the resolution.)
• Practice using right click on a data set to create a Meteotable of the data, which is similar to the meteogram seen in other programs.
• Practice downloading computed skew-T data from GFS model. We discuss these diagrams in our textbook, but we do not include them in our online weather course. This is a nice feature of XyGrib. Expedition is the only other grib viewer app I know of that includes these. Not many mariners use these underway, because we have the forecasts that are based on these, but they do provide a picture of the vertical structure of the atmosphere.
Free Grib File Viewer For Mac
Panoply Data Viewer
Download Panoply
Panoply requires a computer with Java 9 (or later version) installed.
The current version of Panoply is 4.12.9, released 2021-07-15.
- Download Panoply 4.12.9 for macOS, 36 MB DMG, uses native filechooser
- Download Panoply 4.12.9 for macOS, 36 MB DMG, uses Java filechooser
- Download Panoply 4.12.9 for Windows, 33 MB ZIP
- Download Panoply 4.12.9 'generic' for Linux, etc., 33 MB ZIP
- Download Panoply 4.12.9 'generic' for Linux, etc., 33 MB TGZ
- View checksums: [MD5] [SHA1] [SHA256]
Install and Run Panoply
After downloading the appropriate Panoply archive linked above, uncompress the archivefile on your desktop. Within is a README text file with an explanation of the contentsof the download, instructions on how to launch the application, and some notes on possiblelaunch bugs and/or performance tuning.
We would like to point out the following possible installation and launch issues:
If you find that after download and installation, Panoply won't start, a possiblereason might be that you don't have a Java Runtime Engine (JRE) installed on yourcomputer, or that it is not a Java 9 (or later) JRE.
On macOS:Panoply has been notarized in order to work with the heightened security settings ofmacOS 10.14.5 and later. However, it is possible that Panoply might fail to launch ifyour Java installation is not so notarized, in which case you may see an error windowstating that Panoply requires that Java 9 be installed. If so, you might try installinga more recent Java, built after August 2019.
Some users who have a second display attached to their Mac have reported Panoply does notrespond after the select an input file via the filechooser dialog. If you experience this,please download and try the version above labeled (JFC), which uses the Java filechooser.
There have been reports that Panoply for macOS fails to launch on recent Macs built with'M1 silicon' ARM chips. If this is the case for you, you should instead be able to use the'generic' PanoplyJ version and launch Panoply from the Terminal shell. Ford explorer complete service manual.
On Windows:You must extract Panoply from the ZIP archive before you try to run it. If yousimply open the ZIP file and then double-click on the Panoply icon, you will get aclass-loader error because it cannot locate code files.
Panoply for Windows requires that certain keys/values regarding the Java installationbe set in the Windows Registry. However, some alternative Java distributions may not setthese keys or else may require that you explicitly set them during installation.
On Linux etc:The TGZ archive of Panoply 'generic' was created using a BSD tar on macOS. Using GNU-tarto uncompress the package will probably print several 'Ignoring unknown extended headerkeyword' warning messages. You should be able to ignore these messages.
Download Color Tables and Map Overlays
Beginning with version 4, Panoply's 'standard' selection of color tables and map overlaysis built into the application. Additional color tables and map overlays may be opened fora single session or added to your favorites library for continued use.See the Panoply website for some optional support files.
For additional scale color tables, J.J. Green'scpt-city websiteincludes many CPT format files that are compatible with Panoply.