What is GRIB?
GRIB (GRIdded Binary) is a concise data format commonly used in meteorology to store and distribute historical and forecast weather data.
Which weather parameters can PocketGrib display?
PocketGrib can display the following data layers from GRIB files:
- Wind speed and direction - displayed using feathered wind arrows - a small barb is 5 knots, each long barb is 10 knots and a solid triangle barb is 50 knots.
- Pressure at sea level - displayed using isobars at 4hPa (mb) increments
- Precipitation - units are mm or inches of rain per hour
- Air temperature - this is displayed as a colored layer - units are ceslsius, farenheit or kelvin
- Wave height, direction and period - the arrow head shows the direction and the size of the arrow head indicates the wave height which get bigger for bigger wave height
- Cloud cover - as a percentage displayed in shades of white
- Relative Humidity - as a percentage displayed in shaded green
- CAPE (convective atmospheric potential energy) - displayed as a colored layer - units are J/kg - higher levels of this indicate atmospheric instability which can result in severe weather
Why can't I see waves in the Mediterranean?
Select the WW3MED model using the Settings in the map download screen.
What is CAPE?
CAPE stands for convective available potential energy. Wikipedia has quite a thorough article on it. In simple terms, CAPE is an indicator of atmospheric instability, which makes it valuable in predicting severe weather such as cumulonimbus (storm) cloud formation, severe thunderstorms and tornadoes.
The new version crashes on startup or when downloading a file. What can I do?
Please check what version of the iOS software you are running - this can be found in the main iPad/iPhone Settings => General => About => Version
- If the version is 5.0.0 and above
Please try removing and reinstalling PocketGrib which usually fixes the problem. If you do a long press on the PocketGrib icon until all the icons start shaking and then press the small black "x" in the top left corner of the PocketGrib icon then you can delete the PooketGrib application. It will popup a confirmation message - just press "Delete". Then just go back into the App Store, find PocketGrib again and install it (you won't get charged anything for this).
- If the version is 4.2.x or 4.3.x
There is a problem with this latest version of PocketGrib running on these older versions of iOS. The best option is to upgrade your iOS to the latest version which is 5.1.1. To do this you need to plug in your iPad/iPhone to your computer and then within iTunes just select you phone under Devices on the left hand side and then click the "Check for Updates" button.
How can I delete GRIB files?
To save you worrying about deleting old GRIB files, PocketGrib is setup to automatically delete GRIBs after a configurable amount of days. If you do want to manually delete them, you can do so from the GRIB management screen - simply swipe your finger across the GRIB that you wish to delete from right to left and you will get a delete button which you can use to delete that GRIB file.
What should I do if I experience PocketGrib crashing?
PocketGrib is a memory intensive app due to the maps and graphical weather overlays. If you experience any crashing then there are a few things to try
- Check what version of the iOS software you are running (this can be found in the main iPad/iPhone Settings => General => About => Version). Versions 4.0, 4.1, 4.2 have some small issues with memory. If you have version 4.3.3 or later then you should be fine. You can update the software by plugging in your iPad to your PC and press the "Check For Updates" button
- Close some other apps which are running and consuming memory. To do this, double clicking the home button to open the multitasking, then hold down on an icon until you see the red minus, then tap the red minus.
- Reboot. Turn your device off and then on again and then run PocketGrib. This will clear all other applications from memory (until you run them again)
How can I delete GRIB files?
To save you worrying about deleting old GRIB files, PocketGrib is setup to automatically delete GRIBs after a configurable amount of days. If you do want to manually delete them, you can do so from the GRIB management screen by doing a long press on the file that you wish to delete. Then select the 'Delete' option.