The most common sources of errors in official precipitation measurement come from equipment malfunction. If the tipping bucket rain gauge breaks down, then rainfall will not be measured accurately.
For weather enthusiasts who measure their own rain, common sources of error are a bad location of the rain gauge. If the gauge is situated close to buildings or under some other kind of shelter, then it will under-report rain.
12:38 EST Tropical Cyclone Jack has rapidly developed over the warm waters of the Indian Ocean in the past 24 hours, making it the 10th system to be named this season.