There are two ways to think about rain rate. To just say "rain rate" is ambiguous. There is hourly rain rate and then there is instantaneous rain rate. They each represent two different concepts. Once you realize this you can then see that depending on where you are getting the information the "rain rate" is going to be in reference to one of these two totally different things. It is up to each individual online service as to which method they want to use to represent the data that you send them.
AWEKAS uses hourly rain rate. Weather Underground actually will display either one, but only one or the other depending on your station and how it uploads. Since you are using a Meteobridge to upload to WU then you actually get the benefit of being able to choose which method you prefer to send to WU. The Meteobridge calls the instantaneous rain rate an Alternative rain rate method. It is just a little check box right there where you configure your WU settings in the Meteobridge. Turn that off and then you are uploading hourly rain rate to WU. Keep it checked on and it is instantaneous rain rate.
The WS View app displays rain rate as the instantaneous type.
In summary there is nothing wrong with what you are seeing, as in some cases you are looking at hourly rain rate and in other cases you are looking at the instantaneous rain rate.
To understand the difference between these and what they represent I can define them as follows:
- Hourly Rain Rate: This is looking at how much rain has actually fallen in the past hour. This is an accumulation total of the last hour. (Acurite consoles use this method).
- Instantaneous Rain Rate: This is looking at the very immediate moment and seeing how much rain is falling and how quickly it is occurring and then making a prediction that if that current rate of precipitation were to hold steady for the next hour, then how much total rain would be realized. This is sort of making a prediction that if it were to not let up, how much rain would occur within the next hour. It isn't truly a prediction because nobody assumes that rainfall will be steady for an hour. But what this is useful for is to measure the amount of rain fall (like a force) at that given moment in time....basically to tell you it is fast or it is slow. This is akin to like a speedometer giving you your instantaneous speed. You may start your car and immediately speed up to 60 Mph but only drive for 10 minutes. The 60 Mph is like a prediction that if you were to not let up you would have traveled 60 miles in the next hour, but it is not relevant that you actually only drove for 10 minutes, you still got to know how fast you were driving. That is speed. Basically instantaneous rain rate is akin to speed of rainfall. The converse is that you start your car, drive fast at 60 Mph for 10 minutes and then you stop. Then your hourly speed (total for the past hour) is only 10 Mph. Basically then saying that for the past hour your rate was 10 Mph because that is all that you covered gives no indication of how fast you actually drove during the span of the hour and nobody would know if you steadily drove 10 Mph for the whole hour or if you drove really fast at 60 Mph for 10 minutes to then were still for the remaining 50 minutes. (Davis and Fine Offset clone consoles use this method).
Which is better? There is no better. It is nice that WU gives you the option and it supports both. Most people though do not have the option of picking which rain rate method they use because they are bound to whatever method their equipment/hardware/software is pre-programmed to use. You are fortunate with the Meteobridge to have the option (as far as WU is concerned). But with other services like AWEKAS, even you with the Meteobridge do not have this option as that is how that site decides to portray the information.
