I'm Calling You Out

From time to time, I find something that I do not like when it comes to weather observations, recording data, whether it be visual observations like mistaking a funnel for a scud cloud or measuring snowfall on a deck next to the grill and chair; the recording of data that use automated sensors for precipitation and temperature.

This rant includes a couple of new entries.

First, I saw a discussion from the NWS Louisville that highlighted the heavy rainfall in and around the Louisville Metro area yesterday and named the Billtown Road Pumping Station with the highest amount.  Using data from often reliable sources such as MSD telemetered gages throughout the region, we can often get a better understanding on the scope of the rainfall compared to other areas.

Well, I have to call out the MSD pumping station at Billtown Road. There is something wrong about their rain gage. I don't know what it is, but it is not accurate. It seems for every rain event we have in the county, the Billtown pumping station gage nearly always records the most in the county.

So, I looked up some data recordings from the period of March 1 through the present and found an eye-opening statistic that really deserves extra analysis from the 'professionals' about their equipment.

Since March 1, the Billtown Pumping Station has recorded over 30". The next highest measurement comes from outside of the county at like 22 or 23". Most areas are in the vicinity of 16-19" in Jefferson County.

Next, I have used the Acurite manual rain gauge for years. I have often relayed these measurements to other local media, reporting my observations. I know others use the Acurite rain gage as well.

Well, I made my own rain gauge, using a Barilla Spaghetti jar. Using a funnel that is the exact size of the opening, I collect the rainfall.

Of course, this rain gauge has its flaws. It has a curved feature at the bottom that requires a couple of readings to average out the measurements. It takes nearly 0.06-0.07" just to cover the bottom to record a measurement. Estimates less than this have to be performed, which is not always accurate.Values up to 0.50" have to include built-in error numbers as well. However, the more rainfall I have in the gage, the more accurate it becomes.

Based on surrounding, what I call reliable MSD telemetered rain gages, I consult the values during a 'uniform' rain event and compare my numbers. They often fall right in there with their numbers. Therefore, I can say with certainty that my measurement will not be more than 0.04" off, including estimates and recorded measurements.

However, I was surprised when I placed my Acurite rain gage next to my homemade rain gage. A preliminary analysis has revealed an unsettling concern.

To the makers of Acurite, I am calling you out. I am still recording my observations; therefore, my findings are not conclusive. This preliminary analysis, though, reveals that the higher the rainfall amounts, the higher the discrepancy between a homemade rain gage that will not be off by more than 0.04" and your product.

Here are a few examples. I recorded 0.33" from my homemade rain gage just last week. However, the Acurite measured a little bit higher, at about 0.38". Yesterday, I measured 0.95" in the homemade rain gage while Acurite measured 1.24-1.25". Finally, during the remnants of Cindy last month, I collected 1.66" in my homemade rain gage. Acurite recorded about 2.10".

Yes, it is possible that my homemade rain gage may have some underlying issue that I have yet to uncover. But, when I use surrounding data sensors, my values are in better agreement than the Acurite numbers.

MS