What got me confused about figure b above is that the precipitation rate scale is -6 to +6. Using the number 1 as an example, this means the rate anomaly of 1 kg per square meter per second would amount to 3600 kg per square meter per hour. Assuming one cubic meter of water weighs 1000 kg, 3600 kg per hour over a square meter would accumulate a precipitation depth of 3.6 meters per hour. A very unlikely precipitation rate. I'm sorry if my math is in error or if I misread the graphic. I'm not a climatologist but I am a retired licensed professional hydrologist so this is a little outside my expertise. The example you sent with your reply did help clear up my misunderstanding though. Thank you.