Just remember, WATL's rainfall amount maps are an average of 8 models (whose rainfall positioning is then adjusted to account for differing positions of heavier rainfall)so if some of the component models are hardly forecasting any rain, it'll push that average down. Also note that WATL maps won't show any forecast amounts below 1mm because that's the min threshold for the colour scale.
Also worth remembering that the exact rainfall amounts and positioning from patchy convective rainfall are much harder to accurately predict than widespread stratiform rainfall with some locations getting a lot less or more than others. So using a multimodel average will blur these finer details (but this type of consensus approach is statistically more accurate on average than using a single model).

Also, those bands of showers/storms will often look more impressive on radar than the rainfall amounts they produce during dry regimes such as the current one because the constant height of about 10,000ft that the radar scans for the public radar imagery means that a significant proportion of that rainfall evaporates before reaching the ground.