What are retrograde storms happening in Northern California now

Though this is a very rare occurrence the storms are going south into the Sierras then over to Nevada some then north and come out somewhere like Redding and now they are raining on us from about Redding down to Bakersifield in California and everywhere in between. I woke up to heavier rain than we usually get this time of year. Most of the time in late May and June we might get mist from high or low fog but this is actual rain so literally there are mudpuddles from this rainfall which is very unusual here on the Northern California coast. 

However, since the snow pack was bad this spring from temperatures too high where most of the snow melted early there is new snow falling now in the northern Sierras which is good for the snow pack for water for the state later in the Year.

However, Southern California and the entire Colorado River area are having real problems water wise this year. So, I guess people in California and Arizona and Mexico and Colorado and Utah are all sort of trying to figure out how to manage on not enough water for everyone from the Colorado River this year.

However, rain this late for northern California will likely put off most fires wherever the rain is hitting for some time because of how soaked everything is getting from Redding to Bakersfield and all along the Coast and snow now in the Sierras.

I hope hikers didn't get snowed in this late while hiking the John Muir Trail along the Sierras.