In the short term, a cooling airmass will result in lowering of snow levels back to the valley floor Thursday morning, but along with that comes a drying pattern Thursday afternoon through Friday. Temperatures will stay in the 30s through Friday before a very wet atmospheric river (Pineapple Express) moves into the region over the weekend. Initially, snow levels will start out fairly low (perhaps even at the valley floors), but will rise as we go through the weekend. The extent of how high they rise will determine to a great extent how critical any flood danger might be, but the elements are there to create a possible flooding situation. As a result, a Flood Watch is in effect from late Saturday night through Monday morning, the period of time that appears to have the heaviest rain and warmest airmass.
It’s a challenge to try and talk about the possibility of flooding without unnecessarily alarming the public, and this is one of those times. With the memory of the New Year’s Flood of 1997 still fresh in my mind, I would probably err on the side of the worst case scenario, but at this time I don’t see the same conditions happening this weekend. But it never hurts to be prepared in case it all comes together again.