Flood Day

It was kind of surreal for me this morning....I biked to work absolutely dry and in warm conditions, while ten miles to the south there was moderate rain and all hell was breaking loose in the mountains. One of the most profound rain shadows I have experienced in a while (see the radar). On the radar this morning you also see how the focus of the heaviest rain has moved east and south of Seattle since last night. And NO rain in an east-west band from Seattle to Lynnwood stretching west towards the Olympics. You don't have to go too far east to pick up heavy rain--North Bend is being pummelled. The computer models have consistently showed the development of this rain shadow and is a prime example of how for the weather prediction enterprise has come in the last ten years. Forecasting rain shadows is FAR easier than predicting snow!

An interesting graphic based on the radar I have never shown you is the storm-total analysis. Basically, one can relate the radar signal scattering off the rain to precipitation rate, and then add that up over time. So weather radar can be used as a rain gauge...although an imperfect one.

I have attached the storm total rain for the past three days. Remember, there is major blockage of the beams by the Olympics and Cascades...so you are not seeing the whole picture. But what you can see is fairly daunting. The is a broad region of greater than 6 inches (yellows) surrounding the rain shadow and substantial areas of ten inches or more (reds) on the windward slopes of the Cascades. We cannot see the heavy rains on the SW side of the Olympics because there is no radar coverage there (another reason why our congressional delegation needs to secure the resources to acquire a coastal radar! With all the infrastructure spending being discussed this essential piece of warming and prediction infrastructure should be a high priority. If we can spend 7 million for solar panels on top of Qwest field, surely we can afford the radar which would greatly improve weather prediction and warnings!).


Both Stevens and Snoqualmie passes have gotten more than 7 inches so far. North Bend has received around 5 inches. And we are only half-way through this event.

The hydrological models are going for a very major event on many of our local rivers, with extensive flooding to be expected. As I noted in my last message, the NWS has an excellent web site with detailed river flow information. I should mention that Chapter 3 of my book describes the nature of NW floods and reviews major floods of the past.

Want good news?...the weather models are going for a dry day on Friday, some light showers over the weekend, and an extended dry period next week. You will think you are in California.