11:15 AM Update: Snowing at Orcas Is, Friday Harbor, and Whidbey Is. Naval Air Station
Tomorrow morning will be a great test of weather prediction technology. The high-resolution models, the leading edge of numerical weather prediction, are going for a few inches of snow over much of the western Washington interior. In contrast, the much older statistical guidance products (Model Output Statistics, MOS) that use past statistical relationships and coarser model output have no snow. And the temperature are really not that cold over the region: at or near freezing at the surface at most locations. However, we all that said, I believe the high-resolution models are correct for a number of reasons, most of which I won't go into here. Snow is coming.
So what do the latest model runs indicate? The high-resolution US WRF model has snow, but delayed a few hours from the previous predictions. Let me show you a new product produced by David Ovens, the person you can thank for building and running the UW WRF model system. In these new graphics, 3-h snowfall is in color and rain is shown by gray shades. This way you can tell where it is raining and snowing on the same chart! Very nice.
In the new runs, the snow holds off in the central Sound until about 3-4 AM. Here is the three-hour total rain and snow for the period ending 4 AM Snow over NW Washington, but just reaching Seattle.
What about the 24h snow total ending 4 PM? More than a foot in the mountains and 2-4 inches around Seattle. More over parts of NW Washington.
This is a complicated situation with fronts, mountains, melting snow, sublimation and evaporation, and many other processes acting simultaneously. And the front is coming off the ocean. It will be fascinating to see if we get this right.
You see why forecasting is so much fun? Combines science, technology, and gambling. Meteorologists don't need casinos, we've got something much better.
I will be doing an update on KPLU FM Friday Morning at 9 AM.
Help The Seattle School District Pick Better Math Textbooks for K-5
Most Seattle elementary schools are using very poor math textbooks: Everyday Math. FINALLY, the district is replacing them and you can help ensure that decent books are selected. For the next few weeks the finalist books will be available at the Seattle Schools HQ and you can peruse them and provide comments. Here is more information on this opportunity. With information form concerned citizens and parents, a math committee will make recommendations to the district.