Wetand News

There are few more important weather data sets collected by the National Weather Service than weather radar. article in the Washington Post  and a tsunami of negative comments in social media . Software engineering has never been a strong suit of the National Weather Service and they have had problems on their online weather web sites for year and software issues have plagued their numerical weather prediction efforts for decades.   Even today, local National Weather Service offices lack sufficient communication bandwidth to secure all the high-resolution weather products they could use profitably. Recently, the National Weather Service, crippled by lack of an ability to get data out to the national community, has started to restrict access to their servers , a move that could undermine the use of its model data by the private sector (including major weather companies like IBM/WeatherChannel, Accuweather, and others). A key issue is that the National Weather Service insists on using ea

There are many wonderful imports we enjoy from the Hawaiian Islands, from Kona coffee and macadamia nuts, to music and wonderful foods.    But during the next fews days, we will enjoy the imports in a more visceral, direct sense, as moisture streams to us from southwest. The satellite moisture imagery this afternoon shows the a plume of enhanced water vapor (lighter shades) direct from the big island to the Northwest. And as this moisture moves into us, it will be lifted by two mechanisms that will convert the water vapor into precipitation.     The first is obvious: our substantial terrain, which forces air in the lower atmosphere to be pushed upwards, cooling as it rises, and thus converting the water vapor into rain and snow (cool air can "hold" less water vapor than warm air and thus some of the moisture condenses out).   The second source of upward motion is a potent upper level disturbance that is moving it (see 500 hPa upper level (about 18,000 ft) map below for tomorr

As we pass the holiday period, we naturally think about snow.... in the mountains and near the surface....particularly considering this is a La Nina year, which tends to arc cold and wet after January 1st here in the Northwest. The current snowpack over our region is very much near normal (see below), so ski areas and water resources are in decent shape at this point. But as I noted in earlier blogs, we are now in a moderate La Nina, with the tropical Pacific cooler than normal (see plot of temperature anomaly from normal below).  Blue indicates cooler than normal. Turning to the most skillful extended forecasting system--the European Center weekly predictions, it is going for cooler than normal conditions during the next 46 days (through 8 February) over the region.  Good for snow. And the precipitation prediction (again, difference from normal) for the same period shows wetter than normal conditions over Washington and Oregon (see below).    That, again, is good for our snowpack.  

 While western Washington residents were amazed by the extreme weather of December 21, including snow, heavy rain, flooding, record temperatures and more, another extreme event struck the eastern slopes of the Cascades near Leavenworth, resulting in very strong winds, downed trees, and power outages for over a thousand customers.  The picture below provides a sample of the bedlam. Picture courtesy of Heather Murphy and Don Schaechtel  The cause of the eastern Washington destruction? The same as in the west. A very strong cold front. The eastern slopes of the Cascades have been the scene of extraordinarily powerful downslope windstorms on several occasions as strong westerly (from the west) flow accelerated down into the Columbia Basin.  A famous event occurred in 1974 when a number of train cars were derailed and fell into the Columbia River near Vantage. On Monday evening, strong winds from the west followed the passage of the powerful cold front, with a large pressure difference (g

 We a moist lower atmosphere, a cool air mass over the region, and relatively clear skies (which allows good cooling to space),  we had good conditions for frost and fog across the region. So be careful this morning .   Fog and freezing temperatures are the most dangerous combination, capable of laying down a thick layer of ice on cold roadways. But first:  the sunrise.  It is spectacular this AM, with a poor sample from a cam this morning. Surface air temperatures dropped to below freezing over much of the state this AM (see below, click on image to enlarge), with near 0F numbers in really cold locations (like Mazama to Winthrop). And never forget the differences around our region, with temperatures near the water above freezing, but well below freezing in the interior (e.g., Woodinville, Duvall) For road safety, the temperature of the road surface is what counts and that temperature can be VERY different than the temperatures of the air, which is measured 2-meters above the surface. 

 The intense front has bogged down over central Puget Sound and very heavy rain is causing serious flooding.   The latest one-hour radar-based precipitation estimate (ending 3:11 PM) shows 3/4 inches in that period/ The National Weather Service has a flood warning out now for central Puget Sound.  A number of roads are flooding, particularly at dips and valleys. And here is an amazing video by Joe Zagrodnik of water jetting out of manhole covers: And look what happened in Lynnwood: Be careful not to drive through deep water. This reminds me a bit of the 2006 event that led to the tragic death of a woman in the Madison Valley in her basement.  After that event, Seattle supported the development of a protective system:  RainWatch--the brought together radar and rain gauge information, plus the best model forecasts.   Unfortunately, the city decided to defund RainWatch, so the warnings it would have provided of this event are not available to city managers.

 It is snowing around Northwest Washington....from the northern Olympic Peninsula, to Victoria and the San Juans to Whatcom County....and central Puget Sound is next. And you can thanks an extraordinarily strong front for the white action.  This is very good example of how precipitation intensity can bring the snow level down to the surface when temperatures are right on the edge for snow. But first some pictures to "warm up". Here is a snowy scene near Bellingham from a WSDOT cam looking at I5. And definitely some snow around the Peace Arch near the international border. Plenty of snow at the WSDOT site on the northwest Olympic Peninsula And there are many reports of snow around Port Angeles...some folks have an inch already.                Picture courtesy of Rick Sistek in Port Angeles      An extraordinarily strong front is moving through the region right now with an INTENSE temperature gradient and driving rain.   Rain is hitting my windows in waves and there is practic

Many of you  in western Washington are going to see snowflakes tomorrow.   But there is going to a huge variation from flurries to several inches. The mountains and foothills are going to get hit hard and the snow-level will be low. This is a very complex, marginal event with the potential for some surprises.   But like the COVID-19 vaccines, scientists/forecasts have better tools than even a few years ago. Not this much. Before I go into detail, let me give you the bottom line for the Monday snow situation.    Temperatures will be marginal for snow, but where there is sufficient precipitation, snow will reach the surface. The northeast Olympic Peninsula will be hit hard by 2-12 inches and snow will increase to several inches quickly in the Cascade foothills. Elevations above 200 ft and away from the water could get a dusting to an inch.   There is the potential threat of a localized convergence zone that could set up in central Puget Sound that could lay down several inches. The situ