Take today. Yesterday's front and moderate rain has pushed through western Washington and sunny skies have spread over the lowlands (see satellite picture), including much of the WA coast. There are some low clouds on the western slopes of the Cascades and the coastal mountains--extending to the mountain crests. Temps will be in the upper 40s. Perfect raking and walking weather.
Tomorrow a weak disturbance will bring increasing clouds and rain for the northwest portion of the state, but the computer models suggest the lowlands will be mainly rainshadowed by the Olympics and coastal mountains.
Want dry? Go south!On Sunday the ridge builds up again and rain will end.
In fact, for much of next week a very high amplitude ridge aloft will provide dry conditions. Little wind.The only problem with all this is that when high pressure and clearing skies are parked over us, with weak low-level winds, there is a real chance for fog this time of the year.
Now, I can be pretty sure about this forecast...using a technology I often don't talk about, but use all the time--ensemble predictions. The National Weather Service runs a forecast ensemble--many forecasts all starting slightly differently. If the atmosphere is sensitive and the forecasts uncertain, the slight changes in the initial state will cause the predictions to vary greatly. If there are all on the same page...we can have more confidence in the predictions. Take a look at the ensemble predictions for Sunday (this is called a spaghetti diagram for obvious reasons). Virtually all the predictions are going for the ridging!
Look at the spaghetti diagram for Tuesday afternoon....amazing agreement that far out. Ridging is in!
And remember, we are now finishing the historically wettest period of the year. We have ascended the meteorological peak...we now move slowly (very slowly at first) towards summer. The worst may well be over...especially considering this is an El Nino year.
