Autumn this year in the Northwest is strangely warm and dry.
Lots of sun and perfect temperatures. My tomatoes have been glorious. And the warmth has reduced the need for heating, helping to reduce global warming.
But all good things must come to an end and major forecat systems predict a transition to more typical cool/wet weather next Friday.
The weather is pretty typical for the first half of October in our area which is sunny and warm, but most years there is a transition to cool/cloudy/wet weather during the third week of the month. And this year is no exception.
Here are the latest temperature predictions from Central Europe’s multiple projections set. One last phase of warming this week with a steady rise into the 70s on Sunday. Perfect weather for any outdoor activity. Then a small depression moves south of us early next week, bringing temperatures down to the upper 60s. Still good.
But the bottom fell on Friday and Saturday, with the high only rising above 50 years old.
And they are going to rain.
Here are the cumulative precipitation from each forecast in the Central Europe group (top panel), the high-resolution group member forecast (blue line) and the all-member average in the group (light blue bar). These are people with severe rain (1-2.5 inches).
The key element of the transition was a major reorganization of the atmospheric structure over the Pacific Ocean.
I will show you.
Below is an upper level model (500 hPa, about 18,000 ft) for today at 5pm (the Central Europe group average is adept at many forecasts). The visor shows the wind speed.
Today, there are strong elevation/pressure undulations, with a large peak of high pressure off our coast. Strong winds (jet streams) go far north of us. A dry/warm style for the Northwest.
But now look at the forecast for next Friday at 5am. Well… a big change. The rippling nature of the overhead current is gone, replaced by a strong jet stream heading straight for our region.
The flame in the atmosphere will be heading directly towards us.
Here’s the total rainfall through Wednesday, October 26. Substantial.
But we need to be careful. Forecasting skills actually decrease after 7 days. But the consistency in time and between major modeling systems really suggests that our warm/dry weather will soon be history.
