Do You Like Pineapple?

Growing up as a future meteorologist in northern California in the 70s, we used to call it a Pineapple Express. Now the more technical term that is often overused is Atmospheric River. Whichever name you use, the result is the same: warmth, water and wind to the West Coast. 

I can describe it best with a weather map of atmospheric moisture across the North Pacific.  Asia is on the left, the West Coast on the right, the equator at the bottom.


The first thing you notice is all the bright colors near the equator (bottom of the image).  It’s very hot down there, the ocean is very warm, and the atmosphere holds a LOT of moisture.  If you look closely, you’ll see a plume of green and blue extending from the tropics and pointing at Washington and Oregon. That is an atmospheric river. And it’s pointed right at us next week.  The weather pattern will bring lots of tropical air and moisture to us (hence the Pineapple nomenclature).

The result is a familiar one. 

Warmth

Snow levels will rise considerably. Only the highest mountain peaks in the north will still get snow. The low lands will see temperatures in the 40s and 50s while nighttime temperatures remain above freezing. 

Water

Atmospheric Rivers bring copious amounts of rain, especially to the west side. Here’s the rainfall forecast for the next 7 days. 5-12” over western Washington and the Cascades.  4-5” in the Panhandle mountains.  1-2” in eastern Washington.


Wind

The jet stream will be located just to our north next week. We’ll see periods of windy weather, especially on Monday night and Tuesday morning. 


Thursday morning may be even windier, but that’s 6 days away, so a lot can still change.



The rain will come about every 36 hours next week. So there will be some breaks. Here’s how the next 10 days shapes up for Deer Park.  Get your rain gauges ready.

The latest European model shows the warmth continuing through next weekend, although the Atmospheric River may be pointed north of us by then, bringing us a break from the rain. 

In case you’re wondering, yes this pattern can resulting in flooding. Especially over western Washington. For us in the East, we don’t have a heavy lowland snowpack to melt and our ground isn’t deeply frozen. So impacts on our side will probably be lessened and may be more from the wind than rain. 

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