November 06, 2008

Pineapple Express

We are now about to enter a period of very wet weather, and I can't help remember two years ago when we had extraordinarily rain and Mt. Rainier park sustained terrible damage.

A warm front is now approaching our area and rain has spread over the region (see radar image). It is raining off the coast and in that triangular area over the Olympics, but the Olympics are blocking it (why we need a coastal radar!). Also, you can see the rain show to the NE of the Olympics. A stream of moisture is entering our region, with roots in the subtropics (see satellite photo)..the pineapple express.

The warm front will move through this morning and temps will increase, winds will increase, and the rain in the mountains will rev up as moist, strong, southwesterly flow ascends the terrain. Two images of forecast three hour rain (in hundredths of an inch) are shown here for two different times. Note that the Olympics and north-central Cascades get the worst of it.
The 24h precip amounts forecast ending tomorrow morning and saturday morning are shown here. Huge amounts over the mountains--the red areas are between 5 and 10 inches! Some areas in the mountains might get 10-20 inches and flooding is a real threat on several river drainages (the National Weather Service has flood statements out already).

And there is more...we will have some windy periods...and particularly strong southeasterlies over N Whidbey Island and the San Juans (see figure). In my new book I describe why this occurs.
Anyway, November is here and that is when we get the big weather action.


  1. Cliff - I love your blog and read it most everyday. Please keep it up.

  2. Cliff
    This is some fantastic information.
    We are a community of kiteboard and windsurfers who rely heavily on proper wind predictions.
    The Mesolow that forms off the lee of the Olympics is our saving grace for a great day on the water.

    Which of the MM5 are the best to view winds from Bham south to Purdy?

    Thanks for a great site!


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