August 31, 2014

Major Precipitation Contrast and Holiday Forecast

Saturday was a day of real precipitation contrasts as the first fall weather system moved through.  Here are the totals for the 24-h ending 9:15 AM on Sunday. The red boxes were over 2 inches, yellow 1.5-2, dark green 1-1.5. In contrast, only a few hundredths fell over Northwest Washington, the eastern slopes of the Cascades, and over SW Washington and the north Washington coast.

The reason for this contrast?  A narrow zone of precipitation associated with yesterday's disturbance, enhancement on the western slopes of the Cascades, and a weak convergence zone over central and southern Puget Sound.

And the Camano Island radar broke as well for virtually all day Saturday.  You feel naked as a meteorologist without your radar!  Fortunately, the new Langley Hill coastal radar provided a lot of information about the approaching system, such as the image at 5 AM Saturday that showed the limited region of moderate precipitation moving our way (see image).

The good news is that the Camano Is. radar is repaired (our colleagues at the NWS are on the job 365-24-7) and the regional radar image this morning shows a relatively dry pattern, except for some showers on the windward (western) side of the Cascades.

This showers should fade during the afternoon, but a hike on the western slopes today might be drizzly and cloudy.  Head to the eastern slopes.

A weak disturbance is now approaching us and could bring some clouds and showers to the northern portion of Washington tonight. The infrared satellite pic at 9:30 AM shows it offshore.

But today should be decent for most of you, with highs getting to around 70 or a bit above, with partly cloudy skies away from the western slopes.

Monday looks quite good, particularly over the interior and mountains.  Eastern WA will be warm.  Go hiking, hit Bumbershoot, or paint your fence.

A much stronger disturbance will come in Monday night and Tuesday, but the action will not reach the interior during the day Monday.  So Tuesday will see clouds and rain...but you have work or school anyway, right?


  1. Interesting to read Camano Island radar was down early Sunday morning? I awoke to rain about 2AM and looked on my phone to see the radar map, and it showed no rain in the Kirkland area. The rain was heavy enough to be visible on radar I thought.

  2. Not only was there a contrast from region to region but, within a region there was high variabiity. I live in Olympia. I have a rain gauge in my front yard, which I use for COCORAHS reporting, and a weather station in my backyard. Between 7:00 am on Saturday and midnight of Saturday, I had 1.38 inches while another station less than 5 miles away reported less than 1/4 inch. When you add the rain which feel after between 1:00 am and 7:00 am on Saturday, my gauges registered over 1 1/2 inches of rain.


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