May 27, 2010

Memorial Day Weekend: One Day Out of Three

What a difference a year makes.

In 2009 the last week of May was nearly dry with temperatures above normal. 2010 will not be a repeat, unfortunately. I think we have a very good idea now of what will occur, and the weekend is going to be a mixed bag.

Lets start with Friday. WET. In fact, quite wet.

Rain will be moving in overnighttonight and will stay around most of the day over the western side of the state. Here is the 24-h rainfall ending 5 PM tomorrow.

Amazing amounts of rain (1-4 inches) over the N. Cascades, with bountiful amounts rotated into NW Washington. Even eastern WA will get a good soaking. So if you are going to take Friday off to enjoy of four-day weekend, don't plan any picnics or barbecues. Or surprise your boss and say you would rather work.

So cross off Friday.

Saturday will be better, which will not be hard to do. Here are the three-hour rain forecasts ending 8 AM and 2 PM (below).

Showers will be continuing over the mountains and western slopes, with some showers over the lowlands. Mostly cloudy. If you can head to eastern Washington you can do better, with sun and temps rising into the 60s (except the northern portion).

The 24-h rainfall ending 5 PM Saturday is shown below. Still plenty of liquid sunshine.

Sunday will clearly be the best day of the weekend. It will be dry during the first part of the day in the interior with light rain approaching the coast during the afternoon (see graphic of 3-h precipitation ending 5 PM), associated with an approaching Pacific system. Sun and temperatures in the mid 60s west over the western interior. Dry for hiking.

Monday, Memorial Day, will be cloudy with light rain, with temperatures falling back into the lower 60s.

Memorial Day weekend has never been dependable around here and probably never will be, but by maximizing outdoor recreation on Sunday and heading east of the Cascades on the others, you could have sun every day.


  1. Cliff- I live in Aberdeen, and it seems as there is almost a "reverse rain shadow" from the Olympics shielding us here on the coast- Am I reading these precip forecast maps correctly? I hope so!

  2. M's fan: This is one of those odd cases in the PNW where the band of rain is being dragged around the top of a small low to the NE of us. So the rain band moves from the north to the south and east to the west.

    This shows up rather well in the cold cloud tops of the current IR sat picture.

  3. Hey Cliff,
    What happened to our rain shadow? Here in Anacortes I usually get one of the lowest rainfall readings in the state. This morning I had 1.81 inches in my gauge, the highest reading in WA according to Cocorahs. And since my reading at 7 AM, I've collected another .60 inches. What kind of rainfall pattern is causing this?

  4. Im ready for those "dryer than normal" climate forecasts I read on the NOAA site to kick in any day now.

    I hope this cold and rain is not indicative of the kind of summer we will be tomatoes are just sitting here looking at me.

  5. I though I'd posted this but ...

    There is a small shortwave (a low) sitting to the NE of Seattle. The precipitation is rotating around this counter-clockwise so the rain band moved from NE around the clock to the south. This is the opposite of the the direction we usually see rain approach from. So those normally in a rain shadow get the rain (Jefferson County and Island County).

    So the rain progresses from north to south over the day so I suspect the Aberdeen folks will get some later though it may be lower total rainfall.

    The GOES IR imagery shows the rotation nicely.

  6. Very wet day at my work in Oak Harbor. So much for that rainshadow!

  7. Forecast update

    Memorial Day Weekend: Zero days out of Three

    It appears that the window of sunshine on Sunday is closing fast, so embrace your inner Mallard and enjoy the weather anyway.

  8. Friday, Seattle had the coldest high temp in the lower 48. Colder than Anchorage even


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