November 21, 2011

Major Storm: Heavy Rain, Flooding and Very Strong Winds Along the Coast

A VERY serious storm is going to hit the Northwest during the next two days--one that will cause flooding and coastal wind damage.  And the urban areas are doing to experience a deluge.

Here is the forecast precipitation over the next 48h over the region and over western Washington.The Olympics, the north Cascades, and the mountains of southwest Washington and NW Oregon are going to get hammered with 5-10 inches of rain (reds).   Even Seattle will get nearly 4-5 inches if this forecast verifies.

Folks, this will be a major event.


There is a serious threat of flooding on a number of rivers.  The Skokomish is a given.  It looks like there will be flooding of the Chehalis...and that means those near the river should prepare.  The NWS River Forecast Center is going for a major flood at points along the Chehalis....here is an example:

And there are others that I won't list now.

The other threat of this event is wind--HUGE winds along the Washington and Oregon coasts (worst along the Oregon coast).  Take a look at this forecast of sustained winds for 1 AM on Wednesday morning.  Sustained winds of 50 kts with gusts heading to 70-80.


The Washington coast will get the strong winds earlier...tonight...see below:
Regarding snow, the models are putting a few feet over the north Cascade...and far less to the south where the freezing level will be relatively high.  An interesting aspect of this case is that it is NOT a pineapple express event with a moisture plume extending from just north of Hawaii.

Anyway, I believe a major storm event is about to unfold...and it will be fascinating to use the new Langley Hill radar.
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24 comments:

  1. kevinfreitasNovember 21, 2011 at 10:15 AM

    Thanks for the update Cliff. Riding it out here in Tokeland. There's a serious chop out on Willapa Bay right now but we'll see how bad it gets. Follow along via my webcam pointed right at the bay over at http://tokeland.me/?view=h20

    Cheers!

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  2. TraceyNovember 21, 2011 at 10:46 AM

    Thanks for this post! Great graphs and info! I'll pass it along!

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  3. JennyMNovember 21, 2011 at 10:56 AM

    What about snow in the mountains? Will it be cold enough for that?

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  4. JennyMNovember 21, 2011 at 10:56 AM

    What about snow in the Cascades? Will it be cold enough for that?

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  5. Scott K.November 21, 2011 at 1:49 PM

    Excellent update, Cliff. I'm really looking forward to this one. I'm down in Spanaway and hope to get some good winds if not rain as well. We have enough candles to last us through the winter already, heat will be the only issue.

    It is rather unfortunate that the really fun winds are going to occur overnight. It would be fun to watch the trees.

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  6. weatherloverNovember 21, 2011 at 3:39 PM

    Where do you think the rain shadow will dominate?
    We definitely missed out on rain today over by Anacortes where we haven't even got a tenth of an inch and I'm hoping that we get some good rain before this is all over.

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  7. Carol {Everyday Delights}November 21, 2011 at 3:50 PM

    Thanks for the post and info Cliff! I'll be wearing my rainboots!

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  8. Michael DeMarcoNovember 21, 2011 at 6:34 PM

    Sequim in full rain shadow today. Some stars our right now at 630 PM. Dungeness River is still low-we could use some of that wet,

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  9. MattsterNovember 21, 2011 at 7:41 PM

    What's this about a storm coming on on Thanksgiving now? Is it time to check out our gas grills?

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  10. ColinNovember 21, 2011 at 10:04 PM

    Yay! I love stormy weather! I was enjoying the rain shadow up in bellingham today. Tomorrow I'll have to get my kite out take it for a ride! I've got 2 questions:

    1. What are the units for rainfall in the figures you posted (I cant quite read it, but it looks almost like cm or cin. Researching online I can only find mm and in as standard units (but that seems like past rain, not predicted.) Anyone?

    2. Where do these figures come from? Do you put them together yourself? NOAA doesnt seem to have much of anything like this on their website. It would be nice if I could see this without having to have you post it!

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  11. ChrisNovember 21, 2011 at 10:46 PM

    So, I'm supposed to head out to Idaho Tuesday night (have engagements until 8pm, leaving straight afterwards). Do you think Snoqualmie will be passable?

    Any bad weather forecasted for central WA?

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  12. AnonymousNovember 22, 2011 at 12:01 AM

    http://www.atmos.washington.edu/mm5rt/

    has all the graphics he uses

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  13. AndrewMNovember 22, 2011 at 5:38 AM

    Cliff, grabbed a screen shot from the UW radar page at 3:22AM 11/22/11. Any information on the almost 200 mile long band of precipitation from BC to off Astoria?

    http://www.macmillen.com/temp/squall_line.png

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  14. SkokomishNovember 22, 2011 at 7:58 AM

    Looks like the Langley Hill Radar went offline for a bit at 4:22 A.M. Tuesday morning. You can see the difference from our old view to our new view. Interestingly enough, I wasn't sharp enough to notice initially and I thought "well, I guess that's the end of the plume of moisture." We used to be blind!

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  15. AnonymousNovember 22, 2011 at 8:18 AM

    Very strong frontal passage early this morning with high winds from the southwest. Wind has died down to light. Clear sky to the north. Canadian Coast Mts. clearly visible. Most of the weather to the south of the San Juan Islands now.

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  16. CarterNovember 22, 2011 at 8:21 AM

    is the rain spigot shifting to the south, or is the radar just fooling me?

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  17. John MarshallNovember 22, 2011 at 8:28 AM

    We got 0.71 inches of rain out of this storm in our neighborhood, located 900 feet up on Bell Hill in Sequim. Not much wind though.

    That's a really good rain for us, but less than the 1.6 inches that was predicted for Sequim. Seems the storm either fizzled or went further south than predicted.

    Hopefully the Dungenness has a little more flow today. Its been little more than a stream during this (so far) dry Fall. We need water.

    John M

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  18. ColleenNovember 22, 2011 at 10:51 AM

    Quite boring up here north of Bellingham. Incredible south winds overnight, but without the frigid temps that accompany our standard northeaster, nothing particularly notable. Nothing more than a light breeze right now ~ and no rain, either. Still cold enough to snow at Baker, so our river (Nooksack) is manageable, too. I suppose I should be grateful, but I confess I was anticipating something a bit more interesting!

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  19. Aaron M.November 22, 2011 at 12:15 PM

    Looks like NOAA blew the snow level in the passes. The forecast calls for rain but it's clearly still dumping with a general cooling trend at all telemetry sites in Snoqualmie and Stevens passes. This should make for fun travel over the Cascades for Thanksgiving...

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  20. NeilNovember 22, 2011 at 2:13 PM

    Interesting tidal anomoly today on Kilisut Harbor (south of Port Townsend)of about +2 to +2.5ft. We are conducting a study of beach spawning baitfish and could barely get a sample off of the beach at a +8 level when the tide was predicted to be +5 to +5.5 Low pressure and onshore flow! The NOAA tide gauge at Port Townsend showed the anomoly peaking at about +2 this morning. Nice that they have all that info online.

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  21. SnowkingNovember 22, 2011 at 3:38 PM

    This comment has been removed by the author.

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  22. AnselNovember 22, 2011 at 5:37 PM

    Cliff, I thought this was going to be a Pineapple Express! That usually means 50-60 degrees. What's up with this 40's stuff? I was looking forward to some subtropical mild weather after those frosty nights.

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  23. ThompsonizedNovember 22, 2011 at 6:51 PM

    Cliff, I just want to say that you are clearly "The Man" when it comes to deciding if I should go from Ellensburg to Seattle. Being from Texas, I always had a fascination with severe weather down there...but you have taught me with your blogs how to predict the weather over Snoqualmie Pass much better than the official ones. Thanks again, I wasn't stranded in the I-90 mess all day!!

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  24. TulipbabetteNovember 23, 2011 at 4:09 PM

    I'd like to know why the Weather Service had no wind watch or warning out for the high winds in Grays Harbor County, particularly Montesano, on Tuesday evening. They only posted flood watches and warnings. Quite the shock to hear the wind blasting away at 2:30 this morning and find power was out here and all over the county because of the wind.

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