October 14, 2019

The Meteorological Switch is About to Be Turned On

It is not unusual for the first few weeks of October to be relatively dry and sunny in the Northwest.

But quite typically, something happens during the third week of the month..  The jet stream sags south, storms--lined up in the Pacific-- make their way into the region.

A series of Pacific cyclones and fronts are lining up to visit us

And this year will be no different, with the first of a line of systems reaching our shores Wednesday morning.   It is going to be wet, so get your rain gear ready.

The first two weeks of October have been cool, but dry.  Perfect fall weather that seems to have enhanced the quality of autumn colors.  Here in Seattle, we  have received about .25 inches of precipitation, while normal is about 1.3 inches.   My soil is quite dry, even after a wetter than normal September.

But everything changes Wednesday morning as the first Pacific front (evident in the satellite image above) reaches our coast.  Below  is the forecast precipitation total through 5 PM Thursday.  The region is soaked, with over two inches in the mountains, but only about a half inch in the rain-shadowed lowlands.


But this is just the warm up.  The next 72 hours?  Still more, particularly over Oregon.


Now let me show you a state of the art precipitation forecasting tool:  a plot of the precipitation forecasts for Seattle from the European Center--the best in the world.  And we will look at their ensemble of many forecasts--looking at one forecast doesn't give you an ideas of the uncertainties of the prediction.

Each horizontal stripe is an individual forecast (there are 51 of them) and the colors give you the daily forecast totals.  The bottom panel shows you the mean of the many forecasts (ensemble mean), often a very good forecast.  You are seeing the forecasts from today to October 29th.

Lots of rain on Wednesday and Thursday in nearly every model run.  Plenty of rain after that.  You can be confident in the rain forecast.



The slugs and ducks will be happy!




31 comments:

  1. i know we are talking rain, when will we start talking snow?? My dad is saying we are gonna get lots a rain and all the cold air is gonna be pushed up into the rockies this winter with alot of snow, but what about us will we be in another state of alot of snow at least more than last year??

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  2. Yes! The best time of the year is arriving. Pineapple Express season!

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    1. that's not what he is saying, if anything we will get a good winter with plenty of snow

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  3. Cliff,

    The Weather Channel's website indicates that 'The Blob' is back in full force and unlikely to dissipate any time soon. Is this accurate and, if so, will the parade of storms forecast to affect the PNW have any mitigating impact?

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  4. Jonathan...unfortunately, the weather channel used an old sea surface temperature map and are not correct. In fact, the blog has weakened considerably, with water off our coast normal or below normal right now..cliff

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  5. No drought in Glacier this month....again !

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  6. Hi Cliff,
    Have you watched this past Sunday's Last Week Tonight show with John Oliver? He did a segment on Trump's nominee to run the N.W.S.: One of the owners of Accuweather. Your thoughts?

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  7. Here's hoping for lots of frozen precipitation this coming winter! Thanks for your dedication to accurate, reasoned data analysis and simplifying the message!!

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  8. cliff the weather channel is saying that the bob is back and that's not good next week we will be reaching ting highs into the lower 50s and lows in the 40s but up near the foot hills were i love it gonna be around 38 during the night when will we hit our 30 degree highs

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    1. The blob is not back, cliff answered this same exact question on a comment in the previous blog or possibly this one... his answer was that the Weather Cannel was incorrect, and it was using an old sea surface temperature map, and that in fact the water has cooled to near normal and even a bit below.... so Cliff said the blob has weakened considerably... probably not having much of any effect on our Winter, so basically the weather channel was not using correct information, yet still published a video, I saw it too, and wondered, but Cliff has answered here in his blog answers...... Thanks.

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    2. Look at the answer above too Johnathan Doe, cliff answers the question, Weather Channel is wrong.....Thanks

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  9. Not the Northwest, but related to weather elsewhere in the country- isn't this cool?
    https://twitter.com/WxZachary/status/1184189534789160960?s=19

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  10. Its a rainy period but not for too long. CPC 8-14 day outlook is now showing higher probs of above normal temps and below median precip. Probably a dry Halloween.

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  11. best time of year to be a slug, hands down

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  12. Cliff, I am always fascinated by the European Center ensemble forecasts. I'll be ready for the rain. Cute ducky!

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  13. Love the weather. But don't want the Ducks to be happy this week. Go Huskies!

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  14. Well, it rained lightly for about an hour in North Bend this morning, and that's the extent of it in the last 24 hours. Hardly any wind either. Disappointing forecasting on the NWS' part.

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  15. stevens pass ski resort is supposed to get 2"on thursday , friday 4", saturday its gonna be good!! 15" of fresh snow this adds up to 21 inches but wait that not all on sunday this could open up stevens pass for good early season but on sunday 5" this ads up to 26 inches wich is 2 inches over 2 feet plus the snow they have up there right now

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    1. Most if not all of Stevens Pass snow has melted from late Sept and early October Storms, so they have no where near 2 feet of Snow...Snow really doesn’t start piling up until a week or two into November, very common for early snow to melt out. Just over Stevens today, not much up there, raining in fact and low 40s. Be lucky to open by Thanksgiving, but you never know... but there is now way they will have over 26 inches , sorry...

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  16. Max wind gust today at my location in NW Bellingham was 34mph; 46mph at BLI.

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  17. funny thing is Accue weather is saying we are n the 50s all through winter that just made me laugh so harddd

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  18. The biggest drop—with the most freefalling, frigid temperatures—is forecasted to take hold from the northern Plains into the Great Lakes. The Northeast, including the densely populated corridor running from Washington to Boston, will experience colder-than-normal temperatures for much of the upcoming winter. Only the western third of the country will see near-normal winter temperatures, which means fewer shivers for them

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  19. Just to clarify, they may get some snow Saturday as cooler air comes in, snow level around 4000 feet it goes back up again next week, there will be very little if any snow at the base mid next week, so no opening, there is definitely more on top, but snow level way too high to open any ski areas, not sure where you get the two feet they already have, their is hardly any at the pass as of today, just too warm still, cold shots, followed by warm shots don’t get the base going, it will happen, it’s just still a bit early, again your looking Thanksgiving time before you get enough....I would love to see it earlier, but there is none there now, just went over it today...,

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  20. Mike, the comment about Stevens Pass was using a sum total of 26" of snow over the weekend, "plus the snow they have up there right now" which is unspecified.

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    1. I understand what he/she said, or you, I am just saying at the base there was no snow at all, I was just up there 24 hours ago, I know the weather people that they have up there, they are saying 6 maybe 10 inches of snow at the base, all I am saying, of course more the higher you get, over 5000 feet, but at the ski area, no where near 26 inches,( for the whole weekend) this from the guys who would know, who are employed at Stevens doing weather...there is no snow up there from previous storms, as it had mostly melted out..and 6 inches of wet snow is not going to do much. dont take winter storm warning with a grain of salt, I was told this just yesterday, it says above 4000 feet, but that doesnt mean it going to snow 2 feet at 4000 feet, sure you will get some snow, but this is still a higher elevation event, more like Paradise and Sunrise, just trying to get people to realize that, even after this weekends event, next week dries out, at least for 4 or 5 days sun comes out, still at a high angle, going to be hard to keep any base till November...Typical fall weather, fighting of the seasons...I def understood what the person was saying, but we all get too excited when we hear 2 feet, but look at that forecast carefully..most forecasters including those at the base of Stevens are saying 6-maybe 10 inches...and yes more up over 5000 such as Paradise and Sunrise, of course, but not at ski area bases, thats the point I am making, read forecasts carefully, esp in the Fall...it might say above 4000 feet, but that usually doesn't mean 2 feet at 4000 feet esp early on, still very early...

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