Tuesday, October 2, 2018

Wet Week in the West and Snow Hits Washington State

Recent newspaper articles talk about a prediction for dry conditions in the western U.S. over the winter, but the atmosphere this week has other ideas. 
Today, a hurricane is moving through the southwest, a frontal system is hitting California, and a weaker system is moving through Washington State (see pic below).   It is hailing outside as write this.


Want to be really shocked?  It is snowing at Steven's Pass, where the temperature is 32F.  Don't believe me?  Check out the latest picture from the WSDOT cam there.

The WRF model forecast for cumulative precipitation over the next week (through 5 PM next Tuesday) is mighty soggy, with rain over the entire domain.  1-2 inches in part of Washington and previously dry Utah gets hammered with up to 5-10 inches in places.  Northern California is wet.  This rain event will be the end of most western U.S. fires.


As noted in the media, we just finished our "water year"-- which runs from October 1 through Sept 31 each year.  In some ways, this period is our natural precipitation period, since October 1 is roughly the start of the time when rain is significant around the Northwest.

Our recent water year (2017-2018) at Seattle was above normal by about 3-4 inches (see cumulative precipitation chart, light green is normal, dark green is cumulative amount above normal)


And  the previous water year (2016-2017) was even wetter than normal!


To put it mildly, we have not been in drought the past few years.

The extended forecast of dry conditions is heavily dependent on the projection of a weak to moderate El Nino for this winter, with low pressure offshore.

 However, the patterns of the last few weeks and the upcoming week are very different...in fact, very La Nina like.  A characteristic of La Nina winters is a ridge offshore, with northerly, cool unstable flow over our region.

The upper level pattern this afternoon shows an upper trough pushing over Washington.  In January we would be talking about lowland snow with such a pattern.


Another trough on Friday, and this will be a wet one

 High pressure builds offshore during he weekend and a very deep trough will bring cold temperatures into the southwest.

 And next Monday evening, the pattern continues, with weak disturbances over our region.

So forgot warm/dry conditions for the next week.  Showers and cool temperatures will reign over the Northwest, with more sun from Saturday onward.

13 comments:

Organic Farmer said...

Hard frost Wednesday AM, near the Admiralty inlet.

Super frustrated with the lack of weather forcasting for the same day, let alone weeks, months or years.

With all the money spent and all the fancy education. I find it very disappointing, that a farmer can't even get a frost advisory from the weather people. (Heck a simple farmer with no fancy education or equipment, could smell it in the air last evening.)

I feel ripped off! I am not seeing my tax dollars well spent on, weather forcasting.

mig said...

Western red cedars have not enjoyed our recent hot, even drier than average summers. Their wood is supposed to be red, not their needles.

Ted Stern said...

30 days hath September ...

sunsnow12 said...

"Recent newspaper articles talk about a prediction for dry conditions in the western U.S. over the winter..."

Except Cliff, as you well know, this is every year that they do this. Every year.

Want me to go back to the prediction for 15/16 - where they talked breathlessly about how everything had changed, and we were headed for permanent drought, that the "climate deck was stacked against us"? You were the *only* one who pushed back on it. And, of course, you were 100% correct; they were - once again - 100% wrong.

As I noted last spring in the comments, the only prediction that we could make - with certainty - about the coming forecast for the fall/winter was that someone would be loudly predicting it would be dry. And how about that, like clockwork, we've got a chorus this year saying it.

Here’s another prediction: Unless we are well above average in snowpack by the end of December, expect the drought talk to really ramp up. It happened last year when we had a week of sunshine in January… that is the month (and February) for the real fear-mongering.

One of these years - just statistically - they will actually be right (...has not happened in a long, long time). And whoa boy, just wait for that. That will be one for the ages.

Kathryn said...

your comment poses an interesting question. why aren't we incorporating biological indicators in weather forecasting. Some humans can do it, if they are well acquainted with the outdoors. surely animals or other living.organisms can do it even better

Kathryn said...

Organic Farmer, don't ignore your own weather instincts!

TW B said...

Looks like this is the start of a massive swing in the jet stream that is going to cause all sorts of weather problems throughout the country.

Stephen Murdock said...

What do you mean by "hard frost"?

AnneScott said...

We haven't had a true winter drought since 2000-2001. Even the 13-14 winter, although drier than normal, was certainly not a "drought" especially since it was followed by a wet March and normal spring rains after that. One could argue 2015 was a drought year because of the lack of snowpack and a dry spring and early summer that year but a couple of big rainfalls in late summer 2015 put an end to that pretty quickly.

John Marshall said...

Given that our western WA winters are sort of like standing under a waterfall -- sometimes it's a Niagra and other times only roaring -- dry is a very relative term. Either way, you're going to get very wet.

The only interesting question is much snow and when, both mountains and western lowlands. And for the lowlands, we rarely know that answer until our lawns turn white.

I am sympathetic to Organic Farmer who complained about the unforecasted hard frost the other morning. Frost forecasts in early October are critical for farmers and anyone gardening. For a night with a forecasted low of 40, I was dismayed to see white frost all over my yard. There was no clue in the forecast, other than a clear night. Seems frost forecasting isn't a priority for the Seattle office, unlike in many AG areas.

Ian Reed said...

Th issue really comes down to microclimates. NWS forecast offices, tv weather guys, etc, have a hard time covering large areas AND super small microclimates.

It’s difficult to forecast which specific valley will drop to freezing, since factors such as wind, and fog development which are tough to pinpoint on their own often can mean the difference between 40° and freezing. You can have frost in one are, and a mile or two away, none.

Ansel said...

I had a light frost Wednesday morning. It may be the earliest one I have seen at my house.
Stephen, in my book a light frost is one where areas open to the sky see a temp. at ground level below 32, due to radiational cooling under a clear sky, and frost forms on my car, but the air temp is actually still a little above 32, and sensitive plants near the house or under trees are not frost-nipped.

I'd say a hard frost is where the free-air temperature is at least below 30 F and sensitive plants are killed back. But it's relative. I don't worry about my citrus trees until the ground level temperature goes below 26-28.

Ansel said...

Cliff, I asked this before once but I will repeat the question: Can a layman meteorologist gardener predict morning frost (or no frost) by checking the dew-point and the evening temperature? I know that once fog forms it greatly slows radiational cooling... or is the wind too much of a wild card?