Monday, March 2, 2015

The Ridge Will Shift and the Northwest Will Warm

The last few days there has been substantial sun, but there has been a chill in the air because we have been on the eastern side of a big ridge of high pressure.  As I have described several times in this blog, there is northerly flow on the eastern side, with cooler air moving out of the north.   Today's (4 PM) upper-level chart at 500 hPa (roughly 18,000 ft) illustrates this situation.

As illustrated by the temperatures at Seattle-Tacoma Airport, today's temperatures were near normal, even with a lot of sun (red line, average high; blue line average low). Fairly strong northerly winds were blowing and they had a decidedly cool edge to them.
But everything is going to like the change and most of you (except skiers) will like the change.

The ridge will not be going away, but will shift eastward so that by early next week we will be on the western side of the ridge, a region with southerly flow and warm air.  

Here is the upper-level flow (500hPa) that I showed you above.

By Saturday morning (8 AM) , the ridge has moved eastward and tilted.

And by Tuesday morning it has strengthened and moved to the Rockies, with the Northwest under warm southwesterly flow.  A small shift further eastward and we could be in heavy rain.

Now lets watch the surface air temperatures evolve (purple is cold, red/orange is warm).
Tomorrow's highs are in the lower 50s.

Major warm up by Friday (4 PM), with upper 50s getting into western Washington, 60s in western Washington, and 70s in CA.

By Monday afternoon, 60s are into western Washington and Tuesday will be even warmer.

Precipitation?  According to the Weather Services forecast of the accumulated precipitation from the GFS model, we will be essentially dry (white).  But those poor devils in the eastern U.S. will be wet...and much of that will be snow in the Northeast.

The persistence of the ridging/high pressure over the west this year is extraordinary.  Based on the latest forecasts,  It appears that there is little chance we will build much snowpack during the next week or so.


Upupaepops said...

I bet my boss a box of donuts that we would get snow of some kind ( any kind) in the north convergence zone the first week of Spring

I am doomed.

Ansel said...

Cliff, this comment relates to your last blog but I want to comment on seasonal lag... it is as I suspected: It appears that here in the NW there is a LOT more seasonal lag at the 3000 foot level: At sea level the temperature minimum comes in early January and the summer maximum is at the end of July. But at the 3000 foot level, according to your graph, the temperature maximum is as late as early September and the minimum is flat from January through March... Why is there so much more lag at altitude?

dpc said...

It rains from Oct to June. You won't see the sun until July. *BULL*
Doesn't snow much in Seattle but the mountains have plenty. Just a short drive away. *Uh, no*
Plan your vacation during Feb when you're sick of the perpetual gloom. *Utterly wrong-headed*
We deserve a hot summer be/cs we suffer so much in winter. *yeah right*
East winds are rare. *absolutely false*
Winters are cold and rainy and the summers are simply warm, not hot. *both assertions are untrue*
Gonna be ever NICER here during global warming! *only if you prefer California weather*

JewelyaZ said...

DPC, you sound so bitter. I have to admit, except for the worrying snowpack, I think this weather is great. Unlike most of CA, we do still have four distinct seasons, and I doubt that will go away, if for no other reason than the radically changing sunlight amounts from month to month.

I've been here almost 17 years and this year and last were quite unusual. I'm guessing next winter will be more normal for us.

kermitzii said...

Cypress mountain ski area on the north slope of Vancouver is making snow like mad. They know they have one day left. They have been closed for 3 weeks but will open tomorrow. Excellent snow making conditions the last 3 nights.

dpc said...

@JewelyaZ - nah, not bitter. Just disappointed. As you can tell I much prefer the cool seasons (I've learned to think like my dog). The worst for me: hot summer days and warm sunny winter days. Only exception is when I have reservations at the beach. Then I love the sun!
4 seasons in Seattle? Not so sure, but won't argue.
The warming earth troubles me. If our future is 85+ in summer and 55/sunny in "winter" I'll move to a cooler climate.
As for next year..who knows? We are due for El Nino (last one was 09-10: remember the Vancouver spring olympics?). And last year was normal - neither el nino nor la nina - and look what happened.

Jeff said...

I have to agree with dpc about the summertime heat. I've been quite frustrated by the last two summers' persistent heat, though still I wouldn't trade Seattle's weather for anywhere else in the country. I think what made the heat especially frustrating was the bizarre celebratory nonsense from news and weather anchors about how great it is to have temperatures above 80. If your only use for the outdoors is shuffling around in a sun-dazed drunken stupor in your yard or on a beach before retreating to your air conditioned home or car, then sure, 80+ is nice for that. If you prefer to do anything outdoors, like hiking, biking, running, kayaking, and any competitive sport, then no, 80+ sucks. Every activity's optimal temperature range is different of course but only for kayaking would 80 be approaching OK... all the others are certainly better at cooler temps, which is why Seattle's summers are the best in the country for outdoorsy people.

This winter, though, the lack of snow has been mighty frustrating, which I think we all agree on. I broke my leg skiing at Mission Ridge when I slid out on a compressed ice patch. It was the first run on a Sunday, after a night of snow-making, so on this steep portion there was just enough new powder to hide the ice but not enough to hold an edge. The only silver lining to this weather is that life on crutches is a lot easier to deal with on rain-free days.