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windfind
Joined: 18 Mar 1997 Posts: 1905
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Posted: Sat Jun 04, 2022 12:47 pm Post subject: Blog: Cool showery May and early June in the Gorge: La Nina |
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Hi Gang,
Have you noticed that for much of the Pacific Northwest the weather has been a tad unusual this spring?
This spring has been different for the entire west coast from the tip of Baja to Seattle. For most of the season, there have been strong unending NW winds on the California coast while the Gorge has had frequent cloudy showery days punctuated with strong winds out east. And La Ventana in Baja Sur had the best winter season in decades with much of its wind coming from the North Pacific High rather than the 4 Corners high pressure.
This blog gives you an overview of the factors behind our winds this year so far:
http://blog.weatherflow.com/west-coast-wind-blog-cool-showery-may-and-early-june-in-the-gorge-la-nina/
Mike Godsey
IWK
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isobars
Joined: 12 Dec 1999 Posts: 20936
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Posted: Sat Jun 04, 2022 6:10 pm Post subject: Re: Blog: Cool showery May and early June in the Gorge: La Nina |
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windfind wrote: | the Gorge has had frequent cloudy showery days punctuated with strong winds out east |
While I certainly couldn't have explained the causes you have presented, I've been describing the results for a couple of years now as LONG strings of nada punctuated by brief drive-bys -- often just hours -- of too much wind for most visitors and many locals. This year has been by far the best -- er, worst -- example, at least out east. I don't mind showers or clouds, and I got lots of neoprene, but I've received and seen too many injuries to good high-wind sailors to appreciate this 35G50 or 38G55 stuff any more. I haven't seen a season this on-or-off in any of the 40 years I've been sailing the Gorge. Thank goodness for foils and kayaks, and thanks for telling us why we're living in Jonesville lately.
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windfind
Joined: 18 Mar 1997 Posts: 1905
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Posted: Sun Jun 05, 2022 8:59 am Post subject: |
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Hi Isobars,
Thanks for the season report with historical context. I might point out that those that live out east, like Isobars, have a broader wind perspective than those who visit only on the strongest days.
Here is a simple way of thinking about the sometimes extremely gusty conditions this season.
Normally during April to early June we occasionally have storms to our north bump the NPH a bit southward. Then as the storm passed the NPH moves closer to us creating strong SURFACE westerly wind in the Gorge.
At the same time, several thousand feet above the Gorge, strong GUSTY westerly winds on the backside of the storm impact the surface winds. This moves the focus of the surface wind east AND adds a gust factor to the wind, especially in the corridor with its complex topography.
This La Nina year as storms pass we are getting those strong GUSTY westerly winds aloft but with the North Pacific High to the south the baseline surface wind is less reliable.
This leaves us with lulls from the less robust surface winds interspersed witih blasts and deeper lulls as the winds aloft randomly drop to the surface. Another factor is that storms level unstable air in their wake which adds to the gust factor.
I am ignoring, for now, the longer-term changes in the Gorge winds this last decade ie. the mean position of the NPH, thinner marine layer, changes in average wind direction etc.
This old blog is an example of one of those longer term changes:
https://blog.weatherflow.com/west-coast-wind-blog-the-wall-wind-direction-and-2-venturis/
Mike Godsey
iwindsurf.com
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isobars
Joined: 12 Dec 1999 Posts: 20936
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Posted: Mon Jun 06, 2022 9:31 am Post subject: |
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Every spring some people ask how the Gorge wind looks
for "July 4-11", or "July", or "this summer". Mike/Windfind has addressed the latter question, but as one fine tunes the forecasts, the bigger challenge emerges. Temira's forecast for later this week includes this telling observation of a mere 3-4 days out:
"Forecast certainty plummets as we move into the Thursday-Sunday period. Some models have us under the biggest rainstorm in decades. Some have us warm and dry."
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windfind
Joined: 18 Mar 1997 Posts: 1905
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Posted: Mon Jun 06, 2022 3:07 pm Post subject: |
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The first graphic shows why we are likely to see some rain. Look at the storm train extending all the way to Japan in the first image.
Normally this would not mean much since the winds in the loops in the upper troughs and ridges could steer the storms far from the Gorge.
But the next few days all those troughs and ridges are loops are ironed flat so the upper-level winds mostly go straight from W. to E in what meteorologists call "zonal flow" and are modeled to make a beeline towards Seattle. So this looks like another atmospheric river that could bring significant rain... somewhere on the Pacific Northwest coast into Canada.
The second image shows the output of 12 different models. Notice how similar the models are for the temperature for the next 5 days. Temperature is the easiest thing to model. But notice how widely the models vary for temperature for next Saturday when the rain supposedly arrives.
Large-scale temperatures are mostly determined by those same upper ridges and troughs that steer storms. So it means there is a lot of variation in the possible pathway of the rainy storm.
Notice the amount of rain forecast for Hood River, Oregon.
Mike
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