| View previous topic :: View next topic |
| Author |
Message |
windfind
Joined: 18 Mar 1997
Posts: 1837
|
 Posted: Sun Jul 24, 2022 10:50 am Post subject: Tuesdays huge 300 mile wide eddy dies then... |
 |
|
Hi Gang,
UPDATE Tuesday, July 26: See new image below. Overnight the eddy expanded from about 20 miles wide to almost 300 miles wide creating southerly winds along most of the coast. This huge ballooning effect typically occurs just before the eddy dies. So by Wednesday, we will see mild NW ocean winds building with stronger NW Thursday.
UPDATE Monday July 25: The 2nd image below shows how Euro model predicts the eddy will die Tuesday and the NW ocean winds return Wednesday. And if you look very carefully at the last frame you can see why we will probably be forecasting the strongest winds in the Golden Gate to Pt. Isabel zone.
Below is an updated satellite animation of today's eddy from dawn to 5 PM July 25.
For days now I have been babbling about a big eddy developing west of the Bay Area Sunday and especially Monday. So below is imagery of the eddy t as seen from the satellites in the dim morning light.
The eddy will endure all day and be easier to visualize as the sun becomes higher in the sky.
This blog has the details about the eddy and how it forms:
https://blog.weatherflow.com/west-coast-wind-blog-eddy-breaks-up-prolonged-nw-wind-pattern/
Mike Godsey
Weatherflow
| Description: |
|
| Filesize: |
1.79 MB |
| Viewed: |
4498 Time(s) |
|
| Description: |
|
| Filesize: |
1.88 MB |
| Viewed: |
4568 Time(s) |
|
| Description: |
|
| Filesize: |
1.87 MB |
| Viewed: |
4686 Time(s) |
|
| Description: |
|
| Filesize: |
1.87 MB |
| Viewed: |
4686 Time(s) |
|
| Description: |
|
| Filesize: |
1006.49 KB |
| Viewed: |
4769 Time(s) |
|
| Description: |
|
| Filesize: |
1.91 MB |
| Viewed: |
4769 Time(s) |
|
Last edited by windfind on Tue Jul 26, 2022 7:18 pm; edited 7 times in total |
|
| Back to top |
|
 |
WNDZRFR
Joined: 28 Mar 2000
Posts: 120
Location: Greater East Bay Area
|
| Posted: Sun Jul 24, 2022 1:21 pm Post subject: |
|
|
Eddy! Eddy! Eddy!
_________________
Sponsored by Starboard and The Loft |
|
| Back to top |
|
|
dllee
Joined: 03 Jul 2009
Posts: 5294
Location: East Bay
|
| Posted: Sun Jul 24, 2022 1:30 pm Post subject: |
|
|
| Hope you get some SPEED runs at PI!
|
|
| Back to top |
|
|
dvCali
Joined: 23 Aug 2007
Posts: 1314
|
| Posted: Mon Jul 25, 2022 10:37 am Post subject: Re: Blog: 12 hours in the life of Eddy |
|
|
| It must have broken? After a week of 4.7 conditions at Coyote, yesterday I went to Stick for a great day of powered up 6.5 with my AV Modena 88L! Ideal conditions (for Stick) in 16-18 knots.
|
|
| Back to top |
|
|
windfind
Joined: 18 Mar 1997
Posts: 1837
|
| Posted: Mon Jul 25, 2022 12:44 pm Post subject: Re: Blog: 12 hours in the life of Eddy |
|
|
| dvCali wrote: | | It must have broken? After a week of 4.7 conditions at Coyote, yesterday I went to Stick for a great day of powered up 6.5 with my AV Modena 88L! Ideal conditions (for Stick) in 16-18 knots. |
Hi DvCali,
Nope, the eddy did not break. Take a look below at the satellite view of the eddy from 8AM to about 5 PM yesterday. It was spinning full speed full size until about 5 PM when the NW wind finally sent it crashing into the Marin coast where it shrunk and weakened but never died.
Looking at the eddy flow you can see that its winds were mostly SSW to SW which is great for Larkspur, Pt. Isabel and Sherman Island but not for Candlestick since southerly flow would actually weaken the wind there.
Mike
Weatherflow
| Description: |
|
| Filesize: |
1.87 MB |
| Viewed: |
4630 Time(s) |
|
|
|
| Back to top |
|
|
dvCali
Joined: 23 Aug 2007
Posts: 1314
|
| Posted: Mon Jul 25, 2022 3:06 pm Post subject: Re: Blog: 12 hours in the life of Eddy |
|
|
| windfind wrote: | | dvCali wrote: | | It must have broken? After a week of 4.7 conditions at Coyote, yesterday I went to Stick for a great day of powered up 6.5 with my AV Modena 88L! Ideal conditions (for Stick) in 16-18 knots. |
Hi DvCali,
Nope, the eddy did not break. Take a look below at the satellite view of the eddy from 8AM to about 5 PM yesterday. It was spinning full speed full size until about 5 PM when the NW wind finally sent it crashing into the Marin coast where it shrunk and weakened but never died.
Looking at the eddy flow you can see that its winds were mostly SSW to SW which is great for Larkspur, Pt. Isabel and Sherman Island but not for Candlestick since southerly flow would actually weaken the wind there.
Mike
Weatherflow |
The wind must have slipped in somehow. It was very south at Ocean beach, where I live, at 1:00-1:30pm. You could see the wind direction on the water, with white caps from the south. But at Stick it was a normal westerly. As I said a very nice sunny afternoon. I was on 6.5 but two other people were going with 5.5.
The microclimates of the Bay are really something!
|
|
| Back to top |
|
|
windfind
Joined: 18 Mar 1997
Posts: 1837
|
| Posted: Mon Jul 25, 2022 3:59 pm Post subject: Re: Blog: 12 hours in the life of Eddy |
|
|
| Quote: | | dvCali:The wind must have slipped in somehow. It was very south at Ocean beach, where I live, at 1:00-1:30pm. You could see the wind direction on the water, with white caps from the south. But at Stick it was a normal westerly. As I said a very nice sunny afternoon. I was on 6.5 but two other people were going with 5.5. The microclimates of the Bay are really something! |
Hi dvCali,
The amazing microclimates of the Bay are largely produced by the distribution of gaps in the mountains on the coast range and East Bay mountains.
Once the wind passes over the Bay's ocean coast the pathway it takes crossing the Bay waters is largely determined by...
1. Which Entry gaps are favored in the coast mountains. Like the huge Golden Gate and San Bruno Gap and tiny ones like the Alemany Gap near Candlestick. But all those cubic miles of wind pouring into the Bay through Entry gaps has to go somewhere.
2. And which wind direction is favored is determined by which Exit gaps are favored which in turn is determined by the location of the max pressure gradient in the Central Valley.
So yesterday the pressure gradient in the Peninsula in the late afternoon was. strongest towards these Exit gaps: San Joset to Pacheco Pass route to the Central Valley with a lesser gradient towards Stockton via the Altamont Pass.
So looking at this model graphic you can see that weirdly the southerly ocean winds curved through Alemany Gap near The Stick and "feeling" the gradient to Stockton they flowed as Westerly unit mid Bay where the gradient towards San Jose/Pacheco pass caused them to continue to curve until there were WNW winds near 3rd. and NNW winds near Palo Alto.
The model graphic below is pretty accurate.
Can you see why forecasting the launch site winds at 3rd. is extremely difficult whereas the channel forecast is much easier.
Mike Godsey
Weatherflow
| Description: |
|
| Filesize: |
1.48 MB |
| Viewed: |
4597 Time(s) |
|
Last edited by windfind on Tue Jul 26, 2022 9:34 am; edited 1 time in total |
|
| Back to top |
|
|
dvCali
Joined: 23 Aug 2007
Posts: 1314
|
| Posted: Tue Jul 26, 2022 1:03 am Post subject: Re: Blog: 12 hours in the life of Eddy |
|
|
| windfind wrote: | | Quote: | | dvCali:The wind must have slipped in somehow. It was very south at Ocean beach, where I live, at 1:00-1:30pm. You could see the wind direction on the water, with white caps from the south. But at Stick it was a normal westerly. As I said a very nice sunny afternoon. I was on 6.5 but two other people were going with 5.5. The microclimates of the Bay are really something! |
Hi dvCali,
The amazing microclimates of the Bay are largely produced by the distribution of gaps in the mountains on the coast range and East Bay mountains.
Once the wind passes over the Bay's ocean coast the pathway it takes crossing the Bay waters is largely determined by...
1. Which Entry gaps are favored in the coast mountains. Like the huge Golden Gate and San Bruno Gap and tiny ones like the Alemany Gap near Candlestick. But all those cubic miles of wind pouring into the Bay through Entry gaps has to go somewhere.
2. And which wind direction is favored is determined by which Exit gaps are favored which in turn is determined by the location of the max pressure gradient in the Central Valley.
So yesterday the pressure gradient in the Peninsula in the late afternoon was. strongest towards the Pacheco Pass route to the Central Valley with a lesser gradient towards Stockton via the Altamont Pass.
So looking at this model graphic you can see that weirdly the southerly ocean winds curved through Alemany Gap near The Stick and "feeling" the gradient to Stockton they flowed as Westerly unit mid Bay where the gradient towards San Jose/Pacheco pass caused them to continue to curve until there were WNW winds near 3rd. and NNW winds near Palo Alto.
The model graphic below is pretty accurate.
Can you see why forecasting the launch site winds at 3rd. is extremely difficult whereas the channel forecast is much easier.
Mike Godsey
Weatherflow |
Oh wow, look at that, I would never have guessed that a southerly eddy on the coast could produce a "westerly" at Stick or Coyote! Fascinating. I am used to think of a Eddy as a kiss of death for the wind but it is apparently not necessarily so! (Today Stic was weaker but still fine with 6.5)
|
|
| Back to top |
|
|
windfind
Joined: 18 Mar 1997
Posts: 1837
|
| Posted: Wed Jul 27, 2022 5:40 pm Post subject: |
|
|
| Quote: | | Oh wow, look at that, I would never have guessed that a southerly eddy on the coast could produce a "westerly" at Stick or Coyote! Fascinating. I am used to think of a Eddy as a kiss of death for the wind but it is apparently not necessarily so! |
Actually, southerly eddy winds can be the kiss of death for Coyote and 3rd. Ave. and sometimes Stick winds.
Looking at my graphic notice how the southerly eddy ocean winds end up as WNW flow in the 3rd. Ave. channel. That is because a strong pressure gradient towards Bakersfield on this particular day caused that WNW curve.
If the pressure gradient to Bakersfield had been weak the gradient from the San Bruno Gap to Stockton via the Altamont Pass had been stronger both Coyote and 3rd. Ave. would have kissed by death as the wind took at W to WSW pathway from the San Bruno and Hwy. 92 gaps in the coast range.
Mike Godsey
Weatherflow
| Description: |
|
| Filesize: |
343.8 KB |
| Viewed: |
4406 Time(s) |
|
|
|
| Back to top |
|
|
|
|
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You can attach files in this forum
You can download files in this forum
|
|
|
Search
Profile
Log in to check your private messages
Register
