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3 Videos: Weasel words in the forecast: marine surge

 
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windfind



Joined: 18 Mar 1997
Posts: 817

PostPosted: Mon Jul 14, 2014 10:54 am    Post subject: 3 Videos: Weasel words in the forecast: marine surge Reply with quote

Hi Gang,

Reading Claire's 7AM Bay Area forecast did you notice the Weasel Words about a possible late afternoon marine surge? That tidbit was my contribution to the forecast despite it being my day off.

Here are the weasel words: Note: There is a chance of a SW marine surge late today due to air traveling from a huge eddy near SoCal. This will probably by disrupted by all the hot air over the Bay but it is worth keeping in mind.

I know some of you hate these Weasel Words since they look suspiciously like we are just covering our a$$s.

Of course we would never do that! But why do we insert these little notes? Basically because in forecasting we look at many different computer models and tons of data from weather balloons, sensors, profilers, satellites etc. Generally the high resolution models are best for venues like the Bay Area where there is complex topography since those models can see smaller features like the San Bruno Gap. And today all the high res. models show weak winds for the Bay Area. Hence the low winds forecast for most of the Bay Area.

But dawn today, after feeding the chickens, I spent some time researching the Catalina Eddy in Southern California. I was looking at the mid and upper level winds above Southern California when I noticed that there is a 700mb counter-clockwise spinning low pressure about 10,000 feet above the surface Catalina Eddy. I reasoned that this might really jazz up the Catalina Eddy killing Southern California winds. But that led to more exploration.

This led to a possibility that the Catalina Eddy would get so big that it could possibly trigger off a marine surge this evening near the Bay Area jacking up the Sherman Island winds very late this afternoon and/or early tomorrow morning. Since none of the high res. models supported this hypothesis. I began looking at the sensor data and the Low Res. models from the coast north of Southern California. And there were some hints in the data that it was worth sticking in the note in today's forecast.

So will the weasel words come true? Watch the Half Moon Bay ocean buoy. If it goes SSW in the next 6 hours I will be the hero. If it does not then at least I covered our a$$es.

Meanwhile below are 3 videos I annotated so you can see my reasoning.

Mike Godsey
iwindsurf.com/ikitesurf.com



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coachg



Joined: 10 Sep 2000
Posts: 2019

PostPosted: Mon Jul 14, 2014 12:09 pm    Post subject: Reply with quote

Hi Mike,

Yes, the Sherman Island forecast has me very confused. All the local & national forecasts for Sacramento only call for extreme heat today, followed by low 90's to upper 80's for the rest of the week. My experience is a change in Sacramento from 105+ to 94+ is a sure sign of a marine surge which we feel in Sacramento as a Delta breeze. So our local forecast for strong steady low to mid teen Delta breezes all week with mild low 90's doesn't align with the extended no wind/heat wave forecast on the Extended Discussion.

Coachg
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MULLDE102f



Joined: 15 Jun 1997
Posts: 91

PostPosted: Mon Jul 14, 2014 2:04 pm    Post subject: Reply with quote

Hey Mike,

If these guys think your work to micro-forecast wind (at sites a couple of miles apart) is not good enough, let them give it a try.

I remember having to listen to NWS buoy reports to try to figure out if it was worth going out or not. Good luck with that.

I think you do a great job.
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coachg



Joined: 10 Sep 2000
Posts: 2019

PostPosted: Mon Jul 14, 2014 3:20 pm    Post subject: Reply with quote

I didnít realize I was complaining about the forecast. All the time I thought I was acknowledging the discrepancy pointed out by Mike? But what do I know?

Rolling Eyes

But since I have from 70 liter/4.0 up to 10 meter/Formula & SUP with light wind freestyle skills Iíll give it a shot.

Sailable every day at Sherman this week.
Laughing

Coachg
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windfind



Joined: 18 Mar 1997
Posts: 817

PostPosted: Thu Jul 17, 2014 11:32 am    Post subject: Reply with quote

Hi Guys,

Coachg, I did not take your comment as a criticism. I was off for that day and the next 3 days but I wanted to give you guys and Claire a heads up that things were changing fast.

The reason that the extended forecast was for no wind was that the heat and the resulting low pressure was modeled to expand to the coast which is a Sherman Island wind killer.

At that point none of the models were allowing for the very atypical marine surge you see in the videos.

And that pattern you see in the videos has morphed into the southerly flow that continues even today.

Hope to see you guys at Sherman later this month.

Mike Godsey
iwindsurf.com
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