Autopsy of a blown SoCal coast wind forecast

[windfind]

Hi Gang,

I know it sometimes looks like we ignore occasions when we totally blow forecasts. But actually we are acutely aware of our errors and when the mistakes are really big we work together to try figure out what happened.

Normally this all happens behind the scenes but I thought since my Southern California forecast last Sunday was especially bad I thought a blog would give you an insiders glimpse of the gory e-mail details sent during a forecast autopsy.

http://blog.weatherflow.com/an-inside-look-autopsy-of-a-blown-southern-california-coast-wind-forecast/

And if you would like better forecasts take the time to mail me your insights about this fog bank wind pattern at mike@iwindsurf.com. That sort of feedback actually works better than using my F word nickname even though it takes more time and is not as satisfying.

Mike Godsey
iwindsurf.com/ikitesurf.com

[Jorionw96]

Big winds at Sherman tomorrow? That is what local sac news says?

[daKine]

I think you do great work.
Predicting anything means you are going to be wrong sometimes.
Plus, trying to predict what is going to happen in the boundary layer is really tough.
We have a lot of fog here in the Great Lakes along with three big bodies of water surrounded by mostly flat land.

I'm trying to think this through.
Fog happens when air becomes supersaturated.
From the air's point of view that means that either the temperature or the pressure have changed.
Regardless of why the fog formed, when it does the condensing water releases a lot of heat.
I think many fog banks are really standing waves where moisture is being continuously removed from the system
Predicting wind at low altitude on the beach means you really have to think about boundary layer behavior.
With our ice water lakes in the spring it is common to see a bowl of fog filling the valley a lake sits in.
On a sunny, windy day the wind will not usually displace that cold, moist layer and deflects over it.
Your forecast may well have been right at 500 feet up.
My randomly linked thoughts anyway.
Then there is climate change which has obviously changed weather norms in a surprisingly short time.
I still can't quite get my head around the fact that the weather I grew up with doesn't exist anymore!

[windfind]

Hi daKine,

Thanks for the useful input. The funny thing about these fog induced very local winds is that they are fairly easy to "now cast" when you are at the beach and can see the fog bank setting up in the right place.

The challenge is to forecast that happening at 7AM or 11:30 AM. Since the blog discussion amongst the Weatherflow forecasters we have actually forecast this fog induced wind in Southern California correctly twice when the models said "no wind". Time will tell if that was only luck.

Mike Godsey
iwindsurf.com

[jp5]

Hey Mike;

It has been warming up in the San Fernando Valley lately. Usually a good sign for wind at Leo Carrillo.
When I left the office in Woodland Hills at 4 yesterday it was 95. The Wind meter was showing 16 gusting 26
at 3, the Surfline cam at Country Line was showing significant wind bump and no clouds, the NWS satellite
showed a nice pocket of clearing in the area. All systems GO!

When I got to Leo the clouds were nearly on PCH and there were few white caps but not sailable. GAME OVER!

This used to be the classic setup for wind in the 90's with almost a guarantee of wind but more commonplace
now is the hotter it is in the valley, the foggier it is on the coast.

Climate change?