Several decades ago it was impossible to forecast when a counter-clockwise eddy would spin up and change the Bay Area summer coast winds from the prevailing mild NW winds to mild SW winds. For wind sports enthusiast the direction of the coast winds determine which launch sites are windy and where the strongest winds will be inside the Bay. So folks north of the Bay Bridge hope for and enduring eddy while those on the coast and Peninsula hope for its early death.
Eddies, by their nature can change their location and location very fast. And they can spin up very quickly and sometimes die equally fast. Dust devils do all these things even faster. As you watch this dust devil video imagine forecasting its fate as it rapidly changes.
While the eddies off the Golden Gate are far larger and slower they are equally hard to forecast.
Through the years WeatherFlow-Tempest meteorologist have gotten very good at forecasting the
development of eddies and often their location. But forecasting the time of their death still defies us.
Take a look at my extended forecast above for tomorrow Friday July 25, 2024.
I sound pretty confident about the eddy dying in the AM. In reality the eddies death depends on the NW winds building on coast.
This animation shows a situation where a Monterey eddy dies very fast while the eddy off the Golden Gate lingers. This shows how difficult it is to forecast when an eddy dies. Sometimes they die very fast like the eddy at the bottom of the image they can vanish in minutes.
Since the variables causing an eddy are complex and hard to forecast I could easily be wrong about tomorrows forecast. This graphic I made at the start of the current eddy shows some of these variables. We need almost every one of those variables to change for my forecast tonight for a NW ocean wind pattern to develop tomorrow.