Check out this forecast for Pt. Isabel and Berkeley today.
When there is a heat wave and no marine layer or a thin marine layer that retreats fast, it becomes very difficult to forecast East Bay winds.
This is because the hot air from the East Bay hills and the Central Valley extends towards Sherman Island and the Pt. Isabel, Race Track and Berkeley launch sites. This hot air creates a “bubble” of low-pressure air. If the low pressure is just inland of the launch sites, the cool inbound WSW winds actually accelerate.
But if the Heat Bubble moves over the launch sites, a windless to weak wind zone will form near the shore, making it difficult to reach the stronger winds outside.
Sherman Island can have related problems, unlike the Pt. Isabel, Race Track and Berkeley zone Sherman
is in a natural fog and wind channel extending into the Central Valley. So, strong AM winds can fade midday as the Heat Bubble moves over Sherman Island. Then as the cool marine air flows through that channel the Sherman Island winds pick up in the PM.
Since it is impossible to accurately forecast the time the Heat Bubble advances or retreats, you should use our 11:30 AM forecast to fine-tune your own forecast in the early to mid-afternoon before making a long drive. Here are some hints:
Go to the iwindsurf or ikitesurf wind map websites. Zoom in the greater area around your launch site. Click on the sensor at your site. In the small box that pops up, note the launch site’s air temperature. Then click on sensors inland at different distances from your site. If you find the temperatures are much the same and you see building winds at the launch site, head towards your site with the window down. If you feel the air cool down as you near your site you will probably find great wind.
If your data collection finds heat near your launch sites, stay at home or work until you see cooler air. Of course, you should also watch the animated satellite imagery for fog movement.