A sea breeze forms because of temperature differences between land and water.
On a hot summer day, the land heats up quicker than the gulf water. The air over the water is about 10 degrees cooler and more dense that the warm air.
So the cool air is able to push inland and create a strong breeze off the gulf.
This cool breeze will plow into and undercut the warm air forcing the air to rise.
This rising motion will initiate a line of cumulus clouds that sometimes grows into showers. We can usually see them to our southeast late in the afternoon.
It acts like a miniature cold front coming in from the gulf. Ahead of it you can see a few clouds and showers. As the breeze moves further away from the gulf it loses strength. That's why most of the showers reach us and then quickly fall apart.
The prime target for sea breeze showers is normally east of Austin.
If high pressure is not present and there is a low pressure in place keeping the atmosphere more unstable with the sea breeze, the showers will have a better chance of reaching our area late in the day.