How does high and low air pressure work?
The low pressure means that the atmosphere is pressing on the sea less than usual. For every millibar that the atmospheric pressure falls, sea level rises by around 1cm. That means that if there is a serious low with a pressure of around 960 millibars then sealevels could rise by around 1/2 metre. Low pressure also affects sea level by blowing more water onshore. This, along with the bulge in sea level due to the low pressure creates something called a storm surge. This is what caused the flooding in New Orleans during Hurricane Katrina – seriously low pressure led to the sea level bulging upwards and the strong winds piled the water up shorewards. I’m guessing you might be east coast UK because they have just recently had very large tides. In the UK we thankfully don’t get hurricanes meaning that storm surges are usually ok as they don’t co-incide with high tide. However if you get a storm surge co-incide with high tide then it results in sea levels being much higher than they would n
