Cruising Weather Knowledge - Barometric Pressure Explained

All cruising sailors know the importance of a goodwhen the weather changes. This is usually due to
weather forecast. Whether a weekend lake sailora change in atmospheric pressure ahead of
or a blue water passage maker, knowing whatdeteriorating weather. The average sea level
kind of weather is in store is vital to a safe andpressure is roughly 1013mb.
more tolerable trip on the water. Paying attentionBut different temperature air will have a different
to atmospheric pressure is one way of helpingpressure. Heat rises because hotter air is lighter
make decisions like when to reef or not going outthan colder air and the result is low pressure. A
at all.high barometric pressure reading means that cold
Air actually has a weight factor. And because ofair has sunk. A rising high pressure is usually an
this weight and gravity, a downward pressure isindication of good weather ahead. A falling
formed and measured as atmospheric pressurebarometer means get ready for bad weather.
or barometric pressure and measured in terms ofYou can see how important having a barometer
millibars (mb). Certainly everyone has seen thison board a cruising yacht is. Studying changes in
measurement on their local news stationthe pressure along with any weather forecast
weathercast and is usually given more attentionyou can obtain is crucial to preparing the boat for
to in measuring and predicting hurricanes. Thethe impending storm. Along with all the other
lower the pressure, the stronger the hurricane.critical gear like GPS and radar, invest in a good
We all experience atmospheric pressure whetherbarometer. You'll agree that it's a must-have on all
we notice it or not. You'll hear some folks talkblue water yachts and not a bad addition to even
about an old injury or their arthritis flaring upyour lake sailor.