Be aware of a fall in the barometer below the known value of the diurnal change. It can mean significant changes in weather, such as an approaching tropical cyclone. Squalls, on the other hand, have relatively constant pressure except near their center. Tropical cyclones will be discussed later. Now, let s move on to squalls.
Squalls usually occur in the region south to south west of the High center.
Expect to deal with squalls for about 3 days towards the end of the race. Cool air traveling from the north is warmed and gains moisture as it moves southerly over a thousand miles of ocean. Local areas of instability due to temperature differences cause pockets of rising air. As the air rises, it cools, condensing moisture and clouds form. If the instability is strong enough with accelerating vertical motion then squalls may develop.