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.
Squalls are small-scale feature of disturbed weather embedded in the trade winds.
Cloud tops tower over surrounding clouds and appear dark as they are laden with moisture. They are steered by upper level winds usually 15-20 degrees to the right of the trade wind direction. A boat sailing on starboard jibe with an apparent wind direction of 160-165 degrees will have squalls affecting them from near dead astern. Correct use of them can be a significant factor in gaining considerable distance towards the finish. ULDB s have the ability to stay in front of a squall for long periods of time or until the squall dissipates.