What is an occluded front and what weather does it typically bring?

A. Formed when a cold front catches a warm front — the warm sector is lifted off the surface. An occlusion brings a prolonged period of disturbed weather with cloud, rain, and variable winds; the warm sector advantages (relatively settled weather) are lost

B. An occlusion only forms in tropical waters — not relevant to UK sailing

C. Occluded fronts always bring fog and light winds

D. An occluded front is a front that has weakened and no longer has significant weather

A. Barometric tendency only matters above Force 6 — below that, pressure changes have no predictive value

B. A fall of 6 hPa in 3h is insignificant — barometric changes only matter over 24h

C. A rapid fall (>6 hPa in 3h is defined as "very rapid" in MET Office guidance) indicates an approaching vigorous depression — imminent deterioration. Seek shelter, shorten sail, check position and proximity to lee shores, and reassess the passage plan immediately

D. This indicates a high pressure system building — expect improving conditions

A. Narrow channels always have less wind than open water due to the shelter of surrounding land

B. Funnelling only occurs when wind speed exceeds Force 7 in open water

C. Wind strength is identical inside and outside a strait — only wave height differs

D. Funnelling: wind accelerates as it is constrained between high land masses, often increasing by 1-2 Beaufort forces. The strait may experience Force 6-7 while open water is Force 5. Also expect accelerated tidal streams through the same bottleneck