A synoptic chart shows a 960 hPa depression centred 400nm NW of your position with isobars spaced 4 hPa apart at 50nm intervals. What does this tell you about wind strength at your position?

A. At 400nm from the centre, the depression has no effect — only vessels within 100nm are affected

B. The pressure gradient is steep (4 hPa/50nm) indicating strong winds — likely Force 6-8 in the circulation. At 400nm from the centre you are in the outer band of the depression where the gradient is significant but not maximum. Monitor the system's movement — if it is tracking toward you, conditions will worsen rapidly

C. A 960 hPa depression is a tropical system — not relevant to UK waters

D. Isobar spacing at 50nm intervals indicates light winds — widely spaced isobars mean weak gradient

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. 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