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Module 17 · Interactive

Meteorology Visual Suite

Three interactive tools covering the meteorology topics the MCA examiner tests most heavily: TRS avoidance (which semicircle, which escape action), the warm and cold front cloud sequence, and barograph pattern identification.

What you're practising

Identifying which semicircle you're in during a TRS, reading the full frontal cloud sequence in order, and interpreting barograph pressure traces.

Pass criterion

Name every cloud type in sequence (Ci→Cs→As→Ns), state the correct escape action for each TRS semicircle, and identify all four barograph patterns.

98899299610001004Lsystem moves E ~25 ktswarm frontcold frontocclusionsouthern passagenorthern passageYOU

Plan view, Northern Hemisphere, system moving east. Drag the ship (or use the slider) — in reality you hold your course and the system slides east over you. In the Southern Hemisphere the circulation and all the veer/back rules reverse.

Stage 1 — Open ocean (600 nm ahead of warm front)

Cloud

Clear sky / isolated Cumulus

Pressure

1020 hPa — steady

Visibility

Excellent (>15 nm)

N

Wind

SSE 10 kts

1020 hPayour barograph through the passage

What is the FIRST visual sign of an approaching warm front — and how far out does it appear?

Buys Ballot's Law: face the wind — the low pressure centre is on your RIGHT hand in the Northern Hemisphere (LEFT in the Southern), roughly 8–12 points from dead ahead. Combined with veer-or-back, it fixes where you are on this chart from nothing but your own anemometer and barometer.

Module 17 — Study Notes

Full written notes covering met instruments, pressure systems, fronts, Buys Ballot's Law, Beaufort scale, TRS avoidance, fog types, and weather broadcasts (NAVTEX, SafetyNet, Weatherfax).

Open Module 17 notes →