Meteorological Terms

Veering and Backing winds

  • A backing wind is a wind that turns counter-clockwise
  • A veering wind is a wind that turns clockwise

Veering/Backing of wind: When a wind direction changes such that it moves with the clock, e.g. from east to south through south-east, that is a veering wind; A wind therefore that changes against the normal clock motion is a backing wind.

seamanshipcourses

  • Imminent – Expected within six hours of time of issue
  • Soon – Expected within six to 12 hours of time of issue
  • Later – Expected more than 12 hours from time of issue

Visibility

  • Very poor – Visibility less than 1,000 metres
  • Poor – Visibility between 1,000 metres and 2 nautical miles
  • Moderate – Visibility between 2 and 5 nautical miles
  • Good – Visibility more than 5 nautical miles

Gale warnings

  • Gale – Winds of at least Beaufort force 8 (34-40 knots) or gusts reaching 43-51 knots
  • Severe gale – Winds of force 9 (41-47 knots) or gusts reaching 52-60 knots
  • Storm – Winds of force 10 (48-55 knots) or gusts reaching 61-68 knots
  • Violent storm – Winds of force 11 (56-63 knots) or gusts of 69 knots or more
  • Hurricane-force – Winds of force 12 (64 knots or more)