Format of the Forecast

Every forecast includes:

1. Time and date of the active forecast

2. Current gale warnings

3. General synopsis (overview of pressure systems)

4. Area forecasts (e.g., Thames, Humber, Dover)

5. Inshore waters forecast (for those within 12 miles of the coast)

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Why It's Important to Listen Closely

• Note the time of issue, not just the time of broadcast. All forecast references — like “imminent” or “later” — are based on the issue time, not the time you're hearing it.

• Pay attention to sea areas before your location, especially in the Southwest Approaches or North Atlantic, to anticipate what's coming your way.

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Example Forecast Explained

“Humber, Thames. Southeast veering southwest 4 or 5, occasionally 6 later. Thundery showers. Moderate or good, occasionally poor.”

Breakdown:

• Area: Humber and Thames (eastern UK waters)

• Wind direction: Starting Southeast, changing to Southwest

• Beaufort force: Wind Force 4–5, maybe Force 6 later (i.e. 12+ hours after issue)

• Weather: Thundery showers with possibly reduced visibility

Interpretation:

Force 4–5 is manageable for most sailors (~15–20 knots), especially off the wind. However, the shift to Force 6, possible poor visibility, and veering wind suggest a front may be moving in. Adjust your course, prep your crew, and maybe consider a port of refuge — just in case.

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Interpreting Common Shipping Forecast Terms

Wind Strength (Beaufort Scale Quick Reference)

Force	Description	Approx Wind Speed (Knots)
4	Moderate Breeze	~15 knots
5	Fresh Breeze	~20 knots
6	Strong Breeze	~25 knots

Pro tip: A rough conversion = (Beaufort Force - 1) × 5

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Visibility Categories

• Good: Over 5 nautical miles

• Moderate: 2–5 nm

• Poor: 1,000m – 2 nm

• Very Poor: Under 1,000m

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Timing Definitions

Term	Meaning
Imminent	Within 6 hours of issue
Soon	6–12 hours from issue
Later	Over 12 hours from issue

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Wind & Pressure Terminology

• Veering: Wind direction changing clockwise

• Backing: Wind shifting anti-clockwise

• Becoming cyclonic: Wind expected to change significantly due to a depression

• Rising/falling quickly: Pressure change of 3.6–6.0 mb in 3 hours = gale risk

• Very rapidly: Pressure change >6.0 mb in 3 hours = storm force expected

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Tips for Making the Most of a Shipping Forecast

• Write down notes using a shared shorthand system for crew.

• Combine forecast info with local inshore waters forecasts and your barometer readings.

• Stay alert to pressure systems moving across western sea areas (e.g., Shannon, Rockall), as UK weather often comes from the Atlantic.

• Use it to inform passage planning, including where your nearest safe harbor is in case the weather deteriorates.

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Interpreting the shipping forecast isn’t just about understanding wind and pressure — it’s about knowing how it all affects you and your boat. With regular practice and awareness, you’ll be able to read between the lines and make smarter decisions out at sea.