UV Index
A scale indicating the strength of ultraviolet radiation relevant to the risk of sunburn at the Earth’s surface.
Weather (Meteorology)
Nautical weather terminology is like a secret language designed to keep landlubbers guessing. Why say ‘storm’s brewing’ when you can declare there’s a ‘cyclonic gale on the Beaufort scale’? And don’t even get us started on terms like ‘sea state 5’—is that a weather warning or a new action movie? Mariner-speak turns clouds into ‘cumulonimbus monstrosities’ and drizzle into ‘light spindrift.’ Meanwhile, the rest of us are just trying to figure out if we need a raincoat. Don’t worry, we can help you navigate this foggy jargon without needing a barometer tattooed on your arm!
-
-
Wind Chill
The additional cooling of exposed skin caused by air moving over it.
-
Weather Deck
A deck exposed to the outside environment and capable of being subjected to rain, spray or boarding seas. Openings, vents, fittings and drainage on a weather deck must maintain the vessel’s required weathertight integrity. Loose equipment also needs securing against wind and vessel motion.
-
Storm Surge
An abnormal rise or fall in sea level produced mainly by wind stress and atmospheric pressure during a storm. It is additional to the astronomical tide and can greatly increase coastal flooding or reduce depths. Impact depends on storm track, intensity, timing with tide and coastal or seabed shape.
-
Pressure Gradient
The rate and direction of change of atmospheric pressure over distance. A stronger horizontal pressure gradient generally produces stronger wind, modified by Earth’s rotation, friction and curvature. Closely spaced isobars on a weather chart indicate a steep gradient rather than directly specifying the exact surface wind.
-
Numerical Weather Prediction
The calculation of future atmospheric conditions by solving physical equations in a computer model. Models assimilate observations and represent the atmosphere on a grid, producing forecasts of wind, pressure, precipitation and other variables. Resolution, initial conditions and model assumptions create uncertainty, so forecasts are interpreted alongside observations and ensembles.
-
Offshore Wind
A wind blowing from the land toward the water. It can produce deceptively smooth water near shore while carrying small craft, inflatables or people away from land. Strength may increase beyond shelter, and returning upwind can become difficult.
-
National Meteorological Service
A country’s official organisation for observing, forecasting and warning about weather and related environmental conditions. It operates national networks and issues forecasts or warnings under its mandate, often including marine services. Product names and geographic responsibilities vary, so mariners should identify the authoritative service for their waters.
-
Inshore Waters Forecast
An official marine forecast for coastal waters close to shore. In the United Kingdom it covers named stretches of coast and includes wind, sea state, weather and visibility for stated periods. Area boundaries, update time and warnings should be checked before applying it to a passage.
-
Hail
Precipitation consisting of balls or irregular lumps of ice formed in strong convective clouds. Hail is associated chiefly with thunderstorms and can reduce visibility, make decks hazardous and damage sails, glazing or equipment. It differs from small ice pellets produced by other atmospheric processes.
If you belive the Earth is flat, you're about to fall of the end...
If you belive the Earth is flat, you're about to fall of the end...
