Definitions

Definition : The freezing level

The “freezing level” is not the height at which snow turns to rain as Ben Rich states in this BBCBBC The British Broadcasting Corporation (BBC) is the national broadcaster of the United Kingdom, based at Broadcasting House in London. It is the world's oldest national broadcaster, and the largest broadcaster in the world by number of employees, employing over 22,000 staff in total, of whom approximately 19,000 are in public-sector broadcasting. Weather video, but the lowest height above mean sea level where the air temperature is 0°C. It’s defined by a specific temperature 0°C and not the change of state of solid into liquid. I don’t see why it proves so difficult to explain.

Definition of a Gale

Gales around the coast of the British Isles are a fairly common occurrence, but inland they occur much less frequently. In the media the word ‘gale’ seems to be bandied about with little thought of what it actually means. According to the fourth edition of the Meteorological glossary, published in 1963, a gale was a 10 minute sustained mean wind speed of 34 knots (39 mph) or more. As an observer from 1970 to 1995 that’s what I always thought the definition was, but in the sixth edition of the glossary, published some thirty years later, I notice that the definition has been updated to include gusts of 43-51 knots (49-58 mph) as well. So a gale can occur without a mean of 34 knots or more if a gust reaches Beaufort force nine or higher, which to me confuses the whole issue. The definition of a gale day remains the same.

I notice the definition in the Marine Forecast glossary on the Met OfficeUKMO The Meteorological Office is the United Kingdom's national weather service. It is an executive agency and trading fund of the Department for Business, Energy and Industrial Strategy website rather ambiguously fails to mention at all sustained mean speed of 10 minutes in its definition of various gale warnings.

Frost severity definition

The definition for frost severity as laid down by the Meteorological Office in their Glossary of 1991, has remained unchanged for many years. Frost severity is dependent not just on the lowest minimum temperature, but also on the wind speed, so there are two sets of values for ‘slight’, ‘moderate’, ‘severe’ and ‘very severe’, one for when mean wind speeds are 10 knots or more and one for when they are less.
There are many euphemisms for frost used by today’s weathercasters that are simply misleading and bad practice. Common amongst these are ‘sharp’, ‘touch’, ‘pinch’, ‘hard’, and ‘light’, they’re all bollocks as far as I am concerned. If weathercasters stuck to the same rigid definition the general public might have a better clue to just how severe an upcoming frost might be, what a forlorn hope of mine that will ever happen.
It’s also interesting to note that the glossary mentions just two basic types of frost, an ‘air frostair frost An air frost occurs when the temperature of the air falls below 0.0°C’, and a ‘ground frost’, so forget about ‘grass frost’, even if the thermometer that’s used to measure it is referred to as a ‘grass minimum’ thermometer.