General introduction.

About this FAQ

It is important to note that this FAQ is not a 'do-it-yourself' course in meteorology. It simply aims to answer some common puzzling questions that might be posed by the non-professional whilst browsing met-related web pages, or lurking in one of the weather newsgroups.


The following is an extract from the Charter for the newsgroup: "This group is essentially for the discussion of daily weather events, chiefly affecting the UK and adjacent parts of Europe, both past and predicted. The discussion is open to all, but contributions on a practical scientific level are encouraged. It may also contain postings of observations during interesting weather episodes. The group is expected to be patronised by both amateurs and professionals (including academics), but it is primarily for weather enthusiasts rather than research scientists. Any discussion of climate issues should be from a scientific standpoint and not a political (or environmental-activist) one." (See here for full copy source)

PLEASE NOTE: Binary files, (such as interesting satellite images, or weather charts) should not be posted into the newsgroup. To do so is a great annoyance to users, and contravenes the Acceptable Use Policy of some ISP's and associated peering carriers. Post such files into newsgroups specifically set up to carry binary-encoded information, and then post to the newsgroup the location. Alternatively put on your own web site.

There is a little more about the newsgroup history in the section on USW history.

About the authors

The original author of most of the material here, Martin Rowley, was an employee of the UK Meteorological Office (now known simply as 'the Met Office'), but has now retired. He has now also retired from maintaining this FAQ, and this web site was started in 2007 to hopefully carry on his good work.

A number of other knowledgeable folk have also contributed to the information here, for this I am very grateful.

Note that the current maintainer, while having a strong interest in the weather, is by no means a meteorological expert! He relies completely on input from the many experts on the newsgroup.

Steve Loft   24th January 2008

About the units used in this FAQ

There is always a problem with units in meteorology, because the 'operational' community use, and are used to, different units to those of an academic/theoretical persuasion, and so our trade is littered with anomalies! In this FAQ, I have used degrees Celsius for temperature as this will be familiar to most, but for height/altitude, both feet (used by the aviation world), and metres/km equivalents are given - mostly approximations. Wind speeds, where given, will be in knots (used in practical observing/aviation forecasting) and metres/second. The relationship between the two units is assumed to be knots=2*m/s, as only approximations are quoted. Note also that other approximations are often used, for example the Dry Adiabatic Lapse Rate is quoted as 10 degC per 1 km, whereas it is calculated to be 9.8 degC/km. (See here)