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Description of reliability and sharpness diagrams used to verify seasonal forecasts.
The terms 'reliability' and 'sharpness' used here have specialist meteorological definitions. For more details on reliability and sharpness diagrams please refer to the WMO SVS document and references therein. Standardised Verification System for long-range forecasts The ROC scores discussed
to skill assessment The verification procedures used to measure the performance of the seasonal forecasts are those recommended by the Standardised Verification System (SVS) for long-range forecasts (LRF) developed by the Commission for Basic Systems (CBS) of the World Meteorological Organization (WMO). Relative operating characteristic (ROC) Reliability and sharpness diagrams
. This is in sharp contrast to recent weeks which have seen many areas experiencing below average wind speeds. In fact this summer, some regions, saw their lowest average wind speeds for 20 years, while last winter, spring and summer saw below average wind speeds for the UK as a whole. In the UK our
. The best of the sunshine will still be across Scotland and Northern Ireland through the weekend, where temperatures will be widely in the low to mid 20s. Northern Ireland won’t escape the thunderstorm risk however, with the possibility of some sharp showers here on Sunday. With the warm weather
and snow. The rain turned more showery over Wales and the rest of England during the evening but it remained windy everywhere with gusts between 60 and 70 knots over the Western Isles of Scotland. It was a mild or very mild day nearly everywhere, but temperatures fell sharply during the afternoon
of Sunday will most likely continue for some parts of southern UK through at least the first part of Monday, before starting to clear eastwards. By this time however, confidence falls sharply in terms of both its exact location, and rainfall amounts. We are keeping a further warning for Monday under
By the time we reach the weekend a cold air mass will cover the UK, bringing a dip in temperatures with some sharp night frosts likely. With high pressure to the west of the UK, western areas will see mostly settled conditions, whereas eastern areas, particularly the North East, will see more
Colder conditions The current milder weather many of us have had recently is going to give way to a short, sharp, cold snap lasting through Friday and into Saturday. Met Office Chief Meteorologist Frank Saunders said, “Bands of showery rain will continue to cross the UK today (Thursday) before
-season cold snaps, especially during clear nights when radiative cooling can cause temperatures to dip sharply. Rainfall in the Midlands can vary significantly, and the wettest May on record brought 143.9mm of rain in 1932. While not as extreme as in western regions, this total still represents
to drop, and the end of that month and start of February saw some sharp frosts and snowfall. Much of December was broadly unsettled, with only transitory quieter interludes, and with western areas seeing many dull days. January saw more in the way of high pressure, but increasing numbers of active
