I’ve been archiving text LRFLRF Long Range Forecast. Usually 16 to 30 days or more. from the UKMOUKMO 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 for a month or two now so I thought I would take a look and see just how accurate they’ve been. The recent cold and snowy start to March 2023 seemed a perfect period to evaluate, so here is the text for the 16-30 day forecast issued on the 9th of February, and the 6-15 day forecast issued on the 24 February.
16-30 Day
The ‘bands of rain and strong winds… in the northwest’ in the 16-30 day forecast is clearly wrong, and looked so even when it was first published on the 9th of February. An intense high persisted over N Scotland from the 26th of February to the 4th of March. The ‘low probability of some much colder weather’ is also clearly far from accurate and really should if anything have read ‘high’.
6-15 Day
‘There is also potential for a spell of more unsettled weather in the far north‘ again this is inaccurate. The weather types in the N of Scotland during this period was either A or AN, and the two unsettled spells that did occur were associated with lows that crossed the country much further south than the N of Scotland. ‘A low chance of more organised rain or snow spreading south’ is another faux pas with many areas across N Ireland, N Wales and N England seeing a spell of heavy snow on the 9/10 February. ‘Temperatures generally on the colder side of average’ is partly correct, but anomalies for the 1-10 February were generally between -2°C to -3°C below the LTALTA Long Term Average. This is usually defined as a 30 year period by the WMO. across the UKUK The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Europe, off the north-western coast of the continental mainland. It comprises England, Scotland, Wales and Northern Ireland. with Altnaharra recording two consecutive nights with minima of -15.4°C and -16°C, the coldest March nights since 2010.
Summary
The accuracy of NWPNWP Numerical weather prediction uses mathematical models of the atmosphere and oceans to predict the weather based on current weather conditions. forecasts beyond T+120, sometimes T+96 takes a nosedive, so I don’t know why I should think LRF can be in anyway be more than vaguely accurate. My main complaint with it is the lack of consistency in how they’re written, and the fact that the 16-30 day forecast can remain the same for as long as a week at a time, which can’t be right.
