SSEN's Weather Watch for April 2018
Winter really dragged on with the March UK mean temperature ending up 1.6C colder than average, making it the coldest March since 2013. The coldest and snowiest weather came in two episodes; at the beginning of the month and again on 17-18 March. More data about March can be found on the Met Office website.
Meanwhile, it was interesting to read an article from Met Éireann regarding a maximum individual wave height of 9.84m measured from M2 buoy on 2 March at 0600 - the buoy is anchored 20 miles east of Howth Head and started operating in 2001.
The map above - from the MeteoGroup - shows the extent of the below average temperatures recorded in March 2018.
Looking ahead to April we predict there will be three different weather regimes. The first will show a significant tendency for low pressure to be focused across western Europe, notably over France, during the first and second weeks of the month. The main temperature anomalies from this will be for well below average values across Iberia and well above average readings across Germany and Poland. The low pressure will help to generate plenty of rain and heavy showers, with the risk of localised flooding in parts of Spain and Portugal. Not surprisingly, sunshine levels will be down and some windy days are expected for western Europe.
There are signs for a change to take place in the third week of the month. High pressure could become the dominant feature on the weather maps for mainland Europe, although still with low pressure for a time in the nearby Atlantic. Overall this means a significant improvement in temperature and sunshine levels, so feeling a lot more like Spring especially with lighter winds. One exception could be along the North Sea coasts, where onshore flows will bring breezes from a colder than average sea surface. Current expectations for day time maximum temperatures: the low 20s Celsius in west London, 18 degrees in Birmingham and Manchester, and 17 in Inverness and Glasgow, perhaps a little cooler with 14-16 more likely in Cardiff, Belfast and Dublin.
The MetDesk map, on the main news page, shows the forecast five-day-average pressure pattern with high pressure over southern Scandinavia and low pressure out in the Atlantic. A warmer, sunnier weather type should cover most of mainland Europe for the period 17-21 April.
There is low confidence for the last week of the month, but we think the most likely scenario is for the low pressure in the Atlantic to slide south and east once more. This would bring above average rainfall to parts of the Mediterranean and a drier trend for Scotland and Norway. Temperature levels may start to dip again, after a taste of early summer for some places in the previous week.
Overall for April for the UK and Ireland, the temperatures should finish near average, perhaps above average in southern England, sunshine levels will be below average despite a sunnier interlude in the third week.
We’ll be back in a few week’s time to look at the prospects for May.
For more weather information you can follow our senior meteorologist, Simon Cardy on twitter @weather_king.