Electricity North West weather watch – May
Electricity North West weather watch – May
After seven named storms during the winter, with many hitting the North West and keeping us busy making sure we get the lights back on quickly, is this the end of the bad weather?
This week we all enjoyed the hottest May Bank Holiday on record, but is this nice weather here to stay? Let’s find out from MeteoGroup meteorologist, Stephen Davenport.
A look back
The broad pattern that brought a cold March to the North West continued into early April with unusually chilly conditions up to the 5th April. Daytime temperatures were depressed significantly below average and only improved a little until a more significant warm-up mid-month.
On April 2nd a keen easterly wind brought a mixture of cold rain and snow, chiefly above about 100m. A few slushy centimetres settled just above that elevation while higher locations over the Fells and the North Pennines accumulated 5cm of snow or more with some drifting. Given the marginal rain/snow conditions there were also a few reports of ice pellets and freezing rain but of too short a duration to bring line icing risks.
There was a lift in temperatures on April 3rd and 4th, sneaking into double figures in some locations, but that was short lived with cold air returning through the afternoon and evening of 4th April to turn a wet day into a sleety or snowy one, even at lower levels. The night became frosty and icy ahead of sunshine on the 5th, then changeable and less cold weather for a week or two but with temperatures no better than seasonal.
So what caused this extended wintriness? A weakened jet stream looped southward which forced low pressure systems farther south than usual, often towards France and South West Europe. With high pressure over Scandinavia occasionally extending a ridge westwards there were often easterly winds across northern England, so although the worst was over there was nothing approaching “warm”.
If you thought that the early spring was too wintry in the North West then spare a thought for Canada and the eastern and northern USA, where frigid air got locked in for weeks at a time.
As low pressure systems deepened in the mid-Atlantic this bolstered developing high pressure downstream across Europe after mid-month and the weather changed significantly. It sent a surge of warm air northwards and temperatures lifted to the low 20C at times between April 18th and 22nd with a few thunderstorms around. Cooler, unsettled weather returned through the last week of the month.
A look ahead
We all enjoyed a warm start to the month, but an unsettled and cooler period will follow through mid-month but with temperatures most likely near seasonal.
For later May there are recurring signals for high pressure to settle across the region for the second half of the month, meaning it’ll warm up again. That high pressure ridge looks most likely to edge a little farther north as we go deeper into May, so that by the end of the month there’ll be an easterly or south-easterly flow of winds coming around its southern flank across the North West. That’s a pretty favourable direction for some decent dry and warmer weather before the end of May and potentially into June.
This blocked pattern might still be reflecting the circulations set in train by the late winter. The effects of the tropical Pacific Ocean are far reaching as well, with the change from La Niña to neutral conditions affecting conditions far and wide. This “teleconnection” also looks like it has some predictive merit and suggests the high pressure dominance through later May that forecast models currently predict.