The drought in the UK is over while even France and down into Spain, drought conditions have eased considerably.

In my summer forecast issued back on the 31 March I stated there would be two scenarios which would determine the type of summer season we would likely have here in the UK. One being that if the drought was to continue then I would expect to see a warm or very warm and dry summer with potentially frequent heat wave conditions. The 2nd scenario was that if we had a wet or very wet spring then we would end up with a 50/50 summer of both warm/cool and dry/wet spells or even a slightly below normal summer for temperature thanks to wetter than normal conditions.

So far we’ve had a very wet period really from April 1 through present. During the past winter we remained extremely dry with the NAO holding positive. This meant a trough over the North Atlantic and Greenland while a ridge kept the UK warm and safe from any cold from coming down from the north or east off Europe. The month of February was brutally cold throughout Europe but a firm ridge stretched from the Azores to the Western Isles off NW Scotland meant we were protected. For a 10 day period, the cold pool draped across Europe managed to break through the ridge pushing it north and this brought snow as well as a period of very cold weather to England and Wales.

All in all I believe the effects of the back to back La Nina and the persistent blocking over Britain during the 10-11 winter with increasingly drier conditions meant the persistency of the Azores ridge throughout the past winter.

THE WET SPRING, CAUSED AT LEAST IN PART BY THE ADVANCING EL NINO HAS OBVIOUSLY CHANGED THE WEATHER PATTERN FOR THE REST OF SUMMER 2012 FOR BOTH EUROPE & NORTH AMERICA

Our short term (1-2 years) climate pattern has changed across Western Europe as well as over North America and admittedly what I didn’t see coming was the heavy rains of this spring over the UK which would wipe out our drought. Arguably, the onset of the El Nino could well be blamed on the wet spring and with a wet spring and exceptionally wet soils across the southern UK, this will likely have feedback to the atmosphere, encouraging more lower rather than higher pressure aloft this summer. Despite the wet soils and it’s influence on the atmosphere above, the coming on of the El Nino will likely keep us wetter than normal through July and August. In a likely cool/wet pattern, we may see only 3-4 out of 10 periods from mid-June onwards being warmer, drier as compared to warm/dry and those spells may only last 3-5 days in the North, 5-7 days in the South.

An El Nino redistributes global precipitation in both intensity, frequency and location depending upon it’s intensity. A strong El Nino tends to hold the warmest waters in close to South America, this implies not only a wet but also warm winter for North America as well as Western Europe. As for summer, we here in the UK and NW Europe will likely see a wetter overall summer and with more cloud and rain and that means cooler than normal temperatures. No, it won’t be constantly wet like many papers are saying but the warm spells look short lived.

Eastern North America will continue to see wetter than normal conditions from Texas east to Florida with troughiness likely to be more frequent than ridging or at least the general west-east flow will keep those ridges and troughs moving. A very different summer compared to the last two when recalling the 100-degree weather from Washington DC to New England and sustained and prolonged hot spells in both 2010 and 2011, that won’t happen this year. With the breakdown of the Nina and return of an El Nino which is likely to go moderate, NOT strong means, like we’re seeing now, a progressive North American weather pattern with heat over the Southwest pulsing and it’s north and northeast expansion being supressed by frequent troughs sliding into the Pacific Northwest, Lakes and Northeast will likely produce a normal or slightly below normal summer from the Lakes east.

Tags: el nino influence on north america, europe