Long Term Pattern Shift Likely In Place As Next Week Looks To Hold ‘Unsettled Theme’

Written by Mark Vogan on May 1, 2015 in Rest of Europe, Spring 2015, United Kingdom & Ireland with 0 Comments

The models are now drawing a much more refined solution to next week with a much more ‘unsettled’ look.

Before we go into the details for next week as well as analysing the bigger picture and what that may mean for later, April, as expected was a warmer, drier and sunnier month for the UK despite the cooler, wetter end.

The UK received just 57% of it’s normal April rainfall with the 5th sunniest overall. Scotland experienced it’s sunniest April on record while parts of the South got just 30% normal rainfall with places receiving less than 10mm.

Credit: Met Office/Crown

I believe this prolonged ‘multi-month’ dry spell, similar to what we saw at the end of winter/start to spring 2012, has ended.

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In the video I look at the GFS and in the below write-up I’ve showed the ECMWF. BOTH show the deepening of low pressure just west of Ireland that will make for a dismal late Saturday-Sunday period, showery with improvement by Monday but another low riding the SE flank of the westward retreating trough will drive more wind and rain into the UK Tuesday if not late Monday.

When stepping back and looking at the big picture, the NAO shows where we’ve came and are potentially going.

nao_sprd2

Look at the dip into the deepest negative of 2015, this brought the return of snow and cold but look where it’s heading, back towards positive, hence the retrogression of the trough right back to where that ridge has been of late and where it was 10 days ago before our warm, settled pattern broke. Notice the model has just a brief positive before returning to negative. We must factor in the weakening of the jet, warming of water, moistening of the ground as the season progresses. Feedback changes and so we must throw these ever changing variables in the mix.

While warmth and sun is making a return within 10 days, the 1-3 week sustained stretch is gone, the pattern, ocean and time of year is different and let’s not forget that the El Nino continues to strengthen.

Here’s the latest ECMWF surface through the next 10 days. The return of warm ridging is certainly delayed by about 24-36 hours off yesterday’s runs but it still shows it coming back.