Europe May 2020 Outlook

Written by on April 28, 2020 in Rest of Europe, United Kingdom & Ireland with 0 Comments

April couldn’t have been more different to February for Western Europe with frequent Atlantic lows (active rossby wave train) bringing record rainfall to the UK. This ‘stuck’ pattern was abruptly replaced by only another stuck pattern, a blocked high (stationary wave) which brought 4 straight weeks without a drop of rain for some.

The tap was flowing full force in the first place thanks to an enhanced phase of the MJO over the west and central Pacific. That tap was then switched off becoming one of the UK’s driest April’s due to the MJO finally pushing east replacing it with a suppressed phase which led to slower westerlies and the buildup of pressure.

February 500mb height anomaly

Credit: Simon Cardy

UK February rainfall anomaly

Credit: Met Office

April 1-14th 500mb height anomaly

Credit: Simon Cardy

UK April 1-14th rainfall anomaly

Credit: Met Office

As we depart April, the westerlies over the North Atlantic have restrengthened and the Atlantic flow has returned to the UK. It’s of no coincidence that this shift comes as the MJO heads back towards the maritime continent and expected to return to a west and central Pacific position. This supports an unsettled May to come.

Credit: Michael Ventrice

More Unsettled Doesn’t Mean No Heat!

The AO has been outstandingly positive throughout the past winter but note it went neutral, aided by the final weakening and split of the polar vortex but is expected to return to positive into May.

The NAO, coinciding with AO was persistently positive from Jan 1 through March 20 then shifted negative (dry, high pressure pattern) and while neutral now, it’s forecast to go back positive.

This suggests an unsettled Atlantic setup but with a good likelihood of 2, perhaps 3 Spanish plume events pumping heat north through France, Low Countries up into the UK and Ireland which could make for an overall warmer than normal month.

The CFSv2 sees the low pressure dominated pattern for May.

500mb height anomaly for May

Credit: Tropical Tidbits

Distinctly wetter than normal.

Credit: Tropical Tidbits

Interesting to see the model average to just slightly above average.

Credit: Tropical Tidbits

FEATURED IMAGE CREDIT: Anthony Chalmers @ProfAJChalmers

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