The meteorological summer forecast 2016 is based upon past, present and projected SSTA (sea surface temperature anomaly) atmospheric conditions and ENSO (El Nino Southern Oscillation).

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Background

Following a record tying strong El Nino which peaked in autumn 2015 and profoundly influenced the cold season of 2015-16, there is significantly weakening which will have affect on the summer.

 

Expect to see La Nina conditions develop late summer or early autumn 2016.

Despite the El Nino being thousands of miles from Europe, there’s no disputing it’s significance globally by reshaping the global atmospheric circulation.

Each El Nino can bring differing influence to our global atmosphere depending upon it’s strength and position within the equatorial Pacific. El Nino’s have played a significant role in the UK’s warmest, coldest, wettest and even driest seasons.

Combined with the ENSO, other factors come into play including SSTA’s of the Atlantic as this can influence rainfall distribution and position of high’s and lows.

There’s no question, we’ve seen a cool, wet West and warm East this spring across Europe so far, reflective of the El Nino and strong stratospheric warming episode during March. This drew me to the conclusion mid March that April was likely to be cooler than normal.

The El Nino likely contributes to the behaviour and strength of the polar vortex. During early winter it was record strong and therefore it was no coincidence that this coincided with the peaking of the El Nino and record warmth throughout the hemisphere. When the PV is weak and the stratosphere is warm, like it’s been, cold weather significantly influences the mid latitudes.

The peaking of the El Nino, record strength of polar vortex all led to a strong, zonal jet stream which washed the mid latitude continents in warm oceanic air.

During springtime, if you have the El Nino in a weakening state, you often get cooler springs with stratospheric warming events. Weakening El Nino episodes during late winter often present very cool March through May periods and 2016 is no exception.

Past weakening El Nino’s during springtime bring this 500mb height anomaly.

Check out the striking similarity to the above and the temperature anomaly profile for globe and Europe during April 2016.

The cold conditions have come with snow, making for great late April ski conditions for the Scottish Highlands and parts of the Alps.

I managed to reach the summit of Cairngorm on Thursday 28th April only to endure mid winter conditions with -16C wind chill and a very ice encrusted weather station which earlier in the week reported wind chills of -20C.

So, strong El Nino’s which peak during late autumn and weaken during the second half of winter usually bring mild, wet winters and cold springs but what about summer?

Based on past El Nino to La Nina transition summers including recent and long term past, they all point to one thing. Negative AO/NAO and below normal heights over UK and Western Europe.

Transition years between 1900-1948

1950 till now.

Notice the current -NAO. I’m afraid these Nino to Nina transition summers do tend to favour a -NAO.

So a cooler summer overall?

June-August Breakdown

Given all factors the 90-day June-August 2016 period suggests at least average to slightly below average temperatures for the UK and Ireland.

For southern, central and eastern Europe, I believe it’s another warm, dry summer though not as extreme as 2015 and for Spain and Portugal, this summer could see swings of very warm to cool and wet.

I suspect May will present cooler but drier than normal conditions with continuation of a -NAO/AO. Just  short lived ‘teases of summer’ within a fairly active Atlantic flow pattern in which warmth lifts north ahead of approaching lows and cool follows.

June looks slightly cooler than normal overall for UK/Ireland, France and warmer than normal down over Iberia and the Med but we should see a short lived warm spell of perhaps 5-7 days which boosts temperatures widely between 21-26C over the UK.

July should be average both temperature and precipitation wise but like June, I think we should enjoy a 5 or so day (Scotland), 8-12 day (England/Wales) spell of warm summer conditions with temperatures widely 22-28C over the UK but chilly spells which are unusual for July could outweigh this warmth with similar cool conditions to last July.

August looks to be the summer’s coolest and most unsettled month with an active Atlantic flow pattern bringing frequent spells of wind, rain and cool conditions.

Canadian model month by month.

June

July

August

Rainfall wise, I think May, June and July will be close to average but it turns much wetter late July onwards.

Current SSTA’s.

Projected SSTA’s according to CFSv2 for June-August period. Notice how the warmer than normal 850mb pool is positioned over warmer than normal water stacked north of the UK.

850mb temperature anomaly

CFSv2 June through August

2-metre temperature

Precipitation

Be sure to watch the video for more.

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Tags: europe summer 2016 forecast, featured, UK summer forecast 2016