http://www.cpc.ncep.noaa.gov/products/people/wwang/cfsv2fcst/htmls/glbz700e3Mon.html
Having altered a little since Gav's video, CFS is now agreeing to a greater extent with the UKMET ensemble mean regarding the summer - the key thing is the persistent signal for the summer to have a better June/July and a less fine August. I strongly believe that month-by-month output is far better than 3-monthly, as most summers tend to be of two distinct halves, so I continue to hope that in the future, more institutions will release month-by-month projections. In my opinion CFS has never recently sided with the Brazillian model, as it's not shown a +ve anomaly to the NW - something it often showed in the run up to the last two summers.
For the first two summer months, there's been a fairly consistent signal for pressure to be higher to the east of the UK, and that's very different to the run up seen during recent years. Sure, the height anomalies shown aren't very strong, but due to the fact that Euro Highs don't tend to get much above 1025mb in summer, it would take an extraordinarily strong signal to produce notable height anomaly predictions there.
Looking at the Russian model's temperature and precipitation anomalies (see Gavin's vid), the temperature anomalies weren't all that easy to derive something from, but the precipitation anomalies show below average totals for the North Sea,Scandinavia and a stretch of the mid-Atlantic, and above average totals across Greenland. To me this indicates a -ve NAO with troughing through Greenland and heights often just east or northeast of the UK - similar to the UKMET and CFS outlooks.
The BBC also shows above average heights to the NE but less to to the east - a more changeable signal for the summer but not nearly as cool as would be suggested by +ve anomalies to the NW. Perhaps the model sees the summer shifting towards a trough across the south more quickly than CFS and UKMET.
So here's my take on what the overall signal from the models is:
Going by the much favoured option of +ve anomalies to our NE and perhaps E, and -ve anomalies to our NW but also across or near to the south, I'm seeing an overall signal for a summer warmer than 2011 and 2012, perhaps considerably so, but not without substantial unsettled spells, these being most prominent later in the summer. June and July have good potential for some fine, warm or even (briefly) hot periods as ridging from the SW interacts with the heights to the NE and/or E, but it seems likely that troughs will tend to develop to our south and drift up into the UK, probably giving a lot of rain in a short period of time. The cold North Sea temps could lead to below average nighttime temperatures. August sees the higher heights tending to locate further away from the UK, leaving us open to lengthy spells under the influence of troughs either from the continent or the Atlantic - perhaps a dire month that drags the whole summer down?
The above would actually mean more of a westerly-driven June and July for the NW in particular, perhaps more continental across the SE, before an unsettled easterly-driven pattern comes to dominate for August.
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