On Tuesday, August 18, 2015 at 9:59:08 AM UTC+1, Dawlish wrote:
On Saturday, August 15, 2015 at 7:05:29 PM UTC+1, Dawlish wrote:
If only t'were January!

**At T240, on 25th August, a large and persistent high pressure system will be located over Scandinavia/Baltic sea. It will lead to one of several types of weather for the UK, depending upon its exact location and orientation, but low pressures will be stalled in their passage across the UK from the west. If the stall occurs with the low centre over the UK, some areas may be experiencing heavy rain and flooding may well result in some areas. If the high is a little further north, dry easterlies will be affecting the UK and if the lows stall further to the west, with the high pressure itself a little further west, warm air from the south will be drawn across the UK.**

Thus, very difficult to predict the UK's exact weather, as a small change in location of the centre of the high could lead to a large change in our weather type, but high pressure will have become firmly established to our NE by the 25th.

Persistent swine, this blocking high, isn't it? All models, including GEM, which has shown a more progressive situation over the last few days, are showing a Scandinavian high still present on the 28th. If this agreement is still there tonight, I'll be forecasting an extension to my forecast for the 25th. (I've always given a gap of three days between forecasts of a similar set-up).

And tonight's output rather scuppers an extension to that forecast. Perhaps a change from the blocked situation is afoot!