July 12…What’s To Be Expected?…

3 Jul

Well there goes one summer month, that’s if you can call it a summer month and clearly June has gone down in the record books for various reasons, most particularly in terms of precipitation.  I’m sure many were expecting that after the scenes and pictures from various areas of the UK over the last number of weeks, as low pressure brought persistent rain and flooding to parts of NW England and Cumbria and then also the severe thunderstorms late in the month.  Overall quite a month, clearly not for the right reasons, but a month which all the medium and long-range models highlighted would be unsettled and clearly it was…

Early July is up and running and as you may have gathered from the shorter range forecasts and information, a change of month hasn’t brought a change in the weather and unfortunately I don’t expect any changes in the near future;

Throughout the first half of July I expect and predict that the predominantly unsettled synoptic pattern will continue.  The broader synoptic pattern is likely to maintain a trough across the UK, whilst higher pressure is dominant across Eastern Europe and more importantly to the North-west of the UK.  As we have experienced for numerous weeks now, high pressure to the North-west of the UK in summer is never a good place for it to be.  The importance is that it is likely to maintain the trough and unsettled conditions across the UK and there is little signs of this pattern, which has been evident for numerous weeks, changing.  This can also be seen within the latest ECMWF and GFS ensemble mean charts;

Both charts have a marked trough of low pressure across the UK, with pressure generally higher to the North-west of the UK and also across more Eastern Europe where it has been for weeks.  Note as well, the usual summer-related main Azores high pressure continues to be held well to the south-west of the UK, with little or no sign of this influencing the weather across the UK as July progresses.  The persistence of the predominantly cyclonic conditions is also represented well within the latest GFS ENS atmospheric pressure graph, randomly selected for Central areas of the UK (Northern England);

 

That really is quite a shocking prediction at the moment with also relatively good, if not very good ensemble model agreement that up to the 18th or 19th of the month at least, the atmosphere pressure is unlikely to get above 1020mb, which for the time of year, is again, shocking. You can also clearly see that directly associated with this signal for relatively low pressure is the consistent signal for precipitation across the bottom of the graph as well throughout the forecast period, which continues to support the likelihood of further precipitation, some of which could be significant at times as well, not just across Northern and Western areas of the UK, but also across Southern regions too.

So in summary, I have quite high confidence to suggest that the first half of July will continue (unfortunately) in the same pattern that we have had to endure throughout June.  Low pressure is set to dominate and as a result further relatively cool conditions are forecast with perhaps some additional large rainfall totals at times depending on the specific events and details as the next few weeks progresses.

So, what about the second half of July?…Any potential changes?…

Unfortunately, at the moment I don’t envisage any significant changes;

Given the time frames involved then clearly confidence levels do drop away, but what I do expect is further unsettled and cyclonic conditions to continue after mid-month as well, at least for a time.  I have highlighted this as an issue in some of my previous blogs and that is particularly during the summer, long-term pressure trends become insignificant and weak given the nature of the weather during the summer and at the moment that is the case for say the final 7 to 10 days of July.  As a result the far end of July may well begin to see a pattern change.  It is often a time for the broader synoptic pattern to change if it has been ‘stuck in a rut’ for a long time, so as a disclaimer please acknowledge the above image with some open thought and also hope that the final week or so of July may begin to see a change to something warmer and more settled.

So in summary and it doesn’t bring me any joy to highlight this, but the first half of Summer 2012 looks to be a complete washout with the first half of July now expected to be unsettled and predominantly cool.  The second half of July may well maintain these unsettled conditions, particularly for at time after mid-month, before perhaps changing at the end of the month.  Clearly however, overall July may also now turn out to be quite poor as well, particularly if 2 or 3 of the 4 weeks of the month do end up being predominantly unsettled.

As ever, all thoughts and comments are welcomed and as usual I’ll review the first half of July mid-month and also take a closer look at the second half of the month and into early August…Here’s hoping by then there is something on the horizon in terms of summer-like weather, as clearly these weeks and months are ticking by!.

Regards to all,

M.

 

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