Good morning. A little late but here is the report on the midnight outputs of the big 5 models for today Tuesday July 30th 2013.
All models show a weak SW flow across the UK with a ripple on a frontal boundary crossing East over Southern britain today while the North sees another showery day. Later tonight the main front attached to the wave over Southern England is shown to move North carrying some rain and more importantly carrying some warm and humid conditions North across England and Wales which lasts through Thursday and possibly Friday too in the SE. This will be accompanied by dry, very warm or even hot conditions for a time with good sunny spells especially on Thursday. Over Friday and the weekend cooler air will be working it's way back East over the UK behind a weakening cold front which could have enough energy to spark some thundery showers for a time in the East and be followed by a mix of sunshine and scattered showers on a SW flow over the weekend. Throughout the week most of Scotland and Northern Ireland miss out on the warmer phase and maintain rather cloudy and cooler conditions with occasional rain.
GFS then shows a dry start for many early enxtw eek under weak High pressure before Low pressure filters back into the UK from the West with showers or rain at times. the SE could again become very warm for a time before cooler and more showery conditions work there way across from the West later next week. Thereafter the operational shows a cooler and more showery end to the run in light winds, average temperatures but with some warm sunny intervals between the showers.
The GFS Ensembles show growing support for two separate warm ups in the South, one later this week and the other around this time next week when temperatures in the SE reach the very warm category. Further north and West the rise is less pronounced or non-exsistent in the far North and here the whole period is marked by occasional rainfall. Further South and East rainfall is also shown mostly in association from showers on each period when the very warm conditions are ended by some heavy shower potential.
The Jet Stream is shown to spend a lot of the output time flowing across the UK from the SW on its way towards Scandinavia.
UKMO today shows a weak High pressure over Northern Germany and another in the Atlantic separated by a trough lying North South just to the west of the UK. the slack South or SW flow would likely give rise to occasional heavy and thundery showers to begin next week in reasonably warm and somewhat humid conditions.
GEM is largely quite similar to UKMO at 144hrs and moves on to maintain a basic and showery slack airflow pattern over the UK with light winds and temperatures near to or a little above normal in any sunshine. If anything the model firms up on more meaning ful unsettled conditions at the end of the run, especially in the South.
NAVGEM shows pressure building across the UK early next week, especially over the North with fine and bright conditions developing here. Further South Low pressure develops over the near Continent and would promote a more showery pattern for Southern Britain in above average temperatures.
ECM today looks largely similar to UKMO as well at 144hrs with a slack pressure gradient over the UK. Not much changes out to the end of the run with no particular pressure feature having overall control. So as usual in these situations a mix of sunshine and scattered showers is the most likely outcome with the chance of a few of these being heavy and thundery as well as slow moving while many other places stay dry with spells of warm sunshine but on balance from this run the South may be more prone to the showers.
In Summary there is still a lot of detail to be pinned down on the events next week and beyond. UKMO, GEM and ECM do offer some consistency at Day 6 with a High to the East and West separated by a trough close to the West of the UK with scattered showers in rather warm conditions likely. Thereafter the longer term outputs support a fairly similar pattern all the way out to their termination in maintaining rather slack conditions over the UK synoptically with sunshine and showers continuing but plenty of dry and warm weather too though it is important to stress that a return to the searing heat of July on a national scale looks unlikely at the moment.
Martin G
Kilmersdon Radstock Bath Somerset