Updated 13th August - Covering the period 20th August - 11th September
It is expected to continue warmer than average overall, with positive temperature anomalies ranging from under 1C in Northern Ireland to near 2C in eastern England, with most regions about 1.5C above.
Rainfall totals are expected to be below normal with most regions only having roughly half of the normal rainfall amount for the period. Parts of central, southern and eastern England will be especially dry, but central and eastern England will also be prone to localised thundery downpours in late August which will raise rainfall totals near or above average locally.
Sunshine totals are expected to be 20-30% above average over much of England and Wales and south-eastern Scotland, but for much of the rest of Scotland and in Northern Ireland only small excesses of about 10% are expected, and parts of northern and western Scotland may have only near average sunshine.
This week will have a north-south split in the weather, with high pressure often ridging into southern parts of Britain from the Azores and extending towards southern Scandinavia, but westerly winds will remain dominant across Scotland, especially the northern half of Scotland. Frontal systems will cross the British Isles on several occasions but rainfall amounts from these fronts are expected to be small, especially over much of England. There is potential for one or two thundery outbreaks over central and eastern parts of England, most likely around the middle part of the week, which may locally raise the rainfall totals, but the thunderstorms will probably be well-scattered with some places missing them altogether.
Mean temperatures are expected to be close to the 1981-2010 long-term normal in western Scotland and in Northern Ireland and some counties bordering the Irish Sea, but generally above normal elsewhere, with positive anomalies of 1 to 2C typical over much of England, south and east Wales, and also eastern Scotland. With predominantly westerly and south-westerly winds, counties bordering the North Sea and also East Anglia may see positive anomalies in excess of 2C.
Rainfall totals are expected to be below normal for most regions but in many central and northern parts of Scotland they may be close to normal, and they will locally be above normal in the areas that pick up localised downpours midweek.
Sunshine totals are expected to be near or rather below normal over much of Scotland and Northern Ireland, although above average sunshine is most likely for south-east Scotland. For much of England and Wales this week will be sunnier than average, though probably not exceptionally so.
The general north-south split pattern is expected to continue for the most part, but early in the week there is a significant chance of high pressure ridging further north bringing more widespread warm (possibly hot in places, especially towards the south-east) and sunny weather for up to a few days. Again a thundery breakdown is possible during the second half of the week as we see cooler fresher air head in from the west, albeit probably still with relatively high pressure towards the south, but confidence is low on the extent of thunderstorms.
Apart from this, rainfall amounts are again expected to be low for most parts of the country in spite of fronts crossing the country at times, particularly in Scotland. All regions will be warmer than average, but probably by less than 1C in Northern Ireland, while many parts of England will be 2 to 3C warmer than average. Sunshine is expected to be above normal except in northern and western Scotland, though probably not exceptionally so.
I expect that this period will start off quite unsettled with westerlies and relatively low pressure, particularly in the north, but that high pressure will soon build again from the south, bringing a spell of settled weather for much of the country. Although sunshine amounts will be sensitive to the positioning of the high pressure, as low cloud tends to be slower to burn off this late in the season, the odds favour above average sunshine for the majority of the country, and rainfall totals will be below normal again, this time especially for western parts of Britain. Temperatures will be near average to fairly cool early in the period but will soon rise above the normal again as the high pressure builds, and so for much of the UK the most likely outcome for this period is temperatures coming out 1 to 2C above the 1981-2010 normal.
Monthly weather forecast
The month ahead forecast, written by Ian Simpson is updated once a week - every Monday. As with any longer term forecast, it's not possible to go into much detail and accuracy can tend to drop off toward the end of the period but it can still act as a very good guide to the weather during the upcoming month.