Issued at 0830 Tuesday, 4 August 2020
Warmer and more humid air will extend northwards later this week as previous fronts clear away. Although pressure will build for a few days, there is a chance of local thundery showers forming over the weekend, but very hit and miss. During next week, high pressure is likely to gradually give way to a thundery low becoming located to the southwest of Britain, although the timing is uncertain.
Tuesday: Cloudy, becoming mainly dry
Patchy rain this morning will fade out to leave the rest of the day dry, although mainly cloudy. Winds strengthening, to southwesterly 20-25mph later in the day, possible stronger gusts this evening. Max 17C, dropping only marginally to 14 or 15C for a humid night.
Wednesday: Risk of rain early and late, much of day dry
Pulses of rain are likely to encroach in from the northwest as a front pushes southwards tonight, this may be around first thing on Wednesday morning for a few hours, giving a couple of mm most likely, before the front then wriggles back north and breaks up for a time. Low cloud across the hills, but much of the middle of the day should be dry with some brightness. A risk of pulses of rain returning from the southwest later afternoon or evening, with the odd heavy burst possible as the front finally pushes through, with another 2-3mm if this develops. Winds southwest 15-20mph. Max 19C, humid.
Thursday: Warm, cloud breaking
Early low cloud and pockets of drizzle will fade in the morning to leave skies brightening with some sun coming through and the rest of the day generally dry. Warm and humid with light southerly winds, max 23C, staying up around 16C into the night.
Friday: Hottest day of week
Most likely dry throughout. Any early mist soon gone to leave mostly sunny skies. Light southerly winds, rising to 26C by afternoon. Chance of a late thundery burst of rain coming up from the southwest by evening into the night, but very hit and miss.
Weekend: Generally dry, sunny
Generally dry, but less hot. A good amount of sunshine and light winds. Temperatures 20 to 22C by day, and 11 to 13C overnight. Small risk of a thundery pulse of rain drifting up from south late Sunday.
Next week: Rain likely to develop
Likely to start generally dry, as high pressure stays around across Britain. However, as low pressure drifts gradually up from the south, it is likely to give way to bursts of rain. The timing of this change is very uncertain at present, but the general view of becoming frequently wet for a spell into mid-August is the more likely pattern at this stage – so favouring a deterioration as the week progresses.