21 Aug 2014

Bank holiday weather: rain or shine?

The final bank holiday of the year is approaching and it’s likely to be a busy one with many schools still in the midst of the summer holidays.

Bank holidays are never a favoured time amongst us meteorological folk, as there is an added pressure not only to get the forecast spot on, but to wishfully conjure up some sunshine and warmth.

August so far has been disappointing, relative to the first two months of summer. In the first 13 days of the month, the UK had received almost all of the rainfall that would be expected for the whole month. 

rainbow_summer_g_wp

Even though this is undeniably wet, what you might be surprised to hear is that statistically, August is the wettest summer month in the UK.

Across the UK, 89.5mm of rain would be expected in a typical August, compared to 73.4mm and 78.1mm in June and July respectively.

On average, August is even wetter than February in the UK – a month that normally has 88.6mm of rain.

Jet stream position

The reason for the change from a settled to unsettled theme in August has been the position of the jet stream, the fast-moving wind high in the atmosphere that determines our weather at the surface.

jetstream_BHMon_WZ_wpDuring June and July, it spent much of the time to the north of the UK, steering low pressure and rain towards Iceland and northern Scandinavia, leaving us under the influence of high pressure.

However, through August, the jet stream has been over or south of the UK, directing areas of low pressure across us.

Unfortunately, the jet stream looks set to be over or to the south of us for the next two weeks, meaning that the changeable weather is going to continue.

It won’t be a washout though, as the jet stream is going to have bursts of activity. This means that the arrival of low pressure systems will be intermittent, with ridges of high pressure bringing temporary drier, brighter spells, punctuating the cloud, wind and rain.

Bank holiday weather

The main message about the weather this bank holiday weekend is that it is going to be mixed, with no two days the same for most places.

Saturday will be a bright, breezy and cool day with sunshine and showers. The heaviest, most frequent showers will be across Scotland and eastern parts of England. Elsewhere, there’ll be longer drier spells with more in the way of sunshine.

lowpressure_BHMon_MO_wpSunday will be a fine day for most with spells of sunshine – the best of which will tend to be in the morning, before cloud bubbles up in the afternoon. Later in the day, cloud, wind and rain will arrive across Northern Ireland, Wales and south west England.

Monday will be the most unsettled day of the bank holiday, with low pressure bringing a wet start to many places, before sunshine and showers follow from the west through the day.

Don’t forget, you can get the latest forecast on the Channel 4 Weather website. I’ll also be posting updates on Twitter – @liamdutton

Tweets by @liamdutton

One reader comment

  1. Andrew Warren says:

    Last bank holiday of the year? Oh no! They’ve cancelled Christmas and Boxing Day.

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