Highest temperatures and rainfall over the weekend

23 08 2015

Over the past 24 hours the weather has delivered a mixture of hot sunshine, thunderstorms, hail and heavy rain as we highlighted earlier in the week.

As expected, sunny skies and warm air being pushed northwards from the continent allowed temperatures to climb across central and eastern parts of the UK, reaching maximums in the high 20s and low 30s on Saturday with a humid feel:

Table showing Maximum temperatures for Saturday 22 August 2015

Location Maximum Temperature in C
Gravesend 30.9
Kew Gardens 30.9
Heathrow 30.7
St James’s Park 30.7
Northolt 30.6

These high temperatures set off two areas of thunderstorms, one over central southern England and another over the Midlands, moving into northern England. These storms caused localised surface water flooding and flooding of some properties in North Yorkshire as up to 30mm of rain fell in an hour. There were also impacts to the York-Leeds rail line.

Across the northwest of the UK it was fresher and mainly dry with some sunshine, while the areas in between were rather cloudy with some rain.

Overnight, the heavy, thundery downpours continued to move northwards, while heavy rain also spread into western parts of the UK. By this morning at 10am the rainfall totals for the 24 hours were as follows:

Table showing rainfall totals for the 24 hours up until 10am on Sunday 23 August 2015

Location Rainfall in mm
Bramham 62.6
Ryhill 54.6
Tredegar 40.6
Linton-on-Ouse 39.8
Scolton Country Park 36.8

During today, the heavy rain has continued to spread north and eastwards with a mixture of sunny spells and heavy showers following across the south. Ahead of this, temperatures across eastern England have again peaked in the mid to high 20s.

Table showing rainfall totals bwtween 10am and 4pm on Sunday 23 August 2015

Location Rainfall in mm
Hereford 20.8
Llanbrynmair 20.4
Sarn 17.8
Lake Vyrnwy 17.2
Porthmadog 17.2

The changeable weather will continue as we head into next week. Met Office National Severe Weather Warnings have been issued and everyone is encouraged to keep up to date with forecasts and warnings over the next few days and to make plans accordingly.





Summer downpours on the way

11 08 2015

The weather forecast for later this week is presenting a challenge for our meteorologists.

All the ingredients are present to produce significant rainfall on Thursday and Friday, but complex interactions in the atmosphere make it difficult to say with certainty where the rain will be most intense.

An area of low pressure is expected to develop and push north across the Bay of Biscay and western France on Wednesday night and into Thursday, arriving across southern England on Thursday morning. As it comes north, very warm air over the continent is expected to be drawn into the low pressure’s circulation, making it feel very humid across central and southern areas of the UK

Fri1400z

Forecast pressure chart valid for 1am on Friday showing the location of the low pressure system over the southeast of the UK.

Warmer air can carry more moisture, and as such some very heavy rain is possible. However, this type of situation is difficult to forecast accurately a few days ahead and there is some uncertainty about which areas will see the heaviest rainfall. Current indications are that central and southern England and Wales are most likely to be affected. We may also have hail and thunder, this is most likely early on Thursday and then again Friday afternoon.

As we have already seen this summer, this type of weather situation has the potential to cause sudden, localised surface water flooding and hazardous travelling conditions.

Met Office National Severe Weather Warnings have been issued and these will be updated over the next few days as confidence in where and when we will see the heaviest rainfall increases.

Looking further ahead, the whole system is expected to clear away to the east during Saturday, with drier, fresher weather following to all parts with some sunshine.





One metre of rain to fall in the Bay of Bengal

29 07 2015

Parts of the Ganges Delta have already seen over 240mm of rain in just 24 hours and coastal areas to the north of the Bay of Bengal are expected to receive over 1000mm over the coming 48 to 72 hours. The area will also see some strong winds, with gust of up to 60mph along the coast. This severe weather is likely to have significant impacts with a risk of flooding, landslides and damage to infrastructure.

Satellite image of monsoons over Pakistan, Bay of Bengal, and South China

Satellite image of monsoons over Pakistan, Bay of Bengal, and South China

After a break in monsoon rainfall across parts of India through much of July, the region is now experiencing a more active phase. Over the Bay of Bengal, a deep monsoon depression has developed, bringing a period of prolonged heavy rain and strong winds to coastal districts of northeast India, Bangladesh and northwest Myanmar. A monsoon depression is an area of low pressure which brings intense rainfall, and with other ingredients in place, can develop into a tropical cyclone.

The monsoon depression is expected to remain slow moving, tracking into Bangladesh over the next few days before gradually moving west across northeast India over the weekend.

Unusually, this is one of three monsoon depressions affecting South Asia. As well as the monsoon over the Bay of Bengal there is a monsoon bringing heavy rainfall to northwest India and Pakistan with as much as 430mm of rainfall falling in 24 hours. A third slow-moving depression is also affecting northeast Vietnam and southeastern China. 543mm 718mm has fallen in 42 66 hours in Mong Cai City on the border between Vietnam and China, an area that was affected by Tropical Storm Kujira last month.

Elsewhere in the world, the hot dry conditions which have affected southern Europe through much of July have led to some wildfires in Catalonia, Spain, and the Provence region of France. There is expected to be some respite from the high temperatures across Spain and France though in the coming days as a cold front pushes in from the north bringing a risk of heavy showers and thunderstorms to northeast Spain and Southern France by the weekend.

 





A brief spell of heat and thunderstorms

11 06 2015

Southern parts of the UK can expect some very warm and humid conditions on Friday, along with an increasing risk of some heavy, thundery showers.

Partial thickness values from the Met Office Global Model for 1200Z Friday 12 June

Partial thickness values from the Met Office Global Model for 1200Z Friday 12 June

Isolated thunderstorms are possible from Thursday, but they will become more likely and potentially more severe by Friday afternoon, with some locally torrential downpours possible, especially for parts of southeast England. A yellow warning has been issued for heavy rain. There is the potential for large amounts of rain is a short space of time, and this could lead to surface water flooding, but as is the case with showers, some places will stay dry. We are also likely to see frequent lightning, and hail is possible in places – as we saw last Friday.

Away from the south, there will be sunshine for many, though it will be cloudier with a little light rain in the far north.

Into the weekend, temperatures will take a tumble across much of the country. Saturday will see a band of rain across central areas, with occasional brighter spells either side. The rain will become increasingly light and patchy by Sunday with drier conditions developing for many. It will feel noticeably cooler though, with the return of some chilly nights.

Partial thickness values from the Met Office Global Model for 1200Z Sunday 14 June

Partial thickness values from the Met Office Global Model for 1200Z Sunday 14 June

With many people out and about at this time of year including at the Isle of Wight and Download festivals, we should be prepared for all types of weather over the next few days, from humid to cool and from rain to shine.





Why are we now seeing colder weather across the UK?

16 01 2015

Over recent weeks, we have spoken about the very strong jet stream across the Atlantic, driving areas of intense low pressure towards the UK. This has bought spells of very wet, windy but relatively mild conditions to the country.

As many of you would have noticed, although the wind and heavy rain has eased, there is now a colder feel to the weather, both by day and night. But what has caused this change in the weather?

Once again the change is down to the jet stream. It has weakened and its track has moved further south, keeping the deep low pressure systems away from our shores. However, now the UK is to the north of the jet stream we are on its cold side, and this has allowed colder weather to feed in across the country.

Current jet stream

Current jet stream across the Atlantic

So what does this mean for us?

As we look ahead into the weekend and next week, the cold weather looks likely to continue. Daytime temperatures will be near or below average and there will be some frosty nights, as temperatures fall below freezing in many areas. We’ll see some sunny spells around and there will also be showers or longer spells of precipitation in places, giving a mixture of rain, hail, sleet or snow, which may settle in some areas.

Because of the threat of wintry weather over the coming days, we encourage everyone to keep up to date with the latest forecasts and national severe weather warnings and to stay weather aware this winter by following the Met Office on Twitter, Facebook, Google+ and YouTube for the latest weather information. You can find information about how to prepare for every aspect of the winter season at Get Ready for Winter.

As we head towards the latter part of the month, we can see some indications that milder weather may return, but there is considerable uncertainty about this so far in advance.





Thunderstorms bring intense rainfall to parts of England

28 07 2014

This morning has seen some intense downpours across parts of south east England.

They developed across parts of East Anglia in the early hours of the morning, with further areas of heavy showers across Sussex, Surrey, Kent and the south of London following later.

The showers were very heavy in places with thunderstorms, hail, and torrential rain reported, giving high rainfall totals and localised flooding in some areas.

The high rainfall totals were caused by an area of low pressure and a plume of warm air that moved in from the near continent accompanied by light winds, meaning that the showers were slow moving.

Several spots have seen more than half of their average monthly rainfall for the whole of July in just one hour.

Below you can see some of the highest recorded hourly rainfall totals from Environment Agency rain gauges through the morning of Monday 28th July 2014:

Great Dunmow Essex 43 mm (4am to 5am)
Isfield Sussex 37 mm (8.30am to 9:30am)
Ardingly Sussex 35 mm (8.30am to 9:30am)
Santon Downham Suffolk 33mm (4am to 5am)
Weirwood Sussex 28 mm (9am to 10am)
Northolt London 20mm (7am to 8am)

 

The band of showery rain is now easing, but a yellow warning for rainfall remains in place for the south east of the UK as the risk of seeing some further isolated downpours remains.

In addition, the far south east of England could see further persistent and perhaps locally heavy rain later today and overnight, with parts of Kent and Sussex most at risk. Conditions across all areas should then improve through tomorrow.





Rain totals for 19th July 2014

20 07 2014

As forecast there were severe thunderstorms across the UK on the 19th July bringing heavy rain and gusty winds. See the tables below for the largest rain totals across the UK.  Gloucestershire recorded the highest rainfall with 66mm between 6am and 6pm yesterday, the counties monthly average rainfall is 60.6mm.

The Heat-health watch put in place in parts of southern and eastern England in conjunction with Public Health England has now been downgraded. Temperatures in parts of the area covered topped 28C during 19 July, see table below.

Today, 20 July, temperatures are expected to reach low to mid 20’s across central, south and south east of England, with London seeing around 27C.  Northern England will reach mid to high teens and Scotland and Northern Ireland mid to low teens.

More thundery downpours are expected to develop today over some eastern and central parts of the UK.  A yellow, be aware, weather warning for rain is in place for the areas likely to be affected. Not everywhere will see a storm but where they do occur, torrential downpours are possible with lightning, hail and strong gusts of wind. The areas most likely to be affected are across eastern and southeastern England.

Many places will have a good deal of fine and very warm weather this working week although there is the risk of some heavy showers in parts of the south and west later in the week.

 

UK MAX TEMPERATURE 19 JULY 2014
TIME SITE NAME AREA MAX TEMP (Celsius)
16:22 London St Jamess Park GREATER LONDON 28.5
15:13 Northolt GREATER LONDON 28.4
15:22 Heathrow GREATER LONDON 28.3
15:59 Santon Downham SUFFOLK 28.3
13:29 Gravesend, Broadness KENT 28.1
16:51 Cambridge NIAB CAMBRIDGESHIRE 27.7
15:49 Marham NORFOLK 27.7
13:55 Hampton W Wks GREATER LONDON 27.6
16:52 Writtle ESSEX 27.6
14:51 Frittenden KENT 27.5

 

 

12hr UK RAINFALL 19 JULY
SITE NAME AREA PRECIP. (MM)
WESTONBIRT GLOUCESTERSHIRE 66.0
PERSHORE COLLEGE HEREFORD & WORCESTER 36.4
PERSHORE HEREFORD & WORCESTER 30.8
NEWPORT (SALOP) SHROPSHIRE 29.4
KEELE STAFFORDSHIRE 28.2
ASTWOOD BANK HEREFORD & WORCESTER 27.6
NOTTINGHAM, WATNALL NOTTINGHAMSHIRE 26.0
LIBANUS POWYS 25.8
NANTWICH, REASEHEATH HALL CHESHIRE 22.6
MARKET BOSWORTH, BOSWORTH PARK LEICESTERSHIRE 22.6




Saturday’s squally weather and reports of tornadoes

27 01 2014

On Saturday we saw a number of heavy rain showers group together in what’s known as a ‘squall line’ – a narrow band of thunderstorms, intense rain, hail, and frequent lightning accompanied by brief but very strong gusts of wind and possibly tornadoes.

Radar image showing the narrow band of showers moving across the UK.

Radar image showing the narrow band of showers moving across the UK.

This squall line swept across Wales and then moved south east across southern parts of England – bringing about 6mm of rain to places in a very short period of time with gusts of wind of around 60mph or more in places.

It  also had the characteristics of a cold front, with the temperature ahead of it being around 11°C, falling to 7°C once the squall line had passed.

There have been reports of possible weak tornadoes from some locations, however it’s hard to verify them without pictures or footage because these features are generally too small to be picked up by satellites or weather observation equipment.

It’s also worth noting that squally winds can often be mistaken for tornadoes because these gusts can be sudden and strong – potentially causing very localised damage.

You can see more information on tornadoes and how they form on our website.





Stormy weather in the Mediterranean

15 11 2013

The central and western Mediterranean will experience very unsettled conditions through the weekend and next week.

Very heavy rain is expected to affect the northeast of Spain, southern France, the Balearic Isles, Corsica, Sardinia, Italy and the Adriatic facing Balkan nations as the very unsettled conditions move slowly east through the region.

Rainfall totals could be as high as 250mm in places, with a risk of up to 200mm in 24 hours. The average rainfall for November in this region is between 50mm and 100mm.

The rain will be associated with thunderstorms which could also produce hailstorms, very strong gusty winds and the possibility of tornadoes in a few places.

Storms developing over the western Mediterranean

Storms developing over the western Mediterranean

In addition to the rain, very strong winds are expected through the central and western Mediterranean, with widespread gales and a risk of storm force winds for a time. This will lead to rough seas that could pose a threat to shipping in the region.

There is also the risk of strong or gale force southeasterly winds affecting the Adriatic during Tuesday and Wednesday next week. These strong winds, combined with very heavy rainfall across the Venice region over the next few days could bring the risk of flooding in Venice.








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