Wet weekend for parts of the UK

12 11 2015

Heavy rain is expected across parts of north Wales, northwest England and southwest Scotland on Saturday into Sunday, clearing to the southeast on Monday.  We have issued a yellow weather warning for rain for these areas, while the Environment Agency, Natural Resource Wales (NRW) and the Scottish Environment Protection Agency (SEPA) are assessing the potential flood risk.

A slow moving frontal system is bringing moist tropical air across the UK from the west resulting in some heavy and persistent rain, especially over exposed hills.  Parts of the warning area could see 70-100 mm of rain, with some of the more exposed parts of north Wales and northwest England possibly seeing as much as 150-200 mm through the period.

Pressure Chart 15th November 2015

Pressure Chart 15th November 2015

The Environment Agency is concerned that this amount of additional rainfall falling on to already saturated ground could well lead to flooding, either from standing water, or from rivers bursting their banks. Flood warnings have been issued for parts of northern England.

NRW are planning to put flood risk management procedures in place if required and will issue Flood Alerts and Warnings if rivers reach trigger levels. The warnings are updated on the NRW website every 15 minutes.

The warnings will be kept under review and adjusted should the weather system change or develop and potential impacts vary.

Is the first officially named storm heading towards our shores?

6 11 2015


Storm Abigail has now been officially named and is expected to bring winds in excess of 80mph across the far north of the UK on Thursday evening into Friday and has the potential to cause some disruption. You can find out more here

Original blog from 6 November 2015:

Headlines in some newspapers are suggesting storms at the weekend will be the first officially named storms of the winter.

Currently the Met Office and Met Eireann have not issued severe weather warnings for the strong winds this weekend, and we have not named the storms heading towards the UK and Ireland.

However we are continuing to monitor the developing weather situation, and will let everyone know when any storm is officially named.

We are expecting unsettled weather this weekend, with spells of rain and strong to gale force winds at times.

The current forecast is for southern parts of the UK are expected to see the strongest winds on Saturday with 40-50mph gusts along parts of the south coast of England.

Meanwhile during Sunday into Monday the north and northwest of the UK is likely to experience the windiest conditions. Here gusts of 50-60mph are possible.

You can keep up to date with the latest forecast and warnings on our website.

Cyclone Chapala brings flooding rains to Yemen

3 11 2015

Our blog yesterday reported on the imminent landfall of Cyclone Chapala which was located in the Gulf of Aden. As expected the cyclone made landfall over Yemen in the early hours of Tuesday UK time. Winds averaged over one minute were estimated to be near 75 mph at landfall which is equivalent to a category 1 hurricane.

However, it is the rainfall which poses the biggest threat. The coastal strip of Yemen is usually very dry with approximately 50mm (2”) rain per year. Chapala is likely to produce 100-200mm widely and as much as 500mm in some locations. Although Chapala has weakened to a tropical storm it has become very slow-moving near the coast which increases the threat from heavy rainfall.

Cyclone Chapala at 0715 UTC on 03 November 2015 Image courtesy of NASA

Cyclone Chapala at 0715 UTC on 03 November 2015
Image courtesy of NASA

Observing stations are few and far between in this part of the world, but images and videos being posted in online media indicate that flooding is occurring in populated areas under the path of the cyclone such as the city of Al Mukalla.

The last time heavy rains from a tropical cyclone occurred in this region was 2008. This event caused much destruction and loss of life even though it was only classified as a tropical depression. Cyclone Chapala was a much stronger cyclone and thus has a much greater potential for disruption and damage.

Given the disruption caused by Cyclone Chapala, there is heightened interest in an area of disturbed weather developing to the west of India. This has the potential to develop into a tropical storm and latest forecasts suggest it will move west across the Arabian Sea. It is too early to be sure about the likely intensity and precise track of this disturbance, but it is being watched closely for further development.

Image of Arabian Sea at 1130 UTC on 03 November 2015 Image courtesy of US Naval Research Laboratory

Image of Arabian Sea at 1130 UTC on 03 November 2015
Image courtesy of US Naval Research Laboratory

Official warnings for the latest tropical cyclones in the Arabian Sea are produced by the India Meteorological Department. The Met Office routinely supplies predictions of cyclone tracks from its global forecast model to regional meteorological centres worldwide, which are used along with guidance from other models in the production of forecasts and guidance. We also provide updates on current tropical storms via @metofficestorms on Twitter.

Cyclone Chapala nearing landfall over Yemen

2 11 2015

As reported in our blog last week, Cyclone Chapala formed in the Arabian Sea and became the second strongest cyclone on record in this region with estimated peak winds averaged over one minute of 155 mph. Only Cyclone Gonu in 2007 was more intense. Since then Chapala has weakened slightly, but still has winds in excess of 100 mph.

Chapala has been moving westwards and is now moving into the Gulf of Aden. Landfall is expected over Yemen early on Tuesday 3 November UK time with winds still expected to be at least of hurricane strength (75 mph or more). This region has climatologically very low annual rainfall totals (approximately 50 mm), but could receive several times this amount from the cyclone, which raises the possibility of flash flooding in areas not used to much rain. Although central and eastern Yemen has a relatively sparsely populated coastline, the city of Al Mukalla is close to the projected location of landfall.

Cyclone Chapala at 1230 UTC on 02 November 2015

Cyclone Chapala at 1230 UTC on 02 November 2015

The Arabian Sea normally only produces three or four tropical cyclones per year at most. Some years there are no cyclones at all and often they do not reach hurricane strength. Thus for a cyclone of this intensity to be moving directly into the Gulf of Aden with a likely landfall over Yemen is a rare event – but is it unprecedented?

Records back to the 1980s show that no tropical cyclones of tropical storm intensity or greater (winds over 39 mph) have made landfall over Yemen. However, in 2008 a tropical depression did cross the coast. Although winds were not strong, it brought heavy rain, flooding and caused many fatalities in Yemen.

To the east of Yemen, the neighbouring country of Oman has seen several landfalls of tropical cyclones. In 2002 a weak tropical storm made landfall just on the Oman side of the border with Yemen. The two strongest cyclones to make landfall over Oman were Gonu (2007) and Phet (2010), but both of these were over the north of the country well away from where Chapala is located.

For a tropical cyclone to navigate directly into the Gulf of Aden takes a very precise track. The most recent to do this was Bandu in 2010, but it was weak and dissipated without making landfall.

Records prior to the 1980s are considered less reliable due to poor satellite data coverage, but there are a few examples of storms which entered the Gulf of Aden. There is sparse detail of cyclone intensities this far back, but no evidence of any which entered the Gulf of Aden or made nearby landfall at an intensity as high as that currently exhibited by Cyclone Chapala.

Therefore, using the historical information available it can be concluded that Chapala is the strongest cyclone on record to enter the Gulf of Aden and will likely be the strongest on record to make landfall over Yemen if current forecasts are correct.

Official warnings for the latest tropical cyclones in the Arabian Sea are produced by the India Meteorological Department. The Met Office routinely supplies predictions of cyclone tracks from its global forecast model to regional meteorological centres worldwide, which are used along with guidance from other models in the production of forecasts and guidance. We also provide updates on current tropical storms via @metofficestorms on Twitter.

Will you see the aurora borealis in the UK?

2 11 2015

There is a chance you could see the aurora borealis (Northern Lights) tonight in the UK, particularly in the northern half of the country. However, there will be  widespread fog tonight (Monday 2 November), which could be dense in places and might affect your chances of seeing the lights.

It is just a month since the last sighting of the aurora borealis here in the UK but the return of a large coronal hole to the Earth facing side of the Sun means our chances of seeing the Lights have again increased.

What are these phenomena?

Firstly, the Sun goes through an 11 year solar cycle, from solar minimum, through solar maximum and back to solar minimum. We are now in the declining phase of the solar cycle following the solar max which occurred in early 2014. During the current phase of the solar cycle coronal holes that begin the cycle in the Sun’s ‘polar’ regions have now migrated towards the Sun’s equator, meaning they are on a similar line of latitude to the Earth (i.e. facing the planet rather than directed north and south out of the solar system). These coronal holes give rise to high speed solar wind streams that buffet the Earth, disturbing the Earth’s magnetic field.

Coronal hole 2 November 2015. Image courtesy of NASA

Coronal hole 2 November 2015. Image courtesy of NASA


In other parts of the solar cycle these disturbances are largely as a result of coronal mass ejections, which can give larger magnitude disturbances than these high speed streams.

Secondly the season of the year has an influence. The science behind this is not fully understood, but the two equinoctial periods in spring and autumn tend to produce an increase in aurora compared with winter and summer.

What does this mean for the UK?

We are now in a period, lasting a few weeks, where these two factors are working together to increase the chances of geomagnetic disturbances, which in turn bring with them the aurora. The strength of the disturbance directly relates to how far south the aurora is visible (or how far north if you are in the southern hemisphere), and of course you need clear skies to see it.

Keep an eye on our space weather forecasts and if there’s a chance of seeing the aurora in the UK we’ll let you know.

The Met Office works closely with the British Geological Survey to forecast these geomagnetic events and the BGS website provides ‘Tips on viewing the Aurora’


Warm, sunny and dry October

30 10 2015

Early provisional figures (1-28 October) show sunshine and temperatures were above normal in almost all places this month while rainfall has been below average, especially in western areas.

Much of October has been relatively settled, with high pressure dominating our weather. This has led to many dry, sunny days but cold nights and even a few frosts (coldest so far -5.0 °C at Braemar on 17th).  Although the end of the month so far has been more unsettled, it has remained milder than average.

Rainfall has been below average, especially in the west of the UK, with only around 30% of average in eastern parts of Wales.  The exception to this has been a band from Cambridgeshire to North Yorkshire and around Aberdeen where rainfall has been around average (at the time these figures were compiled we would expect around 90% of the month’s total rainfall and sunshine to have happened).

1-28 October 2015 sunshine

1-28 October 2015 sunshine

1-28 October 2015 rainfall

1-28 October 2015 rainfall












Maximum temperatures (daytime) have been above normal in almost all areas for October, with north west Scotland being 2°C above, while south-east England stayed around average.  However cooler nights have led to Mean temperatures (average of daytime and night-time temperatures) over most of England and Wales being near average, but a degree or so above in parts of Scotland and Northern Ireland.

EARLY mean temperature sunshine duration precipitation
1-28 Oct 2015 Act Anom Act Anom Act Anom
  degC degC hours % mm %
UK 9.9 0.4 88.5 96 61.6 48
England 10.6 0.2 89.5 87 50.5 55
Wales 10.0 0.1 89.0 96 64.3 38
Scotland 8.6 0.7 85.4 113 78.4 45
N Ireland 9.8 0.4 94.7 108 64.8 54


Meanwhile Halloween starts off cloudy or foggy for many with some patchy rain across northern parts.  However this clears leaving a mild day with patchy sunshine for many in the afternoon.   Sunday, 1st November, looks much the same staying mostly dry with some sunny spells.  Check out our five day forecast for more details.

Please note that these provisional figures, especially for rainfall & sunshine, are subject to revision. Anomalies are expressed relative to the 1981-2010 averaging period.



Cyclone Chapala approaching the Arabian Peninsula

30 10 2015

Cyclone Chapala, currently over the Arabian Sea is expected to strengthen to the strongest category of Super Cyclonic Storm this weekend which means that sustained winds will be in excess of 140 mph, with gusts likely to be in excess of 170 mph. This is equivalent to a Category 4 storm on the Saffir-Simpson Hurricane Wind Scale.

Meteosat visible satellite image showing Cyclone Chapala in the Arabian Sea at 1130 GMT on 30 November 2015.

Meteosat visible satellite image showing Cyclone Chapala in the Arabian Sea at 1130 GMT on 30 November 2015.

Chapala is rated as an Extremely Severe Cyclonic Storm by the Indian Meteorological Department who are the official tropical cyclone forecasting centre for the Arabian Sea.

This Super Cyclone is expected to slowly track west or northwest this weekend, just west of the Gulf of Aden, producing Hurricane Force winds and waves of up to 15 metres. These conditions are likely to impact on the very busy shipping route from the Indian Ocean through the Gulf of Aden, making it very difficult for marine transport to move through this area for several days.

Chapala is expected to make landfall in southeast Yemen, or perhaps the far southwest of Oman, later on Monday or through Tuesday. However, there remains some uncertainty over the time and exact location of landfall. This Cyclone is likely to have weakened a little by then due to the interaction with land, but could still be an Extremely Severe Cyclonic Storm with sustained winds of 115 mph and gusts to 150 mph. These winds could cause destruction along the coastline if they occur across a town or city, but this is a sparsely populated coastline.

Rainfall is also likely to prove hazardous, with this system possibly producing up to 500mm of rainfall in a 48 hour period. This is likely to cause severe flooding if it falls over a town or city. This part of Yemen usually sees less than 100mm of rain during the whole year.

Official warnings for the latest tropical cyclones in the north Indian Ocean are produced by the Indian Meteorological Department. The Met Office routinely supplies predictions of cyclone tracks from its global forecast model to regional meteorological centres worldwide, which are used along with guidance from other models in the production of forecasts and guidance. We also provide updates on current tropical storms via @metofficestorms on Twitter.

What are the prospects for the weather in the coming winter?

29 10 2015

Anyone who has read the newspapers lately can’t have failed to notice this winter’s weather is in the headlines. Justification for claims of a ‘big freeze’ has come from sources as diverse as the plucky Bewick Swan settling into the comfort of the WWT reserve at Slimbridge, Gloucestershire earlier than ever before, to the strong El Niño and cool North Atlantic Ocean.

But what can we genuinely say about prospects for the coming winter, and what is the influence from phenomena like El Niño? Jeff Knight, from the Met Office Monthly to Decadal Prediction team explains.

In the Met Office we produce outlooks for the UK weather as a whole over three monthly periods. These outlooks are not forecasts in the conventional sense, although they are still made using computer prediction models. While a forecast might say ‘it will rain tomorrow’, the chaotic nature of the atmosphere beyond a few days ahead leads to growing forecast uncertainty, making it meaningless to try to make the same kind of forecast for a day in three months’ time.

Fortunately, atmospheric chaos is only part of the story and, when we consider the broad characteristics of the weather over a three month period, we can see influences from a range of global climate factors that we can endeavor to predict. While the unpredictable part means there is always a range of possible outcomes, the part we can try to predict allows us the opportunity to identify which types of weather are more likely than others. As a result, our outlooks are more useful for professionals who need to assess risk, such as contingency planners, than the public generally. Our current outlook covers the period from November to January.

So what are the global drivers that might influence our weather this winter?

El Niño is the biggest news story currently in global climate. This episodic warming of the waters of the equatorial Pacific Ocean occurs every few years – the last event happened in 2009-10. This ocean warming covers an area about 1,000 km wide and 13,000 km long, stretching along the equator from the South American coast to the West Pacific. El Niño events release a vast quantity of oceanic heat into the atmosphere so it is not surprising that El Niño has effects on weather across the globe.

This year’s El Niño started to grow in April and it has now become a strong, mature event similar to the landmark 1997-8 event. Typically, growth will peak around the end of the year and decline during the first half of the following year. We have already seen its effect on global weather systems: this summer’s Indian monsoon rainfall fell to drought levels and very hot, dry conditions in Indonesia have contributed to widespread forest fires.

Currently, the outlook for El Niño is for further growth over the next two months. Events are often ranked in terms of sea surface temperatures in Central Pacific, and by this measure, this year’s El Niño is more likely than not to become the strongest on record. Temperatures further east near to South America are likely to be not quite as exceptional as in 1997-8. No two El Niños are identical and even very similar events have slightly different characteristics.

What does El Niño imply for the UK this winter?

Unlike some parts of the world, the effect of El Niño on Europe is relatively subtle. In El Niño years there is a tendency for early winter to be warmer and wetter than usual and late winter to be colder and drier. Despite this, it is just one of the factors that influence our winters, so other influences can overwhelm this signal – it is relatively straightforward, for example, to find years where these general trends were not followed.

What about the Atlantic Ocean?

Closer to home, sea surface temperatures to the west of the UK have been notably lower-than-average in recent months. While it is true the westerly winds that we typically get in winter would have to pass over this region, it is unlikely that this will directly have a strong bearing on expected temperatures. This is because temperatures at this time of year are strongly affected by the direction of the wind. Eastern Europe and Scandinavia are 10-20°C colder than the Atlantic Ocean in winter, so our weather will depend much more on how often winds blow in from the north and east than whether the Atlantic is 1-2°C cooler than usual.

More broadly within the North Atlantic Ocean, sub-tropical temperatures to the south of this cool region are widely above average. This combination results in an increased north-south temperature gradient, which is expected to provide greater impetus for Atlantic depressions. For the UK, this would favour relatively mild, unsettled weather conditions.

Global sea surface temperature anomaly 28 October 2015

Global sea surface temperature anomaly 28 October 2015

Our weather is also affected by changes in the stratosphere

European winters are also sensitive to what is happening in the stratosphere, the layer of the atmosphere between 10 and 50 km up that lies above the weather. The equatorial stratosphere is home to the Quasi-Biennial Oscillation (QBO), a cycle that sees winds switch from easterly to westerly and back roughly every 27 months. First noted by Met Office scientists over 40 years ago, the link with European winter weather has stood the test of time. This year, the QBO is in a westerly phase, which implies an increased chance of a mild and wet winter at the surface.

A considerable part of the year-to-year differences between UK winters is related to the occurrence of sudden stratospheric warmings (SSWs). In these events, the polar stratospheric vortex – the fast moving circulation of stratospheric air that whirls around the North Pole in winter – abruptly breaks down. They occur one winter in two on average, and events are most common in January or February. In the majority of cases SSWs lead to the establishment of cold easterly flow at the surface across Europe and the UK. The last SSW was in January 2013, and this event contributed to the cold late winter and early spring in that year.

Whether we get an SSW or not depends on a number of influences, such as El Niño and the QBO. Currently our models suggest an increased likelihood of an SSW from January onwards. If this were to happen, its effects would not be felt much before the end of our November to January outlook period. At the moment, therefore, this is still a long way off, and we consider this suggestion to be tentative.

So what can we expect in the UK this winter?

Most of the global drivers discussed above tend to increase the chances of westerly weather patterns during our November to January outlook period. Our numerical prediction model, being sensitive to these drivers, also predicts a higher-than-normal chance of westerly conditions. This results in an outlook for an increased chance of milder- and wetter-than-usual conditions, and a decreased chance of colder and drier conditions, for the UK. Our outlook also indicates an increase in the risk of windy or even stormy weather.

It should be noted that these shifts in probability do not rule out the less favoured types of weather completely. Also, a general tendency for one type of weather over the three months as a whole does not preclude shorter spells of other types of weather.

Finally, there are hints that the outlook might be rather different in the late winter, with an increased risk of cold weather developing. Nevertheless, it is currently too early to be confident about this signal.

Spooky heat for Halloween weekend?

28 10 2015

Last Halloween saw record breaking temperatures across parts of the United Kingdom, with both Kew Garden’s, London and Gravesend, Kent reaching a maximum temperature of 23.6C.

What can trick or treaters expect this year on Halloween?

The weather’s currently in an unsettled mood, with a mild south or southwesterly flow dominating the weather pattern. Most areas will escape night frosts for the rest of the week, and yesterday (Tuesday) parts of London reached almost 20 degrees during the afternoon. Although the next couple of days are likely to bring rain to all areas, the worst of the unsettled weather should stay in northern and western parts of the UK as we head into the last day of October.

Pressure chart for midday on Saturday 31 October 2015

Pressure chart for midday on Saturday 31 October 2015

Pressure will rise across the south allowing more settled conditions to take hold towards the south and east. The generally mild theme looks likely to continue with warm air spreading northwards from the continent. As a result there is a possibility that parts of southeast England could see maximum temperatures in the high teens, perhaps touching 20 Celsius. The extent and degree of warmth will be affected by how much cloud cover there is which is difficult to forecst accurately 3 days ahead, however therer will be some decent bright or sunny spells. You can keep up to date with the most recent forecast on our 5 day forecast pages.

Sunday sees the start of a new month and it’s looking likely that we will see similar weather to Saturday with many places staying dry with bright or sunny spells after early mist or fog clears. The warm air may hang on across the south where, if sunshine allows, it could turn very warm with temperatures getting close to the UK temperature record for November of  21.7C (reached at Prestatyn, North Wales on 4 November 1946). Record breaking or not, this weekend provides plenty of opportunities to get out and shake off those cobwebs.

World weather this week

26 10 2015

Southern USA
After making landfall on Saturday 23 October as a category 5 hurricane, Hurricane Patricia weakened rapidly as it moved over the mountains of Mexico. Hurricane Patricia became the deepest hurricane on record with minimum central pressure of 879hPa, beating the previous record of 882hPa set by Hurricane Wilma in the Atlantic in 2005. The remnants of Patricia formed an area of low pressure over the Gulf of Mexico over the weekend and brought intense rainfall to the southern states of the USA. Severe flood impacts were reported in parts of Texas and Louisiana with up to 500mm of rain reported. New Orleans reported 220mm in the last 24 hours with an unconfirmed total of 457mm in 24 hours at Corsicana, Texas. This torrential rain also led to delays at the USA Grand Prix. The eastern fringes of Texas, along with Louisiana, Mississippi, Alabama and Arkansas are at risk of receiving another 100-200mm of rainfall today (Monday) bringing further flooding impacts. Looking ahead, further heavy rainfall will affect areas of the Pacific coast of Mexico that were impacted by Patricia; Texas and Louisiana from Friday with another 200mm or more of rain. This will exacerbate the current flooding in these regions.

Hurricane Patricia

Map showing rainfall totals across Mexico and the southern states of the USA

Eastern Mediterranean
A spell of very unsettled weather is affecting the eastern Mediterranean bringing heavy rainfall, localised flooding to the Levant coasts along with reports of baseball-sized hail in parts of Egypt. This weather will continue to move eastwards across countries such as Syria, Israel, Lebanon and into Iraq and Iran over the coming days with daily rainfall likely to approach 100mm. This will lead to a risk of flash flooding and may be accompanied by further damaging hail.

Sri Lanka and SE India

Heavy rain associated with the northeasterly monsoon has brought some high rainfall totals across Sri Lanka with 89mm recently recorded in 3 hours. There is a risk of a tropical depression forming in the southern Bay of Bengal this week which would bring further very heavy rainfall across Sri Lanka and SE India. Some places may see up to 200mm a day, with an event total of up to 600mm. This will lead to significant flood and landslide risk across this region, with the large Indian city of Chennai and Sri Lanka capital Colombo at risk.

Eastern Canada/NE USA and eastern Europe

Over next weekend and early next week, a cold plunge of air is likely to dip southwards across the eastern provinces of Canada and far northeastern states of the USA such as Maine, New Hampshire, Vermont and Massachussetts. Daytime temperatures may only just rise above freezing in what will be a fairly early cold snap for the regions.

Cold air will also sink southwards from the arctic to bring an early taste of winter to eastern Europe affecting Ukraine, Belarus, Poland and also western Russia.


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