Is La Niña on the way?

During 2015 and 2016, the planet experienced one of the largest El Niño events in a century.  El Niño (Spanish for the boy) is actually the warm phase of the El Niño-Southern Oscillation and climate scientists are now suggesting that this oscillation in tropical Pacific temperature is likely tipping towards its opposite cool phase, La Niña.

Ensemble members show an increasing likelihood of La Niña conditions developing during October and November. La Niña conditions are said to develop when the sea surface temperature anomaly goes below –0.5°C.

Perhaps less well known than its larger brother, La Niña (Spanish for ‘the girl’) is an event that can trigger significant impacts.  Professor Adam Scaife, head of monthly to decadal prediction at the Met Office, said: “During El Niño, temperatures in the equatorial Pacific can warm by as much as 3°C. La Niña tends to be smaller and rarely exceeds 2°C, but its effects reach across the globe and can have just as much impact.”

Historically, La Niña events tend to occur about once every five years, but forecasts over the last few months show an increasing risk of La Niña developing this winter.  A really big La Niña like that in 2010/11 is very unlikely, but the chance of a moderate strength event is now several times the historical chance.

La Niña is associated with a shift in rainfall towards the western Pacific. Regions from Indonesia, the Philippines, Papua New Guinea, the Solomon Islands and north-east Australia will all be at risk of heavier than average rainfall if La Niña develops. At the other side of the tropical Pacific, Peru would be at risk of drought, but local fisheries would receive a boost as fish stocks can access additional nutrients rising in upwelling currents driven by La Niña.

The effects of La Niña aren’t confined to the tropical Pacific. If La Niña develops, then North-western coastal communities of North America would be at increased risk of a cold winter as La Niña increases northerly winds there. Meanwhile southern Africa would be more likely to experience a cooler and wetter summer than normal, and Brazil would have an increased risk of heavy rainfall in coming months.

Adam Scaife concluded: “As well as its regional effects, La Niña can cause a temporary cooling of global temperatures but the strength of the current event suggests that this will be no more than a tenth of the global warmth we have accrued so far due to climate change.”

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Atlantic depressions bring above-average rain for some

During the first half of the month, a succession of low-pressure systems tracking close to the UK brought rain to most places as fronts swept from west to east. After a cool, showery interlude around mid-month, a more autumnal pattern emerged with some foggy nights and sunny days interspersed with further bouts of rain.

Following August’s trend, provisional statistics for the UK for September so far suggest it has been slightly cooler than average and rather unsettled, although frosts have been reported by very few stations up until 28 September. The cool trend isn’t apparent everywhere though, as parts of northern Scotland, including Shetland, Orkney and Caithness were the warmest spots relatively in Britain, when compared with average temperatures. Shetland enjoyed mean temperatures during the month more than 1 °C above the long-term September average. In contrast, the maximum daily temperatures in some parts of southern England were around 1 °C cooler than the September average.

Dr Mark McCarthy is the head of the Met Office’s National Climate Information Centre. He said: “The UK receives weather influences from all points of the compass. However, the weather during September has been largely dominated by an influence from the Atlantic. This is evident in the above-average rainfall in parts of western Britain and Northern Ireland. The relative lack of northerly winds will have been partly responsible for keeping the temperatures of parts of northern Scotland above average.”

Up until 28 September, most places had already exceeded their average rainfall for the month, with a UK figure of 108.1mm with two days to go (UK September average is 96.4mm). Some locations, such as Cornwall and Plymouth, have had well above their September rainfall average.

Dr Mark McCarthy added: “Cornwall has experienced it wettest September since 2000 and there is more rain to come before the month concludes.” Other areas with well above average rainfall include parts of northwest England, northern and western Wales, Northern Ireland and northeast Scotland.

In contrast parts of southeast England, Herefordshire and Central and northwest Scotland have been rather drier. Provisional figures for Shoeburyness, in Essex, reveal that it has only received 26.8mm  of rain; just under two thirds of the long-term September average.

For temperatures, values have been close to or slightly below average so far, with daytime temperatures for the UK 0.5˚C below average at 16.0˚C. Some counties across southern England have had an average daytime maximum of 1˚C below normal.

With rainfall amounts generally above average, it’s no surprise that sunshine hours are below or close to average for most areas, with the exception of parts of southeast England near the Thames Estuary. UK sunshine amounts are 102.6 hours, 82% of average (124.7 hours) up until 28 September.

The forecast for the last days of September is changeable, with some persistent and heavy rain forecast for many areas as we head into the final night of the month. This means that rainfall amounts may increase substantially for some areas, while there is unlikely to be a surge of warmth to counteract the cool feel so far.

1-28 September 2017 provisional figures Mean temp (°C) Rainfall (mm) Sunshine (hours)
Actual  Diff to avg (°C) Actual % of avg Actual % of avg
UK 12.5 -0.2 108.1 112 102.6 82
England 13.4 -0.3 84.3 121 114.3 83
Wales 12.6 -0.2 149.5 128 96.4 75
Scotland 11.1 0.2 131.0 96 86.0 82
N Ireland 12.0 -0.3 137.6 150 95.6 84

You can keep up to date with the weather using our forecast pages, on our popular mobile app which is available for iPhone from the App store and for Android from the Google Play store and by following us on Twitter and Facebook, as well as using.

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Harnessing the power of the weather forecast

You will be familiar with checking a weather forecast before planning a day out. But have you ever looked at a forecast to find out the greenest time to put your washing machine on? Well, now you can.

Using data from the Met Office, today National Grid, in cooperation with the Environmental Defence Fund Europe (EDF) and WWF, have launched a forecast to enable the public and businesses to better understand and plan their energy use.

Using hourly weather data from the Met Office and combining it with historical data from the grid, National Grid are able to forecast demand for electricity and also identify the contribution from renewable energy flowing into the grid. Using this information, they can forecast the carbon output of the grid over a 48-hour period, and identify the periods of lowest carbon output and highest carbon output. In other words, how green the grid will be during that period.

Using this information, the partners involved in the project hope that electricity consumers across Great Britain will be able to plan their electricity use around periods of high availability for renewable energy, reducing carbon output.

Patrick Sachon, Met Office Business Group Leader for Energy said: “The green energy forecast is a great example of innovative re-use of Met Office data. As a scientific organisation we encourage the re-use of our data, particularly if it can be applied to develop a deeper understanding of the interrelation between weather and something that is so integral to our everyday lives such energy.”

Accessibility of the new green energy forecast is important to the project partners and they have made it available as an API (application programming interface) so it can be used to develop new apps and services. Duncan Burt, Director of the System Operator at National Grid, said: “We’re providing our forecast data in a format that allows technology companies to build innovative apps and software that could make a real difference to how and when people use energy. Clear and concise information that can tell you in advance when’s best to turn on the washing machine, load the dishwasher or charge your car for example, is a step in the right direction towards a low carbon future. This technology puts people at the heart of it, helping everyone to use power when it’s greenest, and likely, more cost efficient”.

Patrick Sachon said: “We look forward to continuing to work closely with National Grid to explore how our weather data can be used to better understand energy use.”


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Climate models: an essential tool for guiding policy

Climate models have come under scrutiny. Stephen Belcher, the Met Office’s Chief Scientist, explains the nuances of the science and why it is imperative now to reduce atmospheric carbon.

Are climate models accurately predicting global warming?

This question has been a hotly debated this week. Whilst climate models do not represent all aspects of our climate, they provide an essential tool for guiding policy by simulating the warming we have seen since the pre-industrial era. So how well do they do?

The figure below shows observations of global warming (in black) compared to the range projected by the group of models submitted to CMIP5, which was used by the IPCC for their latest assessment report on climate change. The 1880-1919 period was chosen here to represent pre-industrial temperatures so that three observational data sets could be used in the comparison. The observations lie comfortably within the modelled range. For example, the warming seen between the 1880-1919 period and 2016 is 1.10oC in HadCRUT4, 1.19 oC in GISTEMP and 1.12 oC in NOAAGlobalTemp, which compares well with 1.14 oC, the average of the CMIP5 models (which have a 2.5 – 97.5% range of 0.70 – 1.58 oC).

Comparison of simulated temperatures from CMIP5 models (historical and RCP4.5 experiments) with three observed near-surface temperature datasets, as changes from the 1880-1919 baseline. The observational datasets are HadCRUT4 (with an estimate of the uncertainty on the dataset) produced by the Met Office Hadley Centre and the Climate Research Unit; GISTEMP produced by NASS GISS; and NOAAGlobalTemp produced by NOAA. The model and observational data have been re-analysed to the same coverage as HadCRUT4 to enable fair comparison.

What factors need to be considered in making comparisons between observed and modelled warming?

First, during the so-called slowdown during the 2000s the observations sit within the lower half of the model range. This has prompted questions about whether the models have been warming too much. Analysis at the Met Office shows that these variations are consistent with variations associated with the Pacific Decadal Oscillation. We have since seen record-breaking temperatures in 2014, 2015 and 2016 which signal an end to the slowdown and a return of higher warmer rates.

Second, the CMIP5 simulations were initiated in 2005, and emissions of greenhouse gases from 2005 onwards were assessed, based on estimates for socio-economic development. So the CMIP5 simulations do not account for the cooling effects of small volcanic eruptions which recent research shows slightly cools the modelled warming. (Further information on these topics can be found in Ed Hawkins’ blog, and in the Nature journal paper by Medhaug et al)

Third, the observations themselves contain uncertainties, for example due to difficulties of estimating temperature changes in poorly-observed regions such as the Arctic and Antarctica, and due to definition of the pre-industrial temperature, when the observations have greater uncertainties.

So can we limit warming to the ambitions of the Paris agreement?

Policy makers need to have reliable information about greenhouse gas emissions because there is a direct link between the amounts of total CO2 we have emitted and the amount our world warms. By studying this link, it is possible to estimate how much more carbon we can emit while remaining within given levels of warming. There is currently an intense research effort to reduce the current uncertainties in the carbon budget.

One recent study has suggested that remaining carbon budgets may be larger than previously thought. (The close agreement between the models and the observations in the figure above does not change this conclusion.) Meanwhile other areas of research suggest they may be smaller. For example, the next generation of climate models will include processes such as the impacts of thawing permafrost, changes to wetlands, and the impact of the nitrogen cycle on plant growth. Early evidence suggests that accounting for these processes will reduce the amount of carbon we can emit while staying within the over all budget and the global warming targets.

The Paris Agreement to limit warming to ‘well below 2 oC above pre-industrial levels and to pursue efforts to limit the temperature increase even further to 1.5 °C’ is driving a need for greater precision in climate science, both in the need to assess warming above pre-industrial levels, and in the need to assess carbon budgets consistent with these targets.

What remains clear, however, is that the aim of limiting warming to 1.5C remains a huge global challenge that requires rapid cuts to greenhouse gas emissions.

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How are temperature records measured?

At the Met Office we maintain the UK’s climate records and these are used to monitor our climate at a national and regional level. To ensure consistency, weather records are only used from weather observation sites with calibrated, standard instruments and carefully monitored exposure. Although some records have been broken by non-standard stations, these are not accepted as official records for this reason.  Also, on rare occasions an extreme temperature is recorded at a weather station which is so at odds with readings from stations nearby that it will be discounted as unreliable.

How far do records go back?

Historical observations of our weather are stored by the Met Office, with individual station observations in our digital database going back to 1853, however there are historical paper records for earlier dates held in the National Meteorological Library and Archive.

When are temperatures officially recognised as a new record?

The historical observations are used for monitoring our climate and maintaining a set of official climate records for the UK. They are also used to highlight interesting facts about our weather and place current weather into historical context. But these arbitrary calendar dates, such as the recent August Bank Holiday, Christmas or Wimbledon, do not give a complete picture of seasonal or monthly extremes.

Each day real-time data is subject to preliminary quality control before it is released, such as cross checking against nearby stations. A record will not become official until thorough quality control has taken place on the data, which may take several months.

They may even be reviewed again at a later date to ensure they remain valid.

Historical records also undergo continual review. With millions of data points it is inevitable that the database contains very small proportion of questionable data.

Was it the warmest August bank holiday on record?

On Monday 28th August a maximum temperature of 28.2 Celsius was recorded at Holbeach. The highest temperature for the late August bank holiday in the digital archive was 28.3 Celsius at March (Cambridgeshire) on 27th August 1990. However this particular reading is considerably higher than all surrounding sites and therefore considered to be suspect. Therefore the August bank holiday of 2017 would be considered as the hottest bank holiday on record beating the value of 27.2 Celsius recorded at East Bergholt (Suffolk) in 1984.

It should be noted that this is a statistical quirk of the August bank holiday never having recorded a notable temperature extreme, and does not reflect a new national temperature record for the UK. We have seen higher temperatures later in the year than this. For example a brief heatwave in September 2016 saw temperatures reach 34.4 Celsius on 13th, and the highest temperature recorded in October for the UK was 29.9 Celsius on 1st October 2011.

For full weather extremes listings and historical records go the Met Office Climate section



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US total solar eclipse – the most photographed event of all time?

Today, the path of a total solar eclipse will move across continental USA, an event predicted to be the most photographed of all time. The eclipse occurs as the moon passes between the Sun and the Earth, casting a 70-mile wide shadow and moving across the Earth’s surface at an average speed of 1,651 mph. It will take the shadow a total of 90 minutes to travel across from Oregon to South Carolina, moving over an area home to 12.5 million people. Outside this path of totality, the entirety of North America will still witness an impressive partial solar eclipse; resulting in the most widely viewed solar eclipse since the invention of smart phones. It is this fact that has led experts to predict today’s eclipse to be the most photographed event of all time, dependent on the weather.

The yellow line shows the eclipse’s path of totality

Unfortunately, the eclipse will barely be visible from the UK, with the moon’s edge blocking just a small fraction of the sun’s surface. The eclipse will first become visible at around 19:40 BST, before peaking between 19:55 and 20:10, dependent on the location and the weather. To see whether skies will be clear in your area, check our forecast pages or use our app. In most places across the UK, the sun will set before the end of the eclipse, making the sun difficult to see as it sits only a small distance above the horizon. It is important never to look at the sun with the naked eye; methods of producing a homemade pinhole camera are available online.

Past and present, solar eclipses have led to some very important scientific discoveries, including the discovery of helium to the confirmation of Einstein’s theory of general relativity. A new video on the Met Office’s Learn about Weather YouTube feed explores a few of the most significant solar eclipse events.

Further studies

Despite observing eclipses for thousands of years, there is still a lot to learn from them. During today’s eclipse, NASA will study the reaction of the ionosphere to the sudden drop in solar radiation and temperature. The ionosphere is a thin layer of the Earth’s atmosphere, ionised by radiation from the sun. Additional observations will explore features of the sun’s corona, photographed for the first time during a solar eclipse 166 years ago. Monitoring the sun’s corona is an important aspect of space weather, because it is the source of coronal mass ejections. Ground-based and satellite imagery now replicate the effect of a solar eclipse using an instrument called a coronagraph, enabling the Met Office Space Weather Operations Centre to monitor the sun’s corona 24/7.

A coronal mass ejection (CME) is the large release of material from the sun’s surface. These events are not visible to the naked eye, except in the rare case of a total solar eclipse. In the year 1860, astronomer G. Tempel sketched what he saw during eclipse totality, drawing what we know today to be a coronal mass ejection.

Comparison between G. Tempel’s CME sketch from 1860 (left), with modern SOHO satellite’s coronagraph imagery of a coronal mass ejection in July 2017

Currently, a large magnetically complex sunspot region AR2671 can be seen in the centre of the sun’s visible disk. Therefore, there is a chance that a coronal mass ejection could occur. Be sure to check our space weather forecast and follow us on Twitter for further space weather updates.

Total solar eclipses happen somewhere in the world at an average rate of once every three years, but unfortunately you’ll have to wait a while to see one from the UK. The UK’s next near-total eclipse will take place in 2026 (96%), but a total eclipse will not be visible in the UK until 2090.

More information

NASA will be live-streaming the event this evening from 17:00 BST at

For more information on the eclipse and its significance to space weather, follow @MetOfficeSpace on Twitter.

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Jet stream brings cool and changeable start to August

After an unsettled and cool end to July, August has continued in a similar vein. Many places have been showery and cool so far, with a southward-shifted jet stream to blame. This has directed areas of low pressure, which normally skirt to the north of the UK in summer, to instead move across the country.

In between spells of rain or showers brought by these low pressure systems, there have been some drier, brighter days and sunshine amounts have been close to normal. However, temperatures have been a little disappointing, with no locations recording a temperature in excess of 25 °C up to 15 August.

Provisional figures show mean temperatures have generally been below average for August by about 1 °C, but central southern England has seen the greatest differences compared to the 1981-2010 average. For south-east and central southern England the period 1-13 August 2017 has been the coldest since 1987. Interestingly, however, if you compare temperatures for this period to those experienced in the years 1961-1990 then it wasn’t so unusual to see such suppressed temperatures for the first half of August.

In terms of rainfall, many places have seen more than half of the whole-month average already, with locations around the Humber and across parts of central southern and south-east England getting close to their month average. Up to 15 August, the UK has received 60% of the whole-month average for rainfall. Looking back over the last ten years, several Augusts have been wet over large parts of the UK, so the month does have a tendency to disappoint those looking for dry weather.

You can read weather summaries of previous months and seasons for the UK here.

1-15 August 2017 provisional figures Mean temp (°C) Rainfall (mm) Sunshine (hours)
Actual  Diff to avg (°C) Actual % of avg Actual % of avg
UK 14.1 -0.8 53.9 60 79.6 49
England 15.2 -0.9 44.4 64 86.3 47
Wales 14.1 -0.9 61.8 57 75.7 45
Scotland 12.5 -0.5 67.7 58 70.1 52
N Ireland 13.8 -0.5 53.8 55 76.0 56

For the rest of August, it looks like the weather may settle down during next week, bringing some longer periods of dry weather with temperatures also recovering. However, low pressure is likely to bring further spells of wet and occasionally windy weather later this week and early next week.

You can keep up to date with the weather using our forecast pages, on our popular mobile app which is available for iPhone from the App store and for Android from the Google Play store and by following us on Twitter and Facebook, as well as using.

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Torrential monsoon rains wreaking havoc across parts of southern Asia

Torrential monsoon rains over the last seven days have reached life-threatening levels for communities south of the Himalayas from Nepal to Bhutan and northern India to Bangladesh.

Severe floods and landslides have wrought havoc. Already across the affected region communities have faced tragedy, including: loss of life; thousands of homes submerged; extensive crop damage; as well as collapsed bridges and blocked roads.

Further heavy rain is forecast over the next few days and this will extend the zone of flooding downstream to communities lining those major rivers which flow from the Himalayas.

Nick Silkstone is a Met Office forecaster working in the Global Guidance Unit. He said: “The region between the Himalayas and the Bay of Bengal is bisected by some of the world’s great rivers, such as the Brahmaputra and the Ganges, which drain the region normally taking water safely to the sea.

“Even though these are some of the world’s mightiest rivers the forecasts suggest even these giants are going to struggle with the amount of pressure these systems are currently facing.

“Global flooding indicators, such as GLOFAS, are indicating high probabilities of river flows that are only anticipated once every two decades in many of the region’s major rivers, giving an early warning of a significant event to come in the next week.”

There are already reports of extensive loss of farmland due to the flooding, and agencies are reporting waterborne diseases proliferating in flooded areas.

The monsoon is a natural part of south Asia’s weather, but this year rainfall in some areas has been over four times greater, when compared with the average between 1981–2010.

Clare Nasir is a weather presenter and meteorologist with the Met Office. She said: “The monsoon brings life-giving rains to the region, but the conditions in some years can be very cruel.  Extensive rainfall can be more concentrated in some parts than others. This year, the north region has received much more rain than other parts of India.”

With further rain forecast this coming week and a lag time from last week’s rain reaching communities downstream, the risk of extensive flooding continues.

Posted in Met Office News

When will summer return?

It often seems that summer starts hot and sunny but by the time the main holiday period begins, the rain has set in … it is disappointing and frustrating that the weather doesn’t always live up to our hopes, as witnessed in the last couple of weeks.

So, when will summer come back? Well, if you have read some media reports, you may think that August – the last month of meteorological summer – will be dominated by hurricanes or continual deluges. Attention-grabbing headlines may attract interest but they don’t inform readers about what the rest of summer may have in store.

To understand what the rest of the month may hold, let’s look at the weather situation now. After some hot spells in June and early in July, the UK’s weather is currently being dominated by a series of low-pressure systems, steered our way by the jet stream, which is sitting across the UK at present, rather than being positioned further north. Sadly, this relocation of the jet stream has coincided with many people taking holidays in the UK.

Laura Paterson is a Chief Forecaster with the Met Office. She said: “During the summer we would hope that the jet stream might be positioned well to the north of the UK, which brings an increased chance of warm, sunny weather. However many years defy this hope and, as at present, we end up with the jet stream shifted further south, guiding low-pressure systems right across us, rather than steering them to the north of Scotland.”

Will this situation persist? Well, indications are that until the middle of next week the weather will remain changeable – although parts of the country may see some improvement over the weekend, particularly across the south on Sunday, when some sunnier, drier conditions are on the cards. A further improvement may come to pass later next week but this is still quite a long way off and so confidence levels aren’t too high. This is especially the case, since the improvement may be influenced by the remnants of tropical storm Emily – which may actually help to nudge the jet stream further north.

After that it’s difficult to give too many details, but it looks like the second half of August may bring finer weather than the first half, especially for southen parts of the UK. This means that most of us will see some sunshine, but there is still likely to be some rain and showers in the forecast.

With many people on holiday, tourists often wonder about the weather during their vacation. Andrew Stokes, VisitEngland’s Director said: “Whatever the weather there is an outstanding range of quality destinations and attractions on offer and with the ease and convenience of holidaying at home, Brits are discovering more of England and driving the economic benefits of tourism across the country.”

Alex Deakin is a presenter with the Met Office. He said: “To a fair extent the outlook for the rest of August depends upon your philosophical bent and whether your rain gauge is half full or half empty. Pessimists may see rain in the forecast and assume that it’s going to be a washout: optimists see brighter periods in the forecast and make the most of it. However, the reality is that during the unsettled periods there will be brighter spells, which, with the strength of the August sun, could feel very pleasant.

“Despite the headlines it is certainly not all doom and gloom, and whatever the weather, smart people use their smart phones and plan their days and activities around the up to date information from the Met Office weather app.”

You can keep up to date with the weather using our forecast pages and by following us on Twitter and Facebook, as well as using our new mobile app which is available for iPhone from the App store and for Android from the Google Play store.

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The Fujiwhara effect: When Tropical Cyclones go dancing

Did you know that Tropical Cyclones sometimes go dancing? This interesting phenomena is called the Fujiwhara effect*, which can be seen this week in the Eastern Pacific Ocean off the coast of Mexico.

Hurricanes Hilary (right) and Irwin (left) in Eastern Pacific at 1400 UTC on 26 July 2017. Image courtesy of NOAA

Sometimes, when tropical cyclones get close to one another (within about 1,200km), they rotate around each other in an anti-clockwise direction (in the northern hemisphere). They tend to rotate around a point between them, rather like two dancers joining hands and spinning around, this is the Fujiwhara effect. If the Tropical Cyclones are of a similar size, then they can move around one another for perhaps up to a few days, then release and move away on their own paths, like the dancers letting go of each other’s hands.

If the Tropical Cyclones are of different sizes, then the larger of the two will tend to dominate, with the smaller one orbiting around it, similar to the way in which the moon orbits around the Earth. Sometimes, the smaller Tropical Cyclone will be “eaten up” by the larger one. The two systems then essentially merge, with the smaller storm dissipating and the larger storm remaining and moving away on its own. This is what is expected to happen through Thursday and Friday this week, with Hurricane Irwin being consumed by the stronger and larger Hurricane Hilary. Hurricane Hilary is then expected to move away to the northwest, before finally dissipating later this weekend.

Forecast track showing Hurricane Hilary and Hurricane Irwin as they dumbell round each other

When Tropical Cyclones dance around each other due to the Fujiwhara effect, it can be challenging for numerical weather prediction models to accurately represent the interactions that the two Tropical Cyclones have with each other. In fact, if you get three Tropical Cyclones coming within close proximity of each other, they can all interact in a complex fashion, making forecasts even more difficult. The accurate forecast of Tropical Cyclones is very important as these storms can sometimes have huge impacts on tropical regions if they make landfall in populated areas. Fortunately, in this case, Hilary and Irwin are forecast to stay well away from land, remaining instead over the open waters of the eastern Pacific, so are not expected to cause any significant impacts.

Further Information

For more information on Hurricanes Irwin and Hilary, including the official forecast tracks and warnings, please see the US National Hurricane Center’s website.

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.

*The Fujiwhara effect was named after Sakuhei Fujiwhara, who described it in his 1921 paper about symmetrical motions in the atmosphere ( – QJRMetS, October 1921, pages 287-292)  

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