Typhoon Nangka makes landfall over Japan

16 07 2015

In our blogs of 9 July and 13 July we described how the developing El Niño and a cyclical phenomenon known as the Madden-Julian Oscillation have combined to produce a period of high tropical cyclone activity in the Pacific. Nine storms developed inside two weeks – Linfa, Chan-hom, Raquel, Nangka, Ela, Halola, Iune, Dolores and Enrique. This is the highest number of Pacific tropical cyclones to form inside a two week period since 1968.

Typhoon Nangka on 16 July 2015. Image courtesy of The US Naval Research Laboratory.

Typhoon Nangka on 16 July 2015. Image courtesy of The US Naval Research Laboratory.

Typhoon Nangka formed almost two weeks ago close to the International Dateline and made a steady westward journey peaking in strength with winds of near 150 mph. It then turned north and started to weaken, but is now making landfall over southern Japan, still at typhoon strength.

Japan can sometimes receive several typhoon strikes in a season, but each time they bring much disruption and some destruction through a combination of wind, surge and rainfall. It is often the rainfall that can be most devastating as the typhoon draws huge amounts of moisture from the warm tropical ocean and deposits it over land.

Kamikitayama in southern Honshu has recorded 438.5 mm (17.3”) rain in a period of 24 hours and this is before the eye of Typhoon Nangka has even made landfall. It is possible that some locations could record over 600 mm of rain by the time the typhoon has passed. To put that into context, that’s more than the yearly rainfall for some parts of east England.

Typhoon Nangka Radar Image at 1255 (UK time) 16 July 2015 showing rainfall intensity. Image courtesy of The Japan Meteorological Agency.

Typhoon Nangka Radar Image at 1255 (UK time) 16 July 2015 showing rainfall intensity. Image courtesy of The Japan Meteorological Agency.

As Nangka crosses the islands of Shikoku and Honshu it is expected to weaken, but continue to produce heavy rain. Once over the Sea of Japan, Nangka is likely to make a rightwards turn and so could affect parts of northern Japan before finally dissipating.

Official warnings for the latest tropical cyclones in the western North Pacific are produced by the Japan Meteorological Agency. 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.





Record levels of Pacific tropical cyclone activity continue

13 07 2015

The Pacific Ocean has seen an extremely high number of tropical cyclones during the early part of this season, with several more tropical storms developing over the weekend.

Across the whole Pacific Ocean nine tropical cyclones have formed in the last two weeks. The recent high level of activity is a response to the recent strong episode of the Madden-Julian Oscillation combined with the developing El Niño conditions as described in our previous blog.

Several of the recent tropical cyclones have formed over open ocean and have caused little or no disruption. However, others have either affected land areas or are set to do so this week.

Typhoon Chan-hom passed very close to the coast of China at the weekend, with over a million people having to be evacuated from the Shanghai region. Whilst coastal areas saw heavy rain and powerful waves, they were spared the strongest winds as the eye of the typhoon stayed offshore. Chan-hom brought heavy rain to North Korea with 400mm having been recorded at Kimchaek on the northeast coast.

Typhoon Nangka on 13 July 2015. Image courtesy of The National Institute of Informatics

Typhoon Nangka on 13 July 2015.
Image courtesy of The National Institute of Informatics

Typhoon Nangka has just turned northwards in the west Pacific and looks set for landfall over south-western Japan on Thursday bringing the risk of strong winds, heavy rain and storm surge.

Across the other side of the Pacific, Tropical Storm Dolores looks set to become a hurricane as it runs parallel to the Mexican coast. It is most likely to stay out at sea, but there remains a low possibility that it could turn towards the coast in a few days time.

Pacific records

The recent high levels of tropical cyclone activity have resulted in some remarkable statistics.

  • Seven tropical cyclones (including four major typhoons) occurred in the western North Pacific before the end of May beating previous records.
  • The three tropical cyclones which have formed in the central North Pacific this week formed earlier in the season than any previous tropical cyclone in this region. There have never been three storms form in such quick succession in this region.
  • Eight tropical cyclones have formed across the eastern and central North Pacific so far this year – the earliest in the season this has ever occurred.
  • Across the whole North Pacific there have been 19 tropical cyclones so far this year. Taking into account their strength and longevity this amounts to a record 321% of normal activity for this point in the season.

Atlantic calm

By contrast the Atlantic remains very quiet. Two short-lived tropical storms have formed so far (Ana and Bill), but conditions are not conducive for further development in the near future in the tropical Atlantic:

  • Sea surface temperatures in tropical areas are up to 2°C below normal values
  • Wind shear (which inhibits tropical cyclone development) has been persistently high for several weeks.
  • Sea level pressure has been at record high values in the last month.

The growing El Niño is likely to maintain conditions which suppress tropical cyclone activity in the tropical Atlantic for the foreseeable future. However, some tropical cyclone activity cannot be ruled out – particularly outside of the tropics at higher latitudes where conditions are not as harsh as those described above.

Further Information

Official warnings for the latest tropical cyclones are produced by the Japan Meteorological Agency, the Central Pacific Hurricane Center and the National Hurricane Center. 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 on StormTracker and via @metofficestorms on Twitter.





Multiple tropical cyclones in the Pacific

9 07 2015

The Pacific Ocean has seen a lot of early season tropical cyclone activity with a total of 11 cyclones forming before the end of June. This included some intense systems such as typhoons Higos, Maysak, Noul and Dolphin in the west Pacific and hurricanes Andres and Blanca in the east Pacific.

After a brief respite, early July has seen the development of further tropical cyclones across the Pacific Ocean triggered by a cyclical phenomenon known as the Madden-Julian Oscillation (MJO). The MJO is a pulse of cloud and rain which works its way eastwards around the globe in tropical regions. It often is seen to start in the Indian Ocean before crossing into the Pacific Ocean and occurs on a timescale of 30 to 60 days. The magnitude of the MJO will vary, but the event which moved into the western Pacific early in July has been very strong. A strong MJO produces conditions which are very conducive for tropical cyclone formation.

At the start of the month, the MJO event resulted firstly in the spinning up of twin cyclones – storms either side of the equator at the same longitude. Chan-hom formed in the north Pacific, whilst Raquel developed south of the equator. Raquel brought unseasonal heavy rain to the Solomon Islands before dissipating.

Left to right - Typhoons Linfa, Chan-hom and Nangka on 9 July 2015. Image courtesy of The National Institute of Informatics.

Left to right – Typhoons Linfa, Chan-hom and Nangka on 9 July 2015.
Image courtesy of The National Institute of Informatics.

Chan-hom has continued to develop into a typhoon and has been joined by Typhoon Linfa to the west and Typhoon Nangka to the east as seen in the satellite image.

Linfa has just made landfall over southern China and is expected to bring stormy conditions to Hong Kong in the next day or so. Chan-hom is expected to pass close to the Japanese island of Okinawa before making landfall over eastern China. Nangka is currently over open ocean, but could affect south-western Japan in a few days time.

The tropical cyclone activity does not end there, however. As the MJO event moves east it is set to trigger more tropical cyclones in the central and eastern Pacific. Tropical Storm Ela has already formed and is set to pass just north of Hawaii in the next few days. There is also the indication from computer forecast models that one or two more tropical cyclones could develop in the eastern side of the Pacific in the next week.

The strong westerly winds associated with the latest MJO event are helping to enhance the developing El Niño by pushing warm waters in the western Pacific towards the east. A strong El Niño tends to promote tropical cyclone activity in the Pacific whilst suppressing it in the Atlantic.

Conditions are very unfavourable for the development of tropical cyclones in the Atlantic at present and we expect this to continue for much of the season. However, whilst activity is expected to be below average, this does not exclude the possible development of a few hurricanes in this region during the remainder of the year. Meanwhile, the Pacific is expected to see continued above average levels of tropical cyclone activity.

Official warnings for the latest tropical cyclones are produced by the Japan Meteorological Agency and the Central Pacific Hurricane Center. 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.





On the record – observing a ‘heatwave’

7 07 2015

Last week on 1 July the UK saw its warmest July daily max temperature on record (records date back as far as 1853), with 36.7 °C at Heathrow. This has led to considerable interest in the wider context of the record temperatures. Here, Mark McCarthy, Manager of the Met Office National Climate Information Centre discusses records and how we record them.

Where were record temperatures observed on 1 July 2015?

Although Heathrow measured the highest temperature recorded by the Met Office observing network on a July day, record temperatures were reported across a wide stretch of the country, including from some of the Met Office’s very long running climate stations.

Temperatures exceeded 35 °C at a handful of locations in London and the south east, but also reached the low 30s across the Midlands, East Anglia and parts of north-west and north-east England. It is in these areas that July temperature records were broken.

Map showing stations recording new July temperature records, 1 July 2015

Map showing stations recording new July temperature records, 1 July 2015

The table below lists those stations with more than 50 years of observations for which 1 July 2015 was a record. These data show that record temperatures for July were not confined to London or other major urban centres. The records were, in fact, part of a larger scale pattern of high temperatures extending through Spain, Portugal and France.

SITE DATE OF PREV JULY RECORD PREV RECORD JULY MAX (°C) 1 JULY 2015 MAX (°C) YEARS OF DATA
Durham 31/7/1943, 10/7/1921 30.6 31 133
Sheffield 31/7/1943, 10/7/1921 31.7 33.3 130
Bradford 31/7/1943, 13/7/1935 30.6 30.9 106
Cranwell 22/7/1996 32.6 34.3 93
Sutton Bonnington 19/7/2006 32.9 33.6 84
Stonyhurst 3/7/1976 31.1 32.6 75
Manston 15/7/1983 31.4 33.6 74
Goudhurst 3/7/1976 32.8 33.3 74
Waddington 12/7/1949 32.2 33.1 67
Heathrow 19/7/2006 35.5 36.7 66
Nottingham (Watnall) 3/7/1976 32.3 33.9 64
Marham 3/7/1976, 5/7/1959 32.8 33.5 58
Wittering 5/7/1959 32.8 35.3 53
St James’s Park 5/7/1959 34.4 34.7 52

How does this compare to past heatwaves?

Temperatures over 36 °C reported at any station in the UK observing network are very rare, with only a handful of notable heatwaves seeing such extremes. The heatwaves of August 1990, August 2003, and July 2006 each saw a number of stations exceed 36 °C, whereas on 1 July 2015 Heathrow was the only station.

The Met Office maintains a list of climate extremes for the UK. It is standard practice to report the highest and lowest temperature every month as part of our routine monitoring of UK weather and climate. It is therefore always noteworthy when one of these records is broken.

While there is no doubt that some previous heatwaves have seen more extreme or more widespread high temperatures overall – particularly in the climatologically warmer period from late July into early August – 1 July 2015 has the honour of holding the highest recorded temperature for a July day with 36.7 °C at Heathrow.

How do you ensure the data are reliable?

To ensure consistency, Met Office weather records are only given for stations with standard instruments and exposure. This means that our records would not represent the extremes that may have occurred in places where we do not have standard instruments. This may have been the case on 1 July 2015, where the availability of additional data from amateur observers contributing to Met Office WOW show peak temperatures in the range 35 to 37 °C to the west London.

It is reasonable to ask whether Heathrow, as a major international airport, can provide a reliable climatological record. Are the observations biased by the presence of runways and air traffic?

The instrumentation and station enclosure are managed so that they meet the standards required by the Met Office and set out by the World Meteorological Organization. The site has been operating for 66 years and provides an excellent long observational series for west London.

The first thing we can do is compare the climatological temperatures with a nearby station at Kew Gardens. The average daytime maximum temperatures for the two sites are very close:

Site June July August
Heathrow 21.04 °C 23.54 °C 23.15 °C
Kew 21.02 °C 23.48 °C 23.15 °C

On 1 July the maximum temperature recorded at Heathrow (36.7 °C) was higher than Kew (35.7 °C). Modern instrumentation means we can look at the temperatures minute-by-minute at the two sites, as shown below. The two locations recorded very similar temperatures through most of the afternoon and the average temperature at the two sites between 12:00 and 18:00 GMT agree to within 0.02 °C. However, there was a peak in temperature at Heathrow between 14:00 and 14:30 GMT that was not seen at Kew Gardens. What could cause such a peak?

Temperature (°C) graph for Heathrow and Kew Gardens 1 July 2015

There were scattered clouds in the area that afternoon. Both Heathrow and Kew Gardens have instruments measuring solar radiation, shown in the graph below. Both sites recorded a general dip in solar radiation due to clouds from approximately 13:30 to 15:00 GMT which corresponds to a slight cooling at both sites. Heathrow saw a short gap in the clouds shortly after 14:00 GMT which resulted in a similarly short lived peak in temperature, while Kew Gardens remained cloudy. In turn Kew Gardens then saw a brief spell being sunnier than Heathrow just before 15:00 GMT and became warmer than Heathrow for about an hour.

Solar radiation (W/m2) graph for Heathrow and Kew Gardens 1 July 2015





Hotter weather for the start of July

25 06 2015

The weather is showing signs of heating up next week for the start of the Wimbledon fortnight.

In contrast to June so far, which has seen temperatures often near or just below normal, next week could see a real change in the way it feels – with hot days and humid nights, especially across the south.

It looks like heat will start to build across Iberia later this weekend and spread northwards across France early next week as a tropical continental airmass begins to dominate the weather. Temperatures across Iberia and southern France could reach the low 40’s Celsius by midweek with northern France seeing temperatures into the mid to high 30s Celsius.

Data: European Centre for Medium Range Weather Forecasts

Data: European Centre for Medium Range Weather Forecasts

The UK is likely to be near the boundary between this tropical continental airmass and a tropical maritime airmass over the Atlantic, but we do expect to see temperatures rise across the whole of the UK for the start of July.

Scotland could see highs in the low to mid 20’s (although it may be cloudy here at times), and highs across southern Britain are likely to reach the low 30’s Celsius with a small chance of values in the mid 30’s here.

It’s worth saying that there is some uncertainty about how much of the hot weather from the continent will reach us, and it may only last a couple of days before temperatures drop a little. As is traditional with hot weather in the UK in the summer it may end with thunderstorms.





Large solar storm brings spectacular views of the aurora

23 06 2015

Updated 24 June 2015

The Space Weather team at the Met Office has been keeping a close eye on solar activity over recent days. A large solar storm resulted in the northern lights being seen as far south as Dorset and Bournemouth on Monday night.

Taken by Richard Cliff on Exmoor

Taken by Richard Cliff on Exmoor

A particularly active sunspot came into view during the early part of last week. This sunspot continued to grow in complexity which has resulted in a number of moderate solar flares and coronal mass ejections (CMEs) which is when the Sun ejects some of its atmosphere out into space. This can be seen on the image below as a faint circle, almost like smoke. These travel at speeds of around 2 million mph. On Sunday one such CME was launched directly at Earth. Travelling at these speeds it still took almost two days to travel the 93 million miles from the Sun to Earth. When it hit Earths magnetic field it caused a Severe Geomagnetic Storm (A G4 storm on a scale of 1 to 5). It was this which caused the Aurora to appear in the skies of southern England on Monday night.

Solar flare released on 21 June

CME from 21 June visible as a faint circle

Large geomagnetic storms can result in disruption to power grids, which is why it is important that these storms are monitored and warned for, although fortunately the UK grid is more resilient to space weather than the grids in many other countries. There are no impacts on human health as a result of these solar storms, in fact they can have some very welcome effects in the form of increased aurora, both in effect and extent.

Our Space Weather advisors are now watching another CME, which looks like it could be heading our way. This has the potential to bring another night of spectacular aurora views on Wednesday night. To see the northern lights, wait until at least half an hour after sunset, go outside away from artificial lights, let your eyes accustom to the dark and look towards the north. There will be some cloud around tonight, check out our cloud cover forecast for more information.





Met Office staff and affiliates recognised for their work

19 06 2015

World renowned Met Office Chief Scientist Professor Dame Julia Slingo DBE FRS has been awarded the prestigious International Meteorological Organisation (IMO) Prize.

This is the first time, since 1998 that the annual prize, awarded by the World Meteorological Organisation, has been presented to a UK scientist and it is an acknowledgement of her lifetime contribution to world meteorology.

Julia said: “I am very surprised but rather delighted to be recognised by all my meteorological colleagues around the world.  The prize giving will be next June in Geneva where I also have to give a lecture.”

 

Julia Slingo

Queen’s Birthday Honours List

Meanwhile three men who collaborate with or support the Met Office have been recognised in this year’s Queen’s Birthday Honours List.

Dr Kamal Puri, from the Australian Bureau of Meteorology has been awarded a Public Service Medal (PSM) in the Queen’s Birthday Honours List.  The PSM recognises outstanding service by employees of the Australian Government and state.

Kamal has worked in numerical weather prediction and earth system modelling in the Bureau for the last four decades. He is a Met Office Science Advisory Council member and has played a key role in development of our Unified Model partnership. In 2007 he helped develop the Australian Community Climate and Earth System Simulator (ACCESS) which has directly contributed to advanced warnings of hazards such as fires, heatwaves, floods and cyclones, saving many lives.

DR Rob Vertessy, Director of Meteorology and CEO at the Australian Bureau of Meteorology said:  “Kamal’s leadership has enhanced the reputation and standing of Australian weather and climate modelling in national and international circles, and I am sure that you will all agree this award is well-deserved recognition for an exemplary leader and ambassador for the Australian Public Service and the Bureau of Meteorology”.

90 year old Voluntary Weather Observer, Donald Grant, has been awarded the British Empire Medal (BEM) for services to Meteorology after supplying weather readings to the Met Office for the past 30 years from his weather station in Dunbar, East Lothian.

Finally Professor Chris Budd from the University of Bath has been awarded an OBE for services to science and maths education.  He works closely with the Met Office helping improve weather forecasting accuracy and he co-founded an international network bringing together mathematicians working in climate change with policy-makers.





Tropical Depression Bill continues to bring heavy rain to parts of the US

18 06 2015

The second named tropical storm of the north Atlantic hurricane season, Bill, has been making headlines this week after it made landfall in the US on Tuesday night.

Bill arrived southeast of Houston, Texas where it weakened into a tropical depression as it moved inland. It didn’t weaken as quickly as might normally be expected and this was due to Brown Ocean Effect.

Bill-sat

Tropical storms or cyclones tend to get their energy from warm sea water, and weaken once they move across land. However, given the time of year, the ground has warmed significantly across southern states, and the ground is saturated following a recent record wet May. This means that there is enough heat and moisture available to mimic the ocean, hence the name Brown Ocean Effect. The effect is boosting Bill as forecast, and enabling it to dump phenomenal amounts of rain across parts of Texas and Oklahoma.

Radar image of Tropical Depression Bill on 17 June

Radar image of Tropical Depression Bill on 17 June

Tropical Depression Bill brought 70 to 80mm of rain across parts of southern Texas on Wednesday, with many rivers in the region flowing at high levels after recent heavy rainfall. Thursday could see more than 100mm for parts of Oklahoma and Arkansas, potentially leading to some flash flooding. The remnants of the storm are then expected to continue north-eastwards towards the south of the Great Lakes, moving offshore again close to New York.

By the time the remnants of Bill cross the Atlantic towards the UK, it will be indistinguishable from any normal low pressure we’d expect to see at this time of year.

It’s too early to say what impact, if any, Bill would have on the UK – but we wouldn’t expect any possible impacts to be anything out of the ordinary for UK summer weather.





Mixed bag for the start of June

17 06 2015

It has been a very varied weather picture so far this month.

It’s been dry and warm for the south east of the UK, with some places around London having received less than 5 mm of rainfall so far and areas such as Essex, Hertfordshire, Suffolk and Cambridgeshire receiving less than 20% of the month’s average in places.

This year’s highest UK temperature so far, 26.8 °C, occurred at Kew Gardens (Greater London) on the 12 June.

Much of the rest of the UK has seen temperatures in general noticeably below average for June, continuing on from the rather cool May.  While rainfall totals are already close to the whole-month average in the central Scottish Highlands and in Nottinghamshire.

MeanTemp June

June began with two very unseasonal days, due to a deep low-pressure system to the west of the UK, bringing large amounts of rain and some strong winds to the UK, particularly southern areas. Apart from this, and some showery rain on the 5th/6th,

June so far has been relatively settled, especially over southern areas, although we saw a period of thundery outbreaks on 12th June affecting mainly southern areas due to a plume of very humid and warm unstable air moving in from France/Spain.

Mean temperatures for the UK so far this month have been 2 °C below normal in most areas, but colder in the far north-west of the UK and a little closer to normal in southern England. While the minimum temperatures have been well below average, by as much as 3 °C over some northern areas.

mean temperature sunshine duration rainfall
1-15 June 2015 Act (°C) Diff from avg (°C) Act (hrs) % of avg Act (mm) % of avg
UK 11.2 -1.8 117.6 69 31.3 43
England 12.5 -1.6 128.3 70 23.1 37
Wales 11.6 -1.6 121.6 70 41.8 49
Scotland 9.3 -2.0 99.3 66 43.9 49
N Ireland 10.3 -2.5 114.3 76 21.4 28

We would expect figures to be around 50% of the average figures by the mid month point.

For the latest weather forecast go to www.metoffice.gov.uk/weather





New cloud comes a step closer

16 06 2015

Newly discovered cloud Asperitas (Latin for roughness) has taken another step towards being officially recognized and named in the International Cloud Atlas.

The cloud has been named Asperitas because it looks like rough or turbulent seas and has been put forward for inclusion in the Atlas by the UK Cloud Appreciation Society.

Asperatus_Undulatus

Gavin Pretor-Pinney, founder of the Cloud Appreciation Society said “It’s really exciting to see Asperitas that bit closer to becoming official. It’s great that the general public and amateur observations have influenced the atlas, it feels very democratic. The internet has resulted in increased connectivity, these days everyone has a camera at their fingertips, and this has resulted overwhelming evidence for this new type of cloud”.

The World Meteorological Organization (WMO) is currently updating the International Cloud Atlas, first published in 1896, and has now presented details of the new cloud to the World Meteorological Congress.

The WMO are making the Atlas more user-friendly and accessible and expect to publish the new edition next year. It is also expected to include the new cloud species Volutus (Latin for rolled), as well as some new “special clouds” like Homogenitus (from the Latin homo meaning man, and genitus meaning generated or made).

Met Office Meteorologist and Royal Meteorological Society George Anderson is heavily involved in updating the Atlas and said “Science, technology and photography have moved on in the past 40 years, so there is a need to update the Cloud Atlas”.

Met Office Scientist, Graeme Anderson, completed a dissertation on Asperitas, for his Masters degree at the University of Reading. He said “The challenge with this particular cloud formation is its rarity. It is very difficult to get good measurement data from this type of cloud if you don’t know when or where it will appear, or how long it will last. It became clear to me that these cloud formations did not fit into the existing classifications. It’s good to see this update taking place to make the International Cloud Atlas fully comprehensive.”

A scanned version of both volumes of the Atlas is available on the WMO website.  You can use the Met Office cloud spotting guide to help you identify different types of clouds, this can be a fun activity to try with children.

 

 

 








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