Late Season Hurricane Sandra Heading for Mexico

27 11 2015

The North Pacific Ocean has seen exceptional levels of tropical cyclone activity this season as reported in this blog over the last few months. By the end of November it is usual to see the season drawing to a close in most parts of the northern hemisphere. However, the unusual conditions in the eastern North Pacific due to the ongoing El Niño has resulted in a couple of late season tropical cyclones.

Tropical Storm Rick was relatively weak, but has been immediately followed by Sandra which rapidly strengthened into a category 4 hurricane with winds near 145 mph and a central pressure of 935 mb. The last time a hurricane formed so late in the season in the eastern North Pacific was back in 1983 when Hurricane Winnie developed in December. However, Sandra is much stronger than Winnie and has become the strongest hurricane on record to have formed in the region so late in the season.

It is barely a month since Hurricane Patricia came ashore over Mexico as a category 5 hurricane producing a narrow swathe of severe damage to mostly rural areas, but avoiding major cities. Sandra is forecast to make landfall on Saturday, but unlike Patricia is expected to rapidly weaken as it approaches the coast. Thus severe impacts from wind are not expected, although the storm could still produce a lot of heavy rain as it comes ashore. If Sandra crosses the coast as a tropical storm it will be the latest in the year that a landfall has ever been recorded over Mexico.

Hurricane Sandra at 1445 UTC on 26 November 2015 Image courtesy of US Naval Research Laboratory

Hurricane Sandra at 1445 UTC on 26 November 2015
Image courtesy of US Naval Research Laboratory

Hurricane Sandra has added to an already exceptionally active tropical cyclone season seen across the northern hemisphere (particularly the Pacific Ocean). This high activity is primarily as a result of the strong El Niño which has existed for the last few months. This has raised sea surface temperatures well above normal in parts of the Pacific Ocean and also made atmospheric conditions conducive to development of frequent and strong tropical cyclones.

Across the northern hemisphere as a whole there have now been 26 tropical cyclones which have attained category 4 or 5 on the Saffir-Simpson Hurricane Wind Scale (one-minute averaged winds of 130 mph or more). This is eight more than the previous record set in 2004. In the eastern North Pacific (east of the Dateline) there have been 10 hurricanes reaching this intensity which is two more than the previous record set in 1997. It must be noted that records relate to the era of reliable satellite data coverage from the 1960s and 1970s onwards.

Official warnings for the latest tropical cyclones in the East Pacific are produced by the US 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 via @metofficestorms on Twitter.





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.





The latest on Hurricane Patricia

24 10 2015

Hurricane Patricia made landfall at 6.15pm local time on 23rd October as a category 5 hurricane near Cuixmala, Jalisco, on the pacific coast of Mexico.  This is a relatively low populated area, 55 miles from the nearest significant city Manzanillo.  Maximum sustained wind speeds at landfall were estimated by satellite to be 165mph with gusts of 200mph.  100mm of rain has fallen widely in just 24 hours, with up to 500mm in isolated spots and an estimated 5m to 7m storm surge affected coastal areas. Consequently there has been a significant risk of coastal and flash flooding, with mud and landslides.

Patricia is forecast to rapidly weaken as it moves over the mountains of Mexico today and to dissipate as it tracks north east, though further significant rainfall and winds, along with flooding, is expected along the route in the next 12 hours.

Currently Patricia is expected to decrease, becoming a tropical storm, over central northern Mexico with wind speeds of 60 mph and gusts 85 mph later today.

Image courtesy of National Hurricane Centre

Image courtesy of National Hurricane Centre

 

Prior to landfall aircraft flew through the storm and recorded maximum sustained winds of 200mph and barometric pressure of 879Hpa, thus becoming the strongest tropical cyclone on record in the western hemisphere and the first to be recorded at over 200mph.

This will have to be verified by the World Meteorological Organisation before being considered official.

Hurricane Patricia is currently around 85 miles north-northwest of Manzanillo and is traveling at around 20 mph. Patricia has begun to decay and has sustained winds of approximately 130 mph and gust of of 160 mph, making it a category 3 storm with still potentially destructive winds.

A total of 50,000 people are estimated to have been evacuated so far ahead of Hurricane Patricia in three Mexican states. The Met Office has been, and will continue to, provide regular up dates to the FCO to best advise UK citizens in the affected area.

As it it moves across the country moisture and energy from Hurricane Patricia is expected to enhance a weather system across Texas this weekend and early next week boosting its potential rainfall (200 to 450mm over Sat/Sun) and flood threat.  This could potentially affect this weekends F1 Grand Prix in Austin, Texas.

Official warnings for the latest tropical cyclones in the East Pacific are produced by the US 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 via @metofficestorms on Twitter.

 

 





Record breaking Hurricane Patricia expected to make landfall over Mexico

23 10 2015

Hurricane Patricia has developed in the eastern Pacific and after a period of rapid intensification has become the most intense hurricane in the eastern Pacific in recorded history. US Air Force aircraft have been flying reconnaissance missions in and around the hurricane and their latest data suggest 1-minute average winds are near 200 mph and the central pressure is 880 mb. This beats previous records in the east Pacific set by Hurricane Linda in 1997 and also beats the Atlantic record set by Hurricane Wilma in 2005. Only in the western Pacific have there been a handful of tropical cyclones with a lower central pressure, and Patricia is even more intense than notorious tropical cyclones such as Typhoon Haiyan which struck the Philippines in 2013. The lowest pressure for a tropical cyclone globally was 870 mb set by Typhoon Tip in 1979.

Image courtesy of NOAA

Image courtesy of NOAA

 

Many intense tropical cyclones peak in intensity over oceans and either dissipate without making landfall or strike land at a much lower intensity. However, Hurricane Patricia is expected to make landfall over the Pacific coast of Mexico within little more than 12 hours. Thus, if any weakening occurs before landfall it will be fairly minimal.

Records dating back to 1949 indicate that no category 5 hurricane has ever struck the Pacific coast of Mexico, so potentially another record could soon be set. Based on latest National Hurricane Center forecasts landfall is likely just to the west of Manzanillo this evening local time (early hours of Saturday UK time). Whilst the strongest winds are likely to be experienced close to the coast, Patricia is expected to bring heavy rain well inland over the next day or two with several hundred millimetres possible.

Latest official forecast track for Hurricane Patricia from the National Hurricane Center

Latest official forecast track for Hurricane Patricia from the
National Hurricane Center

The exceptionally active tropical cyclone season seen across the North Pacific Ocean is primarily as a result of the strong El Niño which has existed for the last few months. This has raised sea surface temperatures well above normal in this region and also made atmospheric conditions conducive to development of frequent and strong tropical cyclones. Here are some of the recent statistics on tropical cyclone activity in 2015, bearing in mind that any records relate to the era of reliable satellite data coverage from the 1960s and 1970s onwards.

  • 15 hurricanes in the east Pacific east of the Dateline – tied with previous record
  • Nine hurricanes in the east Pacific east of the Dateline have reached category 4 or 5 – more than any previous year
  • 22 hurricanes or typhoons across the northern hemisphere have reached category 4 or 5 – four more than the previous record
  • Three major (category 3 or above) tropical cyclones have been active simultaneously in the North Pacific four times on record – two of those occasions have been in 2015.
  • Tropical cyclone activity in the central Pacific region (140-180°W longitude) has been about six times its normal level.

Official warnings for the latest tropical cyclones in the East Pacific are produced by the US 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 via @metofficestorms on Twitter.

Statistics on recent northern hemisphere tropical cyclone activity are courtesy of Dr. Phil Klotzbach of Colorado State University (@philklotzbach).





Hurricane Joaquin lashes the Bahamas but will it hit the USA?

1 10 2015

In recent months attention has focused on the very active tropical cyclone season in the Pacific Ocean brought about primarily by the strong El Niño which has developed this year. Meanwhile, the Atlantic has been very quiet with most tropical storms remaining fairly weak and only two reaching hurricane strength until now.

However, Joaquin has become the third hurricane of the Atlantic season and the second to achieve ‘major’ status – category 3 or above on the Saffir-Simpson Hurricane Wind Scale. Joaquin is currently lashing the Bahamas with winds in excess of 100 mph near the centre of the hurricane. A storm surge of over two metres is possible and rainfall totals could be as high as 500 mm. Once the hurricane starts moving away from the islands the big question is whether it will make landfall over the US east coast.

Hurricane Joaquin at 1237 UTC on 01 October 2015 Image courtesy of the US Naval Research Laboratory [local copy at http://www-nwp/~frjh/tropicalcyclone/images/nhem15/joaquin_20151001_1237z.png]

Hurricane Joaquin at 1237 UTC on 01 October 2015
Image courtesy of the US Naval Research Laboratory

The forecasting conundrum

Joaquin is currently slow moving near the Bahamas and all computer models agree that a gradual turn north will happen in about two days time. However, beyond this point there is great uncertainty as to what will happen. Joaquin is being pulled in two directions. A developing trough of low pressure over the USA would act to pull Joaquin westwards towards the US coast. However, an area of low pressure to the east – including the remnants of Tropical Storm Ida – would act to pull Joaquin east away from the USA. The situation is finely balanced and any of several outcomes could happen.

One scenario is that Joaquin could make a turn north-westwards and make landfall near the Outer Banks of North Carolina at the weekend. Computer models are now mostly moving away from this as a likely outcome. Alternatively, Joaquin could take a mostly northwards track and reach New York and New England by early next week then continue up the eastern seaboard of Canada. Finally, a third scenario allows for the possibility that Joaquin could turn north-eastwards and avoid a US landfall altogether. We recommend that a close watch is kept on guidance issued by the National Hurricane Center in coming days for updates on which scenario is the most likely to occur.

Irrespective of whether or where Hurricane Joaquin makes landfall on the US east coast, large amounts of rain are expected in this area in the coming few days due to a slow-moving frontal zone. The impact of this will be exacerbated if Hurricane Joaquin does take a turn towards the USA in the next few days with further heavy rain accompanied by strong winds and a storm surge.

 Latest forecast track of Hurricane Joaquin from the National Hurricane Center

Latest forecast track of Hurricane Joaquin from the National Hurricane Center

Recent history of US landfalling hurricanes

Hurricane strikes on the USA have been fairly infrequent in recent years – particularly those at the stronger end of the scale. In 2014 Arthur crossed the Outer Banks of North Carolina as a category 2 hurricane. Going back to 2012, Isaac came ashore over Louisiana as a minimal category 1 hurricane. In 2011 Irene made landfall on the east coast of the USA also as a category 1 hurricane. The USA avoided hurricane strikes altogether in 2010 and 2009, but in 2008 three made landfall, the most significant of which was Hurricane Ike which caused a huge storm surge as it came ashore over Texas as a category 2 hurricane. However, you have to go back to 2005 to find the last ‘major’ hurricane strike on the USA (category 3 or above), when Hurricane Wilma hit Florida.

Hurricane Sandy (sometimes referred to as ‘Superstorm Sandy’) also caused much devastation to parts of the USA east coast in 2012. It is ranked as the second most costly hurricane in US history, although technically ceased to be a hurricane just prior to the time it made landfall.

Official warnings for the latest tropical cyclones in the Atlantic are produced by the US 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 via @metofficestorms on Twitter.

Will Joaquin affect the UK?

With the confidence around the exact track of Joaquin being so low, it is currently too early to tell if this system will affect the weather in the UK. There is, however, already high confidence that we will return to more autumnal and unsettled conditions across the UK early next week. Make sure you keep up-to-date with the Met Office five-day forecast.





Typhoon Dujuan strikes Taiwan

28 09 2015

Typhoon Dujuan has today (Monday 28 September) made landfall over Taiwan on the western rim of the Pacific Ocean with sustained winds well in excess of 100 mph. Dujuan is expected to drop large amounts of rainfall – 500mm is possible – over the mountainous interior of the island which could result in serious flooding and landslides. Within the first few hours of the typhoon affecting Taiwan 142mm of rainfall has already been recorded in Taipei.

Dujuan comes just seven weeks after Typhoon Soudelor struck the same part of northern Taiwan with a similar intensity. Soudelor caused flooding, destruction due to strong winds and some loss of life. Dujuan is expected to take a similar track to Soudelor – crossing the Taiwan Strait and reaching the Pacific coast of mainland China tomorrow (Tuesday 29 September) before moving inland.

Typhoon Dujuan just prior to landfall on 28 September 2015 Image courtesy of JMA

Typhoon Dujuan just prior to landfall on 28 September 2015
Image courtesy of JMA.

Typhoon Dujuan after making landfall on 28 September 2015 Image courtesy of MTSAT

Typhoon Dujuan after making landfall on 28 September 2015
Image courtesy of MTSAT.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Dujuan and Soudelor are two of many strong typhoons and hurricanes which have occurred across the Pacific Ocean this year. One of the main contributing factors to the high level of storm activity is the strong El Niño which has developed. This is characterised by a marked warming of the tropical east Pacific Ocean. A strong El Niño can alter weather patterns in many parts of the world and in particular results in increased Pacific tropical cyclone activity. The last time an El Niño of the current strength occurred was in 1997-8 when high levels of Pacific tropical cyclone activity were also experienced.

In total there have been 43 tropical cyclones across the whole of the Pacific Ocean this year. 19 of these have acquired ‘major’ status – category 3 or above on the Saffir-Simpson Hurricane Wind Scale. The northern hemisphere season usually continues through October and November and in some seasons extends into December as well.

In addition to Typhoon Dujuan there are also two other tropical storms in the Pacific at present. Tropical Storm Niala is located in the central Pacific just south of Hawaii. It is not expected to impact Hawaii directly as it gradually weakens. The central part of the North Pacific Ocean surrounding Hawaii has seen a record number of tropical storms form this season, although Hawaii itself has avoided a direct strike from any of the storms so far.

Over in the far eastern Pacific Ocean Tropical Storm Marty is just under hurricane strength and is moving slowly towards the coast of Mexico. It is not certain yet whether Marty will make landfall, but a tropical storm watch has been issued for coastal areas including the resort of Acapulco.

Official warnings for the latest tropical cyclones in the western North Pacific are produced by the Japan Meteorological Agency. Central Pacific warnings are issued by the Central Pacific Hurricane Center and east Pacific and Atlantic warnings by the US 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 via @metofficestorms on Twitter.





Active Pacific tropical cyclone season continues

2 09 2015

Early September marks the half way point in the northern hemisphere tropical cyclone season and is often the time when we see the highest levels of activity – so how is this season shaping up?

As reported in a news release last week, tropical cyclone activity across the north Pacific has been extremely high this year with numerous intense typhoons in the west Pacific and hurricanes in the east Pacific. These are different names for the same thing – hurricanes occur east of the International Dateline and typhoons to the west.

There has been a fair amount of discussion recently in social and news media as to how ‘record-breaking’ this season has been so far. Reliable records only go back to about the 1960s or 1970s when satellite coverage of the tropical oceans became available. However, bearing this in mind, here are some of the remarkable statistics for the year up to 1st September:

  • There have been 15 tropical cyclones in the northern hemisphere reaching category 4 or 5 on the Saffir-Simpson Hurricane Wind Scale – 6 more than the previous record.
  • Tropical cyclone activity across the northern hemisphere as measured by Accumulated Cyclone Energy (a combined measure of intensity and longevity) is 200% of normal and over 20% above any other year.
  • Six hurricanes have crossed the central Pacific region – more than any other year.
  • Three north Pacific hurricanes have crossed the International Dateline – more than any other year.
  • Hurricanes Kilo, Ignacio and Jimena were all at category 4 simultaneously in the Pacific east of the International Dateline – the first time three major hurricanes have been recorded at the same time in this region.
IDL TIFF file

(L-R) Hurricanes Kilo, Ignacio and Jimena on 30 August 2015. Image courtesy of NASA.

Why the high levels of tropical cyclone activity?

One of the main contributing factors is the strong El Niño which has developed. This is characterised by a marked warming of the tropical east Pacific Ocean. Temperature anomalies here are currently at their highest since 1997-98, when high levels of Pacific tropical cyclone activity were also experienced.

What about the Atlantic?

The existence of El Niño conditions usually results in a quiet Atlantic hurricane season. This is primarily as a result of strong wind shear (winds varying in strength and direction with height) across large parts of the region. There have been six Atlantic tropical storms so far this season. Recently Danny became a major hurricane just east of the Caribbean, but quickly succumbed to the strong wind shear as it entered the Caribbean Sea. Erika threatened to develop into a hurricane, but again dissipated in the Caribbean due to a combination of high wind shear and interaction with islands such as Hispaniola.

In the far eastern Atlantic, conditions were favourable enough for a hurricane to quickly spin up as a cluster of thunderstorms moved off the west coast of Africa a few days ago. Fred became the most easterly forming hurricane in the tropical Atlantic Ocean and the first recorded hurricane to hit the Cape Verde Islands since 1892. However, as Fred has continued to move north-westwards it has also been subject to strong wind shear and is weakening rapidly.

What about the rest of the year?

Seasonal model predictions suggest that the strong El Niño will persist for several months to come. Hence it is likely that the high tropical cyclone activity in the Pacific will continue for the remainder of the season. The Atlantic is expected to have a quiet season overall, but this does not exclude the possibility of the development of a major hurricane. There are notable instances of damaging hurricanes occurring in otherwise quiet seasons such as Hurricane Andrew in 1992 which caused devastation in Miami, Florida.

Official warnings for the latest tropical cyclones in the western North Pacific are produced by the Japan Meteorological Agency. Central Pacific warnings are issued by the Central Pacific Hurricane Center and east Pacific and Atlantic warnings by the US 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 via @metofficestorms on Twitter.

Statistics on recent northern hemisphere tropical cyclone activity are courtesy of Dr. Phil Klotzbach of Colorado State University (@philklotzbach).





First hurricane for Florida since Wilma ten years ago

26 08 2015

Tropical Storm Erika was around 390 nautical miles east of Antigua on Wednesday morning and is moving west at around 18mph. The storm is expected to track close to Puerto Rico and the Lesser Antilles  on Thursday and then towards the Bahamas or South Florida by the end of the weekend, by which time Erika will probably have developed into a Hurricane.

The official guidance from Miami is for Erika to gradually strengthen to a category 1 hurricane by the start of next week. Erika will be the second hurricane of the 2015 season. Hurricane Wilma, in October 2005, was the most intense hurricane recorded in the North Atlantic, with an estimated central pressure of 882 mb.

Image courtesy of National Oceanic and Atmospheric Administration

Image courtesy of National Oceanic and Atmospheric Administration

As well as potentially damaging winds, Erika is likely to produce very heavy rainfall and a modest storm surge.

When Erika passes over the Lesser Antilles on Thursday there is expected to be 120mm of rainfall in 24 hours, but as Erika deepens near to the Bahamas and South Florida, totals of up to 400mm in 24 hours could occur, although there is some uncertainty in the exact location and intensity of Erika at this stage.

It is 10 years since Hurricane Katrina made landfall in Florida. It was the most costly hurricane on record causing an estimated $108 billion in damage in Louisiana and Mississippi. It also caused an estimated 1500 deaths. The strongest winds  were recorded during 25-30 August 2005  and were over the coastal areas of Louisiana and Florida.

No major (cat 3 or above) hurricane has made landfall on the USA since Wilma in October 2005. As for cat 1/2 hurricanes over the USA, Arthur just made landfall in 2014 (glancing blow to N Carolina) and in 2012 Isaac made landfall over New Orleans.  Although technically not a hurricane, Sandy had hurricane force winds at landfall over New Jersey. Other US hurricane landfalls since 2005 have been Irene in 2011, Dolly, Gustav and Ike in 2008 and Humberto in 2007.





Typhoon heads for Japanese volcano

23 08 2015

Typhoon Goni, which was located just east of Taiwan on Sunday morning, is expected to track across the western side of Kyushu Island in SW Japan through Monday.  There is a risk it could bring up to 200mm of rainfall in 24 hours across Kyushu, leading to a risk of flooding and landslides along with the threat of Hurricane Force winds and a storm surge.  This comes as the Japanese Meteorological Agency issues a level 4 alert for a major volcanic eruption on Mount Sakurajima.

Mount Sakurajima is one of 16 ‘Decade Volcano’ around the globe, meaning that it is a potentially destructive volcano close to populated areas. The level of alert suggests that the local population should prepare for evacuation, which would be made more difficult by a Typhoon impact.

Satellite image courtesy of National Oceanic and Atmospheric Administration

Satellite image courtesy of National Oceanic and Atmospheric Administration

Typhoon Goni has already bought heavy rainfall and Typhoon strength winds across the NE tip of Luzon in the northern Philippines.  Goni is expected to remain a Strong Typhoon (equivalent of a Category 2 Hurricane) with sustained winds of 80 knots and gusts to 115 knots, tracking steadily north through the rest of Sunday and Monday across the eastern East China Sea.  There is a risk of a storm surge and coastal flooding up through Kagoshima Bay in southern Kyushu.

Once Goni passes across western Japan, it is likely to lose its tropical characteristics, but could still bring flooding rains to the Korean Peninsula on Tuesday.

 





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.








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