saw as it certainty, like a sea saw as it where it'll sit and where we'll get the warmest air and wettest conditions. on wednesday, it looks like the cloudy wet weather across england and wales, the warmer air to the south. further north a fresher feel across northern england northern ireland and scotland, breezy as well but the best of the sunshine here. northern scotland looking brightest, southern england, looking warmest, as for the end of the week, similar story, come the next weekend, cooler aironce again, take story, come the next weekend, cooler air once again, take advantage of the warm conditions early on in the week. hello. this is bbc news with lukwesa burak. the headlines: after a four—hour armed siege police storm a bowling alley in nuneaton and free two hostages. warwickshire police say

a man has been arrested and is in police custody. the leisure park was on lockdown for most of the afternoon. the ambulance service confirms nobody was injured during the incident. in other news, the zimbabwean president, robert mugabe, is removed as a goodwill ambassador for the world health organisation, two days after his controversial appointment. now on bbc news, a weather world special from florida and the bbc weather centre. the team examines why this yea r‘s atlantic hurricane season has been so active. this time on weather world, i'm in florida in the united states where the power of hurricane irma has had devastating consequences. and we'll be speaking to scientists about forecasting tropical cyclones here in the weather centre. key indicators are the atlantic in august and september. we will be looking at the season's

other major hurricanes, including harvey and maria. plus the science behind these monster storms, and how climate change could be affecting them. from harvey's unprecedented tropical deluge in texas. and irma's record—breaking intensity as it slammed into the caribbean, before heading to florida. to the explosive intensification of maria, as the caribbean took another devastating hit. this is the story of a hurricane season that at times has produced more power, more rain, and more destruction than ever recorded. it's one thing to talk about wind speed, and pressure, but it's a completely different thing to experience a hurricane first—hand. welcome to this special

edition of weather world, from here in florida, where the extensive damage caused by hurricane irma will take months to repair. it was here, in september, when hurricane irma became part of one of the most destructive hurricane seasons, and some say the most damaging since hurricane katrina slammed into new orleans, killing 1,800 people over a decade ago. before hurricane irma, there was harvey, as nick explains. here at the bbc weather centre, we've been following the twists and turns of a remarkable and record—setting atlantic hurricane season. hurricane harvey, bound for the texas in august, brought warnings of catastrophic flooding. and it went on to become the usa's wettest tropical cyclone

it has recorded. 4,323 days, almost 12 years — that is how long it had been since a major hurricane had hit the usa. but harvey changed all that. dan, are you in here? having rapidly intensified since it formed in texas, as a category four storm, with winds of 130mph. it was the most powerful hurricane to hit texas since 1961. did you sleep? no, i secured the roof, and about 10:30pm, there is a tree in my yard. and then their house is completely gone. but, after the initial destruction, worse was to come. harvey stalled near the texas

coast, only slowly edging towards louisiana, still able to tap into the warm sea. it became a prolific rain maker. as streets turn into rivers, the us to prescribe the situation as unprecedented. this was new hurricane territory, and houston, the fourth—largest city in the usa, was in the bull's—eye. and, as the deluge went on, more and more people had to abandon their homes to the rising floodwater, with anything that could float becoming part of a makeshift armada leading people to safety. this is what harvey did to houston, killing it at least 30 people in this area alone, and more than 80 in total. these pictures show the remarkable transformation to the landscape from harvey's rain. as much a 64 inches, over 1,600 millimetres of rain, fell in a week—long deluge, causing billions of dollars of damage. hurricanes — a formidable force of nature that can cause devastation to all in their paths. so just how do they form, and why has 2017 been so intense? let's take a look at

the science behind the storms. hurricanes form due to an area of low pressure that strengthens rapidly over tropical or subtropical waters. a cluster of thunderstorms can form, and these clusters of thunderstorms then draw in a flow of warm and moist air, as they move over these warm waters, creating a low—pressure centre. now, if conditions are just right, a tropical storm is born, which can then strengthen into a full—blown hurricane. now, this year, there has been a particularly strong west african monsoon, meaning bigger and more frequent storms in the hurricane development zone. now, several specific conditions need to come together to trigger hurricane formation. firstly, temperatures need to be

higher than 26 celsius to provide the fuel for these big storms. this year, waters across the western atlantic and the caribbean had often been high for the time of year. and also, we need a lack of wind shear. now, wind shear, in other words, is when winds that don't very much in speed and direction, but in height. but lower wind shear allows a storm to rise vertically. also, el nino has been stuck in a neutral phase this year. that has led to lower wind—shear and increased hurricane prospects. the storm has to be a sufficient distance away form the equator for the coriolous effect kicking to provide the spin. now, all of these conditions have often come together doing this year's hurricane season, producing several hurricanes of more than six miles high, and hundreds of miles wide,

devastating huge swathes of the eastern caribbean. now, earlier, we had how harvey set new records for rainfall. the next hurricane, irma, was also to take its place in the record books for power and intensity, and tomasz experienced it. hurricane irma, bearing down on the caribbean in early september as a maximum category 5 storm, with winds of 185 mph, the strongest hurricane ever recorded this far east in the atlantic. this is what it sounded like as irma moved across the northern islands. and this is what a category 5 hurricane leaves behind. the island of barbuda, from caribbean paradise to ruins. everybody — it's just gone. what do you do now? i don't know. i'm just waiting to get evacuated from here, and then i'm going to come back, and try and salvage something, and help, i don't know. my whole life is here, so... but it wasn'tjust barbuda.

irma caused extensive damage here in the british virgin islands, plus st martin, st barts, anguilla, and the turks and caicos islands. after briefly weakening, irma was back to category 5—strength, with winds of 160 mph. as it made landfall in cuba, creeping along the island's northern shore for most two days. as irma was hitting cuba, i was in the united states, which was waiting for its second major hurricane in as many weeks, and this time the target was florida. hurricane irma is battering cuba, around 300 miles to the south of us. and, even here, you can feel the power of the storm. that's how big it is. irma's florida landfall

was in the keys, causing major damage as a category 4 storm, with winds of 130 mph. as irma moved north, this was the scene in naples. the eye wall is coming upon us, it's getting really intense now at the centre section. and then irma reached my location, in tampa. it had weakened slightly, but it was still a category 2 storm, and i wanted to see if it was safe to experience the conditions outside. it's one thing to talk about wind speed and pressure, but it's a completely different thing to experience a hurricane first—hand. it must be devastating for people caught in the storm. more than 120 people are known to have died as a result of irma, including at least 80 in the united states. but, as the clean—up began here, it wouldn't be long before

the caribbean was in the firing line again. but how do we knowjust how strong these hurricanes like irma are, before they hit land ? here is nick again. commercial aircraft steer around hurricanes, but not the hurricane hunters, including these of the us air force reserve. their mission is to fly when no—one else dares, this time right into the heart of hurricane irma. the more times we pass through the eye wall, the better they can calibrate exacting where the storm is moving. you're flying through stuff no—one else flies through, it's not pretty. but all the training you do has to kick in all at once, because the plane is falling and you are just holding on looking for good air.

we are back now at the bbc weather centre, and i'm joined by professor mark saunders. mark is a climate prediction scientist. he is involved in predicting hurricanes and tropical cyclones right around the world. so thank you forjoining us. just expect to me, how do we even begin to predict a hurricane season? we use computer models. between august and september, two of the key environmental fields are how warm or cold the tropical atlantic sea temperatures are in august and september, and how strong the trade winds are, blowing across the atlantic from west africa to the caribbean. and, if we can pick those perfectly, then you can generally get a very good understanding of how active or quiet the hurricane season will be. 2017 has been a particular hurricane season. did the forecasters get it right, and if not, what went wrong? we got it right to a large degree,

in that most forecasts predicted it would be above normal hurricane season. but not the actual hyperactive levels, they were not anticipated. we think one of the factors that contributed that mis—forecast was the sudden cooling of the waters in the tropical areas called la nina. waters called by a big degree by august, that's quite unusual and contributed to a more stable atmosphere conditions over the tropical atlantic, which enable storms to build up and become stronger, and also have more of them. —— waters cooled by a big degree by august, that's quite unusual. thank you forjoining us. and coming up, from the hurricane front line, i'll be giving my experiences of reporting joined the storm. and what caribbean caves can tell us about hurricanes of the past and future. so far in this weather world special we've been concentrating

on hurricane irma. but it wasn't the only tropical cyclone with the deadly impact. it too would reach category 5 strength and head for the caribbean. nick has the story of hurricane maria. here we go again, september, and yet another hurricane rapidly intensifies. this is guadeloupe, hit by wind and rain, a months worth injust a day. but, by the time maria's eye had passed, dominica had taken a hit. this unverified video was made as the lights went off. after the hurricane, the full horror of what happened here was revealed. these were the strongest winds on record to have hit this island, and at least 30 people were killed. when maria made landfall in puerto rico, it was a category 4 hurricane, and the strongest here since the 1920s.

as ever, it's notjust the winds that does the damage. it's the water, too, both from flooding rain and the storm surge, causing catastrophic flooding. all of the elements combined to leave the entire island without power, amid fears of a high humaintarian crisis. maria then came close to the dominican republic, before turning north, away from the usa. in october, nate followed maria. as a tropical storm, it first made landfall in nicaragua, with severe flooding damaged thousands of homes. nate was blamed for the deaths of at least 25 people, including nicaragua, but in costa rica and honduras, too. next in nate's sights was the usa. strengthening, it became the fastest—moving hurricane ever recorded north of mexico.

it hit mississippi as a category one storm. but, at least with this hurricane, impact in the usa were not as serious as has been feared. we know a lot about hurricanes in the era of modern weather technology, past 100 years or so. but what about the hurricanes that came before that? well doctors james and lisa baldini from durham university running a project in the caribbean to answer that question. thanks forjoining me. it involves being to caves. yes, it does. caves are the most obvious place to look, but in fact they are full of really interesting deposits called stalagmite and stalagtites. what we aim to do in this project is to reconstruct long—term records of hurricane impact, and... you've got a stalagmite here, what does that tell you? they grow up from the ground of the cave, and they are deposited as the drip water

drips onto the ground. that drip water has a chemical signature that reflects the rainfall at the time it was going. hurricanes have a really unique chemical signature, because the water actually evaporates from the ocean surface, and it is drawn up kilometres in the sky, and that is where temperatures are lower, and it impacts the chemical signature of that rainfall, so we can look at the chemistry, going through a time, and we can pick out years when there were more hurricanes, and years when there were fewer hurricanes. so the information you can learn depends on how old the stalagmites are? yes that's right. the record we had to about is back to 1550ad. at about 450 years long. but stalagmite can grow for a very long amount of time. we can date them 600,000 years ago. it is likely we will be able

to extend that record. that will give us the information that we will need to assess what is happening now. i am fascinated to learn what you have learned so far, but the indications for the future, we will look at that, for now, thank you. from science success to an infamous epic fail. earlier on today, a woman on the bbc had heard that there was a hurricane on the way. if you are watching, don't worry, there isn't. michael fish‘s ill—fated reassurance of the storm that hit 30 years ago was technically correct. it was not a hurricane, but a area of low—pressure that felled 15 million trees. the storm's wind gust of 115 mph was recorded in west sussex. —— it was not a hurricane, not even an ex—hurricane,

but an area of low—pressure that felled 15 million trees. the storm's wind gust of 115 mph was recorded in west sussex. sustained winds that strong would rank as a category three major hurricane, but just how are hurricane wind speed ranked? here's sarah. we often talk about the strength of hurricanes in terms of their categories. atlantic hurricanes measured on the saffir—simpson scale. this is a one to five scale based on wind speeds. the skill provides examples of the type of damage and the impacts associated with given wind speeds. category one, winds are between 74 and 95 mph, and can cause some damage to roofs and gutters and topple small trees. category two, winds between 96 to 110 mph. they can cause more extensive of damage and power failures. category three, storm becomes a major hurricane, with winds between 111 and 129 mph, and can lead to devastating damage to buildings.

category four hurricanes produce winds of 132 to 156 mph, enough to caused catastrophic damage to roofs and exterior walls and power cuts that can last for months. category five hurricanes, wind speeds in excess of 157 mph. this will cause catastrophic damage to entire homes and buildings too. affected areas will become uninhabitable. destructive winds and torrential rain. this looks like a hurricane. in fact, it's a typhoon. it was slamming into china's guangdong coast in august. the reason for the similarities that hurricanes and typhoons are the same in everything but name. earlier on in the programme we looked to do a fascinating research project in place in the caribbean. this was true caves through the use of stalagmite. we have not yet revealed what you have found out through the study of what is

happening with the stalagmites. what have you discovered? what we see is a peak in tropical cyclone activity affecting our site and around 1650ad, around 400 years ago. this is in belize? yes, this is in belize. we see this peak in activity affecting our site around 1650ad. now, 1650 was remarkable, because it was the peak of what is known of the little ice age that affected

the northern hemisphere. after that, the northern hemisphere temperatures were warming, but we see a decrease in tropical cyclone over time. i think first it is important to emphasise that there is a lot of randomness with how hurricanes go. so any given year, 2017 is a good example of this, hurricanes can either steer out into the atlantic, or hit central america. there is a lot of randomness about where they go. the average track through time is migrating north. unfortunately, what this means is that hurricanes can still strike in the atlantic basin, but on average, the north—east coast in north america can expect in increase in the number of hurricane landfalls. thinking along the lines of hurricane sandy in 2012. it's could become increasingly normal over the next few decades. is there something in this that may make people in europe sit up and take notice? we see that the dominant cyclone track is moving northward through time, this also means that there could be an increase in the frequency of storms in the north atlantic, and also potentially impacting europe. is this an ominous sign for europe,

and other major hurricane, but this one further east in the atlantic than ever seen before? hurricane ophelia first started wildfires in spain, killing more than 40 people. then, as it sped north, it remains a powerful storm. ireland bore the brunt, with three people being killed. elsewhere in the uk, dust from the sahara carried along by ophelia, gave the sun and unusual red glow. hurricanes rightly leads to mass public evacuations, and one of the biggest in american history trip is ahead of irma. butjust as most people are leaving, weather reporters go to the storm, getting as close as they can, to tell the story. this was in florida, but it requires is national team and technological effort. this is where i was during

the height of the storm in downtown tampa. hurricane irma holds the record for sustaining category five for longer than any other storm in history. to the viewer, it may have seen that i was anyone there, but there was the cameraman and the producer, out in the middle of the street. i lost everything in my home. what can be destroyed in a matter of hours can take weeks, months and maybe years to repair. here in puerto rico, just as many have caribbean islands, the damage was extensive. with power, food and water shortages. in the british virgin islands

they were delivering desperately needed aid. here in the turks and caicos islands, the story is the same. hurricanes come and go, but the effect that they have on millions of lives goes on long after the storm has passed. and that is it for this special edition of weather world, with nick and sarah in the bbc weather centre in london, and from me here, until then, keep checking the weather. with evening, this weekend we have really ta ke n with evening, this weekend we have really ta ken a with evening, this weekend we have really taken a battering, courtesy of storm brian, these are scenes from the cornish coast, ripped up by strong winds. little ridge of high pressure overnight for us, this area of low pressure out here in the atla ntic of low pressure out here in the atlantic will keep us busy on the weekend, with attendant whether from sweeping away across the british isles. it of a breather for the

sweeping away across the british isles. it of a breatherfor the next few hours, showers clearing, chilly for a few hours, showers clearing, chilly fora time, to few hours, showers clearing, chilly for a time, to the east of the british isles, coming into the west, first signs of that weather front. either time we get to monday morning, quite a wet start for many, temperatures rising again. mild enough first thing on monday but a pretty soggy, miserable looking start on the whole, northern ireland should be nice through the morning, then brighter weather, pushing from then brighter weather, pushing from the west as the day goes on. eastern coast, particularly down towards the channel, struggling with merck through the day. biggest change, the fa ct through the day. biggest change, the fact it will feel milder for monday. monday into tuesday, this low still swirling away through the west, looking at the weather fronts, quite mixed fare on tuesday, england and wales cloudy, heavier rain for a time. northern ireland and scotland, bright and breezy, heavier showers. look at the mild air, in the south

of the front, 18 degrees in london, that mild airto of the front, 18 degrees in london, that mild air to the south of the front, trying to nudge its way further north as we go through the middle part of the week. front continuing to snake across the british isles, a lot of uncertainty, seesaw, exactly where that will sit, and we will get the warmest air and the wettest conditions. on wednesday, saudi wet weather across england and wales, warm air to the south, further north, pressure field. breezy as well, but the best of the sunshine here. gloomy conditions, milder air pushing further north on thursday again. some uncertainty about the exact position. northern scotland looks brightest, southern england looks warmest. end of the week, similar story, but next weekend we could be punching into some cooler air. make the most of the warmer conditions on offer in the week ahead. this is bbc world news today. i'm geeta guru—murthy. our top stories: the world health organisation's choice of robert mugabe as goodwill

ambassador prompted a global outcry. now, in an abrupt u—turn, it's revoked the appointment of zimba bwe‘s president. japan's prime minister, shinzo abe declares victory in his country's snap election. us secretary of state says all foreign fighters should leave and all the iraqi people to rebuild their lives. also in the programme — hair styling with a twist. we meet an artist who is getting quite a following on social media hello and welcome to world news today.