Two cyclones to hit Australia

19 02 2015

Whilst here in the UK, we are coming towards the end of our winter season, Australia is coming towards the end of summer, but is in the middle of its cyclone season, and unusually there are currently two tropical cyclones affecting the country.

Severe Tropical Cyclone Lam is currently to the north of Australia’s Northern Territory, in the Arafura Sea. The storm is expected to make landfall on Thursday as a category 4 storm, between Milingimbi and Gapuwiyak. Huge rainfall figures are forecast, with 300 to 600mm daily, potentially adding up to more than 800mm in places throughout the storm event, with flooding likely inland, as well as coastal flooding and damaging winds. Residents close to the coast have been advised to be ready to move to shelter with emergency kit. However, as the area is not densely populated, significant impacts are not expected. The nearest large population centre is Darwin, and although it is likely that there will be some wet and windy weather here, it is not expected to be anything that Darwinians aren’t used to.

Credit: Courtesy of the Naval Research Laboratory

Credit: Courtesy of the Naval Research Laboratory

Storm track and warning areas for Tropical Cyclone Lam

Storm track and warning areas for Tropical Cyclone Lam

Meanwhile, Severe Tropical Cyclone Marcia is heading towards the Queensland coast, and is expected to make landfall between Mackay and Gladstone on Thursday night as an extremely powerful category 5 storm. The Australian Bureau of Meteorology are forecasting Marcia to track inland for a while and quickly weaken, before turning parallel with the coast, which keeps the main risk area to the north of Brisbane. However, there is some uncertainty with the exact track of the storm, and if it were to remain closer to the coast, Brisbane could be in line for a significant amount of rainfall, potentially as much as 400mm. Destructive winds are likely around the coast and abnormally high tides will be experienced with water levels expected to rise above the highest tide of the year. Dangerous storm tides are forecast as the cyclone crosses the coast, as well as treacherous surf on exposed beaches.

Credit: Courtesy of the Naval Research Laboratory

Credit: Courtesy of the Naval Research Laboratory

Storm track and warning areas for Tropical Cyclone Marcia

Storm track and warning areas for Tropical Cyclone Marcia

Met Office StormTracker provides a mapped picture of tropical cyclones around the globe with access to track history and six-day forecast tracks for current tropical cyclones from the Met Office global forecast model and latest observed cloud cover and sea surface temperature. We also provide updates on current tropical storms via @metofficestorms on Twitter.





One year on – A look back to last winter

17 02 2015

This weekend marked the one-year anniversary of the Valentine’s Day storm, which also marked the end of a particularly stormy three-month period. A new review article – ‘From months to minutes – exploring the value of high-resolution rainfall observation and prediction during the UK winter storms of 2013/2014’ – written by 16 Met Office co-authors reviews the accuracy of our forecasting and warning of severe weather during winter 2013-14, and assesses its performance.

The paper concludes that the “prolonged period of high impact weather experienced in the United Kingdom during the winter of 2013/14 was very well forecast by the operational tools available across space and time scales.”

Here Huw Lewis, the paper’s lead author, and Derrick Ryall, Head of the Public Weather Service, look at the extreme weather last year and the role of the Met Office in communicating severe weather through the National Severe Weather Warning Service.

Analysis chart 1200 GMT 26 January 2014

Analysis chart 1200 GMT 26 January 2014

Winter 2013/2014 in the United Kingdom was remarkable. The country was battered by at least 12 major winter storms over a three month period and was officially assessed as the stormiest period that the United Kingdom has experienced for at least 20 years.

The series of storms resulted in the wettest winter in almost 250 years (according to the England and Wales precipitation series from 1766), significantly wetter than the previous wettest winter in 1914/1915.

Snapshot of UK rain radar surface rainfall rate for 2200 GMT on 23 December 2013

Snapshot of UK rain radar surface rainfall rate for 2200 GMT on 23 December 2013

The extreme weather caused widespread flooding throughout Southern England and coastal damage – most notably in the South West and Norfolk coasts. The impact of the severe winter storms on individuals, businesses and the government were substantial, including several fatalities, widespread power cuts and damaged infrastructure.

Recent advances in forecasting, technology and the scientific developments in meteorology have been considerable. These developments and improvements in accuracy mean that a four-day weather forecast is as accurate as a one-day forecast was just thirty years ago. During the course of last winter, the Met Office was able to use these forecasts to warn of any severe weather well in advance. In the case of the St Jude’s Day storm at the end of October 2013 warnings went out to the Government and the public five days before the storm even existed.

rainfall

As the accuracy of weather forecasts has evolved, so has the communication of the potential impacts of severe weather. The National Severe Weather Warning Service enables more ‘weather decisions’ which in turn help to minimise the consequences of severe weather. The Met Office was at the heart of the government response to the storms, providing advice on weather impacts through the National Severe Weather Warning Service and Civil Contingency Advisors. The Met Office also worked very closely with both the national and regional media, who in turn played a key role in ensuring that the public were fully informed about the potential impacts of any up-coming weather.

In addition to the Public Weather Service, commercial partners and customers were also provided with detailed updates throughout the period in order for them to plan effectively for logistical issues. Together, these advanced warnings helped authorities, businesses and individuals to be better prepared to take mitigating actions.

Driving further improvements in accuracy and therefore reducing the lead time and increasing the detail of severe weather warnings is one of the Met Office’s key priorities . The ultimate aim is to improve the potential for users to plan preventative measures for severe weather events much further ahead. Underpinning all of these developments is a continuing programme of scientific research and access to enhanced supercomputing over the next few years.





Cold Weather for UK

26 01 2015

Cold weather is again on the way for the UK.  Later this week colder conditions will spread south, bringing a mixture of sunny spells and snow showers from Wednesday onwards.  Temperatures for many will be below normal for the time of year and the wind chill, due to strong winds, will make it feel very cold.

Snow showers are expected to affect parts of the northern half of the UK on Wednesday and Thursday and the Met Office has issued a yellow severe weather warning  for the potential impacts and this will be updated as required this week.  Don’t be surprised to see some snow showers across southern areas too, but these are not currently expected to be heavy enough for the snow to settle.  The northerly winds and cold weather are likely to continue into the weekend.

Is it due to the polar vortex?

There have been reports the cold weather is due to a “displaced polar vortex”.  The large-scale low pressure area in the stratosphere, known as the Polar Vortex, is displaced towards Russia and looks likely to stay that way over the next few days.  However this is not directly responsible for changes in the weather during the coming days. The cold northerly winds we are expecting at the end of the week are not unusual for winter.

What is the jet stream doing?

The jet stream is forecast to move south of the UK from Wednesday onwards. This means we will be on the ‘cold side’ of the jet and cold air from the poles/Arctic will work its way southwards to affect the UK.

Jet Stream forecast map for Saturday showing the track to the south of the UK.

Jet Stream forecast map for Saturday showing the track to the south of the UK.

Is the snowstorm in the USA coming our way?

The snowstorm affecting the east coast of the USA is not coming towards the UK.  It is expected to move away from the States, crossing the Atlantic to the south of the UK to bring heavy rain to Spain and Portugal at the end of the week.

 

 

 





Why are we now seeing colder weather across the UK?

16 01 2015

Over recent weeks, we have spoken about the very strong jet stream across the Atlantic, driving areas of intense low pressure towards the UK. This has bought spells of very wet, windy but relatively mild conditions to the country.

As many of you would have noticed, although the wind and heavy rain has eased, there is now a colder feel to the weather, both by day and night. But what has caused this change in the weather?

Once again the change is down to the jet stream. It has weakened and its track has moved further south, keeping the deep low pressure systems away from our shores. However, now the UK is to the north of the jet stream we are on its cold side, and this has allowed colder weather to feed in across the country.

Current jet stream

Current jet stream across the Atlantic

So what does this mean for us?

As we look ahead into the weekend and next week, the cold weather looks likely to continue. Daytime temperatures will be near or below average and there will be some frosty nights, as temperatures fall below freezing in many areas. We’ll see some sunny spells around and there will also be showers or longer spells of precipitation in places, giving a mixture of rain, hail, sleet or snow, which may settle in some areas.

Because of the threat of wintry weather over the coming days, we encourage everyone to keep up to date with the latest forecasts and national severe weather warnings and to stay weather aware this winter by following the Met Office on Twitter, Facebook, Google+ and YouTube for the latest weather information. You can find information about how to prepare for every aspect of the winter season at Get Ready for Winter.

As we head towards the latter part of the month, we can see some indications that milder weather may return, but there is considerable uncertainty about this so far in advance.





Strongest winds overnight 14 – 15 January 2015

15 01 2015

As expected, a powerful low pressure system affected the UK yesterday evening and overnight bringing gales and heavy rain to many areas.

The low pressure system will continue to affect the UK today, bringing sunny spells and blustery, heavy showers with the chance of thunderstorms and snow over high ground. Severe gales are again expected around western and northwestern coasts, with the strongest winds likely over Northern Ireland and southwest Scotland, extending to northern Scotland later. You can see detail on this on our forecast and warnings pages.

Below are some of the strongest gust speeds recorded at Met Office observing sites between 7pm yesterday and 7am today.

Strongest gusts 7 pm 14 January 2015 – 7 am 15 January 2015
Date / time Site Max Gusts (mph)
15/01/2015 00:00 CAPEL CURIG GWYNEDD 96
15/01/2015 03:00 WIGHT: NEEDLES OLD BATTERY ISLE OF WIGHT 93
15/01/2015 00:00 ABERDARON GWYNEDD 83
14/01/2015 23:00 MUMBLES HEAD WEST GLAMORGAN 81
15/01/2015 02:00 BERRY HEAD DEVON 77
15/01/2015 02:00 AVONMOUTH AVON 76
15/01/2015 03:00 ISLE OF PORTLAND DORSET 75
14/01/2015 23:00 CULDROSE CORNWALL 73
15/01/2015 04:00 TIREE ARGYLL 73
15/01/2015 01:00 LOFTUS CLEVELAND 70
15/01/2015 01:00 PLYMOUTH, MOUNTBATTEN DEVON 70
14/01/2015 23:00 SCILLY: ST MARYS AIRPORT ISLES OF SCILLY 70
15/01/2015 04:00 SOLENT HAMPSHIRE 69
15/01/2015 01:00 LAKE VYRNWY POWYS 69
14/01/2015 23:00 NORTH WYKE DEVON 68
14/01/2015 23:00 SENNYBRIDGE POWYS 68
15/01/2015 06:00 ISLAY: PORT ELLEN ARGYLL 68
15/01/2015 00:00 PEMBREY SANDS DYFED 68
14/01/2015 21:00 DRUMALBIN LANARKSHIRE 67
15/01/2015 07:00 EDINBURGH, BLACKFORD HILL MIDLOTHIAN 67

Below are some of the highest rainfall totals recorded at Met Office observing sites between 7pm yesterday and 7am today.

Highest rainfall 7pm 14 January to 7am 15 January 2015
Site Rain (mm)
ACHNAGART ROSS & CROMARTY 40.8
TYNDRUM PERTHSHIRE 39.0
TREDEGAR, BRYN BACH PARK GWENT 35.8
KESWICK CUMBRIA 35.0
THREAVE KIRKCUDBRIGHTSHIRE 31.8
LIBANUS POWYS 31.8
SHAP CUMBRIA 31.6
ESKDALEMUIR DUMFRIESSHIRE 28.2
SKYE: LUSA WESTERN ISLES 27.8
USK MONMOUTHSHIRE 27.4
OKEHAMPTON, EAST OKEMENT FARM DEVON 27.1
STRATHALLAN AIRFIELD PERTHSHIRE 25.6
GOUDHURST KENT 25.4
BLENCATHRA CUMBRIA 25.2
TULLOCH BRIDGE INVERNESS-SHIRE 24.2
WHITECHURCH DYFED 24.0
NORTH WYKE DEVON 23.6
CAPEL CURIG GWYNEDD 23.4
MIDDLE WALLOP HAMPSHIRE 23.4
CAMBORNE CORNWALL 23.0

You can share the weather you have experienced through the ‘Weather Impacts’ section of WOW

The stormy weather we have seen over the last couple of weeks is now coming to an end and conditions over the weekend and into next week look calmer but colder with frosts at night and wintry mix of showers.





Untangling the global drivers of UK winter weather

25 11 2014

As we head towards the start of winter, which starts for meteorologists on 1 December, there’s always a great deal of media and public speculation about what weather we might have in store.

To answer that question, we need to look beyond the UK. The worlds’ weather is interconnected, and there are certain large scale global drivers which we know have influences on UK weather at this time of year – so what are these doing at the moment?

El Niño, which sees unusually warm sea surface temperatures across the tropical Pacific and can increase the risk of cold winter conditions in the UK, has been much discussed after initial signs of development earlier this year.

Its progress has been slow, however, and while there remains a good chance of a weak event by the end of the year it is also possible that El Niño conditions will remain neutral. In any case, this factor is not expected to be strong enough to exert much influence on weather patterns in Europe during the next three months.

The North Atlantic Oscillation (NAO) describes differences in the usual pressure patterns over the North Atlantic – with positive and negative phases.

A positive phase is thought more likely than a negative one on average over the next three months. This is characterised by enhancement of the westerly winds across the Atlantic which, during winter, brings above-average temperatures and rainfall to Western Europe.

As we head later into winter, confidence about the heightened likelihood of positive NAO reduces – suggesting chances of drier and colder conditions return closer to normal.

The Quasi-Biennial Oscillation (QBO) sees high level (stratospheric) winds over the equator change from westerly to easterly phases – and it’s currently in the latter of the two.

In winter months this can lead to a greater incidence of high pressure blocking patterns over the northern hemisphere, which would increase the probability of colder and drier weather across Europe. Essentially this is providing an opposite signal to the NAO.

There are other factors to consider too. For example, Arctic sea ice extent is slightly below average but as yet it is not clear whether this might have an impact on weather patterns in the UK.

No single one of these drivers will determine the UK’s winter on its own – instead they all interact together to govern the weather trends we can expect over the coming months.

Disentangling these different influences remains a challenging area of science which the Met Office is improving all the time, but detailed and highly certain UK outlooks are not possible over these timescales.

The Met Office’s long-range outlooks give probabilities based on scenarios of being considerably wetter or drier, colder or milder than usual.

Currently the outlook for December 2014 to February 2015 suggests that milder and wetter than average winter conditions are slightly more likely than other outcomes. However, compared to day-to-day weather forecasts, the probabilities are much more finely balanced – for example, the outlook gives a 1 in 4 chance of the mildest scenario and a 1 in 10 chance of the coldest scenario. These numbers suggest it would be a mistake to interpret the outlook for a very mild outcome as ‘highly likely’; likewise very cold conditions cannot be ruled out.

The outlook gives similar probabilities for precipitation (rain, hail, sleet and snow), with the chances of the wettest scenario being 1 in 4 and the chances of the driest around 1 in 10.

These three month outlooks cover a whole three month period, taking into account both day and night, as well as the whole of the UK. This means that even in the event of, say, an overall mild winter we could still see spells of cold or very cold weather.

With this in mind, what exactly we’ll see for the winter ahead remains uncertain. In terms of strong winds, heavy rainfall, cold snaps or even snow, while longer-range outlooks can give us general tendencies, the details can only be predicted by our day-to-day weather forecasts.

The Met Office’s accuracy over all timescales is world-leading, however, so you can trust that we’ll keep everyone up-to-date with all the latest information on the weather whatever the winter has in store.





Dual Warnings

12 11 2014

Today for the first time we have issued a new dual National Severe Weather Warning for wind and rain.

What is a Dual Warning?

A dual warning is one warning, covering one geographical area, over one period of time in the way a single warning does – but it combines two different types of severe weather. They would only be combined if they were both at the same warning level.

Any of the five types of weather warnings, Wind, Rain, Snow, Ice and Fog, can form a dual warning in any combination. So in theory Wind and Snow could be a dual warning. In practice there are certain weather types that are more likely to form a dual warning; the most likely is Wind and Rain, which is what we see today.  More information on our dual warnings can be found at the bottom of our Weather Warning page.

These new dual warnings have been developed following extensive two-way conversations with emergency responders and feedback we have recieved from the public over the past twelve months.

Until now, we would have issued multiple severe weather warnings to cover the range of warnings in place. Quite often however, situations arise where multiple impacts occur and these can now be shown on one map. This should make the information we issue easier to access.

Today’s Warning

Dual wind and rain warning

Dual wind and rain warning

The warning for wind and rain issued today covers Southwest England, Western Scotland and the Irish Sea between 07.00 and 23.45 on Thursday 13 November. A small area of low pressure will move quickly northwards throughout the day bringing a short-lived period of gales and severe gales and spells of heavy rain.

We encourage everyone to keep up to date with the latest forecasts and national severe weather warnings and to stay weather aware this winter by following the Met Office on Twitter, Facebook, Google+ and YouTube for the latest weather information. You can also sign up for severe weather alerts from us through the Twitter Alerts programme, providing critical information directly to your phone. Find out more about how to sign up for Met Office Twitter alerts.





How will activity in the Atlantic affect UK weather?

15 10 2014

There’s lots of activity going on in the Atlantic at the moment – but how will it affect the UK?

Currently there is a big area of low pressure covering a large part of the Atlantic between North America and the UK.

While it is fairly large in its size, it’s not particularly intense, powerful or unusual.

Forecast chart for 1pm on Wednesday 15 October 2014, showing large area of low pressure in the Atlantic.

Forecast chart for 1pm BST on Wednesday 15 October 2014, showing a large area of low pressure in the Atlantic.

This means that – while it may look impressive on the charts – it’s not going to bring anything out of the ordinary for the UK over the next few days.

It will, however, be generally unsettled across many parts through Friday and the weekend, as the low pressure drives a weather system across the UK.

This will bring strong winds, with gusts of up to 50mph in the most exposed parts of the west, and rain in places. However, some parts will enjoy periods of drier and brighter weather.

Tied up in the general Atlantic circulation is an area of warm air which was originally part of tropical storm Fay.

This will bring very mild air across parts of the country, with daytime temperatures possibly reaching around 20C across southeastern areas by Saturday, well above the October average for the region of 15C.

While it will be very mild, it may not feel particularly warm given the windy and often wet conditions. The unsettled weather is expected to be fairly standard for the middle part of October.

Forecast track of Gonzalo from the US National Hurricane Center.

Over the other side of the Atlantic near Bermuda, Hurricane Gonzalo is currently expected to track north and then east across the ocean over the coming days.

There is large uncertainty about the potential track of this storm, with some models suggesting that the remnants could move across the UK whilst others show them staying away from our shores.

If the ex-tropical storm does move across the country, some parts could see gales and heavy rain, but currently extreme conditions look unlikely.

As ever, we’ll keep a close eye on developments over the next few days and keep everyone up to date if it looks like there is any sign of severe weather heading for the UK.





Severe weather to affect western France

12 08 2014

A spell of severe weather is expected to affect parts of France overnight and through Wednesday morning as an area of low pressure makes its way in from the Bay of Biscay.

The  area of low pressure highlighted in the satellite image above is expected to deepen and develop before affecting parts of France this evening and overnight.

Pressure chart for 1 am Wednesday 13 August

Pressure chart for 1 am Wednesday 13 August

Forecast rainfall for 1 am Wednesday 13 August

Forecast rainfall for 1 am Wednesday 13 August

 

 

 

This brings the risk of severe thunderstorms across western, then southern France overnight and during Wednesday morning. This will bring the potential for flash flooding and will give squally winds, with disruption to local infrastructure and to holiday makers in the region. Very strong winds and high seas are also likely for a time overnight along the western coastline of France. Meteo France currently has severe weather warnings in force.

 

This area of wind and rain should then move quickly across Switzerland and southern Germany during Wednesday afternoon.





Cyclone Quartet Straddle the Pacific Ocean

8 08 2014

In the last few days a quartet of tropical cyclones have been active across the Pacific Ocean. For a period of time all four were simultaneously of hurricane intensity (winds greater than 74 mph). This is the first time this has happened in the Pacific Ocean for 12 years. Here we take a look at each of the storms and their likely impact.

Typhoons Halong and Genevieve and Hurricanes Iselle and Julio seen on 7 August 2014 Original images courtesy of University of Wisconsin

Typhoons Halong and Genevieve and Hurricanes Iselle and Julio seen on 7 August 2014
Original images courtesy of University of Wisconsin

Typhoon Halong formed near the US island of Guam and has been active in the west Pacific for over 10 days. It is now heading north towards south-western Japan and is set to bring strong winds and heavy rain this weekend to the area only recently affected by Typhoon Neoguri.

Typhoon Genevieve originated in the east Pacific and for a long time was a weak storm, even weakening to a remnant low pressure area at one stage. However, in the central Pacific Genevieve rapidly strengthened as it traversed an area of warm waters and gained hurricane status. As it crossed the International Dateline Hurricane Genevieve became Typhoon Genevieve. There is no difference between hurricanes and typhoons except that the former is used to describe tropical cyclones east of the Dateline and the latter to the west of the Dateline. Genevieve looks set to end its life as a tropical cyclone in mid-ocean well away from land.

Hurricane Genevieve as it crossed the International dateline and became a typhoon on 7 August 2014.  Image courtesy of US Naval Research Laboratory.

Hurricane Genevieve as it crossed the International dateline and became a typhoon on 7 August 2014.
Image courtesy of US Naval Research Laboratory.

Hurricane Iselle formed in the east Pacific just over a week ago. Iselle was downgraded to a tropical storm just as it made landfall over Hawaii today, but is still bringing strong winds, surf and heavy rain. Tropical storm or hurricane strikes directly over Hawaii are very rare. The last hurricane to make landfall over Hawaii was Iniki in 1992.

Rainfall radar showing Tropical Storm Iselle approaching Hawaii 8 August 2014. Image courtesy of NOAA

Rainfall radar showing Tropical Storm Iselle approaching Hawaii 8 August 2014.
Image courtesy of NOAA

Hurricane Julio is following hard on the heels of Hurricane Iselle in the east Pacific and has become a ‘major hurricane’ with winds in excess of 115 mph.

 

Julio is also heading in the direction of Hawaii, but looks likely to track a little further north than Hurricane Iselle. However, the US state could still feel the affects of Julio as it passes by on Sunday.

Official warnings of west Pacific tropical storms are produced by the Japanese Meteorological Agency . Central Pacific warnings are issued by the Central Pacific Hurricane Center and east Pacific 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.

Met Office StormTracker provides a mapped picture of tropical cyclones around the globe with access to track history and six-day forecast tracks for current tropical cyclones from the Met Office global forecast model and latest observed cloud cover and sea surface temperature. We also provide updates on current tropical storms via @metofficestorms on Twitter.








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