Meteorologist's Commentary

Issued Sunday noon, 12^th January, 2020 by Evelyn Cusack, Head of Forecasting & Eoin Sherlock, Head of Flood Forecasting.

Storm Brendan will affect Ireland tomorrow, Monday, 13^th January bringing stormy conditions, heavy rain and high seas. Expect disruption to travel and possible localised flooding especially in coastal areas. There may also be some localised structural damage and trees uprooted.

Storm Brendan is currently off the east coast of Canada (991hPa), Figure 1, and is forecast to track eastwards across the Atlantic undergoing rapid cyclogenesis as it engages with a very strong Jet Stream. Rapid cyclogenesis is defined as a depression deepening 24hPa in 24-hours but Brendan is forecast to deepen by about 50hPa in 24-hours, Figure 2.

Figure 1

Figure 2

The following 6 images are from Met Éireann’s high resolution Harmonie forecast model. The images display the evolution of the forecast wind speeds as Storm Brendan approaches, crosses and clears away from Ireland.

The strongest winds will be initially along the west coast early on Monday morning before they spread countrywide during the morning affecting eastern counties around midday into the early afternoon. Disruption to travel and localised structural damage is possible as these winds affect the country.

During the afternoon a second core of extremely strong winds will affect parts of the west and northwest. Gusts are likely to exceed 130 km/h during the afternoon in exposed areas and along the coasts.

We are also in a period of Spring Tides. Storm Brendan will produce significant storm surges and the combination of these high Spring Tides, onshore storm force winds and storm surge will lead to a risk of flooding along all coasts. There is a significant risk to the south, west and northwest coasts with an elevated risk for all eastern coastal areas due to the high tides and the projected storm surge forecast.

The final figure displays the projected significant wave height for Monday evening. Offshore wave heights of up to 14 metres are forecast with high or very high seas forecast along all coastal waters. Met Éireann has issued a Status Red Marine warning for winds reaching violent storm force 11 in the west.

HARMONIE wind and warning isotach chart - Mon 06z

HARMONIE wind and warning isotach chart - Mon09z

HARMONIE wind and warning isotach chart - Mon12z

HARMONIE wind and warning isotach chart - Mon15z

HARMONIE wind and warning isotach chart - Mon18z

HARMONIE wind and warning isotach chart - Mon21z

ECMWF /Wave Ireland Significant wave height chart - Mon 18z

Please keep up to date at www.met.ie for warnings and forecasts for your area.

Heed the advice of the local authorities, the Gardaí and the HSE.

You can access our forecast products via these links:

https://www.met.ie/forecasts/atlantic-charts/precipitation-pressure

https://www.met.ie/forecasts/marine-inland-lakes/waves

At this link you can view the latest weather observations:

https://www.met.ie/latest-reports/observations

Issued by Harm Luijkx at 16:30 on Friday 10th January 2020

Unsettled spell of weather in the week beginning Monday 13th of January 2020

The weather will be very unsettled for the week to come with a sequence of developing depressions tracking across the Atlantic and affecting our weather.

Very windy weather is likely on Monday and possibly again on Tuesday and Thursday.

The forecast model from the European Centre forecasts that a depression, originating on the other side of the Atlantic, will deepen rapidly through Sunday and Monday as it tracks eastwards. The centre of the storm will move in the direction of Iceland and is expected to have a very low central pressure around 935 hPa on Monday night.

The strongest winds will stay to the northwest of Ireland, but there will still be a very strong wind field here as well, with the isobars close together over Ireland on Monday midday.

This chart from the UK Met office illustrates very well that the strong winds on Monday are expected ahead of the cold front.

The next system that will affect our weather can already be seen as a wave in the weather front to the southwest on the mid Atlantic. The pressure is not very low at that stage with 1003 hPa, but in the other charts above it can be seen that the expected pressure 12 hours later has come down to 988 hPa.

Because this system has not formed yet, the details of how it will affect us are uncertain at the moment of this writing (Friday afternoon, 10th of January).

Updated: 11am December 7th 2019 by Andrew Doran-Sherlock

Storm Atiyah (Ah-tee-ya) is forecast to track between Iceland and Ireland during Sunday producing strong winds and heavy rain from Saturday evening through to Monday morning.

• Status yellow winds will affect the country from Saturday evening through to Sunday morning and winds will increase further reaching orange level for Donegal, Galway, Leitrim, Mayo, Sligo, Clare, Cork, Kerry and Limerick. The yellow wind warning will continue for the rest of the country.

• A spell of heavy rain is forecast for all areas this evening (yellow rainfall warning for Donegal) and will be followed by squally heavy showers during Sunday.

This is the Met Éireann high resolution model, HARMONIE, with the forecast pressure and wind associated with Storm Atiyah. The colours indicate the warning levels.

Updated: 2pm December 5th 2019 by Liz Walsh

Met Éireann’s Forecast Office have been monitoring developments for Sunday the 8th December for a number of days now, and confidence is mounting for a period of potentially stormy weather for some parts of the country.

Widespread rain on Saturday night will clear eastwards overnight with a cooler, more showery westerly airflow following into Sunday. There is a threat of strong winds developing, accompanied by severe and squally gusts, chiefly in parts of the west and southwest, but the exact details as well as the timings are still open to change. Whatever the case, Sunday is shaping up to be a windy day countrywide with squally showers in the mix.

Below is an animation using data from the ECMWF of the surface pressure (solid black line), overlaid with the jet stream (in purple) and winds at 925hPa level (around 750 or 800 metres above the surface - sometimes used as an approximate indicator of gust speeds at the surface).

Met Éireann forecasters will continue to monitor the situation as we head into the weekend and warnings will be issued as required so stay tuned for further updates.

Updated 1pm Friday October 11th 2019 by Gavin Gallagher

Typhoon Hagibis is on track to make landfall in Japan on Saturday, October 12th. According to the Japan Meteorological Agency, this typhoon will be their most powerful storm of the year.

Visible Satellite of Typhoon Hagibis from 8am this morning (Irish time)

The centre of the storm is currently (1pm Friday) located 550 km south of the Japanese mainland and approx 750km south-southwest of Tokyo.

It currently has sustained winds of over 200km/h with gusts of 260km/h. This is equivalent to a Category Four hurricane in the North Atlantic.

Latest Track Map from the Japanese Meteorological Agency

It is forecasted that Hagibis will continue to track northwards then gradually turn towards the northeast this evening. Slow but steady weakening is anticipated during Saturday prior to landfall. Landfall is expected around 24 hours from now (10am Irish time, 6pm local Japanese time) with the current forecast bringing the centre of Hagibis passing close to the Tokyo area around 4pm Irish time Saturday, midnight local Japanese time.
Hagibis will then accelerate quickly out to sea to the east of Japan on Sunday.

Numerical weather forecasting model guidance remains in good agreement in terms of direction and speed and there is high confidence in the forecast track.
The Japanese Meteorological Agency has warned of strong winds, very heavy rain along with high waves and storm surge with coastal inundation.

Latest Warning Map from the Japanese Meteorological Agency

Relevant links:Japanese Meteorological Agency Warnings https://www.jma.go.jp/en/warn/index.html
Japanese Meteorological Agency Weather Forecast https://www.jma.go.jp/en/week/
Japanese Meteorological Agency Typhoon Information https://www.jma.go.jp/en/typh/
Joint Typhoon warning Centre https://www.metoc.navy.mil/jtwc/jtwc.html

Ireland play Samoa in the Rugby World Cup at 11:45am Saturday morning Irish time (7:45pm local Japanese time) in Fukuoka. Fukuoka is in the far southwest of the Japanese mainland and is not expected to be directly affected by Typhoon Hagibis.
The weather forecast for Ireland v Samoa on Saturday is dry and cloudy, it will be breezy with a temperature of 20°C.

Updated: 5pm Thursday October 3rd 2019

Lorenzo has moved north-north-eastward parallel to the west coast of Ireland this afternoon as forecasted. The depression is still expected to take a turn eastwards this evening or early tonight whilst weakening. The latest forecast guidance has, however, slowed the eastward progression down. This means that we could see a more prolonged period of heavy rain in north-western parts of the country tonight and early tomorrow. Also, the timing and duration of the wind warnings have been and will continue to be adjusted accordingly - as required.

Storm Lorenzo was located around 180 nautical miles (340 km) west of Belmullet, Co Mayo at Midday today Thursday 3rd October 2019. The analysed pressure at 9z (1000 local) today was 969hPa at the M6 Buoy  which is located approximately 400 km west of Mace Head in Galway as the centre of the storm passed over, with storm force west to southwest gusts recorded on the southern side of the low pressure centre.

Our model guidance is calling for some slight deepening of the Lorenzo low to take place this afternoon as the system tracks north-eastwards to the west of Ireland, reaching a low of possibly 962hPa at 14z (1500 local). Because of this, south-easterly winds will be strong and gusty over much of the country this afternoon, with a countrywide yellow wind warning in operation until 6pm today.

The storm depression is forecasted to then turn east south-eastwards this evening towards the west coast of County Mayo (around 18z/1900local). This turn is due to upper air steering flows high up in the atmosphere. By this time, the depression will be starting to fill. What this means is that the storm force winds on the southern side of the low will begin to slowly subside. At 6pm, the orange level wind warning for western coastal counties of Galway, Mayo, Clare, Kerry and Limerick will come into operation, and the yellow wind warning will become confined to Sligo, Leitrim, Cork, Waterford, Tipperary and Wexford.

Below is some recent track guidance for the centre of Lorenzo from our HARMONIE Irish Regional Ensemble Prediction suite from midnight 3rd Oct to midday on 4th October.

For more information, please refer to our warning page on the website at www.met.ie/warnings

Hurricane Lorenzo in Climatological context

Hurricane Lorenzo is the eastern most and northern most category 5 hurricane ever recorded in the Atlantic Ocean. Hurricane Lorenzo is expected to make its transition from hurricane to extra-tropical storm when it is approximately at 49 degrees North, approximately 1000km to the southwest of Ireland. By comparison, storm Ophelia in October 2017 retained its hurricane status until it was within 500km of Ireland.

Met Éireann’s report on Storm Ophelia here

Met Éireann’s report on Storm Debbie here

Climate Change Context

The World Meteorological Organisation’s Task Team on Tropical Cyclones and Climate Change assessment has produced two reports on the Climate Change and Tropical Cyclones.  A summary can be found here: https://www.gfdl.noaa.gov/global-warming-and-hurricanes/

The main conclusion of the analysis are presented here:

Future Predictions:

• Sea level rise – which very likely has a substantial human contribution to the global mean observed rise according to IPCC AR5 – should be causing higher coastal inundation levels for tropical cyclones that do occur, all else assumed equal.
• Tropical cyclone rainfall rates will likely increase in the future due to anthropogenic warming and accompanying increase in atmospheric moisture content. Modelling studies on average project an increase on the order of 10 to 15 % for rainfall rates averaged within about 100 km of the storm for a 2°C global warming scenario.
• Tropical cyclone intensities globally will likely increase on average (by 1 to 10% according to model projections for a 2°C global warming). This change would imply an even larger percentage increase in the destructive potential per storm, assuming no reduction in storm size. Storm size responses to anthropogenic warming are uncertain.
• The global proportion of tropical cyclones that reach very intense (Category 4 and 5) levels will likely increase due to anthropogenic warming over the 21st century. There is less confidence in future projections of the global number of Category 4 and 5 storms, since most modelling studies project a decrease (or little change) in the global frequency of all tropical cyclones combined.

Past Observations:

• In terms of detection and attribution, much less is known about hurricane/tropical cyclone activity changes, compared to global temperature. In the northwest Pacific basin, there is emerging evidence for a detectable poleward shift in the latitude of maximum intensity of tropical cyclones, with a tentative link to anthropogenic warming.

• In the Atlantic, it is premature to conclude with high confidence that human activities–and particularly greenhouse gas emissions that cause global warming–have already had a detectable impact on hurricane activity.
• A recent study finds that the observed increase in an Atlantic hurricane rapid intensification metric (1982-2009) is highly unusual compared to one climate model’s simulation of internal multidecadal climate variability, and is consistent in sign with that model’s expected long-term response to anthropogenic forcing.
• Reduced aerosol forcing since the 1970s probably contributed to the increased Atlantic hurricane activity since then, but the amount of contribution, relative to natural variability, remains uncertain.
• There is some evidence for a slowing of tropical cyclone propagation speeds over the continental U.S. over the past century, but these observed changes have not yet been confidently linked to anthropogenic climate change.
• Human activities may have already caused other changes in tropical cyclone activity that are not yet detectable due to the small magnitude of these changes compared to estimated natural variability, or due to observational limitations.

Update on the expected Hot Weather over Europe from Joan Blackburn issued at 1300 hrs on Wednesday 26 June 2019

At present we have an upper-air Omega blocking pattern, with an upper ridge in mid-Atlantic, a depression west of Iberia and a ridge over mainland Europe. This is feeding a moist hot southerly airflow, with embedded air from Africa, through Spain, western Mediterranean northwards through France, Germany, and the United Kingdom. Ireland is on the edge of this very warm air-mass and our temperatures will be tempered to some extent by the near Atlantic, but we expect temperatures to be in the mid-twenties in western parts of the country on Wednesday and  mid to high twenties on Thursday. Indeed Met Éireann has issued a Yellow Weather Alert for temperatures which are expected to be in excess of 27°C in Galway, Mayo, Clare, Cork, Kerry and Limerick during Thursday afternoon.

This pattern will persist over Ireland and the UK through to Friday but fresher Atlantic air will break through from the west late Friday and during Saturday. The fresher regime will then extend through much of northern Europe early next week. But the heatwave is likely to remain over Iberia, the western Mediterranean and southern most parts of France.

High temperature warnings are in operation for many parts of Europe.

The following images show the expected Harmonie temperatures for Thursday afternoon, the darker reds reflect the counties that have been issued the Yellow Weather Alert. While the second image displays the ECMWF 850hPa Wet Bulb Potential Temperature for Thursday afternoon. This clearly shows the warmer air extending into Ireland.

Climatological situation

Past: Over the last 100+ years Ireland’s average temperature has risen by about 1°C from pre-industrial levels

Current: Normal average temperatures in June are about 14 – 15°C. While normal maximum temperatures in June are about 17-19°C.°

Future: Latest climate model projections predict that the average temperature of Ireland will continue to rise by the middle of the century. The amount it will rise by is dependent on the level of global greenhouse gas emissions. We would also expect an increase in the number of hot days.

It is important to note that the weather in Ireland is highly variable. When we talk about climate we are talking in ‘average’ terms.

Attribution: We know climate change is happening now and is human caused, but we can’t be certain that it is a direct cause of this particular event (at least not at the moment *). However heat trapping greenhouse gases do increase the odds of extreme heat events. There has been an increasing trend in extreme weather events globally and the heatwave over Southern Europe is likely to be part of that trend.

(* A detailed scientific climate attribution study may identify climate change as the cause of this heat event, but these studies can take a long time to carry out).

Will the expected Hot Weather in Europe cause droughts?

Heavy rainfall over recent days has led to rising river levels nationally, however levels are generally low, with approximately 93% of stations monitored below 50 percentile level. 6% of the stations monitored (16 out 257) are below the 95 percentile level, a decrease of 2 stations since yesterday evening.  Approximately 94% of stations monitored (241 of 256) are above the 95 percentile level. The 95 percentile level is a common metric used in the estimation of drought conditions.

According to the European Drought Observatory (EDO) parts of Spain, Portugal and France are currently suffering both a rainfall and soil moisture deficit. Both of these deficits produce stress in vegetation and the EDO calls this a drought alert.

At this point in time the risk of drought does not extend to Ireland

  Update on Storm Hannah from Joan Blackburn issued at 1400 hrs on Friday

The latest indications are that the centre of Storm Hannah will track east over Ireland between Galway and Dublin with the most severe winds on the southern and western flank of the storm.

Warnings have been updated with a general Orange wind warning in operation across Munster and Galway and a Red level warning in operation for Clare and Kerry for a time this evening. Winds along the coasts of parts of Connemara and off shore Islands are also likely to dip into the red level at times this evening. Yellow wind warnings are in operation for the rest of Connacht and much of Leinster.

The following chart is the Met Éireann high-resolution surface pressure and wind forecast for 10pm this evening showing the status Red winds in over County Clare and the north of Kerry and on the Connemara coast. the centre of Hannah is moving in over the midlands.

The following chart is the Met Éireann high-resolution surface pressure and wind forecast for 2 am Saturday, the storm centre having moved out into the Irish Sea and the severe winds easing

Visible Satellite  picture for 1300 hrs Friday

The Information to follow was included by Siobhán Ryan on Thursday 25th April 2019

Storm Hannah was named by Met Eireann on Thursday morning with orange level winds expected to impact upon counties Clare, Limerick, Cork and Kerry from Friday afternoon (16:00) until late Friday night (05:00 Saturday). A yellow wind has also been issued for the rest of Munster, Connacht and southern Leinster, with this warning valid until 09:00 on Saturday. The situation and warnings will be under constant review and will be amended if required.

The developing storm system currently lies east of Newfoundland, with rapid cyclogenesis expected to occur over the next 24 hours as it tracks eastwards across the Atlantic. Storm Hannah will be positioned off-shore roughly 200km west of Slyne Head by 16:00 on Friday with the closed storm system forecast to track directly inland across the southern portion of Ireland on Friday evening/night. After that it will move away towards Britain and slowly fill, losing most of its strength on Saturday morning.

The public are advised to be prepared for the anticipated conditions, especially those living or travelling to the southwest with some disruption and power outages likely. There is an increased risk of impacts to life and property during times of severe weather with flying debris of particular concern during any wind event. People are advised to take in their BBQ or loose garden furniture, especially after the recent warm spell.

With the trees now in full leaf, there is an increased threat of tree damage and possible felling too. Other impacts may include travel disruption with large and dangerous waves expected to crash into southwest coasts. Whilst Storm Hannah will primarily be a wind event, spells of heavy rain will be wrapped up around eye of the storm too.

The last of the heavy rain will clear the north and east during Saturday morning and winds will abate. However, brisk northwest winds will persist into Saturday afternoon with a mix of sunshine and scattered showers following.

23:00 chosen rather than 24:00 to display the likely peak winds

Information to follow was included by the Duty Forecasters on Wednesday 24th April 2019

After an unseasonably warm and settled Easter Weekend, our weather is looking very disturbed and unsettled as we head through the rest of this week, with potentially stormy conditions for the southwest of the country later on Friday, 26^th April. With many trees now in leaf, this system has the potential to result in trees down leading to power outages and dangerous driving conditions, so stay up to date with the forecast over the coming days.

Met Éireann forecasters are monitoring a developing low pressure system currently tracking towards Newfoundland just off the northeastern Canadian coast, which is expected to engage with the Jet Stream and travel eastwards across the Atlantic over the next couple of days. Conditions look ripe for rapid deepening of the low to take place as it comes across the North Atlantic, and a storm system is likely to form at sea by Friday morning.

Present indications suggest the storm system will be starting to fill as it comes towards Ireland’s west and southwest coasts on Friday evening, however, the track of the system is still a little uncertain. We’ll obviously be firming up on the details over the coming 24 hours, but, for now, a wind advisory has been issued for counties Cork and Kerry.

Images Below include the forecast modelled Infra-red Satellite for 1pm on Friday (Top) and forecast modelled winds at 7pm courtesy of the European Centre for Medium Range Weather Forecasting, the ECMWF.

This is a developing situation and there could well be changes to the location of the most damaging winds so stay tuned to the forecast.

Meteorologists comment by Liz Walsh, Friday 8^th March 2019

Atlantic chart - Airmass

A highly mobile Atlantic regime looks set to dominate our weather pattern through this weekend and the coming week. This will bring a sustained period of unsettled, often very windy and at times wintry weather with showers of hail, sleet and snow.

https://www.met.ie/forecasts/atlantic-charts/precipitation-pressure

A very strong Jet Stream will help to push some vigorous and potentially disruptive Atlantic weather systems over Ireland during the period.

Strong and blustery winds look likely to feature from Saturday (9^th March) through to at least Wednesday (13^th) with frequent gales at sea. Sea conditions will be very rough and there will be exceptionally high seas and swell in Atlantic coastal regions at times.

There is certainly potential for warnings to be issued over the coming days, so please do stay up to date with the Met Éireann forecast.

https://www.met.ie/forecasts/national-forecast

https://www.met.ie/warnings

A rapidly deepening depression, named Storm Erik by Met Éireann, is approaching from the Atlantic and will track to the northwest of Ireland early Friday morning with an expected minimum pressure of 954hPa at 9am 8th Feb 2019.

A Status Yellow warning is in operation for Ireland from 5am Friday to 6am Saturday. For a shorter period, Status Orange warnings are in operation for counties Galway, Mayo and Donegal.
Winds will be most severe in Atlantic coastal areas where there will be dangerous sea conditions. The combination of low pressure, high seas and high tides will lead to localised coastal flooding.
The Status Orange warning is in operation for Galway and Mayo from 5am to 1pm Friday and for Donegal from 9am Friday to 6am Saturday.

Met Éireann’s High Resolution (2.5km) Harmonie model shows Storm Erik as it tracks just to the northwest of Ireland Friday morning.

Storm Erik warnings issued at 11am Thursday, 07-02-2019:

Status Orange Warning for Galway, Mayo (5am to 1pm Friday) and Donegal (9am Friday to 6am Saturday):
Southwest to west winds will reach mean speeds of 65 to 80 km/h with some severe or damaging gusts of 110 to 130 km/h. The highest winds will be in exposed coastal areas, where these values may be exceeded at times.
Very high seas as well with some coastal flooding.

Status Yellow Warning for Ireland (5am Friday to 6am Saturday):
Southwest to west winds will reach mean speeds of 50 to 65 km/h with gusts of 80 to 110 km/h. Along exposed Atlantic coasts these values may be exceeded for a while and with very high seas this will give the risk of coastal flooding.
For the latest updates to our warnings please see https://www.met.ie/warnings

Met Éireann’s High Resolution (2.5km) Harmonie model shows Storm Erik continuing to track northeastwards towards the north of Scotland by Friday night.

Information to follow was included by Meteorologist Liz Walsh on Thursday 10th January 2019

What is Sudden Stratospheric Warming?

The earth’s atmosphere is comprised of layers based on temperature. We live in the lowest part of the atmosphere – the troposphere – which contains most of our weather – clouds and precipitation – and on average it’s about 10 km deep, although the depth does vary from the equator to the poles – greater at the equator, lesser at the poles. The Jet Stream is at the top of the troposphere and most of our weather happens below that.

Above the troposphere is the stratosphere and this layer of the atmosphere extends upwards to about 50km. It contains much of the ozone in the atmosphere which absorbs most of the ultra violet rays from the sun causing it to warm up. Temperatures in the stratosphere are generally highest over the Summer Pole where the sun shines all day and night and, conversely, lowest over the Winter Pole. So in winter the stratosphere is usually very cold at the pole and this is what the Stratospheric Polar Vortex is: a pool of very cold air associated with low pressure 10 to 50 km above the Winter Pole.

Around this pool of cold air we get some very strong westerly winds propagating around it – a stratospheric jet stream – high up above our own tropospheric jet stream – which helps to keep the Polar Vortex intact above the pole. Westerly winds are of course associated with the anti-clockwise movement of air in low pressure systems in the northern hemisphere.

However, the Polar Vortex can sometimes be affected by natural weather systems or disturbances in the lower part of the atmosphere which can weaken the stratospheric jet stream. This then causes the air in the stratosphere to compress leading to a rapid temperature increase. In turn the Polar Vortex breaks down or becomes displaced from the pole and we get what is referred to as a Sudden Stratospheric Warming event or SSW. SSWs are subject to categorization: Major, Minor and Final.

A major SSW event is when the observed stratospheric temperatures rise rapidly over the course of a few days and instead of a pool of cold air associated with low pressure over the pole (a polar vortex) we get an area of high pressure, associated with the rapid rise in temperature. As a result, the stratospheric westerly winds change direction to easterly which is associated with the clockwise movement of air in high pressure systems in the northern hemisphere.

Why are SSWs significant for our weather? 

Normally, the air flow in the stratosphere during winter is westerly, moving around from west and east because we have low pressure at the pole. This enhances the Jet Stream lower down in the troposphere. Typically we tend to get reasonably strong Jet Streams propagating around the winter hemisphere anyway because of the surface temperature difference from equator to pole during winter. But when the Polar Vortex is present in the Stratosphere it helps to strengthen the Jet Stream, which is what drives low pressure systems and winter storms from the Atlantic towards our area.

When the Polar Vortex breaks down or gets displaced from the pole, that helping hand is no longer there and so the Jet Stream lower down in the troposphere can and does weaken. The tropospheric jet also gets pushed further south leading to the development of high pressure systems at higher latitudes. The easterly winds in the stratosphere effectively sink down into the troposphere, altering the weather patterns in the northern hemisphere.

It’s important to note that an SSW doesn’t necessarily mean we’re going to get continuous cold weather for the rest of the winter. What it does mean is that there is a greater chance of an easterly flow type set up which could bring episodes of colder weather depending on the synoptic set-up. 

Has a major SSW occurred this winter? 

In short yes. It peaked at the beginning of January 2019.

What will be the effects and when will we start to see them?

It takes a long time for the easterly winds to filter down into the part of the atmosphere where we live – generally a number weeks at least. The Sudden Stratospheric Warming (SSW) event which occurred at the start of January is expected to impact tropospheric conditions towards the end of January. If the resulting high pressure systems become established over Scandinavia or Greenland, such a synoptic pattern could lead to bitterly cold air from eastern Europe/Russia pushing in over Ireland, as happened in late February/March of last year (2018).  It is important to note that this kind-of set-up can just be the result of normal weather variability, but the main point is that a major SSW can enhance the likelihood of occurrence.

At the moment, our weather is expected to be either milder than or near average out to the next 7 to 10 days, with an Atlantic regime gradually returning as high pressure slips away to the southwest. With the exception of mountaintops, snow is therefore unlikely over the next 7 to 10 day period. As we approach the end of January, though, the guidance suggests an increased risk of colder than average weather with frost and ice likely to be more prevalent than of late. Whether we will get the synoptic set-up which could result in snowfall remains highly uncertain. But as always, we’ll keep you posted.

You can view the Atlantic charts 7 day forecast for rainfall and airmass here

Information to follow was included by Meteorologist Liz Walsh on Tuesday 27th November

The cool easterly airflow which persisted for much of last week has now given way to a much more unsettled but milder Atlantic regime. It’s a complex set-up out in the Atlantic at present with several low pressure centres and frontal waves in the mix. The first active period of weather from one of these low centres, which produced very wet and windy conditions for many on Tuesday morning the 27^th November, has cleared and there will be a lull in the weather through the rest of Tuesday before the next system arrives.

This next low pressure system carries (and will keep) the name of Storm Diana. It was named by the Portuguese Met Service due to the orange level warning conditions it produced for the Azores archipelago on the evening and night of Monday the 26^th November. Storm Diana will produce some severe and potentially damaging winds as it moves northwards to the west of Ireland on Wednesday and a number of warnings have been issued in relation to this event.

    Satellite Image of Storm Diana in the Atlantic

A yellow wind warning has been issued for the 26 counties that we have responsibility for. Winds are expected to reach mean wind speeds of 55 to 65km/h and gusts of 90 to 110km/h. Additionally two orange level wind warnings have been issued for the southern and western coastal counties of Cork, Kerry, Waterford, Wexford, Clare and Galway to warn of the potential for orange level winds – mean speeds of 65 to 80km/h and gusts of 110 to 130km/h. These orange level winds will mostly occur in coastal regions of these counties and about high ground and there is also the added risk of coastal flooding due to very high seas.

The strongest winds on Wednesday will be coming from a slightly different direction (south to southwesterly) than the strongest winds on Tuesday (southeasterly), which will produce some differences in how they are experienced in different parts of the country i.e. weaker or stronger depending on exposure.

Accompanying the wind, some heavy rainfall as well, with Connacht and west Ulster likely to bear the brunt of the wettest conditions.

Information to follow was included by Meteorologist Liz Walsh on Thursday 8th November

Yellow weather alerts have now been issued by the forecast office for Friday 9^th November.

The area of low pressure we have been watching is now about 1200km east northeast of Newfoundland in the Atlantic (circled in red on the satellite image below).  It will soon begin to deepen rapidly over the next 24 hours as it swings eastwards across the Atlantic before it makes a turn northwards on Friday morning around 500km off the west coast of Ireland. Rain and wind associated with this vigorous system will begin to affect the west and southwest of the country between 4 and 6am on Friday.

The rainfall warning covers a number of counties including Mayo, Galway, Cork, Kerry, Tipperary, Waterford, Wexford, Wicklow, Kilkenny, Kildare, Carlow, Dublin and Louth and is valid from 6am to 6pm. Rain will become widespread on Friday with some intense bursts of rain occurring over a relatively short time period which will lead to spot flooding. The heaviest of the rain will occur in the west and southwest during the morning and early afternoon. The focus of the heaviest rain will then transfer eastwards through the early and late afternoon, with the rain giving way to scattered showers in the west and southwest.

The wind warning has been split to accommodate the timing of the strongest winds in different parts of the country. The Connacht and Munster wind warning is valid from 4am to 3pm, while the Leinster and Ulster wind warning is valid from 8am to 7pm.

As the wind is coming from a rapidly deepened low, the atmosphere will be unstable which means that gusts will feature prominently in many areas. Most of the gusts will be within the limits of our yellow warning criteria – up to 110km/hr – but exposed coastal regions and areas of higher ground inland, especially in the southwest, south and southeast, will experience gusts greater than this – possibly up to 125km/hr. Winds of this speed can cause significant damage and caution is advised.

There is also a risk of coastal damage, especially on parts of the east coast as winds, high spring tides and storm surge combine to produce spray and wave overtopping.

____________________________________________________________________________________________________________

Information to follow was included by Meteorologist Liz Walsh on Wednesday 7th November

It’s been a rather unsettled week of weather so far with spells of wet and windy weather. Excess water has occurred on the roads at times, with spot flooding compounded by autumn leaves blocking drains.

Our weather will remain unsettled through the rest of this week, and Met Éireann forecasters have been monitoring developments for this Friday 9^th November particularly closely. There are a number of low pressure systems or depressions dotted around the North Atlantic at present, but the one we are particularly interested in is an area of low pressure over Newfoundland in Canada which is expected to move out into the Labrador Sea tonight, Wednesday night.

This low pressure system will travel eastwards across the Atlantic by Friday, helped by a strong jet stream which will serve to deepen the low significantly by the time it comes close to our shores. The (by then) deep low will travel northwards to the west of Ireland during Friday, and the associated fronts will track in over Ireland during Friday morning and afternoon bringing strong winds and heavy rain and there is potential for severe and damaging gusts, especially on coasts. There is also a risk of coastal damage due to wave overtopping, with the timing of the strongest winds coinciding with high tide on some coasts.

We’ll be closely monitoring forecast data from our 54-hour high resolution model, HARMONIE over the next 12 to 24 hours with further updates to follow.

See the first hourly wind and rain projections for Friday morning 9^th Nov from HARMONIE below:

Information to follow was included by Meteorologist Liz Walsh on Tuesday 30th October

The National Hurricane Center continues to issue advisories for Hurricane Oscar in the western subtropical Atlantic. The system is expected to become a post tropical storm on Wednesday night as it continues to track north-northeastwards. The current track guidance has Storm Oscar tracking between Scotland and Iceland during Saturday.

What is the significance of this to Ireland?

A cooler than average regime has persisted over Ireland since the beginning of the bank holiday weekend. The atmospheric pattern has been, and will continue to be, generally slow-moving and meridional over the next couple of days, dragging cold air down from the north and northwest, while the Atlantic westerly flow we are used to is essentially blocked off. The main significance linked to the passage of Oscar to the northwest of our shores, is that we will see a return to a more mobile Atlantic regime with frontal passages and/or low pressure systems bringing spells of rain and strong winds at times, as well as fluctuations in temperature.

When will Oscar affect us and what will be the effects?

At present, it looks as through frontal zones associated with post tropical storm Oscar will start to push in over Ireland on Friday. Moist tropical maritime air will be transported northeastwards over the country during Friday and temperatures on Friday evening look likely to be up around 12 to 14 degrees Celsius - this despite widespread rain with some heavy falls, and blustery southerly winds. Current indications suggest that the strongest winds associated with post tropical Storm Oscar will likely be in coastal regions of the west and northwest during Saturday, with gales or potentially strong gales in those sea areas.

Current forecast pressure and airmass temperature from our website for midnight on Friday night into Saturday morning.

As is often the case in weather forecasting, and especially with respect to transitioning tropical systems, there will continue to be a level of uncertainty in the evolution of events, so do stay up to date with the latest forecasts. Warnings and advisories will be issued closer to the time, if and as required.

Information to follow was included by Meteorologist Siobhán Ryan on Tuesday 16th October.

One year on from Ophelia, and what an exceptional 12 months it has proved to be.

https://www.met.ie/cms/assets/uploads/2018/10/Ophelia-1.pdf

One year to the day - Blackrock Park, taken this morning October 16th 2018, by Gerry Lumsden

Following on from Ophelia, the only other wind storm to occur last autumn was that of Storm Brian, which affected the country to a lesser extent on Saturday 21^st October.

The winter season was an average one overall, with the usual unsettled spells, which the dark winter months normally deliver. Further stormy episodes followed, especially during January, and overall it was colder than normal. Later in February the jet stream was pushed northwards as a result of stratospheric warming, causing a blocking high to anchor firmly in place, and drawing in the beginnings of the icy cold spell which overlapped into early springtime.

The spring of 2018 was characterised by a cold snowy start, but with conditions improving through the season, as it closed on a dry, warm and settled note. The first week of March was its defining period, when bitterly cold Polar Continental air moved in from the east, and Storm Emma (pre-named by the Portuguese) later moved up from the Bay of Biscay. Record breaking snow fell, but with a relatively quick thaw following the main even on the 3rd of March, the country returned back to normal after the weekend.

The summer of 2018 will be long remembered for heatwave and drought conditions, with intense thunderstorms also a feature of the early season. Large blocking highs were dominant, especially from the 21^st of June to the 14^th of July, which gave rise to well above average temperatures with rainfall well below average generally too. Temperatures peaked late June with the highest air temperature recorded on the 28^th of the month at Shannon Airport, Co. Clare when the mercury reached 32.0 degrees Celsius. Coincidentally that same day Malin Head, Co Donegal recorded the highest daily sunshine hours of the summer, with 16.5 hours in total.  As well as being warm and sunny it was also extremely dry, especially across the midlands south and east. Phoenix Park recorded the lowest seasonal rainfall total, with just 75.3mm of rainfall, which equates to 38% of the LTA.  It comes as no surprise that this was also its driest summer since 1995.

The 2018/2019 wind storm season has got off to an early start with three named storms to date; Storm Callum of course the most recent one.  The other two storms occurred during September and were named Ali (19^th) and Bronagh (20^th). The highest September 2018 wind speed was a gust of 146 km/h at station Mace Head, County Galway on Wednesday 19th at 08:11 UTC during Storm Ali.

In the previous storm season, there were 11 named storms, beginning with Aileen (12^th September 2017) and ending with Hector (13^th June 2018). Storm Ophelia (2^nd storm of the season, after retaining its name under protocols with the National Hurricane Centre in Miami), was of course the most memorable and serious one, with a record gust wind speed of 156 km/h observed at station Roche's Point, County Cork on Monday 16^th October 2017 at 10:59 UTC.

Today of course couldn't be any more different to this day last year, with the skies continuing to brighten up this afternoon as autumn sunshine across Atlantic counties extends eastwards. Though it has been a small bit breezy, with a small craft warning still in play, the winds will gradually ease down too.

Information to follow was  included by Siobhán Ryan and Dr Sandra Spillane on Monday 15th October 2018.

The remnants of Hurricane Leslie have wreaked havoc, mixing with the lower levels of the atmosphere across the eastern Mediterranean. A triple point (where the occluded front, cold front and warm front all intersect) moved into this southern area, resulting in enhanced lifting and significant wind shear. Severe weather can sometimes occur at this intersection point. Case in point, most tragically in this situation, especially given the origins of the airmass, with the local topography (high mountains and rushing rivers) another contributing factor.

The highest RED level warning, issued by by Météo France, remains in operation in the south of the country. Torrential rain and catastrophic flash flooding have majorly impacted upon the area of Carcassonne, with up to 4 months rain falling in just a few hours.  Floods like this (especially around the Aude river) have not been witnessed since the year 1891, with as much as 100 to 250 mm of rainfall recorded in a 4 to 6 hour window. In Trébes the floodwater was reported to be as high as 7 metres.  The death toll has been revised down from 13 to 10.

In Ireland, daily rainfall totals above 150 mm have occurred between August and December, in 9 years since 1941 of which 3 occurrences have been since 2000. Climate models have projected a notable increase in the frequency of ‘very wet days’ (>30mm) over most of the country for the autumn and winter months (Nolan et al, 2015).

 The highest daily rainfall total, since 1942 in Ireland, was 243.5 mm of rainfall measured at station Cloone Lake (Caragh River Area), County Kerry on Saturday 18 September 1993, representing 209% of its monthly Long Term Average (LTA) and has a rainfall return period of 156 years (occurring any month). The highest during October was also observed in County Kerry with 201.2 mm at station Waterville on Monday 3 October 2016, representing 140% of its monthly LTA.

 Nolan, P, et al. 2015. Ensemble of regional climate model projections for Ireland. Environmental Protection Agency.

The Met Éireann Forecaster's Commentary page provides the public with a supplementary severe weather discussion. Posts will only be added when required and will be archived at the end of the page when the event is over, so the details can still be viewed.

Information to follow was updated Friday 12th October by Meteorologists Siobhán Ryan and Dr Sandra Spillane, with contributions from Dr Emily Gleeson and Liz Walsh.

Met Éireann named Storm Callum on Wednesday 10th October. Severe Orange and Yellow Wind Warnings were issued, valid for Thursday night and Friday day.

Note: The Severe Orange Warning extends to 16:00 for Donegal, Sligo, Mayo and Galway, with warnings having lapsed now elsewhere.

South to southwest gale to storm force winds remain in effect for all Irish sea areas, with the risk of violent storm force winds no longer a concern. Those gales will continue Friday evening on coasts from Slyne Head to Malin Head, as well as on the Irish Sea, whilst moderating at sea elsewhere. Swell conditions are forecast well into Friday night, even though the winds will ease off for all sea areas.   

Further warnings were considered across parts of the south and east later Friday, owing to another swathe of wind and rain. However the severity and likelihood of this secondary event diminished considerably from run to run.  

This event was always predominantly a coastal one, though some severe gusts moved inland, especially close to the squally thundery cold front, as it pushed up over the country overnight.  Gusts in excess of 90 km/h were recorded widely, with up to 125 km/h gusts in parts of the west. The severe ORANGE warning still in operation for west and northwest coastal counties will shortly lapse, with the strongest gusts along exposed coasts here.  

Meteorological Situation 13:00, Storm Callum, with central pressure 947hPa, is now centred 150 Nm northwest of Belmullet.  It continues to track northwards towards Iceland and fill, with the south to southwest airflow slowly moderating as it enters a more mature stage. With a tight squeeze on the isobaric gradient however, some very strong winds are still expected in the west and northwest into that late afternoon, along with ORANGE level gusts here.  The trailing waving cold front has been moving back up from the south early this morning.  That heavy swipe of rain will continue to affect much of Munster, Leinster into the afternoon, with other parts of the country seeing some falls of rain, as it tracks northeastwards. Parts of west Connacht and west Ulster may escape dry though, as it clears into the Irish Sea before early evening.  A much drier, calmer and comparitively brighter picture later so, but misty conditions locally where rain has presented today.

Importantly, even though the winds at sea will die down later Friday, there is concern for very high sea swell well into the night-time hours

A complicated set-up as the effects of the same waving front pulsate back up across Ireland tonight and into Saturday. A cut off low will push up over the country too, with slow moving weather fronts wrapped around its centre.  Exact details may prove tricky, but suffice to say it will be a very wet day across most of the country. Rainfall totals may approach 24 hour warning levels in parts, but of course this will be monitored and if need be relevant warnings will be issued. The strong warm conveyor belt has the potential to feed up some locally high totals.

The transient ridge of high pressure still appears to move in on Sunday with a quiescent day in store for all.  The remnants of Hurricane Michael will pass well to the south of Ireland, moving  towards the northwest of Iberia by early nightfall on Sunday.

Meteorologist Liz Walsh of Met Éireann talks about the very latest weather associated with Storm Callum, 12:00 Friday 12th October.

• Highest gust so far 67 Kts Belmullet 7am Friday 12th October
• Moore Park County Cork recorded 20.6mm rainfall in just a 4 hour window overnight, with 30mm by 14:00 Friday.
• Some high totals recorded in a one hour window along the squall line last night too.
• Some significant lightning was also reported by night.
• 17.1 m individual wave height recorded at Buoy M3, off the southwest coast.
• Staggering and record breaking drop in pressure during a 24 hour window - close to 48mb.

The first image below shows the passage of last night's cold front and squall line (the line of rain along the spine of the country brought some intense bursts of rain with thunderstorm activity reported, as highlighted by the coloured cross symbols on the chart below). The second image below shows the radar Friday daytime. 

The following images are HARMONIE forecast wind and pressure patterns for  06:00, 12:00, 15:00 and 18:00 on Friday (06:00 run).

Video below was recorded on Thursday afternoon 11th October in GFD, Met Éireann HQ.

The following is the ECMWF forecast wind and pressure pattern for early Saturday night.

Meteorological Situation 06:00 Thursday 11th October,  Storm Callum is the 3^rd named storm of the 2018/19 season. Not yet formed, but later Thursday into early Friday, a rapidly deepening Atlantic storm depression (936hPa), will advance towards the west of Ireland and track northwards, eventually pulling away towards Iceland daytime Friday.

Main concerns - the strongest winds associated with this event will occur during the night-time hours and Friday morning rush-hour commute. Even though the high winds will be the main concern, a spell of heavy squally rain will occur too overnight too, making for an extremely windy and wet one, as the associated cold front quickly tracks north-eastwards across the country.  Possibly damaging southeast winds will veer southwest after the passage of this front, with the strongest of the winds set to impact coastal areas. Additionally there is a concern for storm surge, coastal flooding, and overtopping of waves around Atlantic coasts, due to the coinciding high spring tides. Very high seas are expected too, along with strong gale to storm force winds at sea. With trees still in part leaf, there is a concern for felling as well. Members of the public should bring in wheelie bins, any garden furniture etc. before the start of the event.

Though the winds will begin to ease down by midday for all but west and northwest coasts; a sting in the tail may yet follow, with a deterioration possible later Friday, as the trailing waving weather front potentially feeds pulses of rain from the south, with the possibility of a further core of strong southerlies too. However the likelihood and severity of this secondary event seems to be diminishing considerably from run to run.

#StormCallum #stoirm #storm                                    https://www.winterready.ie/en

ORANGE WARNING – Be Prepared

An ORANGE level warning is issued by Met Éireann for wind speeds with the capacity to produce dangerous, stormy conditions which may constitute a risk to life and property.

• Stay away from exposed coastal areas for the period of the ORANGE warning.
• Drive to anticipate strong cross winds and other hazards such as falling/fallen trees. High sided vehicles and motorcyclists are particularly vulnerable to strong winds - slow down and give extra space to pedestrians and cyclists.
• Be aware of local conditions in your area; wind strengths can vary significantly from place to place (depending on direction and local topography).

The other two storms occurred during September and were named Ali (19^th) and Bronagh (20^th). The highest September 2018 wind speed was a gust of 146 km/h at station Mace Head, County Galway on Wednesday 19th at 08:11 UTC during Storm Ali. Generally, the winds were south-westerly overall during the month. In the previous 2017/2018 season, there were 11 named storms, beginning with Aileen (12^th September 2017) and ending with Hector (13^th June 2018). This season was notable for Storm Ophelia (2^nd storm of the season, after retaining its name under protocols with the National Hurricane Centre in Miami), with a record gust wind speed of 156 km/h observed at station Roche's Point, County Cork on Monday 16^th October 2017 at 10:59 UTC. In the past 30 years, there has been an average of 6 days per year where storm force winds have been observed at a national wind station.

Wind speed records since 1942 (any month)

• Mean: 131 km/h (Hurricane Force) Foyne's Airport, County Limerick 18th January 1945
• Gust: 182 km/h Foyne's Airport, County Limerick 18th January 1945

Wind speed records during October

• Mean: (Violent Storm) 115 km/h Roche's Point, County Cork 16th October 2017 Ophelia
• Gust: 178 km/ Rosslare, County Wexford 24th October 1995

An average warming of 1.5°C across the whole globe raises the risk of heatwaves and heavy rainfall events, amongst many other potential impacts. For Ireland, climate models also project a decrease in the overall number of storms, however an increase in extreme storm activity by mid-century is projected (Nolan et al, 2015).

Nolan, P, et al. 2015. Ensemble of regional climate model projections for Ireland. Environmental Protection Agency.