The season was prefaced by the
extratropical remnants of Hurricane Helene which affected the UK and Ireland on 17–18 September. This began an active period of storm formation under a fast moving
jet stream over the Atlantic.
Ex-Hurricane Helene {{Infobox windstorm small | name = Helene | image = Helene 170918.jpg | caption = | duration = 16–21 September 2018 | fatalities = None | damage = Undetermined | power outages = None | minpressure = | gust = ,
Cairngorms,
United Kingdom | RSI = | final = | area affected = Portugal, Spain, Ireland, United Kingdom While still a
tropical cyclone, Hurricane Helene affected the
Azores from 15 to 16 September 2018. The system subsequently completed an
extratropical transition on 16 September as it accelerated north-eastwards towards the British Isles, with the outer bands of Storm Helene causing minimal impacts in north-western
Spain and
Portugal. Storm Helene crossed the UK and Ireland on 17–18 September, with the Met Office and Met Éireann issuing yellow wind warnings. The Met Office's yellow warning of wind covered
southern England, the
Midlands and
Wales overnight from 17 to 18 September, with forecasts predicting winds of up to . Helene was downgraded as it approached the British Isles, with winds gusting to only in isolated locations; as a result, all warnings were cancelled on 18 September as Helene was still crossing the UK. Subsequently, Helene emerged into the
Norwegian Sea and stalled off the coast of
Norway as a weakened system, finally being absorbed by
Storm Bronagh approaching from the south-west on 21 September. The highest gust record in the United Kingdom was recorded on the
Tay Road Bridge in Scotland. The winds on this storm were equivalent to a Category 2 on the
Saffir–Simpson scale. Storm Ali killed two people in Ireland and the UK. A caravan was blown over a cliff onto a beach near the village of
Claddaghduff in
County Galway, killing a woman who was visiting from Switzerland. In
County Armagh, a man in his 20s was killed by a falling tree. Falling trees also severely injured a woman in
Cheshire. There was also severe tree damage in the Galway City and County region, which led to numerous school and road closures. Electricity supplies were lost to more than 100,000 homes across Northern Ireland, with more than 25,000 remaining without power into the following morning; the worst affected areas for power outages were
Omagh,
Dungannon and
Enniskillen.
Enterprise trains between
Belfast and
Dublin were delayed for up to seven hours due to debris on the tracks. After clearing the UK, Ali made landfall in Norway, where several thousand homes were left without power in the west of the country. Ali subsequently tracked over northern Scandinavia and into
Siberia, exiting the basin on 22 September. The storm was named on 20 September, and was expected to develop further over the British Isles. Yellow weather warnings were issued with the "possibility" that further upgrades to Amber warnings may be needed depending on how Bronagh developed over the UK. However, Bronagh did not develop over the Isles, and instead strengthened over the North Sea. Thus, no Amber alert for Bronagh was issued by the UK Met Office. Bronagh brought heavy rainfall to southern Ireland, Wales, and northern England. Heavy rainfall fell across Wales and northern England on 20 September as Bronagh approached. In
Sheffield, of rain fell in a 24-hour period, breaking the previous record of set on 14 September 1994 for the city's wettest September day since records began. Rainfall accumulations reached widely across Wales and northern England, with some parts of Wales recording up to of rain. As a result of heavy rainfall from Bronagh, widespread flooding was reported. Flash flooding in Sheffield was the worst to affect the city since June 2007. Along the A6178 Sheffield Road between Sheffield and
Rotherham, rapidly rising floodwaters caused cars and vans to become stranded. In nearby
Tinsley, a woman had to be rescued from her car after becoming trapped in rising water.
East Midlands Trains reported that severe flooding from the
River Sheaf and
Porter Brook was affecting
Sheffield station, with services delayed or cancelled as a result. The storm continued to intensify over the North Sea, tracking towards Norway. The island of
Heligoland and the
Alte Weser lighthouse on the German coast recorded gusts of , while the
Lindesnes Lighthouse in Norway recorded the highest wind speed at . A truck driver in Hamburg suffered injuries after his truck was hit by a shipping container. Bronagh absorbed the remnants of ex-Hurricane Helene over the Norwegian Sea before making landfall in Scandinavia on 22 September, On 11 October, Callum reached its peak intensity on approach to
Cardiff,
Wales. The storm began to weaken due to an impinging weather system. which had an adverse effect on Callum before it made impact on land. The system then brought intense winds with speeds of up to to parts of northern
England, along with torrential rains to parts of Wales with recorded in
Libanus but overall only made a minimal impact on land. Unexpected warm weather was reported soon after, with
Donna Nook in
Lincolnshire reaching in the afternoon. At 21:00 UTC, Callum subsequently moved across
Iceland and the
Norwegian Sea as a weakened system, continuing northwards into the Arctic and out of the basin by 16 October.
Storm Leslie While still a tropical cyclone, the center of Hurricane Leslie passed within of
Madeira. This prompted the issuance of tropical storm warnings to the archipelago on 11 October, the first ever tropical cyclone warnings issued in Europe. Beaches and parks were closed, 180 sports matches were postponed and dozens of flights were cancelled until Leslie began to move away from the archipelago and all warnings were cancelled on 13 October. Leslie transitioned into a powerful extratropical cyclone on 13 October and made landfall in
Figueira da Foz in central
Portugal with sustained winds of at 21:10 UTC that day. Red weather warnings were issued for 13 out of 18 districts in Portugal by the time Leslie made landfall, including
Lisbon. Extreme wind gusts, associated with a
sting jet, were recorded in the Figueira da Foz area after landfall, gusting as high as . High winds and flooding from heavy rainfall caused damage across Portugal and Spain, leaving 324,000 homes without power in Portugal at the height of the storm. Sixty people were evacuated from their homes during the storm, and more than 1,000 trees were blown down across Portugal. Leslie caused two fatalities and 28 injuries in mainland Portugal, and damage estimated at more than €100 million across the Iberian peninsula. Leslie weakened as it moved across the Iberian peninsula, with winds gusting up to a maximum of reported across
Spain. However, heavy rainfall from the system persisted and later fed into a low-pressure system to the north, resulting in record-breaking rainfall across southern France. Severe thunderstorms and flash flooding were reported, with
Carcassonne recording of rainfall in a five-hour period on 14 October. The worst affected town was
Villegailhenc in
Aude; the river
Aude rose to a height of above average, its highest level since 1891, and flooding in Villegailhenc resulted in 14 fatalities. Wind gusts of and wave heights of were recorded in
Sète. In total, damage from Leslie in southern France was estimated at more than €220 million.
Storm Adrian Storm Adrian formed on 28 October over the western
Mediterranean Sea, becoming the sixth named storm of the season and the first to be named by
Météo-France. Adrian strengthened as it tracked between the
Balearic Islands and
Corsica, later making landfall in Corsica on 29 October with winds gusting up to . A trailing weather front from Adrian advanced into northern Italy causing severe
coastal flooding, the
Italian Riviera was severely damaged, the port of
Rapallo completely destroyed with two hundred damaged and sunken boats, partially isolated
Portofino by land with destruction of the coastal road, while on
Adriatic coast, has killed six people in Venice and has damaged the
Basilica of San Marco and left 75% of the city underwater; Two
tornadoes touched down in the centre of
Terracina, killing one person and injuring ten others. before moving into the
Norwegian Sea and dissipating off the coast of
Norway on 31 October. The wider circulation of Adrian additionally caused dust storms in
Algeria,
Tunisia and
Libya starting on 28 October, subsequently directing a dense plume of
Saharan dust over
Italy on 29 October and into
Greece on 30 October. After emerging into the Norwegian Sea on 1 November, Adrian stalled and re-intensified, slowly drifting towards
Iceland. On 3 November, Adrian was absorbed by the remnants of
Hurricane Oscar while centred between Iceland and northern Scotland.
Storm Etienne Storm Flora Storm Deirdre from Storm Deirdre in
Sheffield Storm Gabriel Storm Helena Storm Erik Storm Isaias Storm Julia A
National Weather Service Ocean Prediction Centre analysis showed the low reaching a nadir of .English: NWS OPC synoptic chart of deep low in Atlantic. The UK Met Office produced an analysis chart with the low at .
Storm Kyllian Storm Freya Carnival processions in the German towns of
Bottrop and
Oberhausen were cancelled. One person died in
Ochtrup after their car was hit by a falling tree. A second person died in
Kempten.
Storm Laura A storm-related traffic accident in northern Germany caused three deaths. A wind gust of was measured at on
Aiguille du Midi, a new record since measurements began in 1993 on that mountain. On 7 June, storm Miguel produced gusts up to at the Atlantic coast of France. At
Île d'Yeu, France, one of these gusts set a record for the month of June, last set in 1981. == Other systems ==