As you know, Weak La Nina to Weak La Nina Winters (i.e. Weak La Nina Winters that were preceded by Weak La Nina Winters) were part of my Winter 2017/18 analogues and forecasts. This was the table I created showing the CETs for each Winter month during said Winters and the results were quite frankly surprising, but I also said in my forecast that there was still too many exceptions to consider a month by month summary going by ENSO. I found how December 1890 and January 1985 were in there as very interesting.
The CET anomalies are based on the 1981-2010 average and are originally sourced from the UKMO Hadley Centre.
Since the naming of windstorms in the UK and Ireland began in 2015-16, the worst storm to hit our shores going by damage was of course Storm Desmond that struck us on December 4-6 2015.
Desmond was particularly notable for directing a plume of moist air up from the south to the British Isles, known as an atmospheric river, which brought record amounts of rainfall.
On 4 December, the UKMO issued a yellow warning for wind across the north of the UK with gusts expected to reach 70 mph (110 km/hr) in southwest Scotland. Yellow warnings had also been given for rain in Northern Ireland, the north of Wales and central Scotland. An amber warning for rain was issued in parts of central and southern Scotland where the UKMO forecasted up to 200mm of rain on high ground would fall over a 30-hour period from the 5th into the 6th. Met Éireann issued a red status rainfall warning for parts of Connacht as well as Donegal, Clare and Kerry with Clare County Council issuing a flood warning. Other parts of the west as well as Waterford, Wexford and Wicklow were under an amber warning for wind. Cavan, Cork and Limerick had an amber warning for rainfall. All the rest were under a yellow warning for rainfall. This was the first ever time Ireland received a red status warning for rainfall.
On 5 December, the UKMO issued a red status warning for rain in Cumbria with 150-200mm expected in some places. It was the first red warning in the UK since storm Tini - or known as Darwin for us here in Ireland, in February 2014.
The records and impacts of Storm Desmond on the British Isles were huge. The storm broke the UK's 24-hour rainfall record with 341.4mm of rainfall falling in Honister Pass, Cumbria on December 5th beating the previous record of 316.4mm at Seathwaite, Cumbria on November 19th 2009. I'd like to note that these two flood events, as well as the January 2005 Cumbria flood, all took place during El Nino events. The 48-hour rainfall record for the UK was also beaten with Thirlmere, Cumbria having 405mm falling up to 08:00 GMT on the 6 December. Heavy rainfall from Desmond caused severe disruption. Appleby, Keswick and Kendal in Cumbria suffered blocked roads, collapsed bridges (including one that was 250 years old) and some homes were evacuated. Many houses in Carlisle were flooded and tends of thousands of properties in Lancaster lost power when a sub-station was flooded. About 5,200 homes were flooded in Lancashire and Cumbria and approximately 1,000 people were evacuated from their homes in the town of Hawick in the Scottish Borders as a result of the River Teviot flooding. The River Nith burst its banks in Dumfries, flooding part of the town, with a major emergency being declared in Dumfries & Galloway. Landslides and flooding closed some main roads in Scotland. Down and Tyrone in Northern Ireland suffered road closures from fallen trees.
In the Republic of Ireland, the worst affected areas were Connacht and counties Donegal, Westmeath, Tipperary, Limerick, Clare, Cork and Kerry. Multiple, particularly local, roads were closed as a result of rivers breaching their banks and excess rainfall. In Connacht, the damage was worst in Athleague, Ballinasloe, Carrick-on-Shannon, Claregalway, Crossmolina, Foxford and Galway city. Millions of euro worth of damage was caused in Bandon, Fermoy, Kenmare and Tralee, while the Blackpool area of Cork city was severely affected by a higher level of water flow in the River Lee. Heavy rain has also resulted in severe flooding in communities along the River Shannon, namely Athlone, Portumna, Shannon Harbour, Montpelier, Castleconnell, Clonlara, Parteen, Annacotty and Limerick city. The river breached its banks in Athlone on 9 December. Other areas affected due to heavy rainfall included Bray, Clonmel and Ennis. In Glaslough, County Monaghan, the body of a 70-year-old man was found when his car was believed to have become trapped in a dipped part of a flooded road.
2-day (Dec 4th/5th 2015) rainfall totals for Irish stations, courtesy of Oneiric 3 and Met Éireann.
Looking at the 81-10 averages the coastal stations are generally colder in Feb but anything even slightly inland is colder in January. And anyway I'd say February has underperformed just as much as January (2010 again the exception), especially in the past decade it's felt more like a Spring month most years.
December and March have produced almost all the notable snowfalls I can remember