The other day, I did the first analogue for the Winter 2018-19 season and it was on Winters which followed on from warm Junes. For this blog post, I'm going to be doing an analysis of the same analogue of warm Junes but for the Autumns that followed these months instead of the Winters as part of the Autumn 2018 forecast season. My Autumn 2018 forecast will be released on Tuesday, August 28th.
The analogue of warm Junes going by the 500mb height anomaly reanalysis below suggest that Autumn would be quite cold and rather unsettled one. There is a trough that is over much of western Europe with the centre just lying over the Bay of Biscay. There is also a lot of northern blocking over the Arctic and the way the trough is aligned could suggest northerly to northeasterly winds bringing cold air into that trough from the Arctic. At the same time, we're on the cold side of the jet stream.
Now just like the Winter analogue, let's look at the Autumns in this reanalysis individually one by one to see if we can notice any trends with the individual Autumns to match what this overall reanalysis shows.
1976 - A very wet Autumn following the hot and dry Summer of 1976 along with a lot of dry seasons since October 1974. This certainly ended the drought of that period and was a welcome relief. Each of the months were generally relatively cooler than average though October was fairly close to average outside of Ireland. A blizzard occurred in Cumbria at the end of November.
1940 - A cool September and October generally though November was milder on the whole (by today's standards, it would be a rather cool November in Ireland and Scotland). Very wet October in Ireland and a very wet November for the majority of the places; one of the wettest Novembers on record as a matter of fact. Kind of akin to 2009 in some ways which had a very wet November followed by a very cold Winter just like 1940-41 was.
1970 - September was exceptionally dull and sometimes stormy with variable rainfall. October was very dull again in Ireland and Scotland where it was a fairly changeable month but quite dry in the southern regions of the UK. November was a sunnier month but it was extremely wet with most places having their wettest November since 1940 (oddly enough, 1940 is in our analogue too just mentioned above).
2003 - September was generally dry and for some the driest September since 1986. It was also quite a warm and sunny month continuing on from the dry, warm and sunny August. October was a much colder month as it was the coldest in 10 years (since 1993) but also very sunny especially in Ireland. Rainfall for localised locations in October was above average such as Dublin due to some heavy daily rainfalls during the month, most notably on the 22nd in the form of thunderstorms bringing floods and snow. It was among the driest Octobers on record in Scotland and the west of Ireland. November was a rather unsettled and mild month.
2006 - September was rather dry to the south and east of England but otherwise mostly wet and exceptionally mild; the warmest September on record in fact. October and November were more generally wet whilst being mild again but not so as September was. It was the wettest Autumn since 2000.
1992 - Fairly cold Autumn overall, largely down to one of the coldest Octobers of modern times (along with its following October in 1993). September was also relatively cool and wet whilst October was dry and November was mild but wet.
1960 - North south split in terms of the pattern in September with the south of both countries, Ireland and the UK, being on the wetter and duller than average side whilst the north was the opposite though everywhere it was a cool month. October was one of the wettest Octobers on record over England and Wales whilst it was fairly wet over Ireland but dry in Scotland. October was also very dull and mild. November was a mild and sunnier month but it was still wetter than average with a particular emphasis for wet conditions over England and Wales. As a result, it was one of the wettest Autumns on record overall in England and Wales.
1950 - September was one of the wettest on record everywhere with it being THE wettest in Northern Ireland and Scotland whilst it was also a cool and dull month. October was rather wet though not exceptionally so over Ireland and Scotland with dry conditions elsewhere. By today's standards, October was a relatively cool month with a cool spell setting in at the last week of the month. November was cold and had some snow to the north as part of one of the snowiest Winters of the 20th century (1950-51). It was very wet in November over England and Wales whilst it was dry over Scotland and Ireland.
2014 - September was very anticyclonic with little to no rainfall for many places during the month resulting in one of the driest Septembers on record. It was also quite a warm September. October and November tended to be wetter with a notably wet week for some from the 8th-14th November in particular. Halloween was the warmest on record.
2010 - September had some wet days which made the month wetter than average overall but it was a changeable month rather than persistently wet. October was close to average temperatures everywhere whilst close to average rainfall to the south and west of the UK though drier than average elsewhere including Ireland and a very sunny month in general. Much of November was unsettled and close to average temperatures (also very sunny to the north and west of the UK including Ireland) but the month ended very differently with an almost unprecedented cold and snowy spell which would continue into early December. These were the coldest November conditions since 1985 and the earliest November snowfalls since 1993. Daytime temperatures stayed widely below freezing on both November 28th/29th.
2005 - A rather mild and changeable September was followed by a very mild and wet October with notably wet conditions particularly in the south of Ireland and the UK. November started off wet and mild but soon became more anticyclonic and gradually colder with some early snowfalls during the last week of the month.
2004 - September started off very warm and sunny but soon became changeable after the first week with unsettled conditions prevailing. October was very wet and cool with a notable storm on the 27th/28th leading to severe flooding over the south and west of the UK and Ireland with Cork being especially suffered badly. November was very dull but also an exceptionally dry month with not a lot going on though it was rather cool out to the north and east of the UK with some wintry showers at times.
1933 - Close to average rainfall for September in England and Wales but very dry otherwise with mainly warm and sunny conditions persisting. October had a cold final week with some gale force northerly winds and snow or wintry showers, otherwise much of the month was mild, dull and wet. It was very dull in the north in particular in October. November was dull and wetter to the east of the UK but elsewhere it was sunny and dry whilst everywhere, it was a colder than average month. This distribution of weather was down to the fact that northerly winds were frequent unusually.
1966 - September was fairly mild and dry after an unsettled start though it was relatively wet in Scotland. October was rather cool except in the east and southeast of England whilst it was sunny over Ireland. October was also quite dry over Scotland but elsewhere very wet and stormy. November was cold with frequent northerly winds, variable rainfall and a lot of wintry showers.
2009 - September was wet over Scotland with the northern part of Scotland having a soggy September in particular whilst the rest of the UK and Ireland had an anticyclonic month after an unsettled start. There was a notable drought for places from September 6th to October 6th. October had an unsettled blip near the start but otherwise, the first half continued on from the dry September though the second half was much more unsettled and mild throughout. November was extremely wet with record breaking floods and rainfall totals. It was the wettest November for a large portion of both countries and provided a stark contrast to the earlier part of the season.
2007 - September started off settled continuing on from the dry end to what was a huge soaker of a Summer. Near mid-month, it started becoming more changeable. It was milder than average in September but in comparison to preceding Septembers, it was the coolest since 2001. October was a very dry and calm month whilst November was also very dry and mild - cooler to the south and east of the UK. It was one of the dullest Novembers on record to the north. Autumn was very quiet overall.
1982 - The north was wetter overall in September but largely due to the wet and stormy final third to the month whilst the south was drier than average. It was also a rather mild month in September with a very warm spell during the middle period. October was very wet and cold though becoming drier and warmer later on. November was exceptionally wet for some, especially to the east of Ireland and Northern Ireland (the latter where only November 1963 was wetter up to that point in the 20th century). November also started fairly mild but became cold with some notable snowfall accumulations occurring over Scotland.
1947 - The first few days of September continued the drought across the UK and Ireland that began at the start of August with an anomalous block of high pressure that was about to lose its oomph. The drought lasted up to September 16th in Kent but by then it firmly became more unsettled to most places though it was a rather warm month. October was very dry and one of the driest of the 20th century in England and Wales. November featured huge fluctuations of temperature from -17°C to 18°C in the space of two days. It was a mainly wet November over Scotland and Ireland whilst it was also very sunny with it being the sunniest on record for the northeast of the UK.
1930 - September was very wet and cool in spite of a warm start along with mostly dull conditions (Ireland being the exception). October was wet to the north and west whilst it was dry in eastern England and mild everywhere. In the wet conditions, it was on the dull side. November was wet everywhere but especially in England and Wales. It was a cold November in Scotland whilst close to average elsewhere.
1959 - Extremely dry, sunny and warm September for the large majority of places with parts of England in the midst of a long absolute drought that began in August and was to last 'til October. October started off similarly warm, dry and sunny but became changeable later on with gales. November was a mild and wet month.
I could not fit 2017 into the analogue because NOAA's composite generator only goes from 1851 to 2014 but 2017 was a significantly warm June so I'll include it here:
2017 - September was a fairly cool and wet month but nothing exceptional. October was on the drier than average but very dull with ex-hurricane Ophelia on the 16th. November in contrast to October was a very sunny month with close to average rainfall. It was also a relatively cool November.
I think what we can take from all these Autumns is that the vast majority of them are very unsettled and some have record breaking wet Autumn months though thankfully, Autumn 2000 is not in here (keep in mind, June 2000 was relatively warm too but not as warm as any of these Junes in the years named in the analogue). November in particular seems to be favoured as being an unsettled month with little settled Novembers in here though of course there are exceptions like 2004.
This is only the beginning of the Autumn analogues so plenty more to come.
