The Dismal Muggy Buggy Autumns of The 2010's!

[iapennell]

Dear Friends, 

October has fallen prey, yet again, to that persistent pattern, with low-pressure stubbornly dominating west and north-west of Scotland whilst high-pressure dominates over central and Eastern Europe and over the Azores: This regime' is occasionally interrupted by the wet, windy blast of some ex-hurricane that skirts the western coasts and brings horribly warm sticky air- totally inappropriate for October - to northern Britain as much as anything else! 

But it is the relentless prevalence of the High-Pressure over Europe and Low-Pressure South Of Iceland, and the persistent muggy, yucky and damp South or South-westerly Winds this Stubbornly Persistent Weather-Pattern brings that is the greatest cause of concern. These winds bring warm humid air up from the Azores, plenty of dankness and the wind and cloud-cover at night, not to mention the warmth of the airmasses, prevents anything like frost at night. 

The reasons for this pattern at this time of year are fairly obvious: The North Atlantic is just past it's warmest in October (so strong high-pressure seldom persists over it), whilst seasonal net radiative cooling over Central Europe encourages high-pressure to form there instead.

The other main influence on the weather-patterns in mid and higher latitudes in October is the sharp seasonal cooling of the High-Arctic which quickly becomes very cold, though the Arctic cold is seldom extensive enough to help precipitate cold Arctic outbreaks these autumns it is sufficient to cause a big increase in the atmospheric temperature and pressure gradients between the Arctic and still-warm mid-latitude oceans so as to encourage some deep depressions to form. With high-pressure over Europe and the three-wave pattern of the upper Circumpolar Vortex these depressions have a tendency to linger south of Iceland whilst high-pressure dominates Europe. 

Another elemental reason why we have south-westerlies for much of the year,  with the possible exception of late-spring is due to the fact that the Earth rotates. Easterly trade winds in low latitudes constantly impart westerly Atmospheric Angular Momentum to the atmosphere as a result of the winds blowing in a direction opposite to that in which the Earth rotates. This Westerly Atmospheric Angular Momentum does not dissappear as this would transgress the fundamental physical Law of Conservation of Angular Momentum, which stipulates that the total Angular Momentum of a rotating body must remain constant unless acted on by an outside force: Tidal influences from the Moon and Sun are so small as to have no meaningful impact on Westerly Atmospheric Angular Momentum that could really affect our weather.   What goes up must, therefore, eventually come down and under current climatic conditions the excess Westerly Atmospheric Angular Momentum in stiff west and south-west winds that dominate in higher latitudes. Problem is, we are getting more of the south-westerly variety rather than north-west or even westerly winds that would be just as (if not more) effective at removing excess Westerly Atmospheric Angular Momentum from the global atmospheric circulation. 

For us who live in Scotland and the North of England, in particular the causes of the recent autumn weather-patterns are maybe a little academic, but the persistent mildness, damp air and the proliferation of bugs brought by the muggy October weather that results from persistent south-westerlies is starting to grate! It is utterly shocking that we should have to wait until November for the first air-frost!

Even at my home in the North Pennines, at over 400 metres above sea-level, these are the extreme minima that I have recorded in October since 2010: 2010:-2C, 2011: 0C, 2012: -2C, 2013: 3C (!!), 2014: 0C, 2015: 0C, 2016: 0C, and the weather -pattern remains most unconducive to frost to the end of October 2017 (extreme low so far just 2C).

[iapennell]

To add, I so miss the crisp frosty spells of weather that we had in Octobers past. In October 1983, we had a dry cold spell brought by a Greenland High that brought several bright cold days with clear very frosty nights, the minimum temperature falling to -4C or colder on several nights. Ten years later, mid-October 1993 produced ten days with sharp or severe night frosts as low as -8C and fine crisp sunny days following a spell of Arctic winds with a Greenland High moving in. The last time we had anything below -3C in October was in 2003!!

There has, I fear, been a sharp climatic transition to our autumns, likely down to Global Warming. The area of Arctic cold is restricted further north and with lower central pressure over Greenland - the frigid air is less capable of interrupting the physical dynamics of the atmosphere on our rotating planet that stipulate persistent Westerlies in higher Western-Margin latitudes even temporarily these autumns.

This climatic change away from cold and frosty to mild and wet for our autumns (we regularly used to get air-frost in September as well as October at my home near Alston in the North Pennines) is akin to the big shift from frequently severe winter cold with lots of frost and snow (brought by frequent easterly or northerly winds) to mild wet winter conditions with persistent West or south-west winds that occurred in the late 1980's, as we now know (with a couple of exceptions like 1995-96) this is how winters stayed until the short run of cold winters commencing 2008-09. Since 2013 we have, of course, also reverted back to the mild wet winter pattern! YUCK!!

Edited October 20, 2017 by iapennell

[northwestsnow]

Its horrible!!!

NW England seems to be the main victim of this pattern too.

Wind rain, rain rain and more ran.

I strongly feel this part of the UK is the ABSOLUTE worst you could live in if you dislike rain, i really really do.

Living where i do just on the western slopes of the pennines is an absolute rain magnet.

 

Edited October 20, 2017 by northwestsnow

[iapennell]

Extreme minimum temperatures in October for each year of the past four decades at my home in the North Pennines at over 400 metres above sea-level (with decadal averages) illustrate how starkly October has changed here since the 1980's and 1990's:

OCTOBER (YEAR)   EXTREME MIN (C)

1980:                  Probably below 0C 

                              (based on local reports 

                            of freezing fog. I was 

                           just 11 at the time) 

1981:  -7C reported by farm helper

            overnight 14th/15th October 

1982: No direct records made.

1983: -8C overnight 28th/29th 

1984: -3C

1985: 0C

1986: 0C

1987: -2C

1988: -3C

1989: 2C (no air-frost in October was unprecedented for our location at that time) 

Mean extreme minima for October in the 1980's (based on actual readings): - 2.6C

For October in 1990's:

OCTOBER (YEAR)  EXT. MIN (C)

1990:  -2C

1991: -2C

1992: -6C

1993: -8C (two nights mid-length!)

1994: -3C

1995: 1C (no air-frost in Oct but -3C had been recorded overnight 27th/28th September 1995)

1996: 0C

1997: -5C

1998: -3C

1999: -4C

Average Extreme Minimum for Octobers of 1990's:  -3.2C

And for the Octobers of the 2000's:

October (Year)   Ext.Min (C)

2000:  -1C

2001:  +3C (no air-frost until 7th November) 

2002:  -6C

2003: -5C

2004: 1C (no air-frost until 11th Nov!)

2005: 0C

2006: 0C

2007: -2C

2008:  -3C (the temperature has not got this low in October since then)

2009: -1C

Average extreme minimum temperature for the Octobers of the 2000's: -1.4C

And finally the Octobers since 2010:

October (Year)   Extreme Min (C)

2010:  -2C

2011: 0C

2012: -2C

2013: 3C (no air-frost until 2nd November) 

2014: 0C

2015: 0C

2016: 0C

2017: So far this autumn and this month nothing below 2C; judging from the medium-range weather charts nothing below 2C looks likely for the rest of this month! 

Average extreme minima for October of 2010's to date: -0.1C

So quite a climatic shift for North Pennine Octobers! 

[iapennell]

Interesting too, is the fact that we used to have our first really sharp air frost (with a minimum of -3C or colder) by the end of October in most years during the 1980's and 1990's, yet now we have not recorded an air temperature as low as -3C in October for nine years and (moreover) it's been five years since the air-temperature really got below even 0C in October. 

These warm south or south-west winds go the whole hog and dominate the autumn months to an extent they never used to. They are ruthless in keeping cold weather well away.  Yes, I know that October has traditionally been dominated by cloud wind and rain but there would usually be a few days when Arctic air could break into the North Atlantic pattern and (with the help of a clear night or two) bring the first air-frost of the season, often well before the end of October.  There was also an interruption to the normal south-westerly pattern for much of October last year and during 2015: Fat lot of good it did as pressure dropped in the North Atlantic towards the close of both October's 2015 and 2016 and the wind slewed 'Round Towards The South. So we didn't get the Easterlies at the time in October that could have brought the best chance of cold, crisp weather and night frosts! You may also recall that last year, October's Easterlies were often associated with cloud and rain, particularly for the North East and eastern England as North Atlantic depressions rammed into the western approaches off Cornwall: You see, those Wretched Winds That Have To Blow To Stop The Earth Slowing Down can still mess up our weather and bring dank mildness in October even when they stop just short of the UK!  Better that these winds (and associated depressions) are EAST of Britain, then we get Cold Northerlies : And that sadly, is all too rare (absent!!) in North British Autumns in These Globally-Warmed Years!

Edited October 20, 2017 by iapennell

[damianslaw]

Agree recent Octobers have been poor for frosty conditions, largely due to little in the way of polar air, but not necessarily anticyclonic conditions, last October and the one before and also 2009 and 2010 brought lengthy spells of non-south westerly muck, so it isn't quite true to say this airstream has dominated many recent Octobers. Indeed we received notable northerly late Oct 2008 which brought low level snow, a shot of northerlies in 2010 and also 2012.. Admittedly this October is one to forget, dominated by miserable SW airstream much like 2013 as well.

Novembers in recent years have been a real mixed bag, last Nov brought quite a bit of cold frosty weather, 2013 wasn't bad either.. 

What has been noteworthy is how mild the last week in October has been in the last 4 years, 2015 brought record mild, this year yet again looks like delivering a very mild end.. but I wouldn't be surprised to see a major switch come early Nov, just a hunch..

[March]

Meh, it's not like there won't be a load of frosts between now and May....

[weatherguru14]

it never gets  frosty in October.. BECAUSE ITS NOT COLD ENOUGH,  to suggest  we use to get frosts in October was never the case..

[iapennell]

12 hours ago, weatherguru14 said:

it never gets  frosty in October.. BECAUSE ITS NOT COLD ENOUGH,  to suggest  we use to get frosts in October was never the case..

@weatherguru14, You are correct about recent Octobers, the prevailing wind-patterns in recent autumns hardly allow it. Higher autumnal sea-surface temperatures around Britain's coasts compared to past autumns also helps discourage frost from occurring. 

However, I have records from my Weather Station going back 35 years and the average extreme minimum for October during the 1980's and 1990's was -3C. Most places in England used to get their first air-frost of the season before the end of October, particularly during the 1970's and 1980's.

Why are old gardening books full of warnings about protecting early autumn plants such as dahlias against "September Frosts": Yes! September, Frosts, for the average English County Garden. Frost was viewed as a serious threat to gardens nationwide in September (before October).  Indeed, at the colder northern location that is my home, when I very first started doing weather records as a child of 12/13 I have recorded 0C overnight 19/20 August and then -0.5C overnight 27/28 August. That was in 1982.

Nowadays, of course, we struggle to get such temperatures before the start of November!!! 

[chrisbell-nottheweatherman]

On 10/20/2017 at 16:38, northwestsnow said:

Its horrible!!!

NW England seems to be the main victim of this pattern too.

Wind rain, rain rain and more ran.

I strongly feel this part of the UK is the ABSOLUTE worst you could live in if you dislike rain, i really really do.

Living where i do just on the western slopes of the pennines is an absolute rain magnet.

 

I have a friend on another forum (unrelated to meteorology) who is a frequent contributor to the meteorological thread I started there who lives in SW Scotland.  He's become quite depressed by how cloudy and wet much of the summer and autumn has been there and is wondering where the 'nice weather' as he calls it, has gone.

[Nick L]

On 21/10/2017 at 03:43, weatherguru14 said:

it never gets  frosty in October.. BECAUSE ITS NOT COLD ENOUGH,  to suggest  we use to get frosts in October was never the case..

There has been widespread settling snow in the south in October so no, frost isn't exactly unheard of.

Now going for a couple of weeks with minimum temperatures barely below the teens, now that is unusual for October. 

[hillbilly]

On ‎21‎/‎10‎/‎2017 at 03:43, weatherguru14 said:

it never gets  frosty in October.. BECAUSE ITS NOT COLD ENOUGH,  to suggest  we use to get frosts in October was never the case..

A quick look at Met office data for this area lists we have had 7 air frosts in the last 20 years for October that occored in 4 separate years leaving 16 with no air frost at all.However the previous 20 years gave 38 air frosts in 10 out of the 20 Octobers suggesting that up to 20 years ago we would expect an air frost twice in October on average,how times have changed !

Edited October 22, 2017 by hillbilly

[weatherguru14]

I love how people mention  certain times when its happened and ignore countless of years where it doesn't happen.. it snowed in October once.. so that means what?? frost happens in October a lot?  well maybe it happens  in the last few days when its almost November.. But its not long ago it was  30c on the first of October.Does that mean we expect it every year? October is often to mild for  frost to form.

You can look at weather stats all you want.. But the weather in the  UK does not play ball.. You never know what you will get in any month.. first 2 weeks of October as felt warmer than It did in August.. But October over all  frost is not very likely.

[iapennell]

1 hour ago, weatherguru14 said:

 But October over all  frost is not very likely.

And frost in October, even where I live in the North Pennines, is getting less likely as the years go by.....

One can but hope the period of quiet Sun predicted from 2020 through to the 2040s brings us some cooler years with a return to proper frosty autumns and severe winters before rising CO2 levels wreck our seasons and climate for good!

[AderynCoch]

3 hours ago, weatherguru14 said:

But October over all  frost is not very likely.

Not in most places but it's certainly not unusual at 400m in the North Pennines. Or at least it shouldn't be.

[Weather-history]

8 hours ago, AderynCoch said:

Not in most places but it's certainly not unusual at 400m in the North Pennines. Or at least it shouldn't be.

Doesn't frost formation favour valleys, though? So shouldn't by logic you more like to see a frost in a sheltered valley in October than 400m up a hillside if it is a clear night?

Edited October 23, 2017 by Weather-history

[northwestsnow]

Well late oct into nov looks primed to break this little cycle this year!!

Edited October 23, 2017 by northwestsnow

[hillbilly]

9 hours ago, Weather-history said:

Doesn't frost formation favour valleys, though? So shouldn't by logic you more like to see a frost in a sheltered valley in October than 400m up a hillside if it is a clear night?

That is a very interesting question.I used to live at 340m and the temperature almost all year round was between 2 and 3 degrees cooler winter or summer that 3 miles down in the valley bottom even during times of frost.However during times of severe frost I have only ever recorded -13 deg in 2010,1995 and 1981 whereas I believe it was a few degrees cooler in the valley at that time.Am not sure how that equates to places like Topcliffe in the vale of York which normally gets the lowest readings for Yorkshire,maybe someone else could help out  here how this is all explained.I do believe the topology of the land and obviously how far inland and snowcover has a big bearing .

[Summer of 95]

It's been the one absolutely indisputable change in the last 20 years IMBY, even more so than the change in summers since 2007. Up until 1997 a frost free October was the exception rather than the rule, it wasn't unusual to have a run of frosty nights (remember that week in October 1997 with 4 or 5 in a row, including one -6C; Jan and Feb haven't managed that recently), and of course the frosty nights meant gorgeous clear, sunny days.

The prevailing pattern then was: Summer ends at the beginning of Sept, first frosts of Autumn in October, in between 3 or 4 weeks of rain, cloud and boring 13-18C temps.

Now it is: Summer ends at the beginning of Aug (if it turned up at all), first frosts in mid to late Nov, in between 3-4 months of rain, cloud and boring 13-18C temps.

These warm Octobers have so often been horrendously dull. Except for 1995 (before the change- warm, dry, sunny Oct doesn't really happen any more either) and the early part of 2011, the warmth has been almost entirely at night with the days dull and often damp. That warm Halloween in London a couple of years ago, that "sunny warm" day in late Oct 2005- both were cloudy here. 

The last October that was anything like the old ones was 2003. That was the last time we got the frosty nights/clear days combination to any extent.

[AderynCoch]

14 hours ago, Weather-history said:

Doesn't frost formation favour valleys, though? So shouldn't by logic you more like to see a frost in a sheltered valley in October than 400m up a hillside if it is a clear night?

It depends. If you're talking about the difference between a 400m hillside and a 300m valley you're probably right, but comparing a 400m hillside with sub-100m lowlands? I'm not so sure.

Alston itself is in a valley anyway - that of the South Tyne - but it's "only" at 300m (I'm guessing Ian lives somewhere nearby like Nenthead, which is arguably the snowiest settlement in England). Even so I imagine October frosts are more common there than in the Eden Valley.

Edited October 23, 2017 by AderynCoch

[iapennell]

Could it be that the one night still in October when an air-frost might occur (tomorrow night- i.e. overnight 29th/30th) fluffs-up and the ridge following the brief spell of northerlies tomorrow brings plenty of strato-cumulus to the North Pennines and elsewhere- thereby preventing frost from occurring?!!  It would not surprise me, the cold air will have a long sea-track and the latest charts show the main thrust of the northerlies to be further east 9over Norway and Denmark)- with the air reaching Britain having spent a long time stagnating over the warmer-than-usual Norwegian Sea (the wet warm state of the ground across much of the North and Scotland is another factor that will encourage low cloud to form, thereby stopping frost from occurring). 

Another completely No-Air Frost October for most of us I reckon (I predicted as much in my Autumn 2017 prediction), and Autumn to write off into the bargain!

A look back through my weather records and those few Autumns that have not had an air-frost until November have (invariably) been followed by mild wet winters: Yes, I know about the one exception of October 2001 being followed by some hard frosts in November and December that year (there were mild spells in between), but January/February 2002 were definitely mild, wet and windy- and March 2002 was ridiculously mild. I did not record an air-frost in October 1995, but I recorded -3C in late September 1995 and winter 1995/6 was really cold: Whilst I would not go as far to say there is a direct correlation between warm Octobers and the following winter, it is certainly the case that some of the large-scale conditions that contribute to persistent warmth in Autumn can continue to make the following winter mild: Sea-ice restricted to the High Arctic, above average sea-surface temperatures, and a major lack of snow/ice over Scandinavia/northern Europe (due the first two factors) take a while to change and these result in the jet-stream being guided further north over Britain to bring warm wet south-westerlies across the country (these have the effect of re-enforcing ocean warmth and keeping sea-ice restricted to the far north, thereby encouraging the patterns that bring more warm south-westerlies).  At face value, this does not give one a lot of hope!!

I will soon produce a seasonal outlook for the 2017/18 Winter soon:  I will look at sea-surface temperatures and Arctic sea-ice, but I will look at other factors such as the El Nino Southern Oscillation (ENSO) state, the Quasi Biennial Oscillation (wind speeds and direction in the Equatorial stratosphere), Madden Julian Oscillation (convective wind and pressure pattern affecting the Indian and tropical Pacific Oceans) and, of course, the fact that the Sun is entering the quieter phase at the close of the current Sunspot Cycle.  One can also get strong indications up to a month out from long-range Stratospheric and surface forecast models and weather charts.   On the basis of the direction of some of these global weather-patterns it would be churlish to predict a very mild winter (a Quiet Sun, easterly QBO and ENSO near-neutral are not a combination conducive to persistently mild, wet winters in Britain);  however I can tell you now that anyone expecting a December 1981/January 1982 Arctic spell or a bitter February like that of 1986 is certain to be disappointed, at least this coming winter!

[Mokidugway]

Good. Work that but being a mere marine architect I haven't a clue what you're on about 

[Frost HoIIow]

On ‎23‎/‎10‎/‎2017 at 21:55, AderynCoch said:

It depends. If you're talking about the difference between a 400m hillside and a 300m valley you're probably right, but comparing a 400m hillside with sub-100m lowlands? I'm not so sure.

Alston itself is in a valley anyway - that of the South Tyne - but it's "only" at 300m (I'm guessing Ian lives somewhere nearby like Nenthead, which is arguably the snowiest settlement in England). Even so I imagine October frosts are more common there than in the Eden Valley.

I think lower valley's are definitely colder (the coldest temps in the UK have been recorded in these areas, like Altnaharra 81m asl and Newport Shropshire 75m asl) that's why the Met Office set up weather stations in those areas as they knew they would give interesting readings. At 400m a breeze would be an issue when it comes down to frost formation. As higher areas are generally windier than areas lower down. Calm conditions or at most a very light breeze are a very important factor for frost.

With my experience anything more than about 10 mph and this can start to lift temps pretty quickly at night and early morning. Unless there is a very cold air mass over us with strong winds then we start to see the words "penetrating frosts" in forecasts. This is when higher ground can tend to be colder than lower areas at both day & night. But these conditions have been almost non existent after the breezy cold conditions of March 2013! ..........I set up a weather station at a relatives in Denshaw, Saddleworth (280m asl) and my night time temps under clear skies are always about 3 or 4C colder. They are situated in a valley too. The breezier conditions higher up in Denshaw seem to be the main factor why they struggle to see temps lower than here (93m asl). It snows more on higher ground because of lower dew point and when precipitation is heavy enough (as it usually is on higher ground) it can cause evaporative cooling and therefore turn rain & sleet more readily to snow than lower areas, basically tied into orographic lifting.

Edited October 28, 2017 by Frost HoIIow

[sundog]

14c here atm ,at this time of night and in late Oct just shows what a shambles our autumn's have become.

[lassie23]

another winter down the drain

41 minutes ago, Mokidugway said:

Good. Work that but being a mere marine architect I haven't a clue what you're on about 

i'm a tesco shelf stucker, what i got from that was that winter is going to be cack.