UK Weather - Autumn 2012

[Simon Culling]

The change to Autumn will be a little delayed this year as we are expecting the next 3-4 days (at least) to be warm and sunny. Yesterday (Tues 4th Sept) was warm and humid ahead of a SE moving cold front which was no more than a band of low Sc.....all the rain had died out. The maximum temperatures on Tuesday (ahead of the front) were 26.5*C at Frittenden (Kent), 26.3*C at Gravesend and 26.1*C at St James Park, London.

It was much fresher and cooler today here in Milton Keynes (winds from the north) with only a few puffs of cumulus and unbroken sunshine all day....although the max was only 20*C it was a glorious day.

The air source will back to SW over the next day or so and we will see the mercury back up to 26-27*C by the weekend with plenty of sunshine.

The change to autumn colours on the trees has not started yet, but this late sunshine might help add a bit more colour when it does.

[stepr]

Surprisingly up here the trees have actually started in some cases (turning), I'm not sure why.. I assume it's the cooler and relatively sunny conditions we've had recently (sugars work with sunshine etc etc). It will probably be a very drawn out late turning of the leaves though. Last year the first leaves started turning around late September, but didn't fall until early December. The year before, in contrast, the leaves started turning in late August and we're mostly bare by late October.

[Simon Culling]

CET for September up to the 6th was 15.6*C (+1.1*C) and the EWR just 1mm. The average rainfall for the month is 78mm.

A wall to wall sunshine day for much of England + Wales today (Fri 7th) with max temps of:

26.7*C at RAF Northolt
26.4*C at Shoeburyness (Essex) and London Heathrow
26.0*C at Andrewsfield Aerodrome

A warm and sunny weekend for those of us in England + Wales, but the unsettled and rainy weather will make a return from Monday (10th) onwards.

[Janos]

Autumn colours are showing on some of our trees down here in Berkshire. Been a magnificent run of warm sunny weather. Back to NZ next week for 6 weeks i might need to acclimatise.

[Orion]

Sounds as if it's been very pleasant - with, as you say, a change to come:
http://www.telegraph.co.uk/topics/weath ... winds.html

[stepr]

Tonight it is expected to get pretty chilly across parts of the British Isles. In towns and cities around 6-9C in general, but potential for 2-3C in more rural areas. I suspect in the most sheltered frost hollows though sub zero is possible. There is the chance of grass frost. That said in most areas just a chilly Autumnal morning.

Today saw some intense showers across parts, with some unexpected flooding in northern England.

Winds have been getting up in northwestern parts of Britain with some more gales expected.

[Simon Culling]

Yesterday morning (Thurs 13th) was a little cool but the lowest temperatures I could find (1.1*C at Benson and 1.7*C at Sennybridge) are not exceptional. The lowest recorded temperatures for September in the UK are -6.7*C at Dalwhinnie (Highlands) on 26-9-1942 and -5.6*C at Santon Downham (Suffolk) on 30-9-1969.

Current CET for September is 15.1*C (+0.9*C) up to the 12th and the EWR is just 10mm also up to the 12th which is about half of the proforma average....monthly average is 78mm.

A decent weekend ahead for getting out and doing the garden chores before the autumn gets going properly, although recent years have seen very warm and dry autumns in general. We are overdue a wet and stormy one.

[Simon Culling]

A complicated synoptic set up has been worrying the forecasters for a few days, with the headache being caused by ex hurricane Nadine which is still a tropical storm and located near the Azores. It has thrown a lot of warmth and moisture north eastwards towards the UK and a depression is now forming to our south west over the Atlantic to the west of Portugal. This will probably move across the Bay of Biscay to be over the SE of the UK by Monday and somewhere around 980mb. It will bring a wet, windy and cold day to the south of England and Wales tomorrow (Sunday) extending to the north on Monday. The low is forecast to stick around until midweek giving us plenty of showers.

It was cool this morning (Sat 22nd) with a frost over parts of Scotland, N Ireland and northern England and a ground frost further south. Minimums recorded include:

-3.1*C at Tulloch Bridge
-2.6*C at Shap Fell (Cumbria)
-1.8*C at Eskdalemuir Observatory (Southern Uplands)
-0.8*C at Warcop (Cumbria) + Bainbridge (N Yorks)
+0.1*C at Benson (Oxfordshire)
+0.2*C at Newport (Salop)
+1.0*C at Coton-in-the-Elms (Derbyshire)

Here in Milton Keynes local stations recorded between 2-4*C with a local ground frost. It has been cool and sunny today, but rain will be here by mid-morning tomorrow. The first colours of Autumn have just started to appear on the trees. Lets hope the wind tomorrow does not blow them all away.

[Simon Culling]

The low duly progressed north and is currently (2100 on Monday 24th) located on the N Yorks coast at 979mb, having produced a lot of rain and wind yesterday and today over the UK. Yesterday (Sun 23rd) was a cold day over the south of England + Wales with max temps of:

7.7*C at Tredegar Bryn Bach Park (S Wales)
8.9*C at Liscombe (Somerset)
9.4*C at Little Rissington (Glos)
9.8*C at Stowe (Northants - just up the road from Silverstone)

In the 24 hours to 0600 this morning (Mon 24th) the rain totals were highest in the SW of the UK:

62mm at Dunkeswell Aerodrome (Devon)
56mm at Exeter Airport + Liscombe (Somerset)
51mm at Hereford Credenhill (Worcs)

The rain transferred north today with similar totals being seen in N Wales and Northern England.

[Manukau heads obs]

I see that a NZ women was killed from a falling branch from a tree in a park during the strong winds and rain from this system

[Simon Culling]

The BBC link below contains details on the unfortunate lady and there is a link to the New Zealand Herald at the end of the article with more information.

http://www.bbc.co.uk/news/uk-19693499

Very wet today in N Wales with 56mm at the coastal town of Rhyl in the 12 hours to 1800GMT. Some considerably higher totals will be seen for the 24 hour period, available tomorrow. Cold day in N Ireland in persistant rain, with daytime max's of just 8.5*C at Lough Fea and 8.8*C at Glennane.

[Manukau heads obs]

why is it so cold when its a depression of sub tropical origin?
is it drawing in cold air from colder latitudes?

[Simon Culling]

Hello Brian, the depression is not really of sub tropical origin. It formed over the Bay of Biscay on Friday/Saturday as a sharprening upper trough moved SE from the Atlantic and was able to source moisture and some warmth from Tropical Storm Nadine which was to the SW over the Azores. The drivivg force was a strong jet stream further south than normal rather than the TS. it just provided plenty of moisture.

TS Nadine is still going (it became a TS on the 12th September) and has just meandered around the Azores area ever since. It was at 32N 30W at 1500GMT today (Tues) according to the latest NOAA update with a central pressure of 997mb and max sustained winds of 45mph. It is expected to strengthen slightly as it drifts to the SW.

The wet and stormy weather has continued over the UK with a lot of local flooding in the north of England. The Met office have provided some rain stats for the 55 hours to 0700GMT this morning (Tuesday 25th):

107.8mm at Ravensworth (N Yorks)
98.2mm at Killylane (Co Antrim, N Ireland)
87.0mm at Stormont Castle, Belfast
73.2mm at Levens Hall (Cumbria)
72.4mm at Filton Airport, Bristol

These are stations located on low ground and probably half as much again has fallen over higher ground in northern England and N Ireland.

Interesting story from eastern Scotland. Watch the short video to see the knee deep foam caused by wave action on phytoplankton forming what is known as 'spume'.

http://www.bbc.co.uk/news/uk-scotland-n ... d-19716141

[Orion]

Thanks for the link to the videos:
what a mess - fallen trees, flooding, froth

[jamie]

saw the froth on tv thismorning and the flooding. The froth would stink once it begins to dry would it not?

[stepr]

Still raining here.. That's 103.8mm over 48 hours in total!

Roads are numerously flooded on the peninsula, and some train and bus services were/are not running.. Although trains should be back to normal today.

Just to clarify that's roughly 15% of our yearly expected rainfall in just 48 hours.. Unbelievable amount!

[Simon Culling]

Jamie, I would imagine the foam will take an organic smell when it dries, when it might become a bit of a skin or respiratory irritant. The link below gives another example from Australia:

http://www.hoax-slayer.com/whipped-ocean-foam.shtml

[Simon Culling]

stepr, that is a lot of rain! As reported on UKww, a station not too far from you at Wrightington (not far from Wigan) has recorded 104.4mm over the same 48 hour period and another (on wunderground) near to this station at Parbold also recorded 96mm. These sort of falls seem to be quite widespread over N England and N Wales.

[Simon Culling]

This depression is being described as the deepest in September for 30 years with the lowest pressure of 973mb being recorded in NE England. It moved up from the SW on Sunday as previously explained, but then behaved in a very unusual way. During the next 3 days it slowly moved northwards up the east coast of England, then swung westwards across N England on Tuesday and then overnight and into today (Weds) it moved south down the west coast of Wales + England to be located over the Hampshire coast (at 993mb) this evening at 1800GMT. It is forecast to drift away to the east over the next couple of days and into Europe.

I did Nadime a bit of an injustice in a previous post as she did supply a lot of warm moist air which reacted with much cooler air coming south from northern lattitudes. The large thermal contrast has certainly been a key ingredient in providing so much rain. An illustration of the warm air can be seen from observations made in SE England (to the south and east of London). During Sunday afternoon and evening it was cold and wet with temps of 10-11*C being reported. However, overnight the warm air on the SE side of the depression moved into this area lifting the temperature to 16-17*C. However, this warm air was squeezed away to the east as the back bent wrap around front/occlusion moved east across the area with more heavy rain after dawn and reducing the temperature to 11-13*C by lunchtime on Monday.

[Simon Culling]

CET up to the 26th of September was 13.4*C (-0.3*C) and the last few days have been cooler than normal. EWR up to 28th has risen to 83mm compared to the monthly average of 78mm, with the bulk of the month's rain coming in just 3 days. This the fourth wetter than average month in a row.

The week ahead is looking rather cool and showery......Autumn has arrived.

[Simon Culling]

Final CET for September was 13.0*C (-0.6*C) and the EWR was 90mm which is 115% of average.

Nadine is still going but has been downgraded to a Tropical Storm and at 1500GMT today (Tues 2nd Oct) was located near 34*N, 37*W at 994mb and still packing max sustained winds of 65mph. She is expected to turn back to the NE and brush past the Azores again and finally be absorbed into a depression by Friday in the mid-Atlantic. The models are not sure where this low pressure goes into the weekend.

[Simon Culling]

CET for October up to the 6th is 11.3*C (-1.0*C) and the EWR is 25mm up to the 5th. The monthly average for October is 87mm, so ahead of the curve at the moment. The week ahead is still looking unsettled with most of the rain coming Weds/Thurs and a little milder than the last week. It was cool and foggy last night (Saturday into Sunday morning) with a frost again in the north.

[Manukau heads obs]

so how long did Nadine last for in the end?
I do remember a TC that looped around off queensland for a month way back in the 90s sometime

[Nev]

According to the NHC's Final Discussion, at 21.75 days, Nadine is the fifth longest-lasting tropical cyclone (i.e. U.S. tropical depression, tropical storm or hurricane) on record in the Atlantic Basin.

It would seem that Nadine's Final Advisory forecaster is also a Grateful Dead fan …

REMNANTS OF NADINE ADVISORY NUMBER 88
NWS NATIONAL HURRICANE CENTER MIAMI FL AL142012
1100 AM AST THU OCT 04 2012

...BYE BYE NADINE...
...WHAT A LONG STRANGE TRIP ITS BEEN...

Tropical Cyclone Rewa holds the South Pacific (incl. Coral Sea) record of 25 days set in 1993/94. Hurricane/Typhoon John in the NE and NW Pacific Basin holds the overall record of 31 days set in 1994.

[Simon Culling]

From reading the various updates from NOAA, the forecasters got rather fed up with Nadine as she kept on going out over the sea and never really threatening land......apart from a couple of side swipes at the Azores. This blog on Weatherunderground gives some further details:

http://www.wunderground.com/blog/JeffMa ... rynum=2249

The interesting point is that she never made much progress across the Atlantic and took nearly 3 weeks to finally be steered north into temperate lattitudes. She certainly pushed plenty of warm and moist air north over the western side of Europe inluding the UK. There were also some very serious floods in the south of Spain a couple of weeks ago (at the end of September) associated with this air and a sharp upper trough coming in from the north Atlantic.