Dr. Eddy Graham's Hebridean Weather Blog

Edward Graham's Journal RSS

¡Adios Tenerife! ¡Hasta Luego La Laguna!

Eddie ha terminado su año sabático. ¡Qué aventura en Tenerife! Aquí hay algunas fotos y películas meteorológicas. Muchas gracias a todos, Eddy.

--------------------------------------------------------------------------------------

After six and a half glorious months on Tenerife, Eddy's period of sabbatical leave is now over, and he has returned to Stornoway. What an adventure! See below for a few memorable meteorological photos and movies. It was certainly the "time of my life". With great thanks for everyone, Eddy.

Time Lapse Cloud Movie Videos (Tenerife playlist) here:https://youtu.be/xcWloQsuT0g?list=PL95LKZN9i_Qf4Wlnws8u0OVZ04msIRbpB&t=1

Tenerife

Teide (3708m) rises majestically above the stratocumulus clouds of the trade-wind inversion.

Tenerife

Eerie and stunning view of the Alisio trade-winds across Anaga to Roque de la Forteleza from La Laguna at dawn.

Tenerife

Stunning view towards Santa Cruz de Tenerife (and Gran Canaria more than 100km beyond in the distance), from San Roque, La Laguna.

Tenerife

El Bronco (725m) and Pico Cancelita, Pico Amarillo and Pico Colorado (775m) , La Laguna.

Tenerife

El Bronco and Vega de Las Mercedes, La Laguna.

Tenerife

The Solar Eclipse of 21 August 2017, captured by Eddy from San Roque, La Laguna.

Tenerife

A bumble bee searches for some nectar on La Gomera.

Tenerife

View from Guímar to Izana mountain.

Tenerife

'Purpi-heaven' at Garajonay, La Gomera.

Tenerife

Eddie's final day at the Institute de Astrophysics, La Laguna.

The Weather of Bloomsday 16th June 1904

For all James Joyce fans around the world - today, 16 June, is 'Bloomsday'!

Bloomsday is named after Leopold Bloom, the central character in Ulysses, the novel by James Joyce, arguably one of the greatest works of literature of all-time . The novel follows the life and thoughts of Leopold Bloom and a host of other characters – real and fictional – from 8am on 16 June 1904 through to the early hours of the following morning, in Dublin, Ireland.

Eden_Quay,_Dublin_1900.jpg

 

Ulysses is riddled with enigmata (plural of enigma), tricks and conundra (plural of conundrum). Joyce even got the weather right on the day in question (it was a warm summer's day in Dublin, with a high temperature of 23-24degC, but there was a thunderstorm in the evening!

After a little bit of detective work (sorry, only a little), I have uncovered the following weather gems in Joyce's magnum opus:

"Warm sunshine merrying over the sea"

"His frocktails winked in bright sunshine to his fat strut"

"Thunder in the air. Was washing at her ear with her back to the fire too. He felt heavy, full: then a gentle loosening of his bowels"

"The deafening claps of thunder and the dazzling flashes of lightning which lit up the ghastly scene testified that the artillery of heaven had lent its supernatural pomp to the already gruesome spectacle"

"past ten of the clock, one great stroke with a long thunder"

OK, ok, next time I'll use 20th century reanalyses by NOAA-CIRES or ERA20C by ECMWF - sorry time does not allow today.

Happy Bloomsday 2017 to all!

@eddy_weather

 

 

Anaga 'Foehn Waterfall' Captured by Eddy in Tenerife

The sub-tropical trade winds have been blowing more strongly than normal across the Canary Isles in recent weeks. Here is an (otherwise) rare example of a foehn waterfall cloud, captured in time-lapse mode (at 1/50 hertz) by @eddy_weather on 2 June 2017, from Santa Cruz de Tenerife - wow!

If you cannot see the animation here - click here!

Bow Waves in the Trade Wind Cloud Inversion Layer

Today in the #CanaryIslands as seen by the NASA Terra sensor (713km above us): Lovely 'bow waves' appear in the trade wind cloud layer as it approaches the mountainous isles from the N/NE. But Aha! How does the wind know each island is ahead of it? Can the wind itself predict what is ahead of it? (answer below)

Capture.PNG.22

Answer: Much like the way a motorway traffic jam propagates backwards against the flow of traffic, the velocity and air pressure fields change considerably in the airflow ahead of the Isles

@eddy_weather

#NASA MODIS Terra

Ocean Sunglint Trails

There were some spectacular trails of 'sunglint' to the lee of Canary Islands yesterday (18 May 2017), as seen by NASA MODIS Terra satellite sensor. Sunglint is the isotropic reflection of the sun's rays from a still water surface (isotropic means it has a preferred direction). In this case, the wind was blowing strongly from the north/north-east, and in the lee of the mountainous islands, the sea is more sheltered from the wind. Thus it is smoother and hence reflects more sunlight back to the satellite sensor.

Looking more closely, one can see the actual impression of the lee atmospheric gravity waves on the sea surface (these are not regular ocean waves - instead these have wavelengths of several kilometres).

Lee-Sunglint-Canarys-19May2017.png

@eddy_weather, San Cristóbal de La Laguna, 19 mayo 2017

El Tiempo en Tenerife by Eddy!

Eddy is presently on sabbatical leave from the University of the Highlands and Islands and is currently working at El Instituto de Astrofísica de Canarias, San Cristóbal de La Laguna, Tenerife (Canary Islands). Here are a few photographs of his new surroundings:

tn_Santa-Cruz.PNG

The view from el Mirador de San Roque (~725m) in La Laguna, down to the city of Santa Cruz de Tenerife, with the island of Gran Canaria beyond across the sea in the distance.

tn_Guajara-Campus.PNG

View to the Guajara campus of the University of La Laguna.

tn_Vega-de-Las-Mercedes.PNG.1

View across towards La Vega de las Mercedes

tn_P4231604.JPG

San Cristóbal de La Laguna is a UNESCO World Heritage Site, with many beautiful buildings dating back to 17th century and earlier.

17620482_1353090421405641_2093394989436408859_o.jpg

Eddy on his first day of work at the Instituto de Astrofísica de Canarias in La Laguna.

17854898_1353090551405628_1571782812311414740_o.jpg

The view from my workplace to the Anaga mountains in the distance. The large satellite dish sits on top of the roof of the nearby Museo de la Ciencia y el Cosmos.

17855417_1353090534738963_3461806743694836052_o.jpg

tn_Teide2.PNG

Of course, a trip to Tenerife would not be complete without a visit to desert landscape of Mt Teide, the world's 3rd highest volcano at 3,718m in altitude

Lava-Flows.PNG

Inside the huge volcanic crater, many different coloured and solidified lava flows can be seen (the black ones on the mountain slope are thought to date from the late Middle Ages)

@eddy_weather, April/May 2017

Happy World Meteorological Day 23 March 2017!

A very happy #WorldMetDay to you today (23 March 2017) from @eddy_weather in the Hebrides, Scotland!

IMG_0276_eriskay_4.JPG

Stornoway: Exceptionally mild winter so far and driest for 6 years

tn_P1291350.JPG

Based on long-term Met Office records for Stornoway (which digitally stretch back to 1873, one of the longest such series in Scotland), the winter of 2016-2017 so far in Stornoway is the 2nd mildest (out of 144 years), 21st driest (out of 144 years) and 48th sunniest (out of 88 years), according to the latest data from @eddy_weather.

Let's look at the data with the aid of a few charts. Firstly,  air temperature: Up to the end of January 2017, the current winter's mean air temperature of +6.9C has only be exceeded once before, in 1989:

Mild-Winter-Temp-Graph.png

Next, precipitation (rainfall & snowfall): We are having a dry winter, the driest in 6 years (since 2011) and the 21st driest in the whole 144-year record (so about a 1:6 or 1:7 year event):

Mild-Winter-Precip-Graph.png

And finally, days with air frost: There have been only 3 air frosts this December and January, which is the joint 10th lowest total since 1873. Overall, there's been a decrease of about 25% in the number of days of air frost since 1873 for these months (see trend line).

Mild-Winter-Frost-Graph.png

@eddy_weather, Stornoway, 5 February 2017.

 

 

'Fairytale' Highlands: The view from 12,000 feet

Flying from Edinburgh to Stornoway recently, I captured the following stunning views of the Highlands. Fog and low cloud filled into the glens like a rising and invading ocean, but the Munro peaks remained glorious and resplendent in the sunshine, just like Greenland nunataks. Here I have identified some of the mountain summits:

Rannoch-Moor-from-Creag-Meagaidh_LABEL.png

1) Looking south across Rannoch Moor

The-Trossachs-LABELS.png

2) North-west across The Trossachs to Ben Lui and Ben Cruachan (near Oban).

Nevis-Range-LABEL.png

3) The Nevis Range and the Great Glen.

Dalwhinnie-LABEL.png

4) Now looking eastwards (from the other side of the aeroplane): Fog winds its way through the Pass of Drumochter

The-Fara_Dalwhinnie_Waves-Zoom-LABEL.png

5) The Fara and Dalwhinnie (the bow waves indicate the fog is flowing upwards from the south, and perhaps is sloshing in seiche fashion e.g. https://youtu.be/liwEP03SgVw?t=4 and https://youtu.be/bWKiRsHSBFw?t=1)

Speyside-under-stratus-glory_LABEL.png

6) A Broken Spectre 'Glory' from the fog top indicates that the fog droplets were 'old', with a variation in size of more than 20%.

Carn-Eighe-Sgurr-na-Lapich.PNG

7) And finally, out of the clouds: Carn Eighe / Sgurr na Lapich with a rather thin snow cover for the time of year.

A radiosounding taken at Abermarle, Northumberland (which was also lying under the fog layer) at 12z on this day shows a strong temperature and humidity inversion at 700-800m. The air temperature was -1.1degC at 766m with 99% relative humidity, whereas at 1050m it was a shocking +8.2degC but with a relative humidity of only 30%.

2017012012.03238.skewt.parc.gif

@eddy_weather, Stornoway, Scotland, 24 January 2017

 

Drax and Ferrybridge Making Clouds

Flying north from Heathrow to Stornoway (via Edinburgh) on Friday 20 January 2017, I was able to spot a plethora of local cloud features. It's all thanks to (a) the quasi-permanent high pressure and temperature inversion across the British Isles lately, and (b) humans.

Firstly, let's look and see what two of the biggest power stations in the UK are up to (from a viewing height of 32,000 feet):

tn_Drax-Ferrybridge-20Jan2017-Zoom1.PNG

Oh dear, it's looks like some stratocumulus or stratus undulatus pyrocumulugenitus!

Let's look more closely:

tn_Drax-Ferrybridge-20Jan2017-Zoom2.PNG.1

Drax is the bigger plant marked 'A' (with presumably a greater emission of water vapour); Ferrybridge is 'B'. Drax's cumulus thermal (pyrocumulus, as it is caused by an anthropogenic heat source) is so powerful, that when it hits the inversion, the cloud oscillates up-and-down downwind (north) in a wave train - that's the undulatus bit.

Now, let's consider the NASA Terra 721 satellite image of the same time. The Drax plume again is most apparent - I wonder if its total water vapour emissions are proportionate to the cloud liquid water extent across the north of England that day? There is surely a link, whether minor or major, as shown by Graham (2007) for the Energie Wasser Bern (EWB) incinerator in Bern Switzerland.

 Drax-Ferrybridge-20Jan2017-Terra721-Zoom.PNG

Reference: 

Graham, E. (2007). Clouds - Nature's Landscape? Montagsseminar, Institut Fuer Angwandte Physik, Universitaet Bern.

 

NASA Terra satellite spies snow extent over Scotland

NASA's Terra satellite flew over Scotland this morning at a height of 705km and captured the following two images:

Capture.PNG.20 Capture2.PNG.7

There's a near complete snow cover over the country but it's all very ephemeral I'm afraid - it'll disappear as quickly as it came!

(False colours: Left: red=snow; Right: cyan=snow).

@eddy_weather, 14 January 2017

Arctic blueskies and snow: View from Stornoway Ranol today

This was the view from Stornoway Ranol hill today, at the top of the Stornoway Golf course: There was about 3-5cm of crisp, frozen snow lying:

2017-01-13 14.18.00.jpg Capture.PNG.19

Capture2.PNG.6

@eddy_weather, 13 January 2017.

First snow of the winter in Stornoway

After the record mild December, at times it felt like it was never going to come... but finally the first snow of the winter is lying across Stornoway tonight - especially on the town's hilly Golf course, where snow enthusiasts (young and old) were out doing some night-time sledging this evening...

2017-01-12 19.13.19.jpg

A few facts on the current cold snap:

  • #thundersnow was recorded in Stornoway three times in the past 36 hours: 5h30 and 16h30 Wednesday, and 8h50 Thursday
  • About 3-5cm of snow is currently lying on undisturbed ground, with deeper drifts in places (due to the strong wind)
  • The air temperature has been ABOVE zero throughout the event (typically +1.5degC), but due to a lowering dewpoint, the snow began to lie properly from midday Thursday due to the ice-bulb effect (yesterday the high winds meant the latent heat transfer was too large and prevented settling of the snow)
  • Most of the snow is actually graupel - soft rimed hailstones!

@eddy_weather, Stornoway, 12 Jan 2017

 

Eddy on #Thundersnow

#Thundersnow is the new weather buzzword that's recently come across the pond from Amerikay...

lightning-552038_960_720.jpg

Listen to Eddie explaining more on BBC Radio Scotland yesterday here: http://www.bbc.co.uk/programmes/b086lh6q at 1hr 26mins 36 secs (or 10:26a.m.).

@eddy_weather

The Weather of 2016 in Stornoway: At a Glance

tn_P1021338.JPG

I've completed a climatological analyses of the weather in Stornoway during the year of 2016.  Rather than write a tedious monologue, I'be summarised all relevant monthly values in a Table, which is presented below.

Overall the year was mild with the mean temperature about +0.5degC above normal (but not as warm as it was in 2014).  Rainfall was close to average (i.e. much drier than in 2015, which was a record wet year) and there was near average sunshine too. The number of air frosts was below normal.

Station:

Stornoway Town 04004

                       

Status:

Semi-Homogenised

                     

Year

2016

                       

Month

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

 Year

Mean Max

7.1

6.7

9.2

9.6

12.9

15.6

16.1

16.8

15.7

13.3

8.6

9.9

11.79

Mean Min

2.8

0.9

3.8

3.4

6.8

10.2

10.8

10.5

10.2

6.9

2.9

4.9

6.18

Mean (degC)

5.0

3.8

6.5

6.5

9.9

12.9

13.5

13.7

13.0

10.1

5.8

7.4

8.98

Highest Max

12.9

10.7

13.5

12.5

19.7

20.0

22.0

22.2

19.2

17.4

13.3

13.1

22.2

Highest Min

10.8

4.9

8.9

6.9

9.8

13.5

14.9

13.9

13.4

12.8

11.2

9.6

14.9

Lowest Max

2.5

3.6

4.6

5.8

9.7

11.9

14.3

14.2

12.2

9.6

3.9

3.9

2.5

Lowest Min

-1.9

-2.3

-2.1

-2.7

2.8

7.2

6.2

4.2

6.2

0.8

-2.5

-1.7

-2.7

Air frosts

7

8

4

3

0

0

0

0

0

0

6

2

30

Grass Frosts

16

23

19

12

1

0

0

0

0

9

17

10

107

Lowest Grass

-6.4

-5.5

-6.4

-5.4

-1.4

4.0

3.1

3.0

1.9

-4.1

-6.7

-6.7

-6.7

Precip (mm)

157.5

154.7

92.6

53.4

62.9

80.0

143.5

86.8

139.0

38.9

114.6

133.0

1257

Wettest

18.8

24.0

27.7

5.8

11.0

12.5

26.1

20.2

20.6

10.8

23.2

14.3

27.7

Raindays (>=0.2mm)

24

26

22

24

12

17

30

16

23

12

25

27

258

Wetdays (>=1.0mm)

18

23

14

14

10

14

23

12

21

10

21

23

203

Hail

7

12

4

7

2

0

0

0

0

0

6

6

44

Thunder

3

1

0

0

1

1

0

1

2

0

0

2

11

Snowfall

10

16

6

7

0

0

0

0

0

0

5

5

49

Snow Lying

7

2

1

1

0

0

0

0

0

0

0

0

11

Max snow depth (cm)

2

2

2

2

0

0

0

0

0

0

0

0

2

Cloud percent

0.8188

0.7349

0.6956

0.7318

0.7042

0.8073

0.9346

0.6821

0.7243

0.5559

0.6170

0.7917

0.73

 

@eddy_weather, Stornoway, 2 Jan 2017

Record Warm December in Stornoway

With one day of the month yet remaining, December 2016 looks like being a record-breaking mild month in Stornoway.

Eddy reports that the average air temperature for this December will clock in at approximately +7.7°C, almost a full 3°C above normal – or about half a degree warmer than the long-term average temperature for April!

Such a degree of warmth is ‘highly unusual’, and follows very high global air temperatures during both 2015 and 2016. This December will also rank as the warmest of any winter month (December, January or February) for the full period of the Met Office archives, which stretch back over 150 years in Stornoway (one of the longest such series in Scotland).

The following chart places the warmth within the long-term context of all winter months from 1873-2016:

Dec2016-wrm.png

The weather is set to change over the weekend, however, as a short cold snap ushers in wintry flurries and chilly north wind for the New Year.

@eddy_weather, Stornoway, 30 December 2016

#stormConor was Cat 1 Hurricane over Faroes on Christmas Day

You may have missed him, but #stormConor was a fighting wee monster as he passed through Thorshavn (Faroes) on Christmas Day.

 output_xajflx_cropped.gif

The 4pm SYNOP for Thorshavn WMO station 06011 read as follows:

Air Temp: 4.0C Dewpoint: 1.4C Pressure: 966.6hPa Wind dir: NW Mean speed: 72kts (Hurricane Force 12), gusting 102kts (117mph)

and again at 6pm:

Wind gust: 102kts (117mph)

That's several mph stronger than the Stornoway 03026 Hurricane of January 2015. Thorshavn 06011 also recorded 4 consecutive days from 23rd-26th of wind gusts exceeding 95mph (and 3 consecutive days of over 100mph).

The satellite animation above (courtesy of sat24, images copyright METEOSAT)  shows that Conor was a classic Shapiro-Keyser low, with a probable #stingjet being the reason for the exceptional wind speeds (Shapiro-Keyser 1990). Further evidence for the stratospheric intrusion of very dry air (usually found in the region of a tropopause lowering with a #stingjet) can be seen in the following METEOSAT 6.7µm water vapour channel image for 12h (below).  A prominent dark area (dry intrusion) lies directly east of the cloud head tip, and also west of the main frontal boundary:

meteosat-msg_wv062_overlay-vector-overlay.jpg

This dry air arrived in Stornoway during the evening of Christmas Day. A dewpoint of -6.4C was recorded at 18h with a relative humidity of only 45% (due to the 'ice-bulb' effect, the ground was freezing despite an ambient air temperature of +5.5C). The NAVGEM global met model also indicated that widespread tropopause lowering was taking place near #StormConor (red blotches on following chart):

nvg10.tpause.006.europe2.gif

@eddy_weather, Stornoway, 29/12/2016

Reference:

Shapiro, M.A. and Keyser, D.A., 1990. Fronts, jet streams, and the tropopause. US Department of Commerce, National Oceanic and Atmospheric Administration, Environmental Research Laboratories, Wave Propagation Laboratory.

 

#StormBarbara at T+24

Update by Eddy, Friday 11am: The #stingjet of #stormBarbara now looks like staying offshore. Hence maximum expected wind gusts can be reduced from the extreme values given below. So staying wild, but not crazy (thankfully!). See my latest posts on Twitter at: https://twitter.com/eddy_weather

---BEGIN--- (original post)

Please note this is Eddy's final prognostic on #StormBarbara. I will however, be posting analyses and diagnoses during and post-event on Twitter (should power supplies permit so).

Here's how I view the development of #StormBarbara:

Barbara will be a very powerful storm, with maximum wind gusts within the #stingjet* of probably over 100mph. However, there is disagreement still between the models over the exact track of the jet. The final track of this jet will prove crucial regarding the impact of Barbara.

Currently the Global Forecast System (GFS) mean has the #stingjet remaining out to sea, to the north-west beyond St. Kilda, Butt of Lewis, Flannan Isles and Sulisker (see charts below). In this run, gusts of 70-80kts affect N and W Lewis, with up to 100kts (120mph) within the #stingjet, well offshore:

gustkt_033.jpg

However, the all met model ensemble mean (the best estimate from all met models at the moment) indicates that GFS has slow wind bias for the region 58.0degN, -4.0degW (see next chart):

ens_58.0_-4.0_384_kt_06.png

In contrast the COSMO European model (run at highest possible resolution) has a quite frightening prediction with windspeeds in excess of 115mph (180km/h) blasting into west Harris and westside Lewis at 17-18h (see next chart). If realised, this would make it almost as strong as the 'Stornoway Hurricane' of 8-9 Jan 2015.

COSMO-Fri23Dec2016-17 h.PNG

Conclusion: With such disagreement, analyses of real-time satellite imagery will prove key as to the position and area of the sting jet / cold jet which will cause the most violent winds, as well as indicating the Langrangian (relative) speed of the system itself.

p.s. Late addition: I notice the US NAVGEM model is now pulling Barbara further NW again, in line with GFS.

Likely temporal Sequence of Events (very rough guide ± 2-3hrs):

6am: Frontal trough of storm reaches Barra, torrential rain and wind gusts reach 60-70mph.

8am: Same reaches Stornoway

9am-12 noon: Winds increase to gusts of 75mph

~Lunchtime: As frontal trough clears, a temporary 'lull' back to 60-70mph gusts

2pm-8pm: The main hooley, with the most violent winds moving northwest across the Hebrides from Barra to Lewis. Highest wind speeds are likely to last 2-3 hours in duration (depends on speed of system herself). Max gusts are as indicated above (between 80-115mph). If the #stingjet stays well offshore, this stage will be reduced in severity.

10pm-midnight: Worst hopefully over.

The Christmas Day Storm (perhaps #StormConor): It looks like it will also be a strong storm, but current model runs suggest a track further still to the NW. Let's deal with him only after ##StormBarbara!

22 Dec 2016, @eddy_weather, Stornoway

  * Please note that I am using the term 'sting jet' for both sting jets and cold jets (or cold conveyor belts). This is not strictly correct meteorologically speaking - but since the public are more familiar with the term sting jet, I am using this term alone to avoid confusion.

---END---

 

Thundersnow in Stornoway on the Winter Solstice

There was snow with thunder and lightning in Stornoway today (21 December 2016). It was captured by the Stornoway Lews Castle College radar (see below):

C0N2CfLXEAA-dMu.jpg

The occurred just after 16h: See the bright red colour (top right image) & pink (bottom left), as well as large vertical velocity Doppler shifts (shades, bottom right). These are indicative of large hail, large snowflakes and considerable turbulence respectively, leading to the exchange of electrical charge. You can learn more about what the colours mean here: https://uhi-mahara.co.uk/view/view.php?id=24843

Known as 'thundersnow', it is a common misconception that thunderstorms require heat and warm weather for their development. This is a false premise: What thunderstorms really need is atmospheric instability, which is a frequent occurrence in deep cold polar airflows over warm ocean surfaces, such as happens fairly often in NW Scotland during wintertime.

@eddy_weather, Stornoway, 21 Dec 2016

 

Storm #Barbara to be first major storm of winter

#StormBarbara - here she comes Friday (23 December) at 90mph+. Another storm is possible late Christmas Day. The devil will be in the detail, so please keep alert to Met Office warnings, as the exact track of each storm (yet to be pinned precisely) will determine their severity on land. Don't be fooled by any temporary lulls - it may be just the eye of the storm passing over (though I think both eyes will stay out to sea on these x 2 occasions). I shall be tweeting updates on Twitter (as long as the power holds): https://twitter.com/eddy_weather

C0HED8ZWEAAD7QH.jpg

Official Met Office Warning:
http://www.metoffice.gov.uk/public/weather/warnings/#?regionName=he&from=rss&sn=07EA8E4A-143C-8CC5-83B2-1B54CA34F60A_3_HE&utm_source=dlvr.it&utm_medium=twitter&tab=warnings&map=Warnings&zoom=5&lon=-3.50&lat=55.50&fcTime=1482451200

@eddy_weather, Stornoway, 20 Dec 2016

Big Change in Weather For Xmas

Well you've heard it all already - I'm pretty confident that the big change in Atlantic weather that I mentioned last week is now imminent (caused initially by the collapse of an intense cold air dome over Canada last week).

Expect severe gales in the run-up to Christmas, with (brief) snow Wednesday night/Thursday; otherwise torrential rain, violent hail squalls, storm force gusts, thunder and lightning too. Keep alert too to closer short-term warnings (from reputable providers of course e.g. The Met Office) - some of the individual storms could be very potent, and blow up (and out) within less than 24hrs.

'Tis the season...

Podcast from the Met Office today:

@eddy_weather, Stornoway, 19 Dec 2016

Warmest December Fortnight on Record in Stornoway

The past fortnight (5th-18th December 2016) has been the warmest fortnight on record in December in Stornoway, confirms @eddy_weather. Digitised meteorological records in the town go back to 1873, one of the longest such series in Scotland. The mean daily high temperature has been +11.9C, and mean daily average has been +8.9C.

This statistic will be easier to understand when presented in the following graph. The last time it was nearly so mild in December was in 1971 (with a mean daily high of +10.9C and mean daily average of +8.4C in the two weeks up to 20th December), but it has never been as mild as present at any time in recorded history.

December warmth

This news exposes the absurd "post-truth" forecasts of last month (e.g. "Four months of Snow Ahead") in the true light and fact of day.

@eddy_weather, Stornoway, 18 Dec 2016

Eddy's Outlook for Christmas week: Very stormy with frequent severe gales, torrential rain and hail squalls - with snow likely over the winter solstice (Wed night 21st/ Thurs 22nd Dec) - but it will be the most unpleasant type of snow (dull, raw and wet rather than deep, crisp and even!). Possibly even stormier for Christmas Eve and Day, watch out! 

October mildness in December: But major weather changes in Atlantic this week!

The past week has been astonishingly mild in Stornoway: The average daily high has been +11.8C, with a daily low of +7.1C; these values are more akin with early-to-mid October than December!

However, major changes are afoot in Northern Hemispheric atmosphere over the next few days. In stark contrast with the winter so far, a dome of extremely cold air (with a 1000-500hPa thickness of less than 480dam) will collapse over eastern Canada, surging out over Labrador and Newfoundland during mid-week. This will create an intense thermal (baroclinic) gradient, likely leading to super-powerful storms in the western North Atlantic (933hPa is forecast near Newfy on Thurs). It's not certain yet whether such energy will transfer east to Scotland - but it's worth keeping on eye on my blog and Twitter in the coming days just in case (NAVGEM met model T+84 and T+126 charts below).

11dec2016_nvg10.thk.084.atlantic.gif

11dec2016_nvg10.thk.126.atlantic.gif

@eddy_weather, Stornoway, 11 Dec 2016

Am faic sinn sneachda aig àm na Nollaig?

Saoil am faic sin sneachda aig àm na Nollaig am bliadhna?

Bha mi a 'bruidhinn ri an fìor-àlainn Cathy Bhàn seachdainn seo chaidh! Seo an clàradh:

Cathy.PNG

Faodaidh tu èisteachd ris a 'clàradh anseo: http://www.bbc.co.uk/programmes/b08305s3#play 

@eddy_weather, Steornabhagh, 7mh dhen Dùbhlachd 2016

Post-Truth Meteorology

Met Office Predicts White Christmas for All Scottish Cities

Four Months of Snow and Bitter Winter Ahead

Do either of the headlines above seem familiar? Did you read them in any of the Scottish newspapers recently? 

Both statements actually come from leading Scottish daily newspapers printed during the last fortnight. The unfortunate reality is that both are lies - such predictions are no more accurate than the average horoscope or crystal ball gaze. But surely these are 'White Lies'  (lies told without any intentional harm)?

Alas, this is not the case either. They are cases of 'Post-Truth Meteorology' - a term I recently coined on the television programme Sunday Politics Scotland, based on the new word of the year 2016: Post-Truth. The meteorological aspect works like this:

Deliberately false media reports about the weather (such as above) are becoming increasingly commonplace.  These 'forecasts' are not made by scientists, but are instead created by journalists with a political agenda and other attention-seekers. However, the publishing newspapers falsely attribute them to scientists and meteorologists (e.g. The Met Office), so as to increase public doubt and confusion over weather and climate change. This can have serious political ramifications, as the public are then less likely to support mitigation measures against climate change (such as renewable energy), or take precautions in the advent of severe weather.

You can view Eddie talking on the BBC here:

@eddy_weather, Stornoway, Scotland (December 2016)

Details