Posted by Dr. Eddy Graham on 30 June 2015, 8:59 PM
It is official, May and June 2015 together will go down in the met history books as two of the most awful months (of their namesakes) ever recorded in Stornoway.
Overall, the May+June 2015 period was the 2nd wettest on record since 1873 in Stornoway, the 4th dullest (lack of sunshine) and 10th coolest since 1900. Put altogether, these are by far the worst weather statistics for May & June combined since records began in Stornoway in the mid 1850s.
Graphically, we view these statistics are follows:
Temperature: But for a milder final five days of June, it would have been the 4th coldest June on record. Instead, it works out to be the coldest since 1987, and the 10th coolest May-June on record in Stornoway:
Sunshine-wise: Need I say anymore: There's an horrendous vitamin-D deficiency for all concerned (4th dullest on record) [BTW, the values for 2004 are missing due to a changeover of instrument at Stornoway Airport]:
And rainfall - mein Gottlieb Daimler! 2nd wettest on record, and if it pours again tonight (30th June), we'll break the record (as June rainfall-month officially ends at 09h00 on 1st July).
Eddie, Stornoway, 30/6/2015
Posted by Dr. Eddy Graham on 26 June 2015, 10:32 AM
On the evening of 23 June, I was very fortunate to be offered a lift to visit the El Teide Volcano and the Izaña Astronomical Observatory (the largest in the northern hemisphere)
El Teide Volcano, Spain's highest mountain (3719m). We are above the trade-wind inversion cloud layer, which sloshes back-and-forth in the valley below, just like waves on the beach - see more here: https://vimeo.com/23205323
The obligatory selfie (I'm sure that I must win the "try to get the UHI logo as-far-as-possible" competition, as I have done nearly equivalent photos at Sutherland (South Africa) and Paranal de Atacama (Chile).
And here's the summit of Izaña mountain (2400m), with its plethora of telescopes
And again, the obligatory selfie & UHI 'lets-win-this logo' competition!
The approach by road to El Teide Volcano
Note the fossil red and yellow soils between the lava flows
The Sun Photometer at Izaña is one of the longest serving instruments in place at the location - it has run non-stop since the 1970s.
View to the clouds and Gran Canaria island far, far below.
At night, I got to see the new Laser Guide Star in action (it helps the focusing of the telescopes by creating an artificial star [made by a powerful laser beam which excites sodium atoms in the upper atmosphere]) - wow, it's like alien star wars!
Eddy, Tenerife, 26/6/2015
Posted by Dr. Eddy Graham on 26 June 2015, 10:09 AM
What a beauty the island of Tenerife is - I am here for a week, attending a conference on astronomy and presenting a review talk on the influences of meteorology and climatology on astronomical observation.
Let me show you round; firstly let's visit Santa Cruz de la Tenerife (where I am staying):
Iglesia de la Concepcion
Plaza del España
Hang on a sec -What this? The Scottish Saltire flying proudly from a government building in Santa Cruz? (can you work out the riddle)
Santa Cruz harbour
Walking the narrow calle (streets) of Santa Cruz
Red Flamanco trees are everywhere, adding their beautiful colour to the already azure skies.
Lovely Spanish architecture dating from the colonial times.
General O'Donnell - come on, what Irish maverick came to Tenerife?!? (Actually he was a brutal military leader who later became Prime Minister of Spain,)
The Recova (Open Market) in Santa Cruz is a experience to remember
Now let's take a tour of the north of the island: Firstly, to La Laguna, where the conference is taking place:
The location of the Guajara Campus of the University of La Laguna is second-to-none.
A selfie, overlooking the valley of La Laguna
View from the Guajara campus of the University
Order of priority on the trams - bikes over (fit and able) people, yay!
And grassy green tram tracks - we could learn a few environmental lessons from the Canary Islanders!
Eddy, Tenerife, 26/6/2015
Posted by Dr. Eddy Graham on 24 June 2015, 10:04 PM
On the night of the 13/14th of June, the air temperature at Lews Castle ('The Meadows' at Alt nam Brog) dropped to below freezing, with -0.2C recorded at 04h00. This represents only the 2nd time in the history of record-keeping in Stornoway that an air frost (an air temperature below freezing 0.0 degC) has been measured during the month of June. The only previous occasion was on 10th June 1888 (127 years ago) when an air temperature of -0.6degC wasalso recorded near Lews Castle.
Overall, climatologically speaking, it is no exaggeration to say that the month has been an 'ice-bath'! It looks like being the coldest since at least 1987, and possibly even 1927 - at least the 5th coldest on record. Coupled with a sequence of consecutive very poor weather over the past 6 months, we are frankly at at the rock-bottom of climatological anomalies.
If it doesn't warm-up in Stornoway over the next 5 days, this is where June 2015's average air temperature will lie in met history:
It's all due to the very cold North Atlantic ocean at present, and persistent onshore westerly winds - sea temperatures change only very slowly, typically many months. The past month's sea surface temperature anomaly can be seen here (reproduced below): http://www.esrl.noaa.gov/psd/map/clim/sst.shtml (blue = cold).
The month has yet to finish - but with only 88hrs of bright sunshine recorded to date, Stornoway may also be heading for the one of dullest Junes on record since 1929 (worryingly, 5 of worst 7 have been recorded in the past 25yrs).
Posted by Dr. Eddy Graham on 01 June 2015, 2:59 PM
Two separate funnel clouds were spotted over Stornoway at 17h15 on Saturday 30 May 2015, during another miserable downpour of rain and hail. All photos by Lorna Dodd - see @eddy_weather.
Posted by Dr. Eddy Graham on 27 May 2015, 11:56 AM
Eddy (2 June 2015): I can now confirm that May 2015 was the 7th wettest May on record in Stornoway (in 143 years of record keeping), at least the 29th coolest but probably in the top ten coolest (due to a change of observing site since 1942), and the 20th dullest (out of 86 years). So all-in-all, awful!
Although a few days remain until the month's close (at the time of writing), we can safely say that it has been one of worst Mays in 20 years across the Isles, according to the weather statistics.
Temperature-wise, it will come as no surprise to learn that with an average temperature of hardly 8degC, it will be the coolest May since 1996 (nineteen years ago). On the 1st of the month, a low temperature of -4.3C was measured at Lews Castle Meadows, Stornoway, almost equalling the May low-record for Stornoway of -4.4degC recorded in 1938.
The daytimes were particularly cold, with a brisk, cool westerly wind on most days. The graphic below shows that we haven't seen as cool a May during the daytime since at least 1979 (the two coolest in the series are 1979 and 1923).
Sunshine-wise, it was also a very dull month - some places in Scotland have seen hardly more than half the average sunshine for the month. At Stornoway Airport, it is within the bottom 10% of dull Mays ever measured at the Airport.
It was also another wet month (although May 2011 was wetter) - about 150-200% of average May rainfall has fallen across most regions of Scotland this month.
Eddie, Stornoway, 27 May 2015
Posted by Dr. Eddy Graham on 15 May 2015, 2:29 PM
So you think May's weather can't get any worse, can you?
Well, sorry, have I got news for you... a frigid blast of cold Canadian air (direct from the Davis Strait between western Greenland and Labrador) is expected to impact the Highlands and Islands Saturday-Monday. Expect frequent rain/hail showers with blustery squalls from Saturday afternoon onwards - some sleet is even possible at times, with snow on the highest hills.
n.b. See 2nd image below - sea surface temperatures in the North Atlantic are considerably below normal at present. The negative anomalies are some of the lowest on the globe with respect to the rest of the world at present.
Posted by Dr. Eddy Graham on 11 May 2015, 4:49 PM
Monday 11 May 2015
A rare hook echo was apparent in the Lewis radar scan of this morning's torrential rain (see below). This is BAD NEWS meteorologically speaking, and rather unusual for a maritime location of British Isles in May.
Hook echoes (the curvilinear feature on the rainfall radar image, over Lewis and Harris) indicate rotation in a storm clouds, yielding possible severe thunderstorms, hail, flooding rains and possibly even tornadoes (when the hook is well developed).
A very bright infra-red image (see next image) also indicates powerful convection to the tropopause.
Spring and summer, oh summer, have you deserted us?
Eddy, Stornoway, 11 May 2015, 17h.
Posted by Dr. Eddy Graham on 10 May 2015, 11:01 PM
With another soaking near-inch of rainfall (20mm) in Stornoway on Sunday 10 May 2015, many folk are rightly beginning to ask "Where is Spring?" (let alone summer!).
There's no definite answer to this, other than saying no prolonged respite from either the unseasonal cold, nor recurrent rain, appears likely over the coming week. Certainly sea temperatures in the North Atlantic ocean are considerably below normal at present (see map below) - but there is no straightforward link between weather conditions in the Hebrides and the above.
So we will have to wait and see what summer brings - let's just hope it won't be another 1816, aka 'The Year Without a Summer'.
N.B. From NASA: Two nice satellite images of line convection over the Isles, Fri & Sat 8/9 May 2015:
And the current sea temperature anomalies - blue means cold!
Posted by Dr. Eddy Graham on 05 May 2015, 5:19 PM
There's still no sign of a lengthy pause or calming-down of the weather situation, with respect to the latest St. Kilda swim attempt.
Presently, a 36-hr window that was previously forecast from early Friday 8th - Sat 9th May now seems to be closing-in slightly (with a N/NE swell of 1-2 metres remaining). However, a new window starting around 00h Sunday 10th May may be opening (see NOAA WWIII chart below for Sun 00h - green means a mean wave height of 5ft or greater)
E. Sty. 5.5.2015
Posted by Dr. Eddy Graham on 01 May 2015, 10:19 PM
With a min temp of -1.3degC this morning in Stornoway town, it was the 2nd coldest night of the 'winter' period 2014-2015. At Lews Castle meadows (Alt nam Brog, a frost hollow site), the min temp was an incredible -4.3C, just short of the lowest on record for May in Stornoway, which is -4.4C set in 1938.
Meanwhile, Tulloch Bridge in Lochaber on the mainland went down to -5.6C.
Today (daytime), despite strong sunshine all day, the air temperature reached only +8.2C in Stornoway town (a value more akin to March).
Eddie, Stornoway, 1st May 2015
Posted by Dr. Eddy Graham on 28 April 2015, 10:16 PM
Update to Outlook:
The good news is that it's going to become much milder by the end of the coming weekend. The lovely spring sunshine will continue Friday and Saturday too, as breezes swing into the east.
A period of strong cold easterly winds is likely early on and during the day of Sunday. Some rain is likely too (snow on hills), but hopefully showery in nature. The good news is that it will become much, much warmer by Monday, though with the increased risk of heavy, blustery showers breaking out.
In closer detail, a slack flow will prevail till Friday or so, followed by a strengthening easterly flow later. There is disagreement between the met models on how soon the east wind picks up, moves in our direction, and then how soon it dissipates.
As for the St. Kilda swim hopefuls, the NOAA Wavewatch-3 model has swells less than 1m (deep blue) in the inner Minches for midday Friday, increasing by midday Saturday (see images, Fri 12h, Sat 12h).
Sat 12h (below):
Thereafter, larger swells are likely stretching into next week, as active lows swing up from the southwest.
Sea temperatures are also running 1 to 2degC below normal in mid-Atlantic at present (see below):
Eddie, Stornoway, Tues 28/4/2015
Posted by Dr. Eddy Graham on 24 April 2015, 11:46 PM
On the night of the Stornoway Hurricane (8-9 January 2015), I inadvertently left a camera running for 5 minutes on a window-sill in my home at the height of the storm. No visual imagery was recorded (the screen was simply black due to the pitch during the storm) but I realised recently that the audio file might prove valuable.
You can hear part of it at http://youtu.be/8iCHNxmC944 (with the visual backdrop of a few photos - but the sound itself is actually best listened to without the imagery).
Bear in mind that this recording was made using a small camera indoors, located some distance from double-glazed windows.
Eddy, Stornoway, 24 April 2015
Posted by Dr. Eddy Graham on 24 April 2015, 2:25 PM
Yes, it's true - winter is about to make a brief return during this coming weekend, with raw northerly breezes bringing flurries of sleet, hail and snow at times (especially Sunday), and hard frosts by night - beware all gardeners and plant growers!
Posted by Dr. Eddy Graham on 22 April 2015, 2:07 PM
I spotted the following new island in the Minch (NE of Broadbay) this afternoon (Wed 22 April 2015) at 1:40pm. At first, I thought it to be a spectacular superior mirage of Sulisker (a rocky island some 100km distant to north). Later, I noticed it to be moving, so I think now it is rather an unidentified floating object (UFO) linked to the current NATO joint warrior exercise taking place, possibly the warship USS Vicksburg (stretched vertically by the superior mirage)
Posted by Dr. Eddy Graham on 19 April 2015, 10:01 PM
With almost 40 hours of sunshine over the three days (Fri 17th, Sat 18th & Sun 19th April), there was more sun than during the entire months of December 2014 or January 2015 during the past winter!
Eddy says expect more of the same tomorrow (Mon 20th April), but the threatened low cloud, dullness and drizzle is expected to return Tues/Wed.
Posted by Dr. Eddy Graham on 16 April 2015, 9:10 AM
So far this April, the weather has been swinging wildly between spells of warm spring sunshine and sudden blasts of cold wind from the north-west, accompanied by hail and snow on several days. Eddy says this is nothing out of the ordinary for the time of year - April weather is notoriously fickle (changeable) and is a direct consequence of the cool ocean, a relatively dry atmosphere and an increasingly strong Sun.
The outlook for the coming few days is for more settled weather than of recent, as a large area of high pressure is predicted to build over Northern Scotland by the coming weekend. Although it is likely to be dry with light winds, don’t expect a heatwave - indeed it will remain quite cool (especially at night) with banks of low-cloud and fog threatening to spoil the sunshine at times. As winds slowly veer into the east by Saturday/Sunday however, increased amounts of sunshine may develop.
Eddy, Stornoway, 15 April 2015
Posted by Dr. Eddy Graham on 13 April 2015, 9:08 PM
Blue skies, fresh spring breezes, and a beautiful Scottish landscape all make for ideal conditions to create time-lapse animations.
Clouds, when animated at higher velocity, often reveal hitherto hidden features, such as oscillating and breaking waves. Similarly, waves on the ocean or a loch surface resonate at higher frequencies, but these too can be captured precisely to reveal surprising new characteristics. Even people, when moving about, can look curiously familiar to ants, or bees, in their perambulations.
Here's a selection of some of Eddie's favourite spring and summer-time time-lapse movies:
- The grey man of Ben Macdhui and Loch Morlich (Scotland)
- The Dance of the MV Loch Portain (Caledonian MacBrayne ferry)
- Angry, eddying clouds above Marsco and Sligeachan, Isle of Skye
- The European Union Berlaymont building (Brussels): People, flags, clouds, reflections
- The 'Tablecloth' over Table Mountain, Cape Town, South Africa
Eddy, Stornoway, April 2015
Posted by Dr. Eddy Graham on 10 April 2015, 8:49 PM
Sometimes during fine stable weather over Scotland (especially with an airflow from the south or south-west, but ahead of a warm front), a special type of weather and cloud system known as a 'hydraulic jump' develops - such occurred today, Friday 10th April 2015.
Firstly though, a wee graphic to aid understanding - air flowing over mountains and hills is forced to descend rapidly in their lee (as it is stable and therefore tends to try and 'recover' its previous position quickly). In consequence, another wave propogates vertically upwards a short distance to the lee, amplifying as it travels upwards - this is known as a hydraulic jump. It often leads to saturation - usually seen as cirrocumulus lenticularis clouds.
We can see these clouds today, in the following very high resolution NASA MODIS Terra satellite image (below) - cirrus clouds can be seen over Lochs (Lewis, in the lee of the Clisham - thick enough even to cast a shadow), Lochs Shieldaig and Torridon (in the lee of the Skye Cuillin), and more generally over Wester Ross (in lee of many peaks). Tiny hydraulic jumps can even be seen over the Little Minch (to the lee of Benbecula, and possibly Beinn Mhor/Hecla on South Uist!)
Strong dry, descending winds were indeed recorded - gusting 37mph at Stornoway Airport at 4pm, with a very low relative humidity (for the west of Scotland) of 59%. In Stornoway town, air temperatures reached +15degC for the 2nd time this week.
Eddy, Stornoway, 10 April 2015
Posted by Dr. Eddy Graham on 05 April 2015, 9:10 PM
Today (Sunday 5th April 2015) was the warmest day of the year so far, with a sizzling +15.5degC measured in Stornoway town during the afternoon, some +6C above the normal for early April.
On the mainland it was even warmer with 20.0degC measured at both Strathallan and Leuchars, and 20.7degC at Aboyne in rural Aberdeenshire!
Statistically speaking, April is the most fickle month of the year (i.e. it has the most rapid changes from warm to cold and vice versa) - this is enabled by a relatively dry atmosphere (compared to the rest of the year), cool seas, and an increasingly strong sun.
Today, the coolest areas were those coastal areas prone to sea-fog, which lapped onto some western and northern coasts (see satellite pic below), and temperatures reached no higher than +9.0degC on Tiree and only +7.9degC on Fair Isle. In contrast, most of the (dry) Highlands reached 18-21degC.
Focusing in on the specific meteorology of the Hebrides today, the fog layer was very shallow in depth and was blocked by even the smallest of hills. Thus, in a series of photographs taken today from the Lews Castle Grounds, Stornoway (below), show:
- The shallow haar flowing along the Minch (with the peaks of Beinn Mhor Coigach and other mainland mountains rising up beyond it)
- The fog also tried to rise up the Clisham in Harris, but failed - instead flowing through the mountain passes and quickly evaporated in doing so.
- Finally a 'lee wake' of St Kilda is noted in today's satellite image of the fog layer, streaming many miles upwind (see red arrow) - (fog moving up the Minch from the south indicated by green arrow). There are also some rare ship's trails in the fog layer too, see if you can spot them!
Eddy, Stornoway, 5 April 2015
Posted by Dr. Eddy Graham on 03 April 2015, 10:28 PM
The trend towards very wet weather over recent months continues in Stornoway - with March 2015 proving to be one of the wettest Marches in at least 25 years, and possibly the 4th/5th wettest on record.
A closer looks at the stats for the latter part of winter also reveals that from 16th Feb-7th March (inclusive) 226.4mm of rain fell in Stornoway town. Futhermore, during the 48-hr period on 6th/7th, 49.6mm of precipitation fell - making It was at least the 2nd wettest 48-hr period in March in the Stornoway area since 1931.
In addition, before 2013 the absolute daily max for March in Stornoway was only 28.3mm. Last year (2014), 32.2mm fell on the 15th. On 6th March this year (2015), another 30.3mm fell again!
Weather Stats /Summary for Stornoway Town (March 2015):
Mean max: 8.7C
Highest Max: 11.1C on 7th
Lowest Max: 3.0C on 2nd
Mean min: 2.3C
Highest Min: 7.5C on 7th
Lowest Min: -0.6C on 18th, 25th
Diff from average: +0.5C (1873-2010), -0.1C (SYY, 1981-2010)
Precip: 197.8mm (170% / 217%)
Wettest day: 30.3mm on 6th
Lowest grass: -4.2C (25th)
Large Hail: 0
Snow Fall 11
Snow Lying 4
Grass Frosts 19
Air Frosts 5
Eddy, Stornoway, 3 April 2015
Posted by Dr. Eddy Graham on 02 April 2015, 12:10 AM
There's nothing particularly unusual about snow falling in late March or early April - it happens most years. However, after the never-ending winter that we've just had, one does wonder when (indeed, if) any settled, warm and sunny spring weather may arrive.
I made this movie of winter clouds scurrying across the face of the Ben Macdhui in the Cairngorm Mountains last week - watch out for his disappearance. then reappearance within slanting crespecular rays.
Total exposure time was just short of 1 hour, 1 foto taken every 2 secs = 1747 total frames, speeded up to 25 frames/sec = time velocity of reality X 50 (i.e. frequency = 50 hertz)
Eddy, Stornoway, April 2015
Posted by Dr. Eddy Graham on 24 March 2015, 9:46 AM
The recent return to rather chilly late March / early Spring weather will continue for the coming week. There'll be plenty rain (with sleet and fresh spring snow over the mountains) or showers, but there'll still be some nice bright sunshine and blue skies in-between the showers. There are risks of gales from Friday onwards. So, all-in-all, rather typical Hebridean March weather!
Eddy, Stornoway, 24 March 2015
Posted by Dr. Eddy Graham on 20 March 2015, 2:53 PM
A high resolution sensor, recording the air temperature every 10 seconds in Stornoway this morning, reveals a drop in air temperature of 1degC over the course of the Eclipse (see below, arrow).
This data will be submitted to the National Eclipse Weather Experiment (NewEx).
Full Report - The Eclipse in Stornoway:
There were more breaks in the cloud layer than predicted by various models at T+24 (which had indicated a uniform 8 okta low layer). From 06h30 to 09h30 it was predominately 4-7 okta stratocumulus /stratus undulatus with some wave activity apparent. Just after eclipse maximum ~9h30, more general showery 7-8 okta stratocumulus praecip. conditions rolled in from the west bringing showers (just 'smirs' of drizzle / a high density of very fine raindrops giving the broad rainbows, total precip to 9am on 21st was only 0.8mm).
There was a noticeable rise in wind from WF3-4 (before eclipse maximum) to WNW/NW F4-5 (afterwards). From 11-12h onwards, the sun came out again in an open cell cloud structure, with the light showers dying out in the afternoon. With 98% occultation of the Sun in Stornoway, it grew quite dark (though perhaps not as dark as one might expect given a 98% loss of solar radiation, and the darkest period lasted only 2-3 minutes); cars had to put their headlights on, and it certainly felt chiller.
It was quite encouraging to see most people outdoors; most workers stopped their jobs and came outside to line the streets; school-children were also given free time to go outside.
I had three separate dataloggers running in Stornoway, at two different locations. Firstly, here at home in Stornoway town (I am on the summit of a slight hill, SW aspect):
(a) High resolution PRT record every 10 secs (see below): The key thing noticeable here is the delay of the development of the convective boundary layer until 11h00! (identifiable by the sudden increase in high-frequency temp fluctuations).
(b) The same Stornoway town site, Conrad Electronics Temp/RH logger every 1-min (below), red=temperature, green=dewpoint:
(c) A frost hollow site in a small glen near Lews Castle to the west of Stornoway (Gleann nam Brog), also Conrad Electronics Temp/RH logger every 1-min (green=relative humidity; red=air temperature, blue=dewpoint)
Stornoway Town (PRT): -1.0degC drop in temp, 10-15min lag behind eclipse peak
Stornoway Town (Conrad logger): -0.7degC drop, 10-20 min lag
Gleann na Brog (Conrad logger): -1.6degC drop, 10-20min lag
I was expecting a larger drop at the frost hollow site (which was confirmed). Analysis of the satellite animation for British Isles didn't show any obvious or apparent change in the cloud structure, it just looked like a fairly typical WNW flow in early spring. Nor were there any discernible air fluctuations.
Eddie Graham, Stornoway, Scotland
Posted by Dr. Eddy Graham on 20 March 2015, 11:26 AM
Eerie, wasn't it? Did you notice the darkness, with more direct 'polarised' light and enhanced shadows? Did the birds stop singing?
And I'm delighted that the mostly pessimistic weather forecasts were proved wrong, with enough breaks in the cloud forming to see the Eclipse!
I have my own eclipse story - after delivering a pre-Eclipse lecture at the Nicolson Secondary School to 300 pupils 8:50-9:15am, I rushed back through Stornoway town on my bicycle, making my way up to Lews Castle College. All the way through town, people were lining the streets outdoors, glancing up towards the sky, it was quite surreal.
Here's a couple of photos and animations:
Photos (above) by Gareth Davies.
Photo (above) by John Smith (UHI, Stornoway).
And an animation of this morning's satellite images showing the Eclipse pass across NW Europe (below):
Eddie, Stornoway, 20 March 2015