Cold Turkey

The cold air from Axel has spread into the eastern Mediterranean now, and there’s a fair bit of snow in Turkey, especially along the coast with the Sea of Marmara (fig 2), which I expect has picked up a lot of lake effect snow in the last couple of days, although this doesn’t seem to have happened along Turkey’ northern coast with the Caspian sea as much. It’s snowing well on the Greek Island Skyros in the Aegean Sea, and further south at Souda in Crete (fig 1), where I expect the mountains are living up to their name of White. Turkey have always had a first class observational network which is good to see.

Figure 1

Figure 2

 

Downwind of Lake Garda

Figure 1 – Looking up Lake Garda from Desenzano in warmer times during the summer of 2008.

It was handy for Desenzano del Garda in Lombardy Italy that the fresh to strong north northeasterly wind just kept blowing and that they’re situated at the southern end of Lake Garda, because it did a great job at keeping a severe frost at bay (pardon the pun) last night. I think it’s a good bet that the water temperature of Lake Garda is well above 5°C at the moment, and no wonder that lemon tree’s do so well around the lake.

Figure 2

This is the difference that just 30 kilometres or so makes in the thermograms from Desenzano and Brescia for last night.

Figure 3

 

Figure 4

Cold air heads south to Italy and Greece

A moderate frost across southern parts this morning, so I thought that I’d include a reminder that we actually had one down here in Devon, but more of a symbolic rather than an artistic statement I’m afraid. The NWP models on Christmas day got this particular cold snap day spot on, but of course the high to the northwest has now collapsed allowing warm air to ride round the top of the high as per usual and so predictable!

I notice that the cold plunge that we’ve just escaped is forecast to extend southward at around 20° east down through the Balkans, and affect most of Italy and Greece during the remainder of this week – what a topsy-turvy world we do live in – I’m only jealous.

Courtesy of NetWeather

How cold is my valley

It’s not very frequently in the top ten of coldest places in Britain or Ireland, but this morning Northolt in north London was the third coldest with a minimum temperature of -5.8°C [18-06 UTC].

The other thing of note looking at the temperature distribution in the chart below, is how frosty it’s been in the valleys (with fog in Devon), and higher ground nearby has stayed warmer with temperatures above freezing. This is quite common in anticyclonic conditions at this (or any other) time of the year, when the wind on higher ground never falls light, preventing temperatures falling as low they do in the valleys, were perfect cooling conditions allow an inversion to form. I’ve ringed in red the stations where the wind and the temperatures stayed up last night (forgot to put one round Little Rissington).

Exeter and Dunkeswell are another case in point.

Overnight moderate frost

The overnight frost on the night of 26/27 December 2016 made it just that little bit more seasonal after yet another green and mild Christmas over England and Wales, the sharpest of the frost look like the occurred across central southern England.

Snowmageddon still on! *updated*

I was going to call this item ‘Cold snap still on‘, but on further reflection I thought what the hell, using the phrase snowmageddon might attract more views, and hopefully result in a few new subscribers to the 28 that I’ve attracted since May. According to the Urban Dictionary the phrase snowmageddon is defined thus:

When a huge winter blizzard surpasses a previous large winter storm (see snowpocalypse) and dumps copious amounts of snow in a place unprepared for such large snowfall amounts thus grinding entire transportation, retail, school and government systems to nearly a complete halt for several days. Results in extreme cabin fever leading to massive snowball fights and excessive photography.

What may bring this snowmageddon about – well perhaps not huge blizzards but a couple of inches of snow at least – is a scenario like this in the T+192 frame of the latest run of the GFS model for the 2nd of January 2017.

Courtesy of the GFS and OGIMET

The GFS model has been suggesting this for some time, but blows hot and cold on each successive run. What is interesting is that instead of warm air riding over the top of the high pressure to the west as it so often does, the high pressure topples over the UK and links up with a belt of high pressure across central Russia, thus allowing cold easterlies to introduce some very cold air from central Europe. The frame below is the T+264 for the 5th of January 2017, and looks decidedly wintry as you can see.

Courtesy of the GFS and NetWeather

I won’t post any later frames, because suffice it to say, if you are a snow lover they might be very distressing.

Addendum

Looking back on this on the 11th of January the GFS T+192 forecast for the 2nd of January was pretty accurate.

Which is more than can be said for the T+264 for the 5th of January, the very cold easterly was more of a very cold northerly.

Fog in the southwest slow to clear

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View from the Beacon above Bradninch this morning

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If anything this morning’s fog has become a lot more widespread over Dorset and Somerset, and as temperatures are still sub-zero at places such as Yeovilton, it could still be of the freezing variety. In East Devon the fog has thickened up as the temperature went above zero, and the visibility at 1230 was probably around 200 metres with the sky obscured. A quick walk up to the Beacon (our local viewpoint at ~215 M) revealed that the inversion here at that time must have been at the 600 feet level, although it was a fuzzy rather than a sharp inversion if the makes sense, but the sun was shining from a lovely blue sky.

I’ve just been watching Ben Rich on the BBC TV forecast at 12.57 PM, and obviously he can do the weather forecast without looking at the latest observations or satellite imagery, because he never even mentioned that Exeter airport (-0.3°C and 100M) and Yeovilton (-1.4°C and 50M) are still in fog – quite incredible! He did manage to say in his intro though that he was a Weather Forecaster, and as far as they were concerned, today was the start of meteorological winter.

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No blackfrost this morning in Bradninch, just fog and a hoar frost as temperatures dipped to -3.6°C overnight. The fog is very easy to pick out in this visible satellite image filling the Exe and Culm valleys, there’s also a strange patch of stratocumulus over Cornwall, where did that come from? Here are the overnight [18-06] minimums from this morning’s SYNOP reports.

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Black frost in mid Devon

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Another cold night across England and Wales with a moderate locally severe air frost. Here in Bradninch Devon we only managed -1.9°C, but at Exeter airport just 11 km to the south the AWS their recorded -6.3°C. That’s due to the fact that we are set up a little from the valley floor and the north northeasterly just kept running at about 5 knots all night, which is very typical here. It only dipped when the wind fell calm for short spells, for most of the time it was just above zero, and surprisingly thanks to the low dew point of the continental air, the humidity hovered between 77 and 90%, so little in the way of hoar-frost, and no scraping of cars – so a proper black frost in our little part of the world.

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The Met Office did much better last night than the night before with their forecast minimums, that is apart from the Northern and Western Isles where they over did it again.

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I think the same thing may have happened at other sites around the country have a look at this thermograph from High Wycombe.

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Benson to the west had a 18-06 minimum of -8.5°C whilst High Wycombe’s minimum was only -0.7°C due to the wind never falling out. This would have probably dried your washing if you had left it out overnight, but it maybe as stiff as cardboard when you brought it in!

Minus 6, minus 7, maybe even a -8 degrees

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Courtesy of the BBC

How many times do the weather presenters on TV use this old chestnut. I call it either the count-down, if it’s used in the winter for frost, or the count-up, if it’s used in summer for maximum temperatures. I believe there’s a whole chapter on this particular presentation technique in the “The Gamesmanship guide to Weather forecasting” which I’m still waiting to purloin a copy of. In summer there’s the classic “temperatures could reach 22°C or 23°C today, and in one or two places 24°C or 25°C, and I wouldn’t be surprised to see a 26°C from somewhere in the southeast”. Of course this five level count-up can only be used by the more adept presenter, but as you know it does happen. Anyway I digress, back to the overnight minima!

Certainly a moderate frost inland last night across most of England and Wales away from the coast, but not quite just the “minus 6, minus 7,  maybe even a -8 degrees” from this morning’s 06-18 minimum temperatures in the SYNOP reports, even though Leeming did dip to -6.2°C. Another curate’s egg of a forecast from the Met Office, excellent over the north and northwest of the country but the -7°C over East Anglia was out (-4.1) as was the -8°C in the south Midlands (-4.6), but the -5°C was never on in the southwest (-2.7) just too much wind as David Braine picked up on, and the -2°C just never happened in Northern Ireland (+3.3) and they remained frost-free. Out of the twelve ‘countryside’ minimum temperatures in the frame below, I reckon that at least four out of the twelve are just too low.

I prefer the old school definitions of frost by the way as you may have already noticed, and the definition for a moderate frost when wind speeds are less than 10 knots, are temperatures in a range between -3.6°C and -6.5°C. So in my opinion it’s not a hard frost, or a harsh frost (as I heard it called more than once yesterday on the BBC) but a moderate frost. BBC, please bring back Bill Giles and Michael Fish, it would be great to see them back on our TV screens with the latest graphics even if it’s only as guest presenters!

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Clear and frosty in the north – mild and windy in the south

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High speed stratus at 300 feet over Devonshire early this morning

The minimum temperature last night [18-06] dipped to -8.5°C (16.7°F) at Tulloch Bridge, Inverness-shire, meanwhile temperatures at many places across the south didn’t fall any lower than 10°C, that’s because there’s a fresh to strong E’NE blowing across areas south of 53°N, and a full gale blowing down the English Channel – in the opposite direction to which it was blowing on Sunday and Monday just for a change. I just wonder if there’s some kind of theme already starting to play out for the weather over the coming winter months here?

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Alex Beresford – the ITV Weather presenter – says that it will be breezy over Cornwall today, well spotted Alex.