Sea fog continues to plague north coast of Cornwall and Devon

Figure 1

The sea fog that’s been lurking around the coast of southwest England for the last three days continues to affect the coastline of north Cornwall and Devon this morning. If anything it seems to have lifted into a more organised thicker band of low stratus rather than the sea fog of previous days, with no ship tracks visible in it today as there were yesterday.

Ship tracks in the Irish Sea

Figure 1

Some good ship tracks in the sea fog visible in the latest satellite images of the Irish and Celtic sea this morning (fig 1), well they certainly look like ship tracks to me, even if R S Scorer thought that there were a rare phenomenon back in 1967. Perhaps the increase in size of these massive ULCV container carrying ships has something to do with it? Any light breeze hitting the side of one of these monster ships (fig 2) could only really go up I would have thought, and carve some kind of furrow though the fog.

Figure 2 – The Vasco de Gama which ran aground of Southampton on the 22 of August 2016 – Courtesy of Maritime Photographic

In a midday visual satellite image from NASA (fig 2), it appears that the Holyhead to Dublin ferry may have left a ship trail, although it looks like it may have drifted a little in what breeze there is across the Irish Sea (fig 3 & 4)

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Poor and Good visibilities in warm sectors

Figure 1 – Courtesy of the Met Office

Since moving down to the southwest some fifteen years ago now, I have noticed it’s often the case that in warm sectors (fig 1) although Cornwall and west Devon are plagued by extensive sea fog and low stratus, away from high ground, and in the lee of Dartmoor or Exmoor further east surface visibilities are often remarkably good, such is the case this morning (fig 2).

Figure 2

“Just some of these western coasts may stay a little murky…”

Image 1 – Courtesy of the BBC (upper) and the Met Office (lower)

The ECMWF model being used for the BBC forecast by MeteoGroup is not really handling the sea fog that’s rolling into west of Cornwall and along the north coast of Devon too well this morning (fig 1). The UKMO model has at least captured something in the way of cloud across the southwest, what exactly it is in looking at the graphics is a little bit harder to work out, is it cirrus, or stratus or just sea fog? Alex Deakin doesn’t seem overly concerned about it though, he says that’ll it be “just some of these western coasts that may stay a little murky”.

Figure 2

I’ve been watching this fog and low stratus as it rolls in across the southwest and it’s moving quite smartly to say there’s very little gradient (fig 2). I just wonder how much further east it will progress during the rest of the day as well as how far inland it’ll make it.

Figure 3 – Courtesy of the BBC

In the national forecast just after the main BBC news the graphics looked very similar to the ones used during the morning, but in the regional forecast at 1.40 pm it appeared as if they had updated the model which gave a much more realistic fit with the satellite image (fig 3). Ben Rich was too busy demonstrating how proficient he is with the count-up method (you know the one – “temperatures reaching 24 or 25 quite widely, and maybe even a 26 or 27 and possibly a 28 or 29 in one or two spots”) to even be bothered to show any detail of low cloud in the southwest.

Haar Haar

Figure 1

Apologies for the title, I just couldn’t resist it, because its such an awful dreich day down the east coast this morning with temperatures close to 5°C and extensive low stratus and haar (fig 1). The air temperatures correspond closely to the currently observed sea surface temperatures I mentioned in the article about negative North Sea SST anomalies earlier this morning. It’s mixed fortunes weather wise, because meanwhile on the other side of the North Sea in Denmark its blues skies all the way although it’s still quite fresh for early April. Here’s a chart of the relative humidities at 08 UTC this morning (fig 2) to see just how soggy we are on windward side of the North Sea.

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Inconsistencies in yellow warnings for fog

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It’s arguably just as foggy first thing this morning (fig 1) as it was yesterday  (fig 2) in many places across the south of the UK, but the difference is that today there were no yellow warnings in force from the Met Office about it. All I can think is that must have lost all the enthusiasm for the subject after making such a song and dance about Monday and Tuesday. It’s probably to do with the fact that yesterday’s was radiation fog, but today’s is more advection fog covering higher ground – but it’s all fog.

Fog thins more quickly than expected

Figure 1 – Courtesy of the Met Office

I don’t know exactly why, but the fog that formed well before midnight across southern areas (fig 2), thinned quite quickly from many places in the second part of the night (fig 3). There certainly was a little more in the way of low cloud north of Birmingham later in the night, and the gradient may have picked up across other areas, but it’s now quite patchy across southern England at dawn, and in some areas such as the southwest of England and east of London, fog was reluctant to form at all. The thinning may have had something to do with warmer air aloft advecting up from the southwest and permeating down to lower levels, I notice for example that the temperature difference between Dunkeswell (252 M amsl) and Exeter airport (27 M amsl) at 09 UTC here in Devon was 6.2°C.

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Figure 3

Certainly the earlier yellow warning of fog which lapsed at 06 UTC was quite accurately forecast by the Met Office (fig 4).

Figure 4 – Courtesy of Twitter

No logic to the ice warning for tonight – and what about the freezing fog in Glasgow?

I can’t see any logic in the yellow alert for ice that’s been issued this lunchtime by the Met Office for parts of London and the southeast (fig 1). I might be jumping the gun with this one, and they may will issue one later today for the Midlands and Wales, but these parts have seen 10 to 30 cm of snow today, surely this snow will still be around tonight, and any thawing of that snow would refreeze? So why no warning  of ice for these places?

Figure 1 – Courtesy of the Met office

There has been freezing fog since 08 UTC this morning in Glasgow, and the temperature at 12 UTC is still -4.6°C. Why for goodness sake isn’t there a warning out for that? Perhaps they’ve been just too busy with the snow further south.

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Addendum I

I thought that the Glasgow Bishopton was maybe playing up, so with the help of some Traffic Scotland website I’ve managed to find the offending freezing fog patch by the Erskine bridge on the M8 over the river Clyde (fig 3).

Figure 3 – Courtesy of Traffic Scotland

It’s a useful website made available by the Scottish government, but for goodness sake why do they restrict the website to show thumbnail images from their network of webcams?

Addendum II

Suddenly it’s all become clear, and now the Met Office yellow warnings of ice for tomorrow make perfect sense! Two and a half hours after they issued a yellow warning for ice for the southeast England, the forecasters at the Met Office have now just issued another yellow warning for ice (fig 4) that aligns with the earlier one to cover Wales, Midlands and East Anglia – cosmic!

Figure 4 – Courtesy of the Met Office

My question to the Met Office is why the delay between the two? Why not just issue a blanket warning for ice that combines the southeast, Midlands, Wales and East Anglia, and then issue a separate snow warning just for the southeast corner? Of course the tricky bit would be to do all this at the same time, so that people who read the warnings get the impression that your approach was coordinated, which in itself would instill confidence with them that you knew exactly what was happening.

PS It’s still foggy on the M8!

Addendum III

Figure 5 – Courtesy of Facebook

Meanwhile, north of the border

Meanwhile, north of the border in Scotland there’s a covering of snow in many places and there’s been a severe overnight frost. At Aviemore there’s 9 cm of level snow, and the temperature at 08 UTC is -11.0°C at Altnaharra and -11.1°C at Tulloch Bridge. Freezing fog has formed over the Clyde in Glasgow which could last a good while in the light gradient (fig 1).

Figure 1