GFS maintains wintry theme

Figure 1 – Courtesy of OGIMET

The latest run of the GFS model maintains the cold cyclonic northwesterly theme across the British Isles for the next week or so, with a succession of vigorous lows crossing the north of Scotland en route for the Baltic. As each low tracks across it allows a milder WNW flow of for a short time, before cold air re-establishes itself in a NW or N surge. All this of course comes with a government health message that all this NWP stuff could all be science fiction and can damage your health. I know I’ve said this before but these forecast charts are very reminiscent of November 1973 to me.

Later tonight and into the early hours of Friday could get interesting over southern England, with a low tracking E’NE along the English Channel  (fig 2), which could bring a spell of wet snow to the highest ground (>200 M). Yes I know, ‘high ground’ is not usually synonymous with ‘southern England’, but in this blogging game sometimes you have to clutch at straws to eek out a possible story.

Figure 2 – Courtesy of OGIMET

Earlier this week the GFS did suggest that a deepening low would threaten a more widespread area of snow across the north of England and Wales. That threat has now all but vanished, as that low is now forecast to track further south across northern France without much in the way of deepening (fig 3).

Figure 3 – Courtesy of OGIMET

Snowy highlands

Figure 1 –  © Winterhighland Limited

An area of overnight snow has spiralled across the northeast of Scotland overnight, and put a blanket of powdered snow down on all higher ground as this webcam of Cairngorm from Inverdruie shows (fig 1).  Winds have now picked up on the summit and temperatures seem to have levelled off at around -6°C after the clearance of the occlusion like feature (fig 2).

BBC: Yesterday’s flooding

Figure 1 – Courtesy of the BBC

Figure 2 – Courtesy of the BBC

It’s no surprise that there was such widespread flooding across the northwest in England and Wales yesterday with these kind of accumulations (fig 3).

Figure 3

The wild and windy night that the rain washed away…

I have seen many a named stormed storm of the last three years not produce as many gale force gusts as we saw overnight in England and Wales (fig 1). None of them on land topped 60 mph but all in all it was a wild and windy night that the rain washed away, no where have I heard that line before.

Figure 1

Here are the 24 hour rainfall totals till 06 UTC this morning in inches for a change (fig 2). Large totals as was expected over Snowdonia and northwest England, with Shap in Cumbia the wettest of the SYNOP reporting stations with 3.27″.

Figure 2

22 November 2017: Wind

Figure 1

A very windy day across England and Wales today. The chart above shows all gusts to gale force since 15 UTC yesterday (fig 1), I should have perhaps restricted the analysis to midnight but what the hell. Full gales proper, have been confined to coastal areas in the far southwest of England and west Wales and over higher ground in north Wales and northern England. So the Met office were quite correct in not making ‘Reinhard’ storm Caroline. The winds are particularly ferocious across the northern Pennines at the moment ahead of the cold front, the mean speed on Great Dun Fell at 15 UTC was 69 mph with gusts to 89 mph (inset anemograph), that coupled with the torrential rain must make any light that maybe shining in the window of Greg’s hut look very welcoming for anyone daft enough to be attempting that part of the  Pennine Way today.

22 November 2017: Temperatures

Figure 1

A big thermal contrast across our part of the world today, with the temperature at Gravesend as high as 16.1°C at 12 UTC, but only around 3°C across the North of Scotland. I couldn’t resist doodling on the 12 UTC chart and overlaying the approximate positions of the frontal systems (fig 2), don’t worry if it looks far too simple, I’m sure that it’s a lot more complicated that, or should I say it will be in the Met Office analysis.

Figure 2

22 November 2017: Rainfall

Figure1 – Estimated accumulations from weather radar 1800 21 November to 1500 22 November 2017

The rainfall accumulations from the weather radar are starting to clock up over the mountains of Snowdonia and Cumbria. The totals for the last 21 hours till 15 UTC over Snowdonia are already well in excess of 150 mm so far (fig 1). I will have to come up with another colour in my Web Radar application to display anything higher! The inset graph is for the top of Snowdon which has an estimated  accumulation of 177.6 mm since the rain began there around 22 UTC yesterday evening (see inset hyetograph). The rain shadow effect across the northeast of England is absolutely unbelievable, with many stations reporting no more than one millimetre since 06 UTC.

Another warm night in the south

Figure 1

Believe it or not those are the 18-06 minimum temperatures plotted in that chart (fig 1). So another warm night across the south again last night, hopefully it might be the last one for a while. I don’t normally use the term ‘warm’ when describing night-time temperatures in November, but I reckon that this is a notch up on the usually mild category we see. The temperature here at 03 UTC in mid-Devon was 14°C, which to me is rather exceptional, or is it that am I just getting old and forgetful?

Figure 2

Here is a thermograph of the last two weeks from Exeter airport to give you a better feel for the overnight warmth (fig 2), it’s not a great graph and needs a bit of work, but I’m off to the dentist this morning so it’ll have to do! Surely they’ll be a maximum temperature record beaten today somewhere in the south. Many of the deciduous trees in our part of the world have yet to shed their leaves perhaps today’s strong winds will help them on their way.

Devon one two

Figure 1

Chivenor and Exeter were the warmest two places  in the British Isles today, although the 14.9°C was along way of the record for the 21st of 18.3°C.

Snowy Saturday revisited

After my blog about the possibility of a snowy Saturday, I was just looking for some extra detail in the GFS model for Saturday morning when I remembered the excellent wxcharts.eu website. The purple in the 06 UTC map indicates a large area of snow falling over northern England and Wales, and the meteogram for Eggleston in County Durham is forecasting 9 cm of snow.