Answers on a postcard please

Figure 1

The two vortices (or should that be the two vortexes) in this mornings 09 UTC visible satellite image caught my eye (fig 1), because funnily enough they do resemble a pair of eyes. I can see that the one to the southwest of Ireland is connected to the surface low (Gabi) which looks to have a minimum central pressure of around 982 hPa (fig 2).

Figure 2

The more prominent of the two which is sat in the Celtic sea has me stumped though. You would have thought that it was connected to some upper level feature because the clouds spiralling around it look a lot thicker extending to medium or upper levels, but it’s certainly not at the 700 hPa level (fig 3). Answers on a postcard please to the usual address.

Figure 3 – Courtesy of weatheronline.co.uk

Brightening up from the west

Figure 1

Not a lot going on at the moment weather wise across the British Isles, but hopefully it should brighten up in many places today from the west on the passage of this frontal system (fig 1). I did notice that there’s been another minor SSW event that looks to have occurred just before the equinox (fig 2).

Figure 2 – Courtesy of the CPD at the JMA

That, along with some wild NWP output, is what probably led to all those stories of a snowy Easter, stories which now seem to have been summarily dropped like a hot potato. Having said that the models do take each successive Atlantic low a little further south into Biscay as the week progresses leaving the country in an easterly, anticyclonic in the north and cyclonic in the south, so it look’s odds on that’ll it will be a cold Easter (fig 3).

Figure 3 – Courtesy of www.wxcharts.eu

Rapid cyclogenesis in action!

Figure 1

Low Carola is deepening very quickly at the moment, and the curl of cloud she is spinning up makes an impressive site in the latest satellite imagery to the southwest of Ireland (fig 1), as do the plotted observations and barograph from the weather buoy 62029 better known as ‘K1’ (figs 2 & 3).

Figure 2

As far as I can see Carola easily breaks the barrier for rapid cyclogenesis of 24 hPa in 24 hours, the pressure there has fallen by 37.4 hPa in 12 hours, in fact I don’t think I have ever seen sustained pressure falls like that on a chart from an extra tropical low.

Figure 3

No doubt the French will have claimed this low and come up with their own name for it, but I noticed it didn’t even get a mention in the BBC forecast at 12.58 pm from Sarah Keith-Lucas.

Intense rain NE Scotland

Figure 1

An area of heavy rain has developed in the last hour over northeast Scotland (fig 1). It doesn’t get much more intense that 16-32 mm per hour, well actually it does, the pixels turn white with intensities of 32 mm per hour and higher. According to the UKMO analysis it looks like it’s a very active bent back occlusion that’s behind it (fig 2).

I did notice that the rain never even got a mention in the BBC weather at 12.58 pm, although we did get Sarah Keith-Lucas showing us a couple of  nice pictures, one by Geoff of Histon in Cambrideshire, and the other by Alan in Topsham in Devon!

Figure 2

Rapid thaw on Dartmoor and Exmoor

Figure 1

There’s no quicker way to strip snow of high ground than a combination of mild air and heavy rain. The rivers must be in spate after a rapid thaw of the snow on Dartmoor and Exmoor brought about this way overnight by a band of heavy early morning showers tracking N’NE across the southwest (fig 1).

Figure 2

The cold air is still hanging on for dear life further north, so there’s quite a temperature contrast in this 09 UTC chart (fig 2). The Met Office analysis for 06 UTC reckon the rain is from an occlusion.

Figure 3 – Courtesy of the Met Office

The mighty Quinn

Figure 1 – Courtesy of the Met Office

The 18-06 rainfall totals weren’t massive from the frontal system associated with low Quinn, but rainfall since o6 UTC was fairly heavy in parts of the east Devon, Somerset and Dorset (fig 1). The rain might have been behind a couple of road traffic accidents that have led to the closure of the M5, and some local flooding in our part of Devon. It shouldn’t be long though before the clearance behind the cold front brightens things up down here in southwest England.

Figure 2

I would say that a secondary low centre was developing on the triple point in the Bristol Channel at 08 UTC, but I can’t find any sign of warm air! You could almost draw the trough down the 4° line of longitude it’s that straight (fig 3).

Figure 3

Mild air waiting in the wings

Figure 1

It might take the whole weekend before it gets across the whole country, but mild Atlantic air, which has already extended into the southwest of Ireland and England overnight, is waiting in the wings (fig 1). Temperatures of 11°C are already being reported in the southwest, in stark contrast to the -8.4°C over the snow fields of Scotland at the moment (fig 2).

Figure 2

The tendency in the GFS model over the next 16 days is for a gradual rise in pressure across the British Isles, and for an intense anticyclone to become established across the country by the start of February.

Figure 3 – Images courtesy of www.wxcharts.eu

The Glasgow gale of 14/15th January 1968

It’s been 50 years since the Glasgow gale of 1968. I can’t find any better way of describing the events of the night of 14/15th of January 1968 over central Scotland than the one in the Wikipedia article:-

“The 1968 Hurricane (or Hurricane Low Q) was a deadly storm that moved through the Central Belt of Scotland during mid January 1968. It was described as Central Scotland’s worst natural disaster since records began and the worst gale in the United Kingdom. Some said that the damage resembled what happened during the Clydebank Blitz in 1941. Twenty people died from the storm, with nine dead in Glasgow. 700 people were left homeless”.

What astonished me was that although the storm directly claimed the lives of 20 people, an additional 30 people died in the clear up operations after the storm, 11 of those whilst carrying out roof repairs.

Here are the synoptic charts for 18 UTC on the 14th, and 00 and 06 UTC on the 15th (figs 1-3).

Figure 1 – Courtesy of the Met Office Crown Copyright ©
Figure 2 – Courtesy of the Met Office Crown Copyright ©
Figure 3 – Courtesy of the Met Office Crown Copyright © [06 UTC}

Here are the SYNOP observations for 00 UTC and 06 UTC on the 15th (fig 4). Apart from the severe gales I’ve highlighted in yellow, the storm force 49 knot (250°) mean wind speed from Leuchars at 06 UTC stands out, as does the mean of 47 knots (260°) from Shawbury at 00 UTC. There was obviously a lot of funneling of the west southwesterly winds going on across central Scotland, and probably some rotor effect over Snowdonia (260°).

Figure 4 – Courtesy of the Met Office Crown Copyright ©

This infographic listing the highest gusts from the Met Office took some finding but I tracked it down in the end (fig 5). The one thing that you can’t accuse the Met Office of is over dramatizing a severe weather events such as this – “It was a windy day generally…” – and the last time I looked winds of 48 knots or more are classed as Beaufort storm force 10.

Figure 5 – Courtesy of the Met Office

Warm snap comes to an abrupt end

Figure 1

Cold air has returned to put a stop to the warm snap across the eastern United States. That’s the plotted 3 hourly observations for the last week (fig 1) for Albany in New York state. Last Sunday they were reporting temperatures as low as -22.8°C, but a warm snap rapidly warmed things out from Wednesday, and by 00 UTC last night Albany were reporting a 18-00 maximum of 17.2°C, then just 15 hours later the temperature has fallen by 24.4°C as cold air flooded southward, so by 15 UTC this afternoon it was -7.2°C and snowing again. Quite an amazing sequence of rapid warming and cooling. Here’s the thermograph (fig 2).

Figure 2