Unusual medium level shower activity…

Figure 1

I’m probably going to shoot myself in the foot with this one, but it looks to me, and I could be wrong, like much of the precipitation that’s been showing up on this afternoon’s weather radar, especially the belt that stretches across central England is from medium level unstable castellanus cloud, and is producing nothing more than the odd shower. There are some brighter echoes within, and the observing network is pretty thin so it could be falling between the gaps, but I see very few reports of any significant rain or thunderstorms from it.

Figure 2

Here’s the latest visible image (fig 3) that shows the band very well.

Figure 3

The rainfall over western Scotland looks even more dramatic, and this is thundery in nature (fig 4), although the rainfall indicated in the weather radar image looks very intense, it also seems to have escaped the observing network so far.

Figure 4 – Courtesy of Blitzortung

Interestingly, the current Met Office warning that is in force for heavy thundery rain this afternoon, completely omits the west and north of Scotland (fig 5)!

Figure 5 – Courtesy of the Met Office

 

Find the cold front

There’s plenty of orographic rainfall evident in the warm sector across the southwest of England and Wales in this morning’s 0815 UTC weather radar image (fig 1), but you would be hard pushed to find a cold front in the Celtic sea between here and SW Ireland on it though. This reminds me of an almost identical situation that occurred earlier this week.

Figure 1

The cold front is well-marked by the cloud in the visible satellite image (fig 2), it’s just not producing any precipitation at the moment.

Figure 2

Figure 3 – Courtesy of the Met Office

Ingraban continues to play havoc with flaming June

Figure 1

Large 24 hour rainfall totals have been recorded across the northeast of both England and Scotland in the last 24 hours ending 06 UTC, and it’s still raining in Northeast Scotland. There is the odd white pixels in my estimates from the weather radar south of Nairn, which indicate accumulations in excess of 150 mm (fig 1), so I expect that the rivers Spey, Findhorn and Nairn are all now in full spate after the deluge of the last 36 hours. Wettest from the observations was Loftus in North Yorkshire, with 58.2 mm in the 24 hours (fig 2), Edinburgh wasn’t far behind with 48.6 mm.

Figure 2

The inset observation grid are the last 24 hours observations from Lossiemouth, overlaid on a map of 24 hour rainfall totals (fig 3).

Figure 3

The heavy rain brought down the freezing level overnight as well, so the very tops of the Cairngorms could have seen some of this rain fall as snow, that combined with a 50 knot mean northwesterly might put a hold on your plans to knock of a few Munros in the area today (fig 4). The Met Office were too frit to call this storm Fleur, but the Berlin Meteorological Institute ended up naming this particular vortex Ingraban, either way this vortex continues to play havoc with flaming June.

Figure 4

I see the upper cloud from the next feature as got well into Ireland now (fig 5), and looking at the forecast from the GFS model, it looks like Thursday and Saturday will be wet again, in many areas, particularly the further northwest that you are in the country. After the weekend though, things look like they start to settle down, and next week we may well see the return of flaming June.

Figure 5

6 June 2017 – rainfall

Figure 1

It’s the turn of the east coast to take a soaking today, and pretty dreich it’s been down along east coast for much of the day. Wettest place in the list of available observations is Edinburgh with 35 mm in the 12 hours ending 18 UTC (fig 1), I overestimated the total their by around 15% (fig 2), and also managed to underestimate the Weybourne total in Norfolk by a similar margin. Plenty of places on the higher ground of Scotland, Cumbria the North York Moors with rainfall totals well in excess of 50 mm today, which is not bad going in 12 hours.

 

Figure 2

The northwest Highlands seem to have escaped the yellow warning for rain today, as did Gogar Bank with its 35 mm, because it lies outside the yellow alert area just to the west of the city. It looks like eastern Scotland will see a lot more before it’s done.

Figure 3 – Courtesy of the Met Office

Yesterdays rainfall totals

Figure 1

My estimates for Capel Curig were around 20% too high at 102.3 mm for the 24 hour period ending at 06 UTC this morning, the actual there was 82.6 mm, I put the difference down to my mapping, and the low resolution of the radar image on the Met Office website, which is fairly coarse and certainly not up to the 0.5 km resolution that you can find on Netweather, but beggars can’t be choosers.

 

Figure 2

What the accumulations do show quite dramatically is how the east Midlands and East Anglia escaped the worst of the heavier rain, all though they might not be so lucky today.

Monday, 5 June 2017 – rain

Figure 1

My estimate for Capel Curig since 06 UTC this morning is very close to 60 mm of rain so far (see inset hyetograph in fig 1). There are also scattered red pixels over Snowdonia, which means totals in excess of 75 mm, to a lesser extent, there have been totals of between 32 and 50 mm over the southern Cumbrian fells, south Wales and southern Dartmoor. Still some more rain to come in the west as the cold front come through during the evening and night.

Looking at the actual 06-18 UTC rainfall reported totals, I see that my estimate for Capel Curig was around 20% too high – well you can’t win ’em all (fig 2). The Plymouth estimate of 17.9 mm was closer, and the Trawsgoed estimate of 20.9 mm was closer still.

Figure 2

As regards this morning’s yellow warning of heavy rain, which runs through till 10 UTC tomorrow, the Chief forecaster said and I quote:

This has the potential to widely generate 40 to 60 mm of rain and as much as 80 mm over some areas of high ground, most likely in Cumbria and Snowdonia.

Well with over 16 hours to go, we’ve already seen those kind of values across those areas of the country.

Southwest left out of the yellow alert

Figure 1

It may not be long before an additional area is added to the yellow alert for heavy rain for the southwest of England if the rain keeps falling like it is at the moment (fig 1), even though the frontal clearance can’t be that far away and everything is moving quite swiftly. A truly horrendous time for anyone on holiday at the moment in these parts of the UK. The winds have been pretty lively this morning as well, here are the maximum gusts for the last 24 hours (fig 2).

Yesterdays rainfall and thunderstorms

Figure 1 – Courtesy of the Met Office

The track of yesterday afternoons thunderstorms across southeast England, are well-marked out in the image of weather radar rainfall estimates (fig 1) for the 24 hours ending 06 UTC on the 3rd June.

Figure 2 – Courtesy of Blitzortung [020600-030600 UTC]

A little bit too optimistic

Figure 1 – Courtesy of the BBC

There was a little bit more rain than expected in Spotlight forecast at 6.55 PM yesterday (fig 1), and the front was a lot slower and more reluctant to clear Cornwall, with some kind of secondary feature following on behind the initial band of rain (fig 2).

Figure 2

Now that I’ve seen the midnight analysis (fig 3), I now realise that the secondary feature is the cold front, and that the initial rain band is the warm front.

Figure 3 – Courtesy of the Met Office

Here’s a quick look back at yesterday’s estimated rainfall totals in the southwest (fig 4), most of it falling before 15 UTC if truth be said. It finally did brighten in the late evening, as the upper cloud finally began to retreat eastward.

Figure 4 – Courtesy of the Met Office

Dartmoor triggers intense shower

Data courtesy of the Met Office

In the last couple of hours, the high ground of east Dartmoor (possibly around Haytor) seems to have triggered a thundery shower that quickly tracked NNE across the west of the city of Exeter. It looks to have been quite an intense, but short sharp shower. I say thundery, but so far Blitzortung has only detected one flash of lightning from it.

What seems very silly to me, watching the latest forecast on the BBC News channel (which looks like it may have been taped), is how the weather presenters prefer to use NWP model rainfall rather than real-time weather radar images. In a dynamic convective situation like today, you would have thought that’s what they would be most helpful to the public. Likewise the BBC presenters never ever use real-time SFERIC data, or come to that rapid scan 5 minute visible satellite imagery. What’s the point of having all these various ways of observing the weather in real-time, and then not using them?

Certainly use NWP images for forecasting, but masquerading NWP forecast data as real-time observational information is wrong and just plain misleading.

I remember coming home from work on the 16th of August 2004, it must have been just before 4 PM, to watch Michael Fish prattle on in the forecast about how hot it had been recently in Greece. This too was a taped forecast that they used on the same BBC News channel. The news was later interrupted by breaking news about flash flooding that was occurring at that precise moment in Boscastle. It seems to me that little has changed since then in how we present the weather, if this intense shower that I noticed this afternoon had been slow-moving and a little larger, the same thing could have easily happened all over again.