Warning for ice overnight but not strong winds by day

I can’t quite understand the Met Office with regard to warnings, they seem to be more concerned with issuing ice warnings for overnight than they do for strong winds for today. The strong westerly wind is continuing to blow fresh occasionally strong with gusts generally in the range 40 to 50 mph. This is a chart of all today’s gusts to gale force or higher (fig 1).

Figure 1

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.

12 UTC Wind Chill

Figure 1 – Wind Chill [JAG]

Not incredibly cold as far as wind chill goes today across the country, generally in the range of 1 to 4°C using the JAG/TI formula, except of course if you find yourself on top of a mountain such as in the Cairngorms, where the wind chill is as low as -15°C at the moment.

Line convection

Figure 1

I don’t know how long it will persist for, but there’s some interesting line convection (squall line) associated with the cold front that’s just clearing the extreme west of Wales and Cornwall first thing this morning.

Figure 2

Overnight strong winds and coastal gales across NW Europe

Figure 1

As expected low Herwart did bring exceptionally strong winds and coastal gales to much of southern Norway, Denmark, Northern Germany and the Dutch coast overnight (fig 1).

Figure 2

The strongest winds seemed to have been in the German Bight and particularly the Alte Weser lighthouse, where winds got up to violent storm force 11 with gusts to 89 mph at 06 UTC this morning (fig 2).

You have to admit that the Germans did a proper job when they built the Alte Weser lighthouse which sits at the mouth of the Weser estuary, it still looks as elegant and modern now as it did back in the 1960’s when it was built (fig 3). Just for completeness here’s the plotted chart for 06 UTC this morning for that part of the world (fig 4). It certainly would have been an interesting situation if it had occurred in December.

Figure 4

Storm Brian a bit of a no-show

Figure 1

I have to admit it that in the cold light of the synop observations of wind speed for yesterday until 08 UTC this morning, storm Brian was a bit of  a no-show, and the Met Office were correct in distancing themselves from the naming of it. It looked pretty ferocious on Friday, but Brian was already occluding and starting to fill when it arrived in northwest Ireland, as the models correctly said it would be. The yellow warning issued by the UKMO, could have mentioned possible gusts to 80 mph (fig 2), and the state amber issued by Met Éireann was not really necessary, but they are probably still jittery after the intense exposure they got from Ophelia on Monday.

Figure 2

Coastal waters and headlands took a pounding as they always do, but actual gales when 10 minute mean speeds reach 34 knots or more, were confined mainly to the Atlantic coasts of southwest Ireland and southwest England, the eastern coast of the Irish Sea from St Bee’s head south and the Bristol Channel (fig 3).

Figure 3

I’m personally glad to see the back of Brian and move onto Caroline.

Cherry picking wind speeds

Figure 1 – Courtesy of Twitter & the Met Office

It strikes me as strange that when the Met Office need to justify a named storm or a yellow or amber warning that they’ve issued for strong wind, how they can seemingly pluck observing sites out of thin air, some of which you might never have heard of before, such as:

  • Berry Head, Devon
  • High Bradfield, South Yorkshire
  • Needles Old Battery, Isle of Wight
  • Orlock Head, County Down
  • Salsburgh, North Lanarkshire
  • Avonmouth, Avon
  • Lydd, Kent

But when the winds have been a little stronger than they forecast, as was the case today with storm Brian, they seem to be able to exclude some stations from the graphics they generate (fig 2) as if the offending station didn’t even exist. In fact the winds are higher in western coastal districts of Wales than anywhere in Ireland, the difference is that Met Éireann did issue an amber warning for gusts to 80 mph, and the Met Office didn’t. I would like to use observational data from these sites myself, but I can’t access them, the reason being that they don’t have a WMO number, and don’t report a regular SYNOP observation, more’s the pity.

Figure 2

Ophelia wind speed analysis

The highest gust that occurred between 00 UTC on Monday and 07 UTC this morning from Ophelia was 96 mph at Roches Point on the south coast of Ireland, and occurred at 11 UTC (fig 1).

Figure 1

And just for completeness here are all the low-level stations that reported storm force gusts at anytime during that same period (fig 2).

Figure 2

On the face of it the warnings issued for the winds from ex-hurricane Ophelia look like they did there job, and that although three people died in Ireland, the warning saved many more, and that might well be true. But what about the accuracy of the warnings issued by both Met Eireann and the Met Office?

Met Eireann

If you remember Met Eireann amended their status Red and Amber warnings at around 9 am on Monday morning. They jumped the highest gusts expected from 80 mph to 93 mph, and extended the status Red to cover the entire country. If we look at the maximum gusts across Ireland in more detail (fig 3) you will see that the first warning they issued on Saturday for maximum gusts to 80 mph would have sufficed for all stations bar Roches Point, even across the north of Ireland all the gusts from the observing network were within the range of 50 to 80 mph stipulated in the original warning. The one thing that was wrong with Saturdays warning is that it didn’t single out the south coast as particularly vulnerable to the storm force southerly winds from Ophelia, especially the county of Cork which saw the highest gusts in excess of 90 mph. I’m not going to say whether the status red for the entire country was not warranted because I would likely put my foot right in it.

Figure 3

Met Office

Lets remind ourselves what the Met Office were warning us about as regards strong winds from Ophelia for the 16th in the UK.

Figure 4

Well as we’ve seen already the highest gust across Northern Ireland was 63 mph and did fall in the 55-65 mph range mentioned in the warning, but gusts in the range 65 to 75 mph or even 80 never occurred. And there lies the rub, because it’s never entirely clear from any warning issued by the Met Office what limits they use for yellow, amber or red warnings, and the reason why they don’t specify them is because it makes them impossible to verify. There is little doubt that the core of the strongest wind was along the south coast of Ireland, and up through the Irish Sea, in fact three stations in the northwest of Wales reported gusts of higher than 80 mph, and two of those, Aberdaron and Capel Curig reported gusts of 90 mph.

Figure 5

So using gusts of 70 mph or more as the basis for delineating the area of an amber warning, what should the area have looked like for the UK? Well on the basis of the wind speeds from the SYNOP stations it certainly wouldn’t have covered Northern Ireland, but instead stretched in an arc from Islay in the north down the Irish Sea possibly as far down as South Wales in the south (fig 6).

Figure 6

Looking back at the graphic from the NHC from Friday which shows the wind speed probabilities for Monday it shows look remarkably accurate. If the axis of the core of strongest winds had been aligned a little bit further east then it would have been spot on (fig 7). Perhaps we ought to leave it to the NHC to issue the warnings the next time a ex-hurricane heads our way.

Figure 7 – Courtesy of the NHC

The last post!

Figure 1

There’s still a number of stations reporting means of 50 knots or more (black triangles) across Wales, with gusts to 86 mph still occurring across the north of the country at 17 UTC (fig 1). It’s been quite a day, and I hope you’ve enjoyed these hourly reports on Ophelia’s progress. Apologies to those in Scotland where the winds are just starting to pick up, but I’m now packing it in for the day, I’ve been at it for nearly 12 hours! A full analysis on today’s gales and storm force winds from Ophelia tomorrow morning. I did manage to get to Tesco eventually so all in all a pretty good day.