Named Storms

The United Kingdom’s Met Office, in collaboration with their Irish counterpart Met Éireann, decided to introduce a storm naming system following the St Jude’s day storm on 27–28 October 2013 which caused 17 deaths in Europe and the 2013–14 Atlantic winter storms in Europe to give a single, authoritative naming system to prevent confusion with the media and public using different names for the same storms.

Reasoning

The objectives behind the decision were to:

  • Raise awareness of the dangers of storms
  • Ensure greater public safety
  • Avoid confusion if the name of the remnant of a tropical storm is used, for instance “the ex-hurricane Joaquin that reached Europe earlier this month.”
  • Involve the public
  • Operate with a common cross border system

The names will be used on predicted large-scale, cyclonic windstorms with potential for significant land-based wind impacts. This may result in names being allocated to events that are below the traditional Beaufort scale definition of a storm.

Designation

A storm will be named when it is deemed able to have a “substantial” impact on the UK or Ireland. Met Éireann names any storm which triggers a status orange or red weather warning focusing on wind, though consideration will also be given to rain and snow events in 2016–17. The basis for such as outlined on their weather warning service are mean wind speeds in excess of 40 mph (65 km/h) or gusts over 68 mph (110 km/h). Similarly, the Met Office name storms that have the potential to cause medium (amber) or high (red) impacts to the UK. It describes the wind strength relative to observations such as “falling trees or tiles and other items like garden furniture being blown around and even a number of properties left without electrical power.”

  • Status Amber or Status Red weather warnings will be applied to named storms.
  • In the case of ex-tropical storms or hurricanes, the original name allocated by the US National Hurricane Center in Miami will continue to be used.
  • The less common letters Q, U, X, Y and Z will not be used, in common with the US hurricane warning system.

Info courtesy of Wikipedia



For God’s sake just give it a name!

One of my subscribers asked me a good question in a comment he made: Why haven’t Met Éireann already renamed Ophelia storm Brian?

The answer to that is that it’s just a matter of time before Met Éireann do name it storm ‘Brian’, but because Ireland will be impacted first, they probably get to make that call.

To my mind this is a unique and very unusual event, it’s already memorable, and it hasn’t even happened yet!

Here are a couple of questions for you to ask yourselves:

First question : Can you remember storm Clodagh? I’ll give you a clue, it occurred on the 29th of November 2015?

Answer : No, that must be one that passed me by.

Why couldn’t I remember Clodagh? Because like 90% of all named storms it was completely forgettable, that’s of course if Clodagh hadn’t blown a tree down on top of your car or house!

Second question : Can you remember Ophelia?

Answer : Yes, that’s the hurricane than spun up out of the blue in mid-Atlantic, bringing severe gales to Ireland, exactly thirty years TO THE DAY since the ‘great’ storm of the 16th October 1987, how could I possibly forget that!

Come on for God’s sake Met Éireann just name it Brian and be done with it!

Hopefully, in years to come, people will look back and remember it as Ophelia, and not storm Brian.

Was the October storm of 1987 the result of ex-hurricane Floyd?

Figure 1 – Image courtesy of NOAA & Wikipedia

With the 30th anniversary of the ‘great’ storm of October 1987 now just a few days away, I thought it was about time that I looked into the rumours that ex-hurricane Floyd had something to do with it. After looking at some surface pressure charts for the Atlantic from the 12th to the 15th , I can now see how this speculation came about, and also better understand that Floyd was the hurricane that Michael Fish was referring to in his now infamous forecast when he said:

“Earlier on today, apparently, a woman rang the BBC and said she heard there was a hurricane on the way… well, if you’re watching, don’t worry, there isn’t!”

In the prologue to the book ‘Storm Force‘ which he co-authored, Michael Fish does explain that he was talking about hurricane Floyd and:

“…my remark had NOTHING to do with the storm”

He goes on to add that the infamous forecast:

“…was NOT made the evening before and NO woman rang the BBC

Looking at the video on YouTube of the now infamous forecast, it’s not entirely clear to me at what time it was broadcast. It could have been from late the evening before (14th), but it seems more likely it was the broadcast after the midday news on the 15th, because rolling 24 hour news from the BBC started much later than 1987 as far as I remember. Michael Fish reminds us in his prologue is at pains to explain that it was Bill Giles who was the duty forecaster that evening (15th), and it was he who uttered the immortal line:

“…it will be a bit breezy up the channel”

As Michael Fish reminds us:

He kept quiet about this  until he had collected his OBE and retired!

The culprit as we know was not any of the messengers, but a combination of poor guidance from Bracknell, poor forecast from what now looks a rather crude and unsophisticated NWP model, which itself was due in no small part to a dearth of ship observations from Biscay during the afternoon. Anyway I digress, as I so often do these days, so back to the main point of this blog.

Is there any truth in that speculation, that the October storm was the remains of ex-hurricane Floyd?

Figure 2 – Data courtesy of the NHC

Floyd had just slipped past the southern tip of Florida as a hurricane on the 13th of October 1987, here’s the reanalysis chart for 00 UTC (fig 3).

Figure 3 – Data courtesy of NCEP/NOAA reanalysis

The chart below (fig 4) shows the last position listed in the Hurdat2 archive for ex-hurricane Floyd, and this is how Wikipedia described the demise of Floyd.

Unexpectedly the storm turned sharply northeastward into the southeastern Gulf of Mexico. Based on reports from the Hurricane Hunters, Floyd briefly attained hurricane status on October 12. Around the same time, the nearby cold front spawned a low pressure area that cut off the hurricane’s inflow. While moving through the Florida Keys, Floyd became the only hurricane to affect the United States that year. However, its convection was rapidly decreasing over the center due to the front, and shortly thereafter Floyd weakened to tropical storm status. The circulation became nearly impossible to track on satellite imagery, although surface observations indicated it passed just south of Miami, Florida. The storm underwent extratropical transition as it weakened over the Bahamas, and Floyd was no longer a tropical cyclone by late on October 18*. The circulation dissipated within the cold front early the next day.

Figure 4 – Data courtesy of NCEP/NOAA reanalysis

And below (fig 4) is the position of the embryonic low that became the ‘great storm’ at 00 UTC on Thursday the 15th of October. I’ve measured the approximate distance between the last observed position of ex-hurricane Floyd and the first of the October storm, and its a whopping 2,600 nautical miles, and even if it had been doing over a hundred knots as a surface feature, Floyd just couldn’t have made it. Perhaps at the middle and upper levels if there had been a jet that spanned the Atlantic from the Bahamas to western France which was blowing at 240° and 100 knots, tropical air from Floyd could have been pulled eastward to fuel developments in mid Atlantic. I’m no expert, but I suppose it’s possible that tropical air somehow got entrained into a developing extratropical low, Floyd did rather mysteriously turn to the northeast and lose intensity as the Wikipedia article points out, but I would have to download more reanalysis wind data for 500 hPa and above to check if that could have been the cause, there’s nothing quite like a good conspiracy theory is there?

Figure 5 – Data courtesy of NCEP/NOAA reanalysis

As we now know the rest is history (fig 5) even though the coarse grid of the NCEP reanalysis doesn’t quite get the intensity of the October storm.

Figure 6 – Data courtesy of NCEP/NOAA reanalysis

*This slip may be intentional or not, but I reckon that 18 should be a 14 according to the NHC record.

Met Office: 30th Anniversary of the 1987 Storm

There’s been an interesting news release from the Met Office late this morning regarding the anniversary of the October storm in 1987. The best thing about it the news release that it includes a full size jpg of the machine plotted and hand contoured chart for 02 UTC on the morning of the 16th, what a busy night shift that must have been!  I hope they don’t mind me including a snippet from the bottom left hand corner of it in this blog! The news release makes interesting reading about how times have changed in the last 30 years as regards communications, and the power of supercomputers, that now allow NWP models to be run at even higher resolutions.

There’s an interesting video of just how the forecast would be handled thirty years later by Alex Deakin, which unfortunately has an image of a typhoon or cyclone behind him (0:47) rather than a hurricane. The puzzling thing that I can’t understand in the video is the reference to it as storm ‘Quentin’?

The news release even makes a brief, but indirect mention to the possibility that Ophelia might be another one, but if it does, it would be from the remains of a tropical cyclone, which the October 1987 storm wasn’t.

We can’t say we won’t see another storm like the one in 1987, but we are able to better forecast and warn of severe weather, helping to minimise the impacts by working with our partners and emergency responders, and the general public to prepare and take action all helping to protect life and property in the future.

Aileen nul points

Figure 1 – Data courtesy of the CRU/UEA

A bit of a slow day weather-wise, so I thought that I’d just download the latest Objective LWT data from the Climate Research Unit and look at the Gale Index of the named storms since the project started in September 2015, and noticed that storm Aileen had scored the lowest gale index of any of the previous named storms, with a GI of just 15.5 on the 12th and 22.9 on the 13th (fig 1). Because the CRU only calculate the Objective LWT from the daily 12 UTC chart, Aileen must have slipped through the net somehow, although the two previous days (the 10th and 11th) did score considerably higher, with values of 37.4 and 38.7,

I calculate my own 6 hourly GI from NCEP reanalysis data (fig 2), and my 12 UTC values are almost identical to the ones from the CRU, but Aileen does register a GI of 30.9 and 33.4 at 00 & 06 UTC on the 13th. Not particularly interesting and all very nerdy stuff I’m afraid…

Figure 2 – Data courtesy of NCEP reanalysis

I admit I got it wrong!

I admit that I was wrong in predicting that low Wolfgang would probably end up being the second named storm of this season – Brian, and even more reluctantly I have to confess that the Met Office got it right, even if they did screw up the warning for heavy rain for Sunday! I noticed that they also sneakily changed the ploy that they used for their yellow warning for strong winds on Monday, from the old 50 to 60, with some gusts to 70 mph, to 40 to 50, with some gusts to 60 mph. I believe the models from late last week believed that the remains of Maria would be entrained into the low and give it extra energy, but in the end Maria was late and kept to the south of the jet, and so the warnings for heavy rain didn’t pay off. It was a windy day further north, but mean speeds on the whole remained below gale force except over higher ground. Here are the maximum gusts of gale force 8 and above for Monday (fig 1), courtesy of OGIMET, where would I be without them.

Figure 1 – Courtesy of OGIMET

Low Wolfgang, or should that be storm Brian?

As I mentioned in yesterday’s blog, in which I said the single yellow warning from the Met Office was in fact a dual warning for heavy rain and strong wind, it looks like they must like the concept and have issued another one today, but this time they’ve properly labelled it Rain & Wind (fig 1), which is what they should have done yesterday!

Figure 1 – Courtesy of the Met Office

I’m still utterly confused with this warning though. They have adjusted the area by taking the southwest of England out of the area for wind and rain, and they’ve slightly enlarged the area across central Scotland but still stubbornly refuse to extend it further west, perhaps the rain shadow effect is offline for maintenance this coming weekend.

Figure 2 – Friday

The warning impact matrix totally baffles me, it looks at first glance that today’s new yellow warning (fig 2), now has a lower impact, but is more likely than it was yesterday (fig 3).

Figure 3 – Thursday

Today they have issued a separate warning for strong winds from 0005 UTC on Monday (fig 4), the start of which looks a wee bit late if you believe the GFS solution (fig 6). They don’t mention any maximum gusts in the text, so I see it as a of a place holder whilst they decide (tomorrow perhaps) what their forecast will be. Rather confusingly, the Chief Forecaster’s assessment for this warning are the same as the dual warning of heavy rain and strong wind for Sunday!

Figure 4 – Courtesy of the Met Office

The Met Office video* forecast (fig 5) reveals their solution, which is not that much different from that of the American GFS model (fig 5), even though we are left guessing when watching the video what time on Sunday the chart is for!

Figure 5 – Courtesy of the Met Office

Today’s run from the GFS (fig 6) has gradients that are not quite as strong over western and northern Scotland, but it does show severe gales for later on Sunday and during the first half of Monday which will surely mean that this low will be named storm Brian, which is a shame because I think Wolfgang, which the Institute of Meteorology in Berlin have named it, sounds much more menacing – who thinks these names up!

Figure 6 – Courtesy of OGIMET

*Call me picky but the whole feel of the contoured MSLP chart used in the video produced by the Met Office’s new graphics engine Visual Cortex, is totally ruined by how it draws those noddy fronts. The fronts themselves are overlaid directly as a layer on top of the MSLP contours. Just as in the BBC graphics, discontinuities that should exist when a front meets an isobar are ignored, so that isobars don’t trough into frontal boundaries as they should, and spoil the look of the whole thing.

Maria+Lee=Brian

Figure 1

It looks very much that what’s left of ex-hurricane Maria will be absorbed and assimilated into the parent low during Sunday, that’s according to the latest run of the GFS model (fig 1). As you can see Maria at longitude 30° west is absorbed into a trough that extends from the parent low and loses it’s identity during Sunday afternoon. The parent low is forecast to deepen to around 979 hPa and by the looks of it could bring severe gale force west and then northwesterlies winds to much of Scotland during Monday and into Tuesday, as it squeezes the gradient en route to southern Norway (fig 2). It looks quite probable, on the basis of this forecast, that it will be storm Brian, even though the impacts from the wind will be mainly across Scotland. As the Met Office said in their blog yesterday, the tropical air introduced into the mix by two ex-hurricanes does mean that rainfall totals especially in the northwest could be high.

Figure 2

One benefit of this vigorous low, is that according to the model it does introduce a large anticyclone as pressure rises strongly in its wake, but that’s a long way off, let’s see how early next week pans out first.

The weather presenter’s book of dodge’s

Figure 1 – Courtesy of the Watch Forum

When I was a child I use to buy a weekly comic called the Beano out of my pocket-money. One of  my favourite cartoons in it was about a character called Roger the Dodger (fig 1). Wikipedia nicely sums up much better that I can what Roger was about if you are not of that age:

His strip consists solely of Roger’s basic remit to avoid doing chores and homework which usually involves him concocting complex and ultimately disastrous plans, the undoing of which results in him being punished (usually by his long-suffering father). To perform these tasks he enlists the help of his many ‘dodge books’.

Weather Presenters Dodge #1

I sometimes wonder if there is a book of weather presenter’s dodges and what some of them are? A recent Twitter posting from the BBC weather team has led me to believe that I’ve found a dodge worthy of inclusion in their book of dodges. In the next few days, its forecast that the two ex-hurricanes Maria and Lee will merge in mid-Atlantic, and from the remnants of the two, a super low will form and threaten the British Isles with what could be storm Brian. As soon as I think of them actually naming this storm Brian I can’t help but smile, because it immediately brings back memories of Brian Conley’s alter-ego stuntman ‘Dangerous Brian’, anyway I digress. So the thing is, the Met Office ensemble models are split as to exactly which track this low will take and how much it will intensify by, and even if Brian will even happen at all. That’s where dodge #1 is so clever because the gist of it is this – tell the viewer that there are two possibilities and let them decide. Brilliant! It gets you off the hook, because you get it right whatever happens, and this is exactly the dodge that Matt Taylor employed yesterday in his weather for the week ahead video (fig 2).

Figure 2 – Courtesy of BBC Weather and Twitter

I can’t say what the Met Office forecast for later on Sunday looks like, either from their ensemble or deterministic models, because as you know the Met Office like to keep us in the dark about what our model is saying. The GFS model on the other hand has backed off a forecast with an intense low as deep as 946 hPa for 12 UTC on Monday. It now brings the remains of two hurricanes rather quickly eastward as a discrete low at around latitude 50° north, before it’s absorbed into a trough of the dominant parent low south of Iceland during Sunday morning (fig 3).

Figure 3 – Courtesy of NetWeather.TV

Look back at Aileen – the rain

Figure 1

I did expect to say ‘well done’ to the Met Office concerning the yellow warning for heavy rain (that they had adjusted southward) from storm Aileen, which looked like it had covered the wettest areas across Northern Ireland, southwest Scotland and the northwest of England (fig 1). But I found from my estimates of accumulation from the weather radar, that the heaviest rain had turned out to be in the Grampian region of northeast Scotland, with estimates for Fochabers of around 40 mm in the 18 hours between 18 UTC on the 12th to 12 UTC on the 13th. The Met Office did issue a late yellow alert for the area, but as they don’t have any form of archive for warnings, it’s impossible to say when it was issued. The rain certainly came out of left field and caught them on the hop, as most eyes were fixed further south on storm Aileen, it looks like it may well have been the results of some embedded instability, as there a few SFERICs on the archived chart from Blitzortung.

Figure 2 – Courtesy of the Met Office

Look back at Aileen – the forecast

Figure 1

I can’t see much wrong with the forecast charts from either the UKMO or the GFS (figs 2 & 3) when compared with the 00 UTC plotted chart for 13th. It may have been that there was not just enough oomph in Aileen to produce more of an impact, or maybe the explosive development started just a little bit too late and further east. Having said that pressure did fall by around 20 hPa across northern England in 10 hours during Tuesday afternoon and Evening.

Figure 2

Figure 3