Saturday’s low could be another doozy

The GFS maintains that this coming Saturday will be a very windy, maybe even a stormy day over the British Isles. As you can see from the last six model runs, which show the 12 UTC chart for Saturday from progressively later runs, the GFS model just can’t just decide where to plonk the vigorous low it develops (fig 1). The consensus seems to be that the low itself will run east-northeast from the southwest of Ireland (again), across the Irish Sea and the north of England, with a tight west or northwesterly gradient to follow along behind. At this range it’s still impossible to be precise, especially with so many diverse solutions so far. I’m not even going to say anything about this low being a named storm!

Figure 1

Such a beautiful start shame it’s going to rain!

Figure 1

It’s such a beautiful start to the day down here in Devon; with the old moon towards the east high above Venus; it’s a shame that it’s going to rain!

Figure 2

Well that’s what the latest GFS model says (fig 2), it’s a strange finger like feature, that eventually extends northeast to spread a spell of rain across the entire southeast of the country.

Figure 3

Ophelia at T+36

Figure 1 – Courtesy of Wikipedia

This is the only decent visible satellite image that I can find from yesterday of Ophelia as category 3 Hurricane (fig 1). The Met Office of course remain aloof from all the fuss about Ophelia, acting like they don’t have any access at all to high quality satellite imagery, because why on earth would anyone be interested?

What a perfect combination the UKMO and EUMETSAT, just throw in the WMO and you have the perfect triumvirate of ineptitude.

Why is it that I can view any of these types of satellite images or movie loops for the Caribbean, Gulf of Mexico and Western Atlantic courtesy of the Americans:

  • Visible
  • IR
  • IR AVN
  • IR Dvorak
  • IR enhanced
  • IR JSL
  • IR RGB
  • IR Funktop
  • IR rainbow
  • Water vapour

But as soon as a hurricane gets any further east than 35° west, we immediately revert to the dark ages. It would be nice to think that Brexit would change all of this, but it’s for certain that the Met Office will sail on into the sunset oblivious to it all as if nothing really matters.

Figure 2 – Courtesy of Intellicast

Ophelia passed to the south and the east of the Azores overnight as a category 2 hurricane. She is racing northeast at 30 knots, and is expected to turn more north-northeast today (fig 2), because if she doesn’t then watch out Bognor!

Figure 3

There’s a remarkable degree of similarity between the T+36 forecasts from the GFS and UKMO models for 12 UTC on Monday this morning (fig 3). The centre of Ophelia is slightly (~1°) further northeast in the GFS solution than the UKMO, this is probably to do with a slightly faster solution rather than a difference in track I would have thought. The centre of Ophelia is at 972 hPa in the GFS and down at 965 hPa in the UKMO, this may be due to the OGIMET contouring or the resolution of the GFS model they are using, I’m sure the Met Office track the centre of vortices in their models, rather than rely on a fixed grid of MSLP values as the GFS does. The isobars are very tight around the centre of Ophelia, which does mean that you would have to reduce the geostrophic wind quite a bit because of the tight curvature of Ophelia to get the true gradient.

No change in the warnings, either from Met Éireann or the Met Office this morning, although I would expect that they will be tweaked by Exeter this morning,. No mention yet of a yellow warning for heavy rain yet either, although Ophelia is moving through very quickly, the models do indicate a shield of heavy rain lying to the west and northwest of the centre.

The irony of this event occurring 30 years after the ‘great’ storm, is that unlike 1987, the southeast are best placed to get away with quite a warm breezy day, with little in the way of rain compared to places further west and north.

Ophelia now the sixth major hurricane and heading northeast at 20 knots

The latest midday run puts Southwest England in the firing line for a spell of south southwesterly gale force nine winds from ex-hurricane Ophelia by midday on Monday. As well as running Ophelia further east and up the west coast of Ireland, the run is also that bit quicker, then again, I make the centre closer to 975 than 970 hPa, but still with a small intense centre, so reminiscent of a tropical cyclone that she was until a few hours before (fig 1).

Figure 2

I’ve just FTP’d the UKMO T+48 fax chart from NOAA to see what the boys in Exeter make of it, and I must say that they’ve managed to make the gradient look a lot less threatening across the southwest than in the GFS. I’ll be interested to see what they come up with tomorrow morning when they issue their strong wind warnings.

Figure 2 – Courtesy of the Met Office

Meanwhile the NHC have declared that Ophelia is now a category 3 hurricane, and the 6th major hurricane of the season, they also add that:

Ophelia is a quite intense and rare hurricane for its location in the northeastern Atlantic

The maximum sustained winds are now 115 mph, and her central pressure is 960 hPa, and more importantly she is his racing northeast at 20 knots directly towards southwest Ireland. If I were the Chief forecaster on the Sunday night shift, I would be getting slightly twitchy as dawn breaks on the 16th.

Figure 3 – Courtesy of the NHC

A possible candidate for Brian?

Figure 1

They say that a week is a long time in politics, and that may be equally true of reliable seven-day NWP forecasts, but next Saturday could see a potential candidate for storm Brian, as Ophelia introduces a spell of mobile and potentially stormy weather next week across the country.

Ophelia and the latest GFS run

Figure 1

Looking at the last two runs of the GFS for the specific time of 12 UTC on Monday, its noticeable that the T+60 version is just a little faster and brings Ophelia a couple of degrees closer into SW Ireland (fig 1). It’s difficult to count the very tight gradient around the centre of Ophelia, but it looks to be around 970 hPa which is similar to the UKMO T+72 forecast solution for the same time.

Figure 2 – Courtesy of the UKMO

Met Éireann playing it cool with Ophelia

Figure 1

It’s interesting to see the differing approaches to the NWP forecast concerning Ophelia (fig 1), between the Irish National Meteorological Service, Met Éireann and the UK Met Office. As you probably know the Met Office have already issued an advanced yellow warning for strong wind for western parts of the UK, on their website Met Éireann have placed this small message (fig 2) about what their plans are – although I have noticed they do have an advisory out for Monday.

Figure 2 – Courtesy of Met Éireann

The NHC are in no doubt where Ophelia is heading and any possible impacts (fig 3):

Figure 3 – Courtesy of the NHC

And here’s some free advice from forecaster Berg (known to his friends as Ice) at the National Hurricane Center for everyone in Ireland and the United Kingdom regarding Ophelia (fig 4).

Figure 4 – Courtesy of the NHC

So Met Éireann and the UK Met Office, you can’t say that you haven’t been warned!

The latest forecast (T+84) for Monday from the Met Office looks like this (fig 5).

Figure 5 – Courtesy of the Met Office

On the basis of this evidence, I think if I were the Chief Forecaster at Met Éireann, I would issue a red status for Monday pretty sharpish, because after reading reports of the damage caused by hurricane Debbie in 1961 across Ireland, Ophelia has the same potential, and even if Ophelia tracks further west, it will still be a very windy day with coastal gales across Ireland. Of course there’s still plenty of time to inform the public, even if they leave it as late as Saturday or even Sunday to issue warnings, the message would still be heard thanks to the Internet and social media. So maybe they want to see the white of Ophelia’s eyes before they spring into action, but I wonder just how the Governor of Florida might react if he saw Ophelia heading towards Florida?

The GFS handling of Ophelia

It’s quite interesting to see during this week, just how the GFS model has handled the forecasting of hurricane Ophelia as it tracks northward over the weekend. Let me begin by explaining the following chart (fig 1). Because I invariably download the midnight GFS run from OGIMET each day and archive the images, I can afford to look back at how a forecast for any particular day changes as we approach it. The chart shows each individual forecast for the same fixed date and time, the 16th of October at 12 UTC, and each one of the eight frames is from a different model run, so the oldest one is at the top right hand corner, and is from the T+192 (8 day) forecast of the 8th of October, and the latest one in the bottom right frame is the T+84 from last night’s midnight run.

Figure 1

As you can see Ophelia didn’t even appear in the forecast frame for next Monday till the midnight run on Wednesday, before that the GFS had been forecasting quite a shapely anticyclone over the English Channel. Since Wednesday, the GFS has been remarkably persistent at placing Ophelia just west or southwest of Ireland as an intense feature in each subsequent model run. I find it fascinating how the model handled a hurricane that seemingly sprang out of nowhere like Ophelia has done.

Ophelia and other long lasting tropical cyclones

Figure 1

You just couldn’t make this one up could you? It’s thirty years next Monday since the ‘great’ storm struck and now hurricane Ophelia turns up out of the blue in mid-Atlantic and threatens to do the same thing all over again! The midnight GFS run this morning has the track of Ophelia a little further west of Ireland than it did in yesterdays midday run, but the intensity is similar, but if anything the pressure across the east of England remains higher than previous. The NHC seem to be using the GFS as they’re preferred track for Ophelia, as the media circus frenzy begins to pick up intensity on this side of the Atlantic (fig 2), the NHC have mysteriously removed their wind speed probabilities graphic this morning, possibly because it might have been causing some alarm across Éire!

Figure 2 – Courtesy of the NHC

I was going to post on the newsgroups my thoughts about Ophelia as if somehow it mattered. Better still I thought, I could post a blog and have the freedom to say what the hell I liked! Of course you are welcome to disagree, do feel free to comment.

It’s my firm belief that a tropical cyclones can make it across the Atlantic, a bit battered, on their last legs, but still intact as a tropical storm or even a category 1 hurricane as did Debbie back in 1961. So why shouldn’t Ophelia when it reaches our part of the world like Debbie did before her? Here is a chart of all the long-lived tropical cyclones that made it east of longitude 30° west from the HURDAT2 database (fig 3).

Figure 3 – Data courtesy of the NHC

And here’s the full picture, because believe it or not, ex-hurricane How made it to 80° north, and passed across Spitsbergen in 1951 (fig 4), the longevity may have had something to do with all those atmospheric nuclear tests they were doing back then!

Figure 4 – Data courtesy of the NHC

I think that very rarely, a fast-moving tropical cyclone can take much longer to dissipate than is normal, and not lose all of their tropical characteristics before they finally transition into an extratropical cyclone, I think hurricane Debbie was a rare example of that, but certainly not the October 1987 storm of thirty years ago. Ophelia may well not make landfall, if the latest GFS run is to be believed, but it could be another rare example of a very long-lived tropical cyclone.

Of course this crazy idea of mine will be disputed by purists who say that a tropical cyclone can’t survive over open water without a SST of at least 27°C to fuel it, but to the 18 or so people who died in Ireland back on the 16th of September 1961 it made little difference as to what produced those hurricane force winds. There’s still a lot we don’t know about cyclones, be it tropical or extratropical, but with global sea temperatures creeping up as they have been doing in recent years, they might start turning up in places where we might not have expected them to:

  • South Atlantic Hurricanes – I’m not clear from the article at what SST these tropical cyclones form at.
  • Medicanes – are rare meteorological phenomena observed in the Mediterranean Sea and unlike tropical cyclones don’t form in waters with SST of 27°C or higher.

Ophelia slower and a little further east

Courtesy of OGIMET

Similar minimum pressure, but Ophelia is a little slower and further east than on the midnight run.