Ophelia : The life and death of a hurricane

Figure 1 – Provisional track from NHC and Met Office

Ophelia was born on the 9th of October as a tropical depression at 09 UTC in the mid-Atlantic somewhere to the southeast of the Azores. Her early days were spent meandering around the place of her birth, at times it almost appeared that she was going around in circles. Then suddenly one day her life found a new direction, and she decided to head off and take a swipe at the British Isles, so off she went tracking ever more faster each day in a northeasterly direction. She made good progress, and before long she surprised every on by becoming a category 3 major hurricane! She had become the furthest east major hurricane in the satellite era! But then rather unexpectedly (to some people’s mind’s at least) and just as she was closing in on her intended target, someone called (Ice) Berg in America decided that her life as a hurricane was at an end, and he declared her a post-tropical cyclone! Not to be outdone she put on an extra spurt and deepened from 971 to 958 hPa to show them she was not finished quite yet. The rest as they say is history…

Figure 2

 

For the purists out there that say that hurricanes can only survive in oceans with a SST of around 79 °F (26 °C) or more, how did Ophelia manage to steadily intensify from a category 1 to a category 3 major hurricane in the Atlantic Ocean during on the 14th of October southeast of the Azores, with SST that were much colder (fig 2), between only 22°C and 24°C?

Please don’t bother replying with comments about how “the large temperature contrast between the abnormally warm seawater and the extremely cold temperatures in the upper atmosphere” providing instability for Ophelia’s thunderstorms “which allowed the storm to continue strengthening” because I simply won’t’ believe you!

If Ophelia can intensify over cooler waters like she did, then there is no reason not to accept that the NHC killed Ophelia off around 12 hours too soon, I think she survived till at least 09 UTC on the 16th of October and close to 51° north. She might have looked pretty crappy in the visible images as she approached Ireland  early on Monday but her inner core winds that had driven her down to 951 hPa were still spinning.


FAAM and its relationship with the Met Office

Why wasn’t it possible for the Chief forecaster at the Met Office to call on the services of the Facility for Airborne Atmospheric Measurements [FAMM] and get them to fly their modified BAe 146-301 large Atmospheric Research Aircraft [ARA] to the Azores on Saturday afternoon and back again during Sunday, drop a couple of dropsondes into the eye of Ophelia, and run their fancy array of sensors over her?

All their findings could have been passed onto the NHC and fed directly into the NWP models around the world to get a better fix and track on Ophelia during the next 24 hours, all excellent meteorological research.

How come the Americans can afford to send a hurricane hunter out every six hours to investigate a tropical cyclone whenever an island in the Caribbean or the coastline of America is threatened, and yet when the tail end of a hurricane threatens our shores, we just curl up with a good book and issue a couple of warnings?

Of course it may have been that they did ask them, but maybe they were just too busy investigating stratocumulus, volcanic ash or contrails, and just couldn’t find the time for a jolly to the Azores.

When I was an assistant at Kinloss we had installed a boundary layer sonde [BLS] system from Vaisala, as did a number of other RAF stations across the UK. And when there was anything interesting going on meteorologically, we would fill up a balloon with helium, attach a small package of sensors to it, and throw it into the air. The rest was more or less automatic, a radio receiver attached to a PC processed the upper air data into a regular WMO TEMP message.

What I’m rather long-windedly trying to suggest, is that back then we realised the importance of good observational data, even when we had an excellent upper air network, something we don’t have these days. We don’t launch radiosondes from Weather Ships, we don’t even launch them from Stornoway, Shanwell or Hemsby these days, so why can’t we very occasionally just use something that we do have. I know the FAAM aircraft is primarily for research, but for exceptional hurricanes like Ophelia surely this could have been waived. As far as I know not a single aircraft from either Portugal, Spain, France, the UK or Ireland went out to take a look at Ophelia, surely the air force of one of these countries could have?


Just a ‘normal low pressure system’ says Chris Fawkes

I’m personally fed up to the back teeth of being told by weather presenter after weather presenter that Ophelia was now no longer a hurricane, and as Chris Fawkes so eloquently put it yesterday “is just a normal low pressure system”. Many of us don’t need this constantly rammed down our throats, or the 50 second video of Tomasz Schafernaker waving his arms about like some born again Magnus Pyke describing how a hurricane is formed and what powers them, because we already very well what the latest theories are.

That’s torn it – a gust to 90 mph at Aberdaron

Figure 1

That’s torn it, there have been gusts higher than the 80 mph upper limit in the Met Office’s amber alert, but if we keep quiet and don’t mention it, they might just get away with it. The stations in question are Valley with a gust to 81 mph at 15 UTC, and Aberdaron with a gust of 90 mph, you just knew somehow that the upper limit of 80 mph was going to be exceeded, especially with a ferocious southwesterly 75 knot gradient (and I’m guessing here) running straight up the Irish Sea. I can’t see them upping their existing amber warning, although you never know.

23.2°C at Manston equals the warmest 16th of October on record

Figure 1

There’s nothing quite like the British weather, with gusts of 67 mph on the Scilly Isles in the west on the 12 UTC chart (fig 1), and temperature of 23.2°C in the east at Manston, which more than likely makes it the warmest 16th October on record. In Ireland the storm force winds continue, and are still gusting in excess of 90 mph on the south coast, as Ophelia tracks slightly northwest of Valentia on the west coast, what about this for a pressure kick (fig 2).

Figure 2

Storm force 11 at Roches Point and gusting over 96 mph

Figure 1

It’s a good job Met Éireann wisely decided to up the status red this morning because the wind has been gusting to 96 mph at Roches Point on the south coast of Ireland (fig 1), and meaning 62 knots – that’s storm force 11 and just two knots of hurricane force 12 – at 11 UTC. Ophelia has still to make landfall, but must be very close to Valentia now, where the pressure at 11 UTC was 962.3 hPa and fell 9.6 hpa in the last hour.

Figure 2

Is Ophelia regaining an eye like feature?

Figure 1

It almost looks to me that ex-hurricane Ophelia has managed somehow to develop an eye like feature in the 1045 UTC visible satellite image. I did at first think that it maybe a shadow, but it does have the distinct appearance of an eye to it. A better quality satellite image would settle it but of course we can’t access hi-res rapid scan imagery can we. Please don’t bother commenting t o explain that hurricanes can’t survive in the cold waters around the UK without reading this article about Hurricane Debbie in 1961 first!

Storm force 10 at Roches Point gusting 70 knots

Figure 1

There’s a storm force 10 south-southeasterly blowing at Roches Point with gusts to 70 knots on the 09 UTC chart (fig 1), Ophelia is still to the southwest of Valentia, where the pressure is falling like the proverbial clappers (fig 2).

Figure 2

Met Éireann up the status red warning for the entire country

Figure 1 – Courtesy of Met Éireann

I suspected that Met Éireann had limited the area of the status red warning that they had issued on Saturday. I just wondered how much they had been swayed by guidance from the UKMO, and underplayed Ophelia a little. Well they’ve remedied all that now by issuing a status red wind warning for the whole country, and increased the speed of the possible maximum gusts to 75 – 93 mph.

Ophelia – visible satellite image 0830 UTC

Figure 1

There’s no doubt about where the centre of Ophelia is at 0830 UTC anyway.

Met Office enlarge Amber warning for strong winds

Figure 1

The Met Office have just enlarged the area of their Amber warning for ‘strong’ winds. I bet they’re getting a bit twitchy down there at the appropriately named FitzRoy Road in Exeter this morning. The medium level AS & AC cloud has still got that stormy yellowish look about it here in mid-Devon at the moment, very unusual, I’ll have to stop blogging and get snapping before I miss it.

Temperature shoots up to 22.0°C at Trawsgoed

Figure 1

The temperature at Trawsgoed on the west coast of Wales has just shot up to 22.0°C at 07 UTC, just ahead of the cold front, and could end up setting a new highest maximum record temperature for the 16th of October, but this may well be exceeded further east later on of course. Here in mid-Devon, the yellowish sky which was very intense in the last hour, has just started to fade as the front tracks away northeast.