Low Friederike developing rapidly

Figure 1

I’m watching the developments just west of Ireland this afternoon with a good bit of interest because the last couple of cyclogenetic events that have whizzed on a similar track managed to pack a much bigger punch than they were forecast to. The pressure at weather buoy 62095, better known as M6, is falling at the rate of 10.7 hPa in the three hours up to 15 UTC, so things are already well underway. At the moment the T+9  forecast frame from the 06 UTC run of the GFS is not too far out for 15 UTC.

High seas in Atlantic

Very high seas in the eastern Atlantic at the moment, as you would expect with such a long fetch of westerly winds. Yesterday at weather buoy 62081, or to give it it’s more familiar name of K2, instrumental wave heights measured by the buoy peaked at 15.1 metres which is inches shy of 50 feet! All four active buoys are still reporting high wave heights at the moment as you can see from this mornings 09 UTC plotted chart (fig 1).

Figure 1

35 foot waves at K5

Figure 1

The wake from Caroline is producing 35 foot waves at K5 at 08 UTC this morning (59.1° north 11.6° west) (fig 1). The cold front dropped the temperature almost 9°C in three hours on top of Cairngorm in the early hours (fig 2).

Figure 2

No boy scout worth his salt would have been as foolish to camp out on the Cairngorms last night, and if he had been, he certainly would never have got his tent up in a hurricane force 12 and gusts to 116 mph (fig 3).

Figure 3

Atlantic wave heights – Ophelia v Brian

Figure 1

During the gales of the last week across the country from ex-Hurricane Ophelia and storm Brian there have been some quite stormy seas, so I thought I would just compare the wave heights from three of the fixed weather buoys in the network of buoys that’s maintained by the Met Office around the British Isles. They aren’t quite as good as the weather ships of old such as Juliet, Lima and Kilo, and neither do they launch radiosondes or pilot balloons, but they are much more cost-effective. It’s hard to believe that some old observers in the Met Office made a career of manning these weather ships but they did. I never did get the chance to volunteer for that, neither did I get that detachment to Gan, or get a chance to fly in a F6 Lightning,  but that was my fault because I chickened out.

Figure 2

To the northwest of the British Isles (fig 1), neither Ophelia or Brian produced anything particularly high at weather buoy 64045 (K5), although you will notice that wave heights have picked up in the last couple of days thanks to the deep low Florenz much further to the west (fig 2).

Figure 3

Weather buoy 62095 situated to the west of Ireland (fig 1), was obviously too far west to be affected very much by Ophelia, but Brian did produce some 8 metre waves, and like 64045, there have been waves of 6 metres or more there in the last 24 hours or so (fig 3).

Figure 4

Finally 62029, which is situated to the southwest of Ireland (fig 1) responded to both Ophelia and Brian with 11 metre waves (fig 4). The winds from Brian lasted much longer than they did with Ophelia, and produced a 11.9 metres wave (39 feet) at 22 UTC on the 20th of October. This is far from the record wave height reported from an automatic weather buoy of 19 metres (62 feet and 4 inches) that occurred at K5 on the 4th February 2013, but still impressive nonetheless. Can you imagine what it would be like being in a ship with waves that high?

Ophelia Monday 06 UTC – which side of 62029 did she pass?

Figure 1

It’s a crying shame that the anemometer on weather buoy 62029 (K1) has been U/S for several months, because it would have let us know a little more precisely which track Ophelia was taking en route to somewhere on the southwest coast of Ireland. The pressure on the did buoy did bottom out at 968.1 hPa at 05 UTC, but the wind would have clinched it. At 06 UTC it reported a 9.1 metre wave height (~30 feet). There’s a stormy yellow sunrise this morning here in Devon, and it looks like its going to a busy day here at xmetman HQ, so I’d better make sure to feed the cat, because I’m sure to forget later.

Yesterdays 33 feet wave heights

Looking at the instrumental wave heights and winds from some of the UK weather buoys, low Victor certainly generated some big waves yesterday in the eastern Atlantic.

Figure 1

At 22 UTC yesterday the weather buoy 62095 also known as M6 (fig 1) had reported a wave height of 9.0 metres (29.5 feet), whilst at 09 UTC that morning, 457 kilometres further south (fig 3), weather buoy 62442 also known as ‘Pap’ (fig 2), reported a wave height of 10.1 metres (33.1 feet). It should be interesting to see what wave heights they’ll be measuring as the remnants of hurricane Maria pass close by this Sunday.

Figure 2

The strongest winds didn’t occur at either of the above two weather buoys, but from weather buoy 62105 also known as K4, which reported a means speed of 45 knots and gust to 66 knots (76 mph) at 23 UTC yesterday evening, although there may well have been higher values that were missed due to instrument failure (fig 3).

Figure 3

My SYNOP program has been an ongoing project now for almost 20 years, and in all that time I’ve never thought to plot the instrumental wave height from weather buoys, so I’ve decided to correct that omission and add it to my plot from now on. I didn’t know where I should place it, so for the time being I plot immediately below the station circle in a blue font. Here are the relative positions of the three weather buoys that I’ve included plot grids for.

Figure 4

Weather buoy 42060

Figure 1 – Courtesy of NOAA & NDBC

I am always impressed when a weather buoy survives an encounter with a hurricane as did 42060 yesterday with category 5 hurricane Maria. 42060 reported mean winds of 64.1 knots (74 mph) with gusts to 81.6 knots (94 mph) at 1510 UTC yesterday (19 September) afternoon, with a minimum pressure of 955 hPa at that time (fig 1). Looking at the wind directions reported by the buoy it looked like the eye of Maria passed close by to the northeast of 42060. Although the AWS was undamaged and still reporting, 42060 According to NOAA, has now broken a drift from her sea anchors (fig 2). I still can’t understand why the same reliable AWS that are used on these weather buoys aren’t used on land stations?

Figure 2 – Courtesy of NOAA & NDBC