About xmetman

An ex-metman passionate about all things to do with weather, climate and clouds

Arctic sea ice doing better than expected

To say that the Summer sea ice in the Arctic is in a terminal condition according to many scientists, and will soon be no more by this time in August in the years to come, it’s still doing remarkably well, if the latest figures for the 22nd of August from the NSIDC are to be believed. The sea ice extent on that day is only the fifth lowest, in a series that started in 1978, which is pretty remarkable, because if you remember the 2016/17 season ended up on the 5th of March as the all time lowest maximum year.

The red line (2017) series in the graph (fig 1) has gone higher than last years trace (black) and as stayed that way for a week. If you remember, it was about this time last year that sea ice values crashed very quickly. There is little chance that 2016 is going to produce a lowest maximum to add to its lowest minimum record, and is still almost 900,000 square kilometres higher than at the same time in summer 2012.

At the NSIDC there is a now very useful new comparison web tool that allows you to compare any two years. Here is a comparison between 2017 and 2016 for the 22nd of August (fig 2).

Figure 2 – Courtesy of NSIDC

And here’s a comparison for 2017 and the record minimum year of 2012 (fig 3).

Figure 3 – Courtesy of NSIDC

What happens at 85° north?

It’s day 19, and the ‘Arctic Mission’ team have now reached latitude 76° north, and although there is little sign of any sea ice, the air temperature is now down to -2°C, so no skinny dipping and time to break out the thermals. I still wonder what the web team in charge of the ‘follow the mission’ website will do if they ever reach 85° north, perhaps they’ll call it a day because the Google map projection they’re using to plot the course with doesn’t extend any further north than that.

Russian LNG tanker navigates Arctic sea route in record 6.5 days

A little off topic, but it seems that it’s not only Pen Hadow that want’s to sail around the North Pole at the moment.

Seville sunniest this Summer in Mediterranean

Figure 1

Seville in Andalusia, Spain, is the sunniest place across the central and western mediterranean so far this summer, with 1071.5 hours of sunshine up until the 22nd of August, which as far as I can see is 89.4% of the theoretical maximum, and gives them a daily average of 14.4 hours of sun. If you like watching clouds float by, then Seville is not the place for you, because clouds their in summer have been a scarce commodity this year. There are 16 stations across the area with totals in excess of 1000 hours so far this summer. Wikipedia is a great resource for climate data, and for many larger cities they have a climate table, and the Seville entry is no exception. It seems that the average total for the three meteorological summer months is 999 hours, which is quite handy, because already with a week to go the total is already 7% above average.

I can’t compute the anomalies for all the other stations, because I just don’t have access to the detailed climate averages for across Europe, which is a pity. What we need is a global organisation that could collect and collate climate data from all the nations of the Earth, this organisation could then take the lead in the climate change debate, providing accurate climate and observational data for anyone to access. Let me think what should we could call it? I know, why don’t we call it the World Meteorological Organisation!

Jersey still holding onto sunniest place this summer

Figure 1

With just over a week left of the meteorological summer of 2017, it’s still neck and neck at the top of the sunniest places in WMO block #03. The race has been between Shoeburyness in Essex and Jersey in the Channel Islands, and at the moment Jersey has a slight lead of just 5.7 hours over Shoeburyness, with a total of 614.6 hours since the start of June, so it’s all still all to play for. The Essex site might actually have a higher total, because although I’ve received 100% of the Jersey daily totals in the SYNOP reports, I’ve only received 92% of the Shoeburyness sites. I look forward to the day when I can collect the latest daily climate data for the whole of the UK from the Met Office, without having to use external sources, but I feel I might be in for a very long wait.

Warmest day of the month

Figure 1

The 23.5°C at 12 UTC, makes the 21st the warmest day this month by a long way at Exeter Airport. Locally here 14 km to the northeast of the airport, the temperature has been well in excess of 25°C for the last couple of hours in the intense August sunshine, and it feels quite close.

Figure 2

 

Hurricane Debbie September 1961

Figure 1

The above reanalysis chart for the 00 UTC on the 12th of September 1961 (fig 1), shows four simultaneously active hurricanes in the North Atlantic and Gulf of Mexico. I’m not sure if that’s a unique occurrence, but I came across a mention of it in a book called The Atmospheric System which I’ve just picked up from Abe book. The contouring is not perfect because the reanalysis grid is too coarse at 2.5° x 2.5° to pick up the intensity of each hurricane.

Figure 2

Hurricane Debbie reached a maximum category 3 status, with a minimum pressure of 970 hPa and maximum wind speeds of 105 knots, in it’s life of almost 10 days it travelled 7,688 nautical miles (fig 2). This was very early days for weather satellite imagery, which explains the scarcity of tropical storms (2) listed for the 1961 season in the North Atlantic.

Figure 3

Hurricane Debbie was a classic Cape Verde hurricane that curved north and then northeast to brush across the northwest coast of Ireland as a category 1 hurricane causing the deaths of 17 people as it did so (fig 3). In fact it even hit the cape Verde Islands as a strong tropical storm, and was probably responsible for the death of 60 people in a plane crash on the island at that time. Wikipedia has a very detailed article about Hurricane Debbie, oddly they seem to like using the term ‘storm’ when referring to Debbie, despite referencing an article which is in no doubt that it was a category 1 hurricane at the time, as is the HURDAT2 database, which lists Debbie as a hurricane when it crossed Belmullet in Northwest Ireland, as you can see from the table of 6 hourly positions from it (fig 4).

Figure 4

That article mentioned in Wikipedia is from a book Advances in Hurricane Research – Modelling, Meteorology, Preparedness and Impacts by Kieran R. Hickey and Christina Connolly-Johnston, of the Department of Geography, at the National University of Ireland, Galway. Chapter 9 of the book is called The Impact of Hurricane Debbie (1961) and Hurricane Charley (1986) on Ireland is free to download as a PDF. Here are a couple of interesting effects of hurricane Debbie that I hope the authors don’t mind me taking these snippets from that chapter:

  • At Malin Head on the extreme NW tip of Ireland a gust of 182 kph (92 kts) was recorded. Other exceptional gusts were recorded at Shannon Airport, Rep. of Ireland at 172 kph (93 kts), Ballykelly, Northern Ireland at 171 kph, Tiree, Scotland and Snaefell, Isle of Man both at 167 kph (90 kts), Clones, Rep. of Ireland at 161 kph (87 kts), Kyle of Lochalsh, Scotland 159 kph (86 kts) and Mullingar, Rep. of Ireland with 146 kph (78 kts).
  • The severity of the wind can be seen by the fact that as far as 20 km inland all plant life withered and died in a matter of minutes as sea spray laden with salt was carried landward by the wind.
  • A very rare storm-induced tidal bore was recorded as having taken place on the Shannon river near Lanesboro, Co. Longford when the level of the river rose by 1.35 m as the hurricane winds blew water upstream. This reverse flow carried many small boats upstream and onto the river banks leaving them high and dry when the wind changed direction and the river dropped almost equally as suddenly.

Autumn is on it’s way – the last 8,760 hourly temperatures at Exeter

Figure 1

Ever wondered what a scatter graph of hourly temperatures for a year looks like? The chart above (fig 1) does exactly that for Exeter airport, along with a 24 hour (black) and 7 day centred moving averages to boot. The cool morning temperature of 5.8°C from the airport, reminded me that Autumn is on its way, even though for the first few days of the coming week 1000-500 hPa partial thicknesses will be in excess of 564 dm. The 7 day moving average which peaked in June at close to 20°C, and has been declining erratically since the middle of July.

Figure 2

The sunshine stats may well be a little low for Exeter, with an annual total of just 1414.3 hours, this is because the sunshine record is not 100%. There are occasionally missing values from the SYNOP reports that I can do little about, December 2016 had quite a number, and might explain the odd behaviour of the moving average (fig 2). Even so, the sunny spells that did occur in early April, and in the second half of May are clearly visible, as is the warm and sunny June in both temperature and sunshine graphs.

Total ‘rain days’ so far this summer in the British Isles

Figure 1

I thought that I would look and see what were the wettest places in the UK by counting up the number of rain days there had been this summer since the 1st of June. Remember that rain days are days when 0.2 mm or more of rain has fallen in 24 hours, using SYNOP climate data that means in the 06-06 UTC period, either from the 24 hour total reported at 06 UTC, or from adding up the 12 hour totals for the period 06-18 and 18-06. I could have counted the number of wet days, which includes days with 1 mm of rain or more. As you can see from the above infographic (fig 1), Tulloch Bridge in Perthshire has the most number of rain days this summer, with 64 out of 79 days (81%). The lowest number are not surprisingly all across southern counties of England, with nine stations reporting less than 40% rain days so far this summer, headed by the St Catherine’s Point on the Isle of Wight, with only 24 rain days so far (fig 2).

Figure 2

And if we look a little further south across the Mediterranean this summer we’ll see what really dry looks like, with many places seeing only a single rain day so far.

Figure 3

The consistency of the GFS model

Figure 1

The panel of eight charts are all from the GFS model runs of the last eight days (fig 1). They display the same forecast chart for midnight tonight (Saturday the 20th August 2017), but all from different model runs and forecast ranges, from the oldest of T+192 (last Friday midnight’s run), to the latest T+24 (this Friday midnight run). I’ve done this to see just how much the forecasts differs as we get closer to T+0, the forecast day we are interested in. The chart at the top right is from the furthest out (T+192) and the chart at the bottom right is closest to the forecast (T+24), I did this to compare just how the GFS was handling the approaching remnant s of ex-hurricane Gert on Saturday night.

As you can see, the forecast for Saturday night has changed quite radically in the last week. The rain from the approaching warm front was at first [T+168] expected quite quickly over Western Scotland and Northern Ireland, but from Thursdays run the model slowed it down and brought the area further south. The ridge of high pressure that was at 15° west at T+192 also changed position and alignment quite a lot in each run, and by the end is aligned NW-SE rather than N-S as it was at T+144.

What I’ve learned from this little comparison of the GFS, is that there is not a great deal of consistency before T+72, and it’s only from then that things start to firm up, but even when have, this by no means that the model has locked onto the correct solution.