June 2016: Circulation Patterns

The changes in the circulation pattern over western Europe and the eastern Atlantic during June are well captured in these three 10 day mean pressure charts. The change from an anticyclonic NE’ly transitioning through a cyclonic and then into a mobile westerly are easy to see. A large area of positive mean sea level pressure [MSLP] anomalies of +15 hPa dominated the first 10 days over  and to the NE of Iceland, that gave way to a discrete -1o hPa negative anomaly over the British Isles during the middle of June, before negative anomalies of -9 hpa and lower, became established over Iceland, a complete reversal of MSLP anomalies that existed for the first 10 days of the month!

Mean MSLP & Anomalies Monthly (3x3) June 2016

Mean MSLP & Anomalies Monthly (3×3) June 2016

From this chart of anomaly spot values for Iceland it’s easy to see how the positive anomalies of +24 hPa at the beginning of June collapsed as the month progressed, and by the 21st they were negative MSLP anomalies -24 hPa.

Capture2

June 2016: N hemisphere temperature anomalies

Air Temperature Anomalies 01 Jun to 30 Jun 2016

Surface Air Temperature Anomalies 1st – 30th June 2016

It’s the first time in a long time that surface temperature anomalies seem to be back to normal in the Barents sea region of the Arctic. The chart below is for temperatures and anomalies since the start of the year at 80N 40E, which is right in the middle of the Barents Sea between Svalbard and Franz Josef Land. The anomaly values of +20°C or more for much of the Winter look like something out of the film “The day after tomorrow” I know (but in reverse – sudden warming and not sudden cooling), but as far as I can see my application is doing its job and they are correct, and as I said temperatures there seem to have returned to normal since the end of April.

Mean Air Temperature & Anomalies for 1 January - 30 June 2016 [80.000 N 40.000 E]

Mean Air Temperature & Anomalies for 1 January – 30 June 2016 [80.000 N 40.000 E]

Elsewhere warm air dominated, particularly over central Russia (+8), the bulk of North America (+4) and large parts of Europe (+2), but the western North Atlantic ocean is still slightly on the cold side (-1). I’ve added labels for the various extremes to help you read the contours, which are more than a little convoluted this month. Below is a chart of air temperature anomalies since the start of the year have in the mid-Atlantic, at 50N 25W to be precise. As you can see it’s been predominantly cold throughout, with some short warmer weeks.

Mean Air Temperature & Anomalies for 1 January - 30 June 2016 [55.000 N 25.000 W]

Mean Air Temperature & Anomalies for 1 January – 30 June 2016 [55.0 N 25.0 W]

And because the gridded data is also six hourly, I can look back at spot values for any particular hour or day, here is the 1800 UTC on the 30th of June showing how quickly things can change in the very short-term.

1800 UTC Air Temperature Anomalies on Thu, 30 June 2016

June 2016: Rainfall

I thought that because I’d already written about temperature and sunshine across the British Isles yesterday, I should finish it off with a quick look at the rainfall totals in June. So here they are and guess what Capel Curig with 184.8 mm (7.28″) is the wettest place from the list of all the available SYNOPs!

Wettest Places Total Accumulated Precipitation 1 June 2016 - 1 July 2016 WMO Block 03

Wettest Places Total Accumulated Precipitation 1 June 2016 – 1 July 2016 WMO Block 03

I’m still trying to get my head round the 32.1 mm from Herstmonceux on the south coast, I seem to have 98% of the obs but the value looks low. Perhaps the gauge has a spiders nest in it like mine did early last month. The 153.3 mm from Kenly (to the south of London) made them #5 in the list from all the thundery rain they received.

Accumulated Precipitation for 0600 UTC 1 June

Accumulated Precipitation for June 2016

At the other end of the list Kirkwall finished with the lowest total of the month with just 11.3 mm of rain (0.44″). This is another one that’s hard to believe, yes the first 10 day of the month were fairly anticyclonic, but as the westerlies returned mid month, the Northern Isles were again open to all the various lows that tracked across the country.  Is this another spider? Or is it bugs in my program? That is a strong possibility, as you the reader are my testing team, and I’m notoriously bad at testing the applications that I write.  I am heartened to see that Wick only received 45.8 mm (89% received) in June , so hopefully some kind person at the Met Office might let me know how close I got! Who am I kidding, there is very little chance of that happening with just 13 subscribers, but you can live in Hope, well you could if you can afford the house prices.

Driest Places Total Accumulated Precipitation 1 June 2016 - 1 July 2016 WMO Block 03

Driest Places Total Accumulated Precipitation 1 June 2016 – 1 July 2016 WMO Block 03

Accumulated Precipitation for 0600 UTC 1 June

Accumulated Precipitation for June 2016

June 2016: Sunshine in the UK

I’ve just done a quick bit of coding to allow me to produce graphics for the sunshine totals for June from across the UK. The daily sunshine totals I parse from each day’s 0600 UTC SYNOP reports which I download from the OGIMET site. Top of the shop across the British Isles in June was Valley on Anglesey in Wales, with 218.8 hours of sunshine (43.2% of possible), closely followed by a whole host of other stations from western parts.

Daily sunshine 1 June - 1 July 2016

Daily sunshine 1 June – 1 July 2016

Daily Bright Sunshine 1 June 2016 - 1 July 2016

Daily Bright Sunshine 1 June 2016 – 1 July 2016

Across Europe Valley’s 218.8 hours couldn’t quite match the 404.1 hours (90.4% of possible) from Toledo in Spain. Oh to have a field full of solar panels in southern Spain.

Daily Bright Sunshine 1 June 2016 - 1 July 2016

June 2016 – Temperatures across the UK

Here’s a list of the warmest stations by day [06-18] from across the British Isles as reported in their SYNOP observations during the month of June 2016. Unfortunately I still haven’t written the code that’ll allow me to produce an anomaly for each station, so mean temperatures will have to do for now. The remarkable thing is how after a very cool start, the stations in the southeast of England just managed to bounce back and pinch the top two spots in the warmest by day. As you can see the mean maximum temperature [06-18] was almost 21°C  in central London. Exeter came in at joint #9 but I did miss a number of 1800 UTC observations from the station during the month.

Maximum Temperature 0600 - 1800 UTC 1 June 2016 - 1 July 2016

At the other end of the scale, islands around the north and west of Scotland were coolest (the lowest [06-18] maxima) as you would expect at this time of year, along with a number of coastal stations down the east coast of both Scotland and England.

Lowest Maximum Temperature 0600 - 1800 UTC 1 June 2016 - 1 July 2016

Lowest Maximum Temperature 0600 – 1800 UTC 1 June 2016 – 1 July 2016

The southeast didn’t manage to make the warmest place in June which went to Glasgow with 27.3°C on the 6th of June –  do you remember that warm spell at the start of June?

Highest Maximum Temperature 0600 - 1800 UTC 1 June 2016 - 1 July 2016

Highest Maximum Temperature 0600 – 1800 UTC 1 June 2016 – 1 July 2016

The night of the 22/23rd of June was very mild with overnight [18-06] minimum temperatures in London no lower than 18°C.

Highest Minimum Temperature 1800 - 0600 UTC 1 June 2016 - 1 July 2016

Highest Minimum Temperature 1800 – 0600 UTC 1 June 2016 – 1 July 2016

CET: June 2016

The June Central England Temperature [CET] values are now in, and I make the mean temperature for the month around 15.3°C with an anomaly of +1.08°C (wrt 1961-1990 LTA). June 2016 was warm for the first 10 days or so, but temperatures returned to near average for the remainder of the month as the westerlies returned, and it ended up being the #46 warmest in the monthly series back to 1659. One thing I did notice through June was the preponderance of warm nights.

June mean CET & anomalies 1659-2016

June mean CET & anomalies 1659-2016

June’s rainfall up to press

Accumulated Precipitation for 1 - 22 June 2016

Accumulated Precipitation for 1 – 22 June 2016

Sea ice index back

N_daily_extent_hires

The Sea Ice Index from the National Snow and Ice Data Center [NSIDC] is operational again after being out of service since the end of March. The NSIDC say on their web page:

On the 5 April 2016, the vertically polarized 37 GHz (37V) channel of the SSMIS instrument on the DMSP-F17 satellite began yielding compromised brightness temperature data. This channel is one of those used to estimate sea ice concentration shown in the Sea Ice Index, so data processing was temporarily suspended…  After investigating the difference in ice extent as the algorithm tie points were varied, it was found that the current F17 tie points provided the best match in sea ice extent for the overlap period, so no adjustment in algorithm parameters was needed for F18.

For more detailed information follow this link. The latest values for the 16th of June from the Arctic show the sea ice extent to be 88.9% of average for this time of year, the lowest since 1979 when records of this sort began. As you can it’s well out of the x2 standard deviation area and tracking much lower than the previous lowest year of 2014 (in red), although in recent weeks the gap between them as narrowed it still looks odds on to be the lowest Arctic sea ice on record.

Latest Arctic Sea Ice (16 Jun)

Latest Arctic Sea Ice (16 Jun)

The Antarctic is still managing to keep close to the average with sea ice extents currently 99.3% of average for the 16 June, although significantly down on the values for the same day over the last three years.

Latest Antarctic Sea Ice (16 Jun)

Latest Antarctic Sea Ice (16 Jun)

Mid June rainfall totals

Accumulated Precipitation for 0000 UTC 1 June

Accumulated Precipitation for the 1 – 16 June 2016

I read something about the chances of a record wet June have been shortened after the recent unsettled weather with heavy showers and thunderstorms in many parts. So here’s a list of the wettest place that I’ve compiled from the SYNOP reports now that we are mid way through the month:

The Dry

Lowest Total Accumulated Precipitation 1-16 June 2016 WMO Block 03

Lowest Total Accumulated Precipitation 1-16 June 2016 WMO Block 03

Interestingly (I must find another way of starting sentences like this), Lerwick is the driest place so far this June with just 2.1 mm of rain, the Isle of Man is third driest with just 3.8 mm followed by the Isles of Scilly with just 4.7 mm. In fact many place along the south coast of England east of Portland have escaped the heavy rain.

The Wet

Highest Total Accumulated Precipitation 1 - 16 June 2016 WMO Block 03

Highest Total Accumulated Precipitation 1 – 16 June 2016 WMO Block 03

As regards wet places, there are many places across the British Isles that have received 50 mm or more and a few over 75 mm, so if this wet spell continues into the second half of the month, you could expect totals approaching 200 mm. from some locations. But that’s a big if  (or in this case a bold italicised if ), and the weather in the second half of June could return to how it was in the first week, well possibly not, but you do have to look on the bright side don’t you.

Often forgotten

The northern Isles are very often forgotten in weather forecasts on the media, and often weather there is much better than it is further south on the mainland, and that’s been true in recent weeks with some lovely sunny days in the Shetland Isles. Here are the daily sunshine totals and accumulations for the last month from Lerwick.

Sunshine at 03005 Lerwick - United Kingdom 82 AMSL [13 May - 13 June 2016]

Sunshine at Lerwick  [13 May – 13 June 2016]

As you can see over the last month there has been well over 200 hours of sunshine and four days had totals of over 15 hours, because that’s the other thing this time of year in the northern Isles, the days are very long and the nights short. The sunrises at Lerwick at around 3:39 AM and doesn’t set till around 22:34 PM in mid June, which gives a day length of almost 19 hours. Mind you it never gets desperately warm up there thanks to the cold seas that surround the islands, here are the hourly temperatures from the last week.

03005 Lerwick - United Kingdom 82 AMSL 6 June-12 June 2016

Temperature, dew point and humidity at Lerwick 6 June-12 June 2016