March 2017 temperature anomalies

Figure 1 – Courtesy of NOAA/NCEP Reanalysis

You can see why the southeast of England had the highest regional temperatures in the UK during March, it was thanks to that warm anomalous area (+6°C) centred over Eastern Europe, but once again the central Atlantic was a little cooler than average. The central United States had another warm month (+6°C) but most parts of Russia were even warmer, with a massive +12°C anomaly over Novaya Zemlya.

Monthly Weather Report – March 2017

Figure 1 – Data and Images courtesy of the Met Office, Wetterzentrale & the CRU

Hopefully these two infographics will sum up the weather of March 2017 better than any words that I can come up with. There were a number of interesting climatological features of the month as far as I can see:

  • The mildness, exceptionally so in the southeast of England.
  • The dullness of the month in the southwest, in what generally in all other regions was a rather sunny month.
  • The lack of frosts, and very little in the way of snow.
  • Lower than average rainfall away from central areas.
  • No named storms, and low gale frequency.

Figure 2 – Data and Images courtesy of the Met Office

3rd mildest March since 1659

Figure 1 – Data courtesy of the Met Office

The Met Office finally got there act together today, and fixed their web service and updated their CET web page with the latest data. As expected, March 2017 was a very mild month, and when the temperatures were finally confirmed today, it turned out that it had been the 3rd mildest since the monthly series started in 1659. I make the mean temperature for the month 8.68°C, which was exactly 3°C above the 1961-1990 long-term average. It couldn’t quite beat the CET of either March 1938 or 1957, so it ended up being the warmest March since 2012.

Figure 2 – Data courtesy of the Met Office

The month saw four new high minimum temperature records set and one highest maximum record on the 30th.

Figure 3 – Data courtesy of the Met Office

7th mildest March on record to date

With 28 days of the month now gone, March 2017 provisionally stands as the 7th warmest March in Central England back to 1772, with a mean temperature of 8.11°C which is +2.55°C above the 1961-1990 long-term average. Maximum anomalies are a little higher than minimum anomalies this month, indicating that the days have been a little milder than the nights. Mild has it’s been, there was little chance that it would catch the exceptionally mild March of 1957 though.

Figure 1

Dull month so far in the southwest

 

Figure 1

A sunny Saturday makes a welcome change down here in deepest, dullest Devon. Hopefully in the next few days there will be a lot more sunshine to help redress the balance as March draws to an end. As you can see from the table (fig 2), in the first 24 days of March the Isle of Tiree in the inner Hebrides tops the list with over 114 hours of bright sunshine, with Exeter, Camborne and Liscombe at the foot of the table with less than 50 hours.

Figure 2

Joint 7th mildest start to March since 1772

Central England has been super mild this March, with mean CET anomalies almost +3°C above average, but today is maybe the last mild day for a while as colder weather sets in for the rest of the week.

Top ten mild start to March

The first 15 days of March 2017 have provisionally made it the 10th mildest start to March in Central England since 1772. Currently the mean to the 15th is 7.97°C or +2.77°C above the 1961-1990 long-term average. Whether it will be able to keep to through the rest of the month remains to be seen. I did make a rash statement that it wouldn’t beat March 1957 in one of my earlier missives, which may now be looking a bit rash on my part! The blue line in the top chart is the 2017 mean, and the red one 1957 (fig 1).

Figure 1

Dull start to March in the southwest

The first half of March has been disappointingly dull in the southwest of England and Wales. Camborne has only recorded 30.4 hours of bright sunshine, in comparison Boulmer in the northeast of England tops the list with 76.5 hours.

The same Atlantic feed of cloud that made the southwest of the UK so cloudy and dull has also affected much of northern and central France, whilst in comparison many places in Iberia have already clocked up well over 120 hours of sunshine already this month.

March 1957 – warmest in over 357 years

Figure 1

March 1957 stands out as being the mildest in the CET series which started in 1659, and as mild as this current March is, the mean anomaly of which stands at +2.48°C on the 12th, it will have to do a lot more to surpass the mean temperature of 9.2°C of March 1957, which was +3.53°C above the 1960-1991 long-term average (fig 1). Here are the daily surface charts for the month courtesy of Wetterzentrale (fig 2). In fact even 60 years later, the month still holds claim to three of the warmest March days in the CET series, the 3rd, 11th and 12th. The MWR explains how a pulse of warm dry air from Spain on the 10th, produced a period of Summer like weather that lasted to the 13th. Temperatures at several places in England and Scotland reached 70°F on the 12th, at Haydon Bridge (Northumberland) they reached 74°F (23.3°C), and unusually 69°F was recorded as far north as Cape Wrath.

Figure 2 – Courtesy of Wetterzentrale

As you can probably see from the daily charts (fig 2) the country was flooded by mild south or southwesterly for much of the month, the mean pressure chart for the month shows a negative pressure anomaly of -17 hPa at around 30° west and 50° north (fig 3 & fig 4), with higher than average pressure over Greenland (+11 hPa) and Scandinavia (+6 hPa).

Figure 3

Figure 4

This of course resulted in unseasonably warm temperatures, not just affecting the British Isles, but also across much of western Europe as well, with a positive warm anomaly (+4°C) over eastern France and Switzerland (fig 5).

Figure 5

So March 1957 ended up with very few stations reporting an air frost, and ended up warmer than the following April, quite an exceptional month.

March in like a lion

Figure 1 – Courtesy of Met Office

March may be about to come in like a lion, particularly in the southwest of the country, as a flat triple point low runs east along the English Channel tomorrow morning (fig 1). All looks fairly innocuous at first, but behind the trailing occlusion that the low drags in, are some very strong even gale force west northwesterly winds if the latest run of the GFS model is to be believed later in the day, and by that time colder air will have started to turn the rain from it to snow, especially over any hills in the west (fig 4).

Figure 2 – Courtesy of OGIMET

Figure 3 – Courtesy of OGIMET

Figure 4 – Courtesy of OGIMET