Winter arrives with a bang!

Well, perhaps not arrives exactly – we’re already over halfway through winter, but if the forecasters are right then the coming week may see some seasonal cold weather.

The low pressure systems that will be drawing cold polar air across the UK for the next few days have active cold fronts associated with them, and two passed through in spectacular fashion earlier this morning. Overnight temperatures were mild, and rose as the night went on, reaching a peak of 10.6C at 0830 today under grey skies with occasional glimpses of blue sky. About half an hour later, cold front no. 1 arrived bringing heavy rainfall which severely limited visibility, wind gusting to 39kts and a 2C drop in temperature.

The blustery wind stayed with us as cold front no.2 approached. That front arrived here at 1020 with an even stronger gust of 42kts, 1.4mm or rain in about 10 minutes and a temperature drop of 3.3C.

That 42kt gust is equal-third in our records – we recorded 46kts in the St Valentine’s day storm of lst year, and 44 kts way back in December 2008. We’re into the clear air behind the cold front now, but the wind will soon be pulling in showers along with the polar air. Radar showed snow falling on the Welsh mountains earlier this morning, and the question is how far south it will come. Winter is here.

Snow pellets blocking the rain collector

If anyone is wondering why the weather station is reporting sleet while the sun is shining, we had some moderate falls of snow pellets known as “graupel” earlier this morning – snow that has become covered in super-cooled ice and so falls as soft ice granules. This ice blocked the rain collector, and is now melting so the rain gauge is reporting that sleet is falling. This problem always crops up with snow, and quite often when a heavy overnight frost melts in the morning sun.

Despite the overnight weather this has been a mild January so far, even milder than January 2014. The average temperature to date is 7.7C which well above normal for this time of year, but of course there is still plenty of time for that to change. The high of 15.2C last week is a new record, though.

Record temperatures for January

As the north of the UK takes another pounding from a deep low pressure system, we’re seeing some unusual conditions down here as well – though nothing as dramatic as the gales in Scotland.

At 1525 yesterday the temperature here reached 15.2C, by far our highest January temperature – the previous record was 14C in January 2011. Exeter airport recorded an even more extraordinary 16.5C. The average daytime (0600-1800) temperature yesterday was 12.9C, which is our highest daytime average since January 2008, and the temperature hardly dropped overnight – the 1800-0600 average for 9/10 Jan was 12.6C, the warmest January night since 2008.

It didn’t feel all that warm in the WSW wind that has continued for 24 hours, and that wind peaked at 34kts at 0935 today as a cold front passed through and dropped the temperature to a more seasonable 9.5C. That is the highest gust recorded here since February 2014, when the memorable St Valentine’s Day storm generated a gust of 46.1kts.

There are more low pressure systems on their way during the coming week, and we probably haven’t seen the last of the wind. Hang on to your hat!

December and year summary for 2014

December brought an ordinary end to an exceptional year. The average temperature for the month was 6.4C making it our third-warmest December, and the maximum (13.4C) and minimum (-5.3C) temperatures were in the normal range. Rainfall was about average at 63.4mm with no particularly wet days – the highest daily total was 12.4mm on the 12th. Windrun was 2964nm with no exceptional wind speeds.

The only unusual feature of December was an intense area of high pressure that brought a cold, clear spell at the end of the month. The barometer reached a high of 1042.9hPa on 29 December, our second highest pressure since the station was set up (the record is 1043.9hPa in February 2012). The same day saw the lowest temperature of the month with -5.3C recorded at 0725, but there was none of the snow that affected the north of the UK, and for a couple of days it was almost completely calm.

Much of the earlier part of the month was spent in a mild south-westerly airstream, hence that slightly above-average temperature, but most of the Atlantic low pressure systems passed well to our north and we avoided the heavy rain and gales that affected northern areas. One exception was a particularly deep low that tracked south-east across Wales on Boxing Day – at one point it was heading on our direction, but in the event it moved off across the midlands and the only effect here was a blustery wind.

If December was uneventful, the same cannot be said of 2014. The year started with the wettest winter on record here, and January’s total of 157.8mm makes that by far our wettest month. The winter of 2013/4 followed a wet autumn, and generated the floods that brought so much misery to the Levels. The low pressure systems that led to all the rain also generated some spectacular gales, with perhaps the most memorable being the St Valentine’s Day storm – that brought our highest-ever gust of 46.1kts early on the 15th February.

The apparently unending procession of deep lows of that winter had another effect, which attracted little attention with all the damage caused by wind and rain – the air was warm as well as wet, and the winter of 2013/4 was the mildest we have recorded here. January saw only two air frosts and February none at all, and a mimimum of -1.2C recorded in March was the lowest temperature of the year until November.

Spring 2014 was warm and wet, and by the end of June it was already an exceptional year – the rainfall total was double what we would expect at the halfway mark, and each of the first five months of 2014 was the second-warmest on record here. June capped that by being our warmest June on record, so it was already on the cards that 2014 might be an unusually warm year. July didn’t quite match 2013’s high temperatures but it was another very warm month with some spectacular thunderstorms – and then came August.

August was thoroughly miserable, with the lowest average temperature for the month and the second-highest August rainfall adding to 2014’s already high total. Normal service was soon resumed, though, with September and October both producing record high average temperatures. September was remarkably calm thanks to persistent high pressure, but October produced another rainfall total over the 100mm mark – by now it was clear that 2014 likely to be a record-breaking year in several respects.

November was on the wet side but nothing exceptional and, as we have seen above, December was unexceptional. Although rainfall totals ran high for most of the year, the annual total of 973.6mm fell some way short of 2012’s record 1008.2mm: but the average temperature for 2014 came out at 11.6C, and that is a new record and about 1C above the average for this station – but it is only 0.1C above the previous record set in 2011.

With floods and gales, thunderstorms and heatwaves – it may be a while before we seen other year like 2014.