Windrush Weather Station

Monthly Summary for April 2012

Eric — Mon, 30 Apr 2012 08:44:07 +0000

April 2012 was a quite remarkable month and in direct contrast to March 2012. With a mean temperature of 7.4C it was the coldest April since 1989 (6.6C) and 1986 (5.8C) and 1.3C below the long-term average. In fact it was 0.7C colder than March 2012. There were seven days with an air frost,the lowest being -3.4C on the 16th. There were five days when the maximum did not reach double figures, the long-term maximum average being 13.8C. The warmest day was the 30th when the the thermometer peaked at 16.4C.
The rainfall was another contrasting feature. With a total of 145.8mm it was the third wettest April I have recorded, that is after 1998 (151.2mm) and 2000 (165.2mm). There were only four dry days but seven days with totals in double figures. The maximum rainfall was 15.2mm on the 28th/29th (0900-0900) with fifteen continuous days of rainfall from the 16th to the 30th. Last year April gave us just 5.4mm in total. I should also note that there were three days when small hail fell in the heavy showers.
The wind strengths were also noteworthy for any month let alone the beginning of Spring. The average for the month was 4.9mph, the highest for over four years and usually reached during the boisterous winter months. A record for April was set in the early hours of the 29th when a maximum gust of 44mph was recorded. In addition it is important to note the 10-minute average speeds to get a fuller picture. For seven hours during the night of the 28th/29th the average was in excess of 20mph.
The sunshine for April was 86% of the total for April 2011, Solar Energy 73% and Evapotranspiration 63%.

Monthly Summary for March 2012

Eric — Sat, 31 Mar 2012 10:33:48 +0000

March 2012 was notable for the almost continuous high-pressure systems that blocked rain-bearing fronts from making progress into the country This resulted in a very low rainfall totalling 23.2mm, which is only 40% of the long-term average. Almost half the total fell on the fourth with 11.1mm, being the wettest day of the month. It was the fourth driest March I have recorded (March 2011 set the record of 12.7mm) with 26 dry days. It has been the second driest February and March period with a total of 52.5mm, which is 68mm below the long-term average. The record was set in 1993 when I recorded only 33.9mm for this period.
The mean temperature was 1.6C above the long-term average but interestingly this was almost entirely due to the high maximum temperatures. The mean was 13.6c and was the highest I have recorded for March. Another record for my station was set on the 28th when the peak temperature was 21.0C. beating the previous high set in march 1990.
There were seven days with fog that was dense well into the morning and sometimes very reluctant to clear. The solar energy was 10% up on 2011 as was the total for evapotranspiration, thus exacerbating the drought conditions.
The diurnal range has shown a general rising trend for both February and March over the last 28 years with the difference between the day maximum and minimum increasing by 1.5C and 2.2c respectively.

Monthly Summary for February 2012

Eric — Wed, 29 Feb 2012 10:13:33 +0000

With the lack of rainfall regularly in the news and the local River Kennet drying up above Marlborough, it was disappointing to find that the rainfall for February was just 29.3mm which is only 45% of then long-term average, the driest since 1998 and the fourth driest I have recorded. The wettest day on the 4th brought 13.6mm, almost half the month’s total. February 2012 was the ninth below average monthly rainfall in the last twelve months. Compounding this situation I find that the total rainfall for the winter 2011/2012 was 188mm, which is only 78% of the long-term average and the sixth driest winter on record. The rule of thumb, when rainfall is considered to percolate through to the aquifers rather than evaporate, is from mid-October to mid-March. With approximately 14 days to go in this period for 2011/2012 I find that I have recorded only 269mm, which is 68% of the long-term average and the third driest on record. The outlook for the summer water supply and the state of the River Kennet gives cause for concern.
The mean temperature for February was 3.0C, which is 1.2C below the long-term average, the coldest since 2006 and the sixth coldest on record. The thermometer dropped to -13.8C in the early hours of the 11th, which is the coldest February night on record. The all time low was in December 1999 with -14.1C. The mean temperature for winter 2011/2012 was 0.5C above the long-term average and the warmest winter since 2007.
The solar energy for February 2012 was 143% of the dull February of 2011.
There were two occasions when snow fell, 4th and 9th, when moderate falls were recorded with an approximate depth of 5cm and 4cm respectively.