The dry northeasterly winds continue with a much breezier day, gusts rising to 28 mph late evening. After a dry five months, the trend continues with only 3.1mm of rainfall this month whilst the dry, windy conditions persist allowing moisture to evaporate, now totalling 9mm. Although the day was predominantly cloudy there were brief bright periods with just 10 minutes of strong sunshine. This did nothing to raise the temperature, which peaked at 14.4C that is 2C below the average. In fact the strong, cool wind meant a wind chill in that the temperature felt 3C lower.
Overnight the cloud kept the temperature to a minimum of 6.4C but had melted away before dawn to give us strong sunshine as soon as the sun rose above the horizon although after 07.30 occasional thin, high cloud drifted in from the north east. The humidity at 0800 was 85%, a low reading at this time of day.
Maximum 5C below average with wind chill dropping this another 3C
The anticyclone has positioned itself to the northwest of the UK and is fairly static, which is giving us the persistent run of strong northeasterly winds off the north sea. The maximum gust of 25mph yesterday occurred at 16.25. With strong winds for most of the day the wind chill was significant meaning that the temperature felt 3C lower. The maximum temperature occurred 14.36 with a reading of 11.8C, which is 5C below the 33-year average for May. A measly 4 minutes of sunshine did not improve the temperature. Another dry day that continued overnight although the wind abated but did not fall out. The cloud cover meant a minimum of 8.1C last night at 1.30 am recovering to 9.1C at 08.00.
Significant wind chill with brisk northeasterly wind
Tuesday returned to the pattern of a dry day with sunshine, brought on the brisk north easterly winds, gusting to 18mph. The thermometer peaked at 17.1C, just above the average for early May. We enjoyed 6 hours of strong sunshine that felt warm out of the wind. Overnight the cloud cover stopped the temperature from dropping very low with a minimum of 6.1C just after 5am. However, the cool, brisk wind meant that wind chill made this feel like 4C.
Summary for April 2017
The outstanding feature of April was the lack of precipitation, which totalled just 8.2mm from the light rain showers and wet snow that fell during the late afternoon of the 25th.
The record for the driest April was in 1984, when this station started recording, with just 2.0mm, followed by 5.4mm in 2011 and 6.7mm in 2007.
There were 20 dry days in the month with the wettest on the 25th producing 2.2mm and 2.1mm on the 30th.
There just 4 ‘wet’ days in the whole month, which the Meteorological Office class as daily precipitation equal to or above 1mm.
The 33-year average for April was 59.7mm making a deficit of 51mm for April. When an overview of the past few months is reviewed the situation is even more severe. The winter months of December to February produced a deficit of 99mm and March was 9mm below the long-term average.
The precipitation over the past five months was 159mm below the 33-year average or over 6 inches in old money. The slight falls this last month, in both the River Og and River Kennet levels, can be traced not only to the lack of rainfall but also that in April, 69mm of equivalent rainfall evaporated into the atmosphere from ground sources and plant life.
There is a contrast when analysing the temperatures over the past month comparing day and night. The daytime average was +1.5C but the cold nights meant the average was -0.9C. This gives a mean of +0.3C for the complete month.
Looking back over the years the coldest April occurred in 1986 being 2.9C below the average and the warmest in 2011, which was 3.7C above the average.
There were 7 air frosts; the most severe occurring at the end of the month during the night of the 26th/27th when the thermometer fell below zero for eight hours giving a minimum of -3.0C at dawn. This resulted in much damage to new growth and existing spring flowers, sadly, such as my rhododendrons and apple blossom.
There were several windy days towards the end of the month with gusts to 30mph on the 30th.
We enjoyed 150 hours of strong sunshine with the solar energy 4% above the seven-year average.
The dry weather with cold nights was mainly due to the consistent high pressure and winds predominantly from a northerly quarter. The barometric pressure for April was a significant 7mb above the long-term average at 1023mb.
The quotation form Ralph Josselin, a Puritan minister and diarist from Essex who wrote the following in 1649, might be applicable to the past month with its dry weather and frosty nights – “Dry, windie, indifferently cleare in the nights very cold, and much given to frosts … good to purge the aire, and to prevent infection. Oh Lord watch over me and mine”.
Just 8.2mm makes April the fourth driest since 1984
The wind yesterday continued to come from the east with the temperature easing upwards again to a maximum of 15.7C, the first day above average for a week. It was a breezy day with the strongest gust of 30mph occurring at 11.35, the strongest gust all month. There were just 10 minutes of strong sunshine but later in the afternoon the cloud thickened bringing light rain showers in the evening amounting to 2.1mm, stopping before midnight. This brings the total for April to 8.2mm, which is 13.7% of the 33-year average of 59.7mm. Overnight the thick cloud meant that it was a mild night producing a minimum of 7.6C, just above the average for early May.
This morning has arrived with thick cloud giving just brief glimpses of the sun through occasional breaks. A warm start to the day with a temperature of 9.3C at 08.00
Warmest morning this month with very dry air
Another 1 hour of strong sunshine was recorded yesterday although the maximum temperature slipped (13.4C) again to be 0.5C below the April average. Late yesterday evening the wind backed from the southeast to the east and is quite brisk this morning. Overnight the cloud cover and warmer air meant that the thermometer did not drop below 8.5C, a very mild night compared with many this past week. The barometric pressure has been dropping for the past thirty six hours as a depression from the Atlantic approaches with its cold front already over Cornwall and at 0800 gave the lowest reading all month at 1001.7mb.
It is the warmest morning all month but notable is that after so little rain and now a drying easterly wind, the humidity level at 08.00 was 73%, the driest air at this time since June 6th 2016.
