First rain in eleven days

Sunday was cool and cloudy with light rain in the morning amounting to 0.8mm being the first rain since 19th April. Due to the overcast add wet conditions the thermometer did not rise above 11.7C, which was 5.8C below the May average. Overnight brought a minimum of 8.8C, which was 2.4C above average, once again due to the thick cloud cover.

Monday after dawn revealed very low cloud forming fog that limited visibility to 500m at first.

April 2022 Review

The month began with weather more like late winter than early spring with below average maxima, some 6C below, and hard night frosts. The thermometer dropped to -5.4C in the early hours of the 3rd, which made it the coldest April since 1996.

By the 11th the wind backed into the south bringing warmer air from North Africa that saw the thermometer rise to 18.3C being 4.2C above the average.
The warmest day of the month occurred on the 16th when the thermometer rose to 21.4C, which was 7.3C above the 38-year average.

The weather made a major change from the 19th as a large anticyclone developed over Greenland, with its airstream rotating clockwise, that deflected depressions to the south over France and Iberia, the air mass rotating anticlockwise. This resulted in the wind coming from the northeast for 10 consecutive days.

The breeze from the northeast is much cooler so peak temperatures dropped several degrees with very cool nights. In addition, as the air travelled over the North Sea it picked up moisture and resulted in several grey, cloudy days, but no rain.

The final day of April was in complete contrast. After a very cold night with an air frost and a minimum of -2.4C the sun came out strongly for many hours that boosted the temperature to 17.8C. This was aided by a dramatic change in the wind direction from the persistent northeast to south then southwest with little strength in the breeze.

The mean temperature was 0.5C above the 38-year average.

The significant feature of the month was the lack of rain. The total rainfall was just 28.8% of the 38-year average or 41.1mm below. There were 22 dry days and only 3 days that the Meteorological Office describes as wet with 1mm or more of daily rainfall. The majority of the rainfall fell on the 6th with 11.6mm.

It was the driest April since 2017 when just 8.2mm was recorded. A number of the years since 2001 have been drier than average showing a downward trend for April rainfall. By contrast a deluge of 165.2mm was recorded for April 2000.

Set against the minimal rainfall was the significant loss of equivalent rainfall due to evaporation from the ground and plant life that amounted to 63.1mm.

I wondered why the output from my solar panels was less than the previous two years but on analysis found that solar energy was reduced this past April with just 91% of the long-term average.