Windrush Weather

Author: Eric Gilbert

  • Barometric pressure falling steadily

    Thursday brought us a dry day with 4.6 hours of sunshine and the UV level at 1.1, the highest strength since 7th November.

    The initial fog slowly cleared by 11.00 to allow the sun to raise the thermometer from its low start of -2.3 to a maximum of 8.7C being 1.2C above average.

    Overnight the fog returned, limiting viability at dawn to 300m and allowing the temperature to fall to a low of 0.8C. The barometric pressure has fallen from its high of 1037.9mb to 1019.6mb as the anticyclone eases away over the continent and the next depression, named Storm Ciara, to approach the UK.

  • From windy to calm on Wednesday but fog overnight

    After days with strong winds the maximum gust on Wednesday was just 7mph. There was sunshine in the morning amounting to 2 hours but cloud built up after midday.

    The calm conditions with the air mass coming from the west rather than northwest allowed the thermometer to rise to 9.2C, being 1.7C above the average.

    Under the high pressure the sky cleared overnight allowing the thermometer to fall to -2.4C, which was 3.7C below average. During the early hours fog developed limiting visibility to 200m after dawn.

  • High pressure returns

    The wind front the north west on Tuesday was brisk, gusting to 29mph. This cooler wind meant temperatures by day were down again with a maximum of 8.2C, just above average but the wind chill meant it felt more like 6C.

    It was a dry day, the first this month, and the UV level rose again to 1.0 being not surprisingly in the ‘low’ category.

    The barometric pressure has been rising for the past twenty-four hours and is now at its highest since 22nd January with a current reading at 08.00 Wednesday of 1037.2mb. This should give us a drier, brighter and calmer day.

    Wednesday brought a mainly cloudy sky after dawn, just a little brightness on the horizon as the sun got up.

  • Cooler but still above average temperatures

    The brisk westerly wind on Monday, gusting to 22mph, meant a cooler day than previously although the maximum of 9.6C was still 2.1C above average but 2C down on the very mild Sunday. It was a sunless day with light, brief rain mid-morning and more continuous rain between 04.00 and 04.30 Tuesday morning amounting to 1.5mm.

    The thermometer dipped to 2.9C just after midnight but even this was 1.6C above the 35-year average.

    Tuesday initially after dawn saw brightness but cloud soon moved in front the west.

    The barometric pressure has been rising the past twenty-four hours with the humidity at 08.00 reading 84%, the driest air at this tome of day since 21st September.

  • Mild and moist

    Sunday saw just a glimpse of the sun for a brief few minutes but was predominantly cloudy and breezy, gusting to a peak 27mph. However, the southwesterly breeze maintained the mild conditions with the thermometer rising to 11.6C at 12.28 being 4.1C above the 35-year average.

    There was a little rainfall overnight amounting to 0.5mmm but again the cloud provided a blanket to minimise loss of warmth into the atmosphere hence a minimum of 8.2C, which was almost 7C above the average.

    Monday arrived predominantly cloudy with the wind having abated somewhat.

    Review of January 2020

    After a cool start to the month a wedge of warm air from the Azores arrived lifting temperatures into double figures with a maximum of 11.8C on the 7th, which was 4.8C above the 35-year average.

    Shortly afterwards Storm Brendan, named by the Eire Metrological Office, arrived from the Atlantic bringing wet and windy conditions. There was a particularly turbulent period in the second week with maximum gusts of 46mph on the 11th and 42mph on the 14th as squall lines traversed the area.

    Storms bring rain and this storm was no exception as rain fell every day from the 6th to the 17th as depressions followed depressions. There were particularly heavy rainfalls on the 13th and 14th with daily totals of 11.6mm and 21.6mm respectively.

    Notable worldwide unusual events during this period saw 377mm of rainfall lash Jakarta in one day and Texas with 6cm of snow.

    On the 14th it was reported that the world’s oceans were the warmest in 2019 than at any other time.

    Mid-month the Jet Stream pushed a pocket of unusually high pressure over the UK as the result of a greater contrast in temperatures across the USA. The air pressure rose rapidly during the 18th and 19th to peak at a maximum of 1049.6mb. This was a record for my weather station that started in 1984 and was close to the UK record of 1053.6mb set in January 1902, beating the previous high set in January 1957.

    It is no coincidence that the highest barometric pressures have been set in January. In that month the air is cold and thus more dense, therefore heavier.

    The intense anticyclone brought a break from the wet and windy weather to give us three continuously dry days and calm conditions. The 18th and 19th saw maximum gusts of just 8mph and 9mph but many hours of total calm.

    There was all change again for the last week of the month as the intense high pressure slowly ebbed away to reach the lowest pressure all month on the 28th with a minimum of 989.3mb. As a result the wind swung into the quadrant between south and west and brought modest rainfall of 5.9mm and 9.4mm respectively on the 26th and 27th.

    A slight fall of snow, the first of the winter, fell in the early hours of the 28th, which slowly melted as the thermometer edged to a maximum of just 5C, the second coldest day in January.

    There were 12 sunless days in January due to the frequent progression of depressions running across the country. This resulted in a warm month with a mean temperature 1.9C above the 35-year average, the fourth warmest I have recorded since the station started in 1984 and the warmest January since 2008.

    The total rainfall for January of 92.5mm was just 2.1mm above the average. It has been a month remembered for the number of gloomy, dismal days, only 7 were dry when the average is 12. The extreme months were in 1997 with only 9.4mm and the very wet January in 2014 when 219.1mm of precipitation was recorded. The wettest day occurred on the 14th with 21.6mm.

    There were a number of days when the wind was very strong, two in particular, when extreme gusts of 46mph and 42mph were logged on the 11th and 14th respectively.