Category: Commentary

Tuesday saw the arrival of the major change in our weather from the northern regions to the milder, moist air from the Atlantic. The thermometer was depressed during daylight hours due to the ground being still quite cold and pockets of snow remaining with a daytime temperature of around 5C but during the evening a weather front arrived that lifted the temperature to a maximum of 9.8C (2.6C above average) at 01.03 today,Tuesday. It has since dropped back to 6.5C at 08.00.

The rain was heavy between 22.15 and 22.45 last night with the daily total reading 9.7mm.

Wednesday arrived with 8/8 cloud coverage and a low cloud base hovering over the Marlborough Downs and initially some fog in the River Og valley, since dissipated.

Monday saw the continuing thaw of lying snow, accelerated as the temperature climbed to a maximum of 9.4C at 15.04. This was 2.3C above average and the warmest day since 25th January.

Rainfall amounted to 1.7mm in the past twenty-four hours bringing the February total to 20.9mm with the current average standing at 64.9mm.

As the temperature began to fall after 4pm Monday afternoon fog began to form quite readily as I watched in the River Og valley where much snow still lay across the meadows. The colder, moist air below the town, also close to the river, meant that as the air rapidly cooled the moisture condensed and fog began to form. Overnight there was a ground frost as the temperature dropped to a minimum of -0.2C at 05.30 this morning.

Tuesday arrived with the expected fog limiting visibility to 200m. By 08.00 the thermometer had risen to 4.9C so the remaining snow will now continue to thaw.

Sunday brought us much welcome sunshine, 8.23 hours, that raised the temperature to a maximum of 3.8C during daylight hours but overnight it rose again to read 5.8C at 08.00 Monday morning. This resulted in a steady thaw of lying snow.

The UV level at 1.3 was the strongest since 14th November.

In the early hours of Monday a band of heavy rain passed through producing 9.5mm of rainfall that accelerated the thaw. During this period the wind rose considerably giving a peak gust of 28 mph.

Just after 08.00 today a band of light rain and drizzle, emanating from low cloud passed over.

Update on Monday at 15.45: first above average temperature for a week with maximum of 9.4C (+2.3C) and a little sunshine in the afternoon.

Update at 19.20: the thermometer began to fall consistently around 16.30 when fog could be seen forming rapidly in the River Og valley where much snow still lay. The cool air below the town over the snowfield and moisture from the river meant that the still air began to condense, which has developed into widespread fog over the local area. Current temperature is 1.4C, and falling, so a ground frost is imminent.

With the snow having ceased on Friday night it was a pleasure to see the sun shine brightly from dawn on Saturday. However, the extensive snow cover, following a sharp frost, meant that the thermometer only rose a little above freezing. The maximum of 2.9C was reached at 14.32, which was 4.2C below average, however, it did allow a slight thaw of snow but not in the shade.

The UV level at 1.1 was the strongest since 14th November during the 8.05 hours of sunshine.

The driving snow and sharp frost meant that the top most anemometer froze solid, which I eventually managed to free by standing on a step ladder and using a long, extendable fibreglass pole.

The air temperature dropped below freezing at 19.55 Saturday night and continued to fall steadily all night and by 08.06 on Sunday morning, just after dawn, registered a minimum of -11.3C. This was the coldest night since the record breaking frost on 11th February 2012 that saw the temperature plummet to -13.0C.

Sunday arrived with clear skies and sunshine as soon as it got up.

Update on Sunday at 15.40: after a severe frost the thermometer struggled to reach 4.5C at 14.40, (2.6C below average) even though we had over eight hours of sunshine and the UV level of 1.3 the strongest for nearly three months

Friday saw the continuation of the snow that started at 20.34 on Thursday evening and eventually stopped just after 18.30 Friday evening.

With strong winds from the northeast and continuous snow falling is not surprising to find that the thermometer struggled to reach a maximum of just 0.5C, which was 6.6C below average.

The snow depth varied between 15cm where it was windswept and 26cm on the flat vegetable garden. Three samples of snow at varying depths have been taken, as described in yesterday’s report, and slowly melted so that he equivalent rainfall will become evident later today.

The minimum temperature overnight was -3.4C at 07.17 this morning that had risen slightly to -2.8C at 08.00.

Saturday arrived with mostly clear skies and the sun shine brightly.

January 2019 Review

With just 47% of the 35-year average, rainfall in January was in short supply. There were 20 dry days when the average stood at 12. Precipitation totalled just 43.3mm, which was 48.5mm below average. It was the driest January since 2006.

Set against the limited rainfall was the fact that the equivalent rainfall of 11.4mm was lost to evaporation from ground sources and any plant life at this time of year.

There were three days when snow fell, the 31st being the notable occurrence as the snow started at 20.33 and continued throughout the night, not ceasing until 18.30 on Friday 1st. This snowfall produced the equivalent of 9.4mm of rainfall, the wettest day in January. The snow depth varied from 15cm, where the land was windswept, to a more representative 26cm on my large vegetable garden.

With modest amounts of snow, the contents of the rain gauge can easily be emptied into a container and slowly melted to discover the equivalent rainfall. However, the heavy snow at the end of the month, combined with drifting in the strong north-easterly winds, meant the depth of snow varied considerably. At such times the standard Meteorological 5 inch rain gauge is inverted, or similar 5inch cylindrical container, and pushed over three different areas to sample the snow at various depths. A flat surface is then placed at ground level and slid under the container to trap a column of snow. The contents are then slowly melted and averaged to get an approximate rainfall equivalent.

It was a cold month with the mean temperature 1.1C below the 35-year average being the coldest January since 2010. There were 17 days when a frost occurred the most severe saw the thermometer dropping to -7.2C in the early hours of the 31st. At the opposite end of the month we had four consecutive very cold days with the thermometer resolutely refusing to get above a maximum of 1.3C on the 4th being almost 6C below average. Contrasting those cold days was a maximum of 10.8C, which was measured on the 25th.

There were only eight days with n sunshine, which totalled 87.6 hours, with the sunniest day occurring on the 28th with 7.5 hours.

Morning fog was noted on two days.

Update on Saturday at 15.05: thermometer slowly rose to a maximum of 2.9C at 14.32 with the UV level of 1.1 the highest for over two months.

Update at 19.50: thermometer now showing (-0.1C) air frost has set in again.