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Weather Report with Phil Thomas

Let it snow, let it snow . . .

Posted on January 16 2010 at 8:24:42 0 comments

Christmas Day on Newbourne Hill, Alvechurch

Alvechurch amateur weatherman Phil Thomas had a busy four weeks in the snow.

The first couple of weeks of winter appeared be to quite normal with the usual quite mild, dull and damp start to the Christmas holidays. However, there were changes developing in the usual weather set-up for the coming weeks.

Normally, low pressure areas (wind and rain) roll in from the west or south west during the autumn and winter months. This year a very large area of high pressure developed over Iceland and later northern Norway and the northern Russia area. This had the effect of causing a block to the Atlantic weather systems and brought our weather from mostly easterly or northerly airstreams, and hence the very much colder weather over the following 30-plus days.

It started to change around December 17, with the winds coming around to the east during the day and a period of snow in early afternoon – just a taste of what was to follow. The next day a few snow flurries then a period of heavy wet snow on the evening of the 19th which gave a complete white snow cover in the days up to Christmas Day, making it feel much more festive.

The last of the snow, however, had vanished by Boxing Day with slightly less cold conditions up to the New Year.

By New Year’s Day the temperatures were beginning to fall rapidly again. It remained very cold over the next three days with a dusting of snow on the 3rd. On the 5th, however, the snowfall started in earnest with light snow falling from 8am in the morning and becoming heavier during the day, soon causing the usual traffic problems.

By the following morning ( the 6th) there were 14cms of level snow locally. During the morning there were further slight increases to the snow depth during the morning.

Over the next few days the temperature remained very low with three ice days on the 7th, 8th and 9th where the screen temperature did not rise above freezing point. (Temperatures are normally measured in a Stevenson screen at 1.25m-1.75m above ground. An Ice day is where the maximum screen temperature does not rise above –0.1C over the 24 hours observing period.)

It remained very cold up to the 14th before a slow thaw started to show, but with further periods of snow on the 11th and 13th. Most of the lying snow had then cleared by the 16th.

It was one of the longest periods of lying snow in this area for 46 years, since the winter of 1963. There have been shorter periods of heavy snowfall, especially in the 1980s, but we had 11 days of full snow cover recorded at my weather station, the most in the 21 years I have kept records for this area.

Village Winter Records 2009-2010

December 15th to 30th 
Average Maximum Temperature: +3.1C (3.9C below the local average)
Average Minimum Temperature:  -1.6C (3.6C below local average)
Average Mean Temperature +0.8C (3.8C below local average)

January 1st to 15th
Average Maximum Temperature: +1.4C (4.8C below local average)
Average Minimum Temperature: -2.8C (3.7C below local average)
Average Mean Temperature: -0.7C (4.4C below local average)

The lowest ground temperature over the period was -12.7C on the night of January 8. Ground temperatures are measured above the blades of grass with a thermometer suspended in that position, and are nearly always colder than normally measured temperatures but are an indicator of frost.

The coldest temperature screen measure was –7.0C on the night of January 7.

There were 5 days of snow falling in December and 6 days of snow lying.

There were 11 days of snow lying in January and 7 days of snow falling.

“Snow lying” is defined as more than 50% of the ground covered by fallen snow at 9am (the observing time each day). “Snow falling” is defined as any snow or sleet observed from midnight to midnight on that day.

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