September's wettest day, undercover of darkness!

What a strange day! The total of 21.8 mm of rain isn’t an extraordinary amount, but it still beat the previous total of 19.2 mm that had stood for September since 2008. No, the most remarkable feature of this day was that almost the entire total fell under cover of darkness.

Just after midnight on the 7th of September, in the early morning, heavy frontal rain fell from an east-west front straddling the region. The rainfall was accompanied by strong to gale force South Easterly winds. This cleared to the north by first light, which was delayed as it was so dismally dark. Then by 10am the sun was out and it became a beautifully warm, dry day.

Shortly after 8pm the rains returned, this time in the form of a thunderstorm, which ensured we passed the previous September record and we got a clap or two of thunder to go with the lightning too.

Flooding of 17th July 2009

This was an extremely wet day in the North East of England. It was the wettest July day at Ferryhill since 27th July 1998. That day's record rainfall was due to a thunderstorm which dumped it's rain on a very localised area around Ferryhill (see the entry in 1998 further down this blog). The rain of 17th July 2009 was different in that it fell over a very large area and was persistently heavy. The total for the day was 43.6mm.

Radar image, 17th July 2009

Many local rivers burst their banks, including the River Wear in Durham and the River Browney at Croxdale. Both were up to 6ft above normal on the morning of 18th July. There were numerous roads blocked around the County by floodwater, and much damage was done.

Here are some pictures taken in Durham City at the height of the flood.

Durham City Flooding, July 2009

http://www.flickr.com/photos/dkohara/sets/72157621547077013/detail/

29th and 30th November 2008

Both of these days were extremely cold, with averages below freezing. There was an extremely heavy hoar frost, which made it look as though it had actually been snowing, but it hadn't, although 0.2mm of precipitation was recorded on 29th due to the heavy frost. It was the first time i've recorded this in Ferryhill in November, and to have two consecutive days like that is quite rare I feel, in these days of milder winters.

29th Nov Max : 2.3 Min : -3.1 Mean : -0.4
30th Nov Max : 1.2 Min : -1.6 Mean : -0.2

All figures are degrees Celsius.

Cold Front Squall, 8th January 2008

The depression that hit us today had a very active cold front, with a squall of hail around 9pm, accompanied by a 5 degC temperature drop across the front. After it passed, precipitation was of snow above 400ft. Attached is a radar image of the front as it passed, and also a view on the temperature drop (from 8 degC to 3 degC within the hour). Snow was observed shortly afterwards down to about 400ft.

Radar

A report from the Northern Echo. The squalls caused a bit of damage in the Ferryhill Station area (no jokes please). Cold fronts quite often spawn this type of weather, with the large contrast in temperature across the front driving small tornado-like disturbances.

OutsideTempHistory

The trace from Ferryhill Weather Station above, shows the rapid drop of temperature across the front.

Active cold fronts are fascinating things, but we don't get too many of them. This one was quite active because the Polar Front and the Jet Stream are right over the country at the moment, producing colder weather and snow in Scotland and Northern England whilst the South have milder conditions. The cold front marked the boundary between Atlantic and Arctic Airmasses, with the temperature gradient driving some shear and local disturbances. Some people also reported thunder and lightning as the front passed, with a characteristic kick in atmospheric pressure the tell tale sign of passage.