Ascension : Met Office Ascension Island Base - The Met Office Weather Report
Submitted by The Islander (Met Office) 16.06.2011 (Article Archived on 30.06.2011)

UK: An area of low pressure over the west and north of Britain brought rain or showers to many parts.

UK: An area of low pressure over the west and north of Britain brought rain or showers to many parts. Few showers occurred in the far south and east of England were a drought was officially declared late in the week, it having been very dry now for several months. Of cause as soon as a drought was declared it started raining over all of Britain during Sunday as another area of low pressure moved in from the Atlantic. A couple of cold nights early this last weekend with ground frost for some parts.

Falklands: A cold start to the week with frost and snow showers. Turning less cold during Wednesday as low pressure brought milder North to NE’ly winds, rain or drizzle, mist and fog. Much brighter later in the week, though still occasional rain showers.

Ascension: Records continue to be broken as we have had another wet and rather cool week. The day maximum last Thursday was only 26.0C, which equalled the previous coolest June day recorded in 1995. Friday was only marginally warmer with a maximum of 26.2C. After a fairly normal start to last week, an old weather front moved north over Ascension and become slow moving through Thursday and Friday with heavy rain at times. Though the rain was not as heavy, it remained rather cool and cloudy for much of the weekend. The previous record monthly rainfall for June was 38.9mm recorded in 1995. So far this month we have already had 131.5mm at the Airhead, considerably more over Green Mountain as figures for the Residency show. It is not unusual to get rain showers in June, but the persistence and intensity we experienced late last week is rare for this time of year. Having now had the second wettest April and second wettest May on record as well as the now wettest June, is it any wonder that much of the Island is turning very green with tall grass growing in parts where it has probably not grown significantly for many years.

St Helena: Rather cool and cloudy for much of the time early in the week, though mainly dry. More sunshine and warmer later, but also a few more rain showers, particularly Friday.

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Volcanic Ash from Puyehue-Cordon-Caulle Volcano, - and flight disruption.
Magma often contains enormous amounts of dissolved water and gas under high pressure. When an eruption occurs the pressure is released and gasses expand rapidly, rushing from the volcanic and carrying bits of rock with them. The enormous quantity of hot expanding gas can drive a column of ash many miles high into the air. Volcanic ash particles are generally small and have a vesicular structure. They can remain suspended in the air column for extended periods to be carried long distances by the wind.
Eruptions in Chile are not uncommon, the last time this Puyehue-Cordon-Caulle region had a significant eruption was in 1960, also associated with a very large earthquake in the region. The most recent significant eruption in Chile was of the Chaitén Volcano on 3rd May 2008.
Modern jet engines process enormous amounts of air. If volcanic ash is pulled into the engine it is heated beyond its melting point. The ash melts, becomes sticky and then adheres to the inside of the engine. This restricts airflow and can damage the engine. In severe cases causing engine failure.
Volcanic ash can also have an abrasive effect. Flying through it, at hundreds of kilometres per hour, ash particles can sandblast the windshield to a frosted finish that obscures the pilot's view. The sandblasting also removes paint and pits metal on the nose and leading edges of the wings.
The International Civil Aviation Organization, through various Volcanic Ash Advisory Centers, monitors and issues advice on the distribution of volcanic activity and ash plumes.

Compiled by  Chill       

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