Sunday, 14 April 2013

Summer comes to the north Kent coast

Broad warm sector with a slight  anticyclonic bend in the pressure pattern bring summer to Hampton beach,  Herne Bay. I couldn't quite believe the forecast temperature of 19C but at 1500 it was up to 24C - even Manston recorded 22C. 

The huts nestle beneath Hampton Hill and a South Westerly goes straight over the top of them leaving the beach in a Mediterranean micro-climate. At the waters edge there is calm conditions but gust patterns are apparent after about 10m and soon these gusts would be enough to knock an unwary sailor over. Unfortunately the sea temperature doesn't change so quickly, it remains at 5 or 6C, which must have come as a disappointment to those seduced into trying an early season swim.

The winter has brought months of icy North Sea winds to the North Kent coast but conditions flip dramatically with the onset of a South Westerly with Heme Bay to Gravesend recording the highest temperatures in the UK.  There has to be a small Fohn effect caused by the passage of air over the north downs with adiabatic warming as the winds descend to the Thames estuary. For the record, Lydd and Dungeoness (to the south on the channel coast) struggled to get over 15C

Saturday, 13 April 2013

Beauty Near the Centre of a Depression

An active day for Kent yesterday with an extended, complex area of low pressure lying across the North Sea and through our island; there was much weather.  An viscious trough line of showers crossed the county giving down pours and causing Emma to worry about the state of our drain pipes.  After the heavy showers had gone we spent the evening at Fowlmead Country Park for Thanet Road Club cycle training.  My forecasting students often asked: what happens in the middle of low pressure away from fronts? Answer, convection and showers and .... sunshine.  The shots below show a sky with scudding clouds which are the remnants of massive cumulo-nimbus as well as bright sunshine over the atmospheric marshes which lie between Deal and Sandwich.  There was a rainbow too bu my photographic skills were not up to capturing that. All valid at about 1900.

Thursday, 11 April 2013

Cyclonic winds as Kent lies in middle of complex low

I have just checked the aviation met reports for Kent. Manston, to the north, has a light easterly whilst down on Romney Marsh Lydd has a South westerly. The latest weather analysis has a large complex (more than one centre) depression lying through UK. This is causing near Cyclonic (anticlockwise) wins around our County.  Today would have been a good day for a tour de Kent with an option for tail wind for the whole circuit.

Tuesday, 9 April 2013

Convergence of Sea temperature with due point makes murky conditions in Heme Bay

Sandettie light vessel reports due point temperature (if air temperature falls to this there will be fog) of 4.5C. Latest sea surface temperature is 5ish. Sandettie is in mist and coastal Heme Bay is murky with that penetratingly cool sea side breeze. Since air will always try to cool to sea temp it is a misty outlook for the North Kent coast.

Still winter in oceanographic terms,  no coastal fish until temperature of sea rises a bit.

Monday, 8 April 2013

Jet Stream still too far south for Kent summer

The jet steam is an illusive meteorological object: sometimes here sometimes there, sometimes wavy sometimes straight.  But when strong winds blow at 30ish thousand feet there is such a mass transport of air that the surface cannot remain uninfluenced. Rotation of the earth means that temperature differences cause winds to blow parallel to the change rather than from cold to hot. The polar front might be thought of as the border between summer (to the south) and winter (to the north) and represents a strong temperature change. Today's 30 000 ft winds and visible satellite imagery show the jet steam and polar front lies too far south for Kent summer. Chargeable weather will ensue for the next couple of days.

'Extreme' Weather hits Herne Bay Beach Huts

Thunderstorms and snow are note really extreme, they are just part of the normal tapestry of weather experience for us in the UK.  I just wanted to include some pictures on this site showing how things change down at the beach huts on Hampton beach, Herne Bay.

Friday, 5 April 2013

North Sea Ridge of high pressure shows nicely from space

Visible satellite imagery is beautiful to look at; I love to see the shape and texture of the clouds and the pattern of the winds. You can only see it in daylight though and it doesn't tell you anything about temperatures.  This afternoon's picture shows cloud free Ireland and North Sea, a feature of the subsidence beneath the elongated ridge of high pressure extending across the country. High cloud is spilling North and West from the continent; we were under this cirrus in Kent and Essex today. The depression is down over the Adriatic - a cold place for British warships in the winter during the former Yugoslavia crises.

528 Line Down Across Kent -unseasonably cold weather indicator

The isobars and fronts of standard weather charts are not adequate in showing atmospheric temperature.  It remains criminally cold across southern England; snow has no place in Kent in April. This cold weather event can be seen more clearly on an atmospheric thickness chart. Pressure is caused the mass of air above. The same mass of air would be of greater vertical extent (I.e. THICK) if warm or lesser (ie THIN) if cold. It turns out that an atmosphere which has a thickness of 5280 geopotential metres (measured from the 500mb level to the 1000mb level) gives a 50% chance of snow at sea level. Thickness charts like the one attached give an excellent snapshot of the temperature of the air across a region. With old fashioned meteorologists paying great attention to the position of the '528'.