Good morning folks. Here is the report on the midnight outputs from GFS, UKMO, GEM, NAVGEM and ECM for today Monday September 2nd 2013.
All models support High pressure close to the South for the next 48-72 hrs as it transfers slowly East along the English Channel towards Europe. The North lies covered in a slack Westerly flow with cloud, rain and drizzle at times principally in the NW. By Thursday and more notably on Friday a trough of low pressure moves in and across the UK from the West with a Low centre forming close to SE England likely by the weekend while once the trough is passed a High pressure ridge will move in close to the North. In weather terms after several days of fine and very warm weather across the South and cloudier conditions further North the weather turns more showery for all areas for a time later in the week. Over next weekend the North would be likely to become drier again while the South maintains showery weather with limited brightness.
The Fax Charts show the above trend well but as the front clears SE on Friday it shows only the SE half of England left with rain at times with Low pressure developing near SE England.
GFS then shows slack Low pressure close to Eastern England for several days before relaxing it away to the South of the UK in 10 days time or so with rain or showers continuing off and on, especially in the South. Late in the run a new Low from the Atlantic keeps the unsettled and changeable theme going with rain at times extending to all areas in average September temperatures.
The GFS Ensembles are a little cooler in the South than those shown last night with a notable cool and wet slot this coming weekend for the South. Thereafter changeable conditions look like remaining with some drier interludes indicated by many members but with some rain too almost anywhere at times in temperatures relatively close to average.
The Jet Stream currently flowing East to the North of Britain develops an arm which pushes South over the UK and around the developing depression close to SE Britain at the weekend. This cut off low then keeps this weak Jet Stream arm in situ for several days while a new surge of energy within the main core of the flow pushes East close to Northern Britain late in the run.
UKMO today shows Low pressure having formed close to or over the South late in the weekend. As a result some rain and showers will affect many areas but Scotland could escape the worst spare a cool East breeze off the North sea for the East coast.
GEM also highlights the Low at the weekend over the South trapped in situ for several days before easing it away slowly South at the end of the run. There will be several days of rain and showers over chiefly but not exclusively over Southern Britain with the risk declining towards the far South by the end of the run.
NAVGEM too shows a cool pool trough over the UK at the weekend and start of next week with an upper shallow Low maintaining the risk of heavy showers or outbreaks of rain going across England and Wales especially.
ECM shows Low pressure over the South at the weekend gradually pulling further towards the SW with High pressure over Scandinavia bringing dry and bright weather to the North and East while the South and West remain at risk of rain at times throughout the final half of the run.
In Summary today we are back to where we were yesterday morning as this morning's output has reverted to maintaining some sort of low pressure area over or close to Southern England next weekend and the start of the following week. This would mean showers and outbreaks of rain in rather humid conditions for many while the north sees High pressure close by either directly to the North or NE over Scandinavia maintain the chance of some fine and dry periods here. After the dizzy heights of temperatures expected in the South and East through this week it looks like temperatures will fall off somewhat to more like the seasonal average given the large amounts of cloud expected over the UK as a whole.
Martin G
Kilmersdon Radstock Bath Somerset