Good morning everyone. Here is this morning's account of the midnight outputs of the NWP for toeday Sunday January 5th 2013 taken from http://www.norton-radstockweather.co.uk/Model-Analysis(2859336).htm
All models shows another very deep depression crossing slowly ENE across the Atlantic to reach an area to the North of Scotland as a filling feature by Wednesday of this week. The next 72 hours will be characterized by a spell of rain crossing East today to be followed by a couple of days of blustery and heavy showers, especially near Southern and Western coasts but some drier spells in the more sheltered East. Winds will be strong to gale force SWl'y but should subside towards midweek with temperatures holding well up to average of not a little above in the South. Soon after midweek all areas will become quieter with light winds but with slow moving troughs caught up in the slack flow over the South which could give rise to further copious rainfall, not helpful at all to the current flooding situation.
GFS makes less of this feature gradually drying things up after Thursday as High pressure glides east over France. A Southerly breeze develops in it's wake and it isn't long before low pressure once more develops close to the West, moving North-East and renewing rain events to all areas in blustery winds. This format retains it's place then for the remainder of the run with strong winds again shown later with just brief drier spells under transient ridges over the South. Temperatures look like holding largely close to average.
UKMO this morning closes on Saturday with High pressure to the SE and light winds over the UK and a light SW flow over the North. A front looks like being straddled across Southern Britain in light winds meaning a slow moving area of rain could lie close by with largely cloudy skies while the North has the best chance of seeing somewhat brighter conditions.
GEM is the driest model run this morning with events later in the week showing a steady drying up process with all frontal activity removed by the weekend as High pressure develops over Scandinavia. This migrates slowly South and West late in the run to be positioned close to NE Britain by Day 10. The weather would turn cold and frosty with some sunny spells but a cold and raw SE wind would likely develop over many areas though it would likely stay largely dry.
NAVGEM shows slack pressure late in the week and over the weekend over the South with slow moving troughs again running the risk of creating wet conditions over the South before the pattern looks like becoming a little more changeable and mobile again from the West following next weekend.
ECM today also shows slack pressure towards the end of the run and with upper troughs caught up in the slack airflow it looks unlikely to be guaranteed dry with the South most at risk of some prolonged rain while the North sees the best chance of brighter conditions with a little more wind pushing troughs through rather quicker.
The ECM 10 Day Mean Chart today is better news for cold fans as it now supports in a bigger way High pressure over Scandinavia and a slack Southerly feed the most likely bias over the UK. Low pressure has a much weaker bias to towards the NW this morning. With a continental feed injected over the UK there I would think be good support from the members of it's ensembles for very much colder conditions to arrive after next weekend.
http://www.wetterzentrale.de/pics/Reem2401.gif
The GFS Ensembles do show a dip this morning below average in Week 2 with some unsettled and mobile weather still thrown into the mix by some members. There are rather more members though approaching the -10C value later in the run with a wider spread from all the members averaging a bias towards the cold end of the range.
The Jet Stream Forecast shows the lengthy spell of West to East movement over the Atlantic and Southern Britain coming to an end later next week. The flow looks like disrupting late this week and particularly at the European end appears to be forced to lower latitudes indicating the possibility of High pressure over Northern European latitudes.
In Summary there is a change in the weather on the way although changes involving the cessation of rainfall may have to be more patient. From the middle of the week gales will be a thing of the past but some stubborn slow moving troughs could keep things potentially wet at times in the South until the weekend. From thereon we have a split with GFS and NAVGEM going the way of returning unsettled and windy conditions with yet more rain in the second week while UKMO and ECM operational shows a High pressure to the SE with an Atlantic drift over the NW where some rain would become likely again later. The more interesting slant this morning is shown by the ensembles which especially from ECM show their greatest indicator yet of pressure becoming High to the East and NE and throwing much colder weather our way as a result. The margin for error is very fine though and we need to see more cross model support before shouting from the rooftops. Nevertheless, it looks like at last the Atlantic may be running out of steam for a time so all areas look almost guaranteed of becoming rather drier and certainly much less windy and with the natural increased risk of cold weather occurring from Europe later in the Winter it is from these predicted weaker Atlantic synoptics that cold spells can develop quite quickly should things fall into place correctly.
Edited by user
05 January 2014 09:00:39
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Reason: Not specified
Martin G
Kilmersdon Radstock Bath Somerset