Good evening everyone. Here is tonight's account of the 12 noon outputs from GFS, UKMO, GEM, NAVGEM and ECM for today Friday November 15th 2013.
All models show a slack flow over the UK with a ridge of High pressure lying across Central regions. To the SE of it some clear skies allow frost and fog to form tonight while the North, on the other side of the ridge see cloudier, milder Westerly winds but mostly dry weather. With time over the weekend the cloudier weather in the NW wins out covering all areas by Sunday. At that time a trough sinking South over the UK could bring some rain to many areas as it moves North to South through the day. On Monday a more active feature sinks South too with a cold NW flow with scattered wintry showers following mostly over Northern and Western areas on Tuesday.
GFS then keeps things rather cold and showery for a time through the middle of next week with some snowfall over the hills before High pressure develops over the UK with frost and freezing fog likely to become a major problem later in the week as pressure builds across from the Atlantic. Later in the run details are irrelevant but the trend shows Low pressure gradually taking control from the SW with rain at times in rather cold conditions but snow only likely on high ground in more Northern Britain. It looks like it will stay quite chilly feeling though.
UKMO shows High pressure building quickly over the UK later next week following Low pressure moving away South from Southern Britain midweek. Rain and wintry showers will affect Southern areas for a time midweek with snow on the higher hills briefly. Temperatures would be cold everywhere and particularly in the High pressure area later in the week frost and freezing fog will become a big issue, difficult to shift through the days.
GEM shows a cold NW, North then NE flow next week and while it will never be cold enough for snow generally it will feel cold enough in a raw wind with sunshine and wintry showers, especially in the north at first and the South and East later. Pressure becomes very high to the NW and with a serious injection of cold air approaching Eastern areas at the end of the run possibly grazing the SE for a time.
NAVGEM maintains High pressure to the North and then West as we move through next week with the innitial North flow with wintry showers quickly turning North-easterly across the South with rain or sleet at times briefly. Late in the run winds back Northerly again as the cold theme continues with some wintry showers in the North and East a week from now.
ECM tonight shows a chilly NW flow with showers, wintry on hills in the North and West. Soon after midweek High pressure builds in killing the showers and cold wind and a frosty and potentially foggy spell develops as the High sits over the South of the UK. As it moves slowly East late in the run a small Low sinks SE down to the SW with dull and damp weather likely for a time while others stay misty or foggy and cold. The NW would see milder SW winds encroaching by Day 10 as the Jet Stream rides North with Greenland Low pressure developing.
The GFS Ensembles tonight show a short cold snap before the general average of members suggest a milder trend from the mid and end sections of the run. Average level temperatures are then popularly shown with rain at times as the Atlantic gradually regains momentum.
The Jet Stream tonight blows across the North for the next day or so before buckling South as the weather turns colder early next week. Longer term tonight the Northern arm of the Jet appears to remain strnger than on recent outputs and carries East across the Atlantic and across the UK in a week or so time.
In Summary tonight there has been a cross the board downgrade today if it's snow you are after, not that away from higher ground in the North it ever looked like a major problem to be brutally honest. However, High pressure over the UK is likely to promote colder temperatures at the surface with sharp frosts and freezing fog much more likely to feature next week now rather than sleet and snow. It's seems the behaviour and the track of the Jet flow has changed in it's more up to date projections with a UK based Jet flow shown after next week instead of being at a point South of the UK being shown yesterday. The net result looks like a period of UK high pressure giving fog and frost but with little high level blocking in evidence tonight from GFS and ECM it looks like a steady road towards the Atlantic train before too long.
Transcript taken from:-http://www.norton-ra...is(2859336).htm
Originally Posted by: GIBBY